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PHP, co jest skrótem od "PHP: Hypertext Preprocessor", jest powszechnie używanym językiem skryptowym ogólnego przeznaczenia, który jest szczególnie przystosowany do tworzenia aplikacji Webowych, także poprzez zagnieżdżenie wewnątrz języka HTML. Składnia, wywodząca się z języków C, Java i Perl, jest łatwa do nauczenia się. Głównym celem języka jest umożliwienie programistom szybkiego tworzenia stron internetowych, ale PHP umożliwia znacznie więcej.
Podręcznik ten składa się głównie z opisu funkcji, ale zawiera także opis języka, objaśnienie niektórych z głównych cech PHP, jak również kilka dodatkowych informacji.
Podręcznik można pobrać w kilku formatach spod adresu » http://www.php.net/download-docs.php. Więcej informacji na temat prac nad tym podręcznikiem można znaleźć w rozdziale 'O podręczniku'. Osobom zainteresowanym historią PHP polecamy odpowiedni dodatek.
Wyróżniamy najbardziej aktywnych twórców na pierwszej stronie podręcznika, ale jest wielu innych współpracowników, którzy pomagają w pracach, lub włożyli w przeszłości wiele pracy przy tym projekcie. Jest wiele niewymienionych tutaj ludzi, którzy wnieśli wkład w rozwój tego podręcznika licznymi komentarzami. Cały czas te uwagi są one uwzględniane w odnośnikach, i za nie serdecznie dziękujemy. Wszystkie poniższe listy uporządkowane są w kolejności alfabetycznej.
Poniżsi współpracownicy powinni zostać wyróżnieni za wpływ jaki mieli (lub ciągle mają) w rozwój podręcznika: Bill Abt, Jouni Ahto, Alexander Aulbach, Daniel Beckham, Stig Bakken, Jesus M. Castagnetto, Ron Chmara, Sean Coates, John Coggeshall, Simone Cortesi, Markus Fischer, Wez Furlong, Sara Golemon, Rui Hirokawa, Brad House, Pierre-Alain Joye, Etienne Kneuss, Moriyoshi Koizumi, Rasmus Lerdorf, Andrew Lindeman, Stanislav Malyshev, Rafael Martinez, Rick McGuire, Yasuo Ohgaki, Derick Rethans, Rob Richards, Sander Roobol, Egon Schmid, Thomas Schoefbeck, Sascha Schumann, Dan Scott, Masahiro Takagi, Michael Wallner, Lars Torben Wilson, Jim Winstead, Jeroen van Wolffelaar i Andrei Zmievski.
Poniżsi współpracownicy włożyli wiele pracy przy edycji podręcznika: Stig Bakken, Gabor Hojtsy, Hartmut Holzgraefe i Egon Schmid.
Aktualnie najbardziej aktywni opiekunowie to: Friedhelm Betz, Etienne Kneuss, Nuno Lopes, Hannes Magnusson, Felipe Pena i Maciek Sokolewicz.
Te osoby także pracowały nad zarządzaniem notatkami: Mehdi Achour, Daniel Beckham, Friedhelm Betz, Victor Boivie, Jesus M. Castagnetto, Nicolas Chaillan, Ron Chmara, Sean Coates, James Cox, Vincent Gevers, Sara Golemon, Zak Greant, Szabolcs Heilig, Oliver Hinckel, Hartmut Holzgraefe, Rasmus Lerdorf, Matthew Li, Andrew Lindeman, Aidan Lister, Maxim Maletsky, Bobby Matthis, James Moore, Philip Olson, Sebastian Picklum, Derick Rethans, Sander Roobol, Damien Seguy, Jason Sheets, Tom Sommer, Jani Taskinen, Yasuo Ohgaki, Jakub Vrana, Lars Torben Wilson, Jim Winstead, Jared Wyles i Jeroen van Wolffelaar.
PHP (recursive acronym for "PHP: Hypertext Preprocessor") is a widely-used open source general-purpose scripting language that is especially suited for web development and can be embedded into HTML.
Nice, but what does that mean? An example:
Example #1 An introductory example
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Example</title>
</head>
<body>
<?php
echo "Hi, I'm a PHP script!";
?>
</body>
</html>
Instead of lots of commands to output HTML (as seen in C or Perl),
PHP pages contain HTML with embedded code that does
"something" (in this case, output "Hi, I'm a PHP script!").
The PHP code is enclosed in special start and end processing
instructions <?php and ?>
that allow you to jump into and out of "PHP mode."
What distinguishes PHP from something like client-side JavaScript is that the code is executed on the server, generating HTML which is then sent to the client. The client would receive the results of running that script, but would not know what the underlying code was. You can even configure your web server to process all your HTML files with PHP, and then there's really no way that users can tell what you have up your sleeve.
The best things in using PHP are that it is extremely simple for a newcomer, but offers many advanced features for a professional programmer. Don't be afraid reading the long list of PHP's features. You can jump in, in a short time, and start writing simple scripts in a few hours.
Although PHP's development is focused on server-side scripting, you can do much more with it. Read on, and see more in the What can PHP do? section, or go right to the introductory tutorial if you are only interested in web programming.
Anything. PHP is mainly focused on server-side scripting, so you can do anything any other CGI program can do, such as collect form data, generate dynamic page content, or send and receive cookies. But PHP can do much more.
There are three main areas where PHP scripts are used.
PHP can be used on all major operating systems, including Linux, many Unix variants (including HP-UX, Solaris and OpenBSD), Microsoft Windows, Mac OS X, RISC OS, and probably others. PHP has also support for most of the web servers today. This includes Apache, Microsoft Internet Information Server, Personal Web Server, Netscape and iPlanet servers, Oreilly Website Pro server, Caudium, Xitami, OmniHTTPd, and many others. For the majority of the servers PHP has a module, for the others supporting the CGI standard, PHP can work as a CGI processor.
So with PHP, you have the freedom of choosing an operating system and a web server. Furthermore, you also have the choice of using procedural programming or object oriented programming, or a mixture of them. Although not every standard OOP feature is implemented in PHP 4, many code libraries and large applications (including the PEAR library) are written only using OOP code. PHP 5 fixes the OOP related weaknesses of PHP 4, and introduces a complete object model.
With PHP you are not limited to output HTML. PHP's abilities includes outputting images, PDF files and even Flash movies (using libswf and Ming) generated on the fly. You can also output easily any text, such as XHTML and any other XML file. PHP can autogenerate these files, and save them in the file system, instead of printing it out, forming a server-side cache for your dynamic content.
One of the strongest and most significant features in PHP is its support for a wide range of databases. Writing a database-enabled web page is incredibly simple. The following databases are currently supported:
We also have a database abstraction extension (named PDO) allowing you to transparently use any database supported by that extension. Additionally PHP supports ODBC, the Open Database Connection standard, so you can connect to any other database supporting this world standard.
- Adabas D
- dBase
- Empress
- FilePro (read-only)
- Hyperwave
- IBM DB2
- Informix
- Ingres
- InterBase
- FrontBase
- mSQL
- Direct MS-SQL
- MySQL
- ODBC
- Oracle (OCI7 and OCI8)
- Ovrimos
- PostgreSQL
- SQLite
- Solid
- Sybase
- Velocis
- Unix dbm
PHP also has support for talking to other services using protocols such as LDAP, IMAP, SNMP, NNTP, POP3, HTTP, COM (on Windows) and countless others. You can also open raw network sockets and interact using any other protocol. PHP has support for the WDDX complex data exchange between virtually all Web programming languages. Talking about interconnection, PHP has support for instantiation of Java objects and using them transparently as PHP objects. You can also use our CORBA extension to access remote objects.
PHP has extremely useful text processing features, from the POSIX Extended or Perl regular expressions to parsing XML documents. For parsing and accessing XML documents, PHP 4 supports the SAX and DOM standards, and you can also use the XSLT extension to transform XML documents. PHP 5 standardizes all the XML extensions on the solid base of libxml2 and extends the feature set adding SimpleXML and XMLReader support.
At last but not least, we have many other interesting extensions, the mnoGoSearch search engine functions, the IRC Gateway functions, many compression utilities (gzip, bz2, zip), calendar conversion, translation...
As you can see this page is not enough to list all the features and benefits PHP can offer. Read on in the sections about installing PHP, and see the function reference part for explanation of the extensions mentioned here.
Here we would like to show the very basics of PHP in a short, simple tutorial. This text only deals with dynamic web page creation with PHP, though PHP is not only capable of creating web pages. See the section titled What can PHP do for more information.
PHP-enabled web pages are treated just like regular HTML pages and you can create and edit them the same way you normally create regular HTML pages.
In this tutorial we assume that your server has activated support for PHP and that all files ending in .php are handled by PHP. On most servers, this is the default extension for PHP files, but ask your server administrator to be sure. If your server supports PHP, then you do not need to do anything. Just create your .php files, put them in your web directory and the server will automatically parse them for you. There is no need to compile anything nor do you need to install any extra tools. Think of these PHP-enabled files as simple HTML files with a whole new family of magical tags that let you do all sorts of things. Most web hosts offer PHP support, but if your host does not, consider reading the » PHP Links section for resources on finding PHP enabled web hosts.
Let us say you want to save precious bandwidth and develop locally. In this case, you will want to install a web server, such as » Apache, and of course » PHP. You will most likely want to install a database as well, such as » MySQL.
You can either install these individually or choose a simpler way. Our manual has installation instructions for PHP (assuming you already have some web server set up). In case you have problems with installing PHP yourself, we would suggest you ask your questions on our » installation mailing list. If you choose to go on the simpler route, then » locate a pre-configured package for your operating system, which automatically installs all of these with just a few mouse clicks. It is easy to setup a web server with PHP support on any operating system, including MacOSX, Linux and Windows. On Linux, you may find » rpmfind and » PBone helpful for locating RPMs. You may also want to visit » apt-get to find packages for Debian.
Create a file named hello.php and put it in your web server's root directory (DOCUMENT_ROOT) with the following content:
Example #1 Our first PHP script: hello.php
<html>
<head>
<title>PHP Test</title>
</head>
<body>
<?php echo '<p>Hello World</p>'; ?>
</body>
</html>
Use your browser to access the file with your web server's URL, ending with the "/hello.php" file reference. When developing locally this URL will be something like http://localhost/hello.php or http://127.0.0.1/hello.php but this depends on the web server's configuration. If everything is configured correctly, this file will be parsed by PHP and the following output will be sent to your browser:
<html> <head> <title>PHP Test</title> </head> <body> <p>Hello World</p> </body> </html>
This program is extremely simple and you really did not need to use PHP to create a page like this. All it does is display: Hello World using the PHP echo() statement. Note that the file does not need to be executable or special in any way. The server finds out that this file needs to be interpreted by PHP because you used the ".php" extension, which the server is configured to pass on to PHP. Think of this as a normal HTML file which happens to have a set of special tags available to you that do a lot of interesting things.
If you tried this example and it did not output anything, it prompted for download, or you see the whole file as text, chances are that the server you are on does not have PHP enabled, or is not configured properly. Ask your administrator to enable it for you using the Installation chapter of the manual. If you are developing locally, also read the installation chapter to make sure everything is configured properly. Make sure that you access the file via http with the server providing you the output. If you just call up the file from your file system, then it will not be parsed by PHP. If the problems persist anyway, do not hesitate to use one of the many » PHP support options.
The point of the example is to show the special PHP tag format. In this example we used <?php to indicate the start of a PHP tag. Then we put the PHP statement and left PHP mode by adding the closing tag, ?>. You may jump in and out of PHP mode in an HTML file like this anywhere you want. For more details, read the manual section on the basic PHP syntax.
Informacja: A Note on Line Feeds
Line feeds have little meaning in HTML, however it is still a good idea to make your HTML look nice and clean by putting line feeds in. A linefeed that follows immediately after a closing ?> will be removed by PHP. This can be extremely useful when you are putting in many blocks of PHP or include files containing PHP that aren't supposed to output anything. At the same time it can be a bit confusing. You can put a space after the closing ?> to force a space and a line feed to be output, or you can put an explicit line feed in the last echo/print from within your PHP block.
Informacja: A Note on Text Editors
There are many text editors and Integrated Development Environments (IDEs) that you can use to create, edit and manage PHP files. A partial list of these tools is maintained at » PHP Editors List. If you wish to recommend an editor, please visit the above page and ask the page maintainer to add the editor to the list. Having an editor with syntax highlighting can be helpful.
Informacja: A Note on Word Processors
Word processors such as StarOffice Writer, Microsoft Word and Abiword are not optimal for editing PHP files. If you wish to use one for this test script, you must ensure that you save the file as plain text or PHP will not be able to read and execute the script.
Informacja: A Note on Windows Notepad
If you are writing your PHP scripts using Windows Notepad, you will need to ensure that your files are saved with the .php extension. (Notepad adds a .txt extension to files automatically unless you take one of the following steps to prevent it.) When you save the file and are prompted to provide a name for the file, place the filename in quotes (i.e. "hello.php"). Alternatively, you can click on the 'Text Documents' drop-down menu in the 'Save' dialog box and change the setting to "All Files". You can then enter your filename without quotes.
Now that you have successfully created a working PHP script, it is time to create the most famous PHP script! Make a call to the phpinfo() function and you will see a lot of useful information about your system and setup such as available predefined variables, loaded PHP modules, and configuration settings. Take some time and review this important information.
Example #2 Get system information from PHP
<?php phpinfo(); ?>
Let us do something more useful now. We are going to check what sort of browser the visitor is using. For that, we check the user agent string the browser sends as part of the HTTP request. This information is stored in a variable. Variables always start with a dollar-sign in PHP. The variable we are interested in right now is $_SERVER['HTTP_USER_AGENT'].
Informacja: $_SERVER is a special reserved PHP variable that contains all web server information. It is known as a superglobal. See the related manual page on superglobals for more information. These special variables were introduced in PHP » 4.1.0. Before this time, we used the older $HTTP_*_VARS arrays instead, such as $HTTP_SERVER_VARS. Although deprecated, these older variables still exist. (See also the note on old code.)
To display this variable, you can simply do:
Example #1 Printing a variable (Array element)
<?php
echo $_SERVER['HTTP_USER_AGENT'];
?>
A sample output of this script may be:
Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)
There are many types of variables available in PHP. In the above example we printed an Array element. Arrays can be very useful.
$_SERVER is just one variable that PHP automatically makes available to you. A list can be seen in the Reserved Variables section of the manual or you can get a complete list of them by looking at the output of the phpinfo() function used in the example in the previous section.
You can put multiple PHP statements inside a PHP tag and create little blocks of code that do more than just a single echo. For example, if you want to check for Internet Explorer you can do this:
Example #2 Example using control structures and functions
<?php
if (strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== FALSE) {
echo 'You are using Internet Explorer.<br />';
}
?>
A sample output of this script may be:
You are using Internet Explorer.<br />
Here we introduce a couple of new concepts. We have an if statement. If you are familiar with the basic syntax used by the C language, this should look logical to you. Otherwise, you should probably pick up an introductory PHP book and read the first couple of chapters, or read the Language Reference part of the manual.
The second concept we introduced was the strpos() function call. strpos() is a function built into PHP which searches a string for another string. In this case we are looking for 'MSIE' (so-called needle) inside $_SERVER['HTTP_USER_AGENT'] (so-called haystack). If the needle is found inside the haystack, the function returns the position of the needle relative to the start of the haystack. Otherwise, it returns FALSE. If it does not return FALSE, the if expression evaluates to TRUE and the code within its {braces} is executed. Otherwise, the code is not run. Feel free to create similar examples, with if, else, and other functions such as strtoupper() and strlen(). Each related manual page contains examples too. If you are unsure how to use functions, you will want to read both the manual page on how to read a function definition and the section about PHP functions.
We can take this a step further and show how you can jump in and out of PHP mode even in the middle of a PHP block:
Example #3 Mixing both HTML and PHP modes
<?php
if (strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== FALSE) {
?>
<h3>strpos() must have returned non-false</h3>
<p>You are using Internet Explorer</p>
<?php
} else {
?>
<h3>strpos() must have returned false</h3>
<p>You are not using Internet Explorer</p>
<?php
}
?>
A sample output of this script may be:
<h3>strpos() must have returned non-false</h3> <p>You are using Internet Explorer</p>
Instead of using a PHP echo statement to output something, we jumped out of PHP mode and just sent straight HTML. The important and powerful point to note here is that the logical flow of the script remains intact. Only one of the HTML blocks will end up getting sent to the viewer depending on the result of strpos(). In other words, it depends on whether the string MSIE was found or not.
One of the most powerful features of PHP is the way it handles HTML forms. The basic concept that is important to understand is that any form element will automatically be available to your PHP scripts. Please read the manual section on Variables from external sources for more information and examples on using forms with PHP. Here is an example HTML form:
Example #1 A simple HTML form
<form action="action.php" method="post"> <p>Your name: <input type="text" name="name" /></p> <p>Your age: <input type="text" name="age" /></p> <p><input type="submit" /></p> </form>
There is nothing special about this form. It is a straight HTML form with no special tags of any kind. When the user fills in this form and hits the submit button, the action.php page is called. In this file you would write something like this:
Example #2 Printing data from our form
Hi <?php echo htmlspecialchars($_POST['name']); ?>.
You are <?php echo (int)$_POST['age']; ?> years old.
A sample output of this script may be:
Hi Joe. You are 22 years old.
Apart from the htmlspecialchars() and (int) parts, it should be obvious what this does. htmlspecialchars() makes sure any characters that are special in html are properly encoded so people can't inject HTML tags or Javascript into your page. For the age field, since we know it is a number, we can just convert it to an integer which will automatically get rid of any stray characters. You can also have PHP do this for you automatically by using the filter extension. The $_POST['name'] and $_POST['age'] variables are automatically set for you by PHP. Earlier we used the $_SERVER superglobal; above we just introduced the $_POST superglobal which contains all POST data. Notice how the method of our form is POST. If we used the method GET then our form information would live in the $_GET superglobal instead. You may also use the $_REQUEST superglobal, if you do not care about the source of your request data. It contains the merged information of GET, POST and COOKIE data. Also see the import_request_variables() function.
You can also deal with XForms input in PHP, although you will find yourself comfortable with the well supported HTML forms for quite some time. While working with XForms is not for beginners, you might be interested in them. We also have a short introduction to handling data received from XForms in our features section.
Now that PHP has grown to be a popular scripting language, there are a lot of public repositories and libraries containing code you can reuse. The PHP developers have largely tried to preserve backwards compatibility, so a script written for an older version will run (ideally) without changes in a newer version of PHP. In practice, some changes will usually be needed.
Two of the most important recent changes that affect old code are:
For more details on these changes, see the section on predefined variables and links therein.
With your new knowledge you should be able to understand most of the manual and also the various example scripts available in the example archives. You can also find other examples on the php.net websites in the links section: » http://www.php.net/links.php.
To view various slide presentations that show more of what PHP can do, see the PHP Conference Material Site: » http://talks.php.net/
Przed instalacją musisz wiedzieć do czego potrzebne ci jest PHP. PHP jest używane głównie w trzech polach, tak jak to zostało opisane w rozdziale Co potrafi PHP?
Dla pierwszej pozycji w najbardziej popularnej postaci potrzebne są trzy rzeczy: samo PHP, serwer WWW i przeglądarka internetowa. Najprawdopodobniej posiadasz już przeglądarkę, i zależnie od systemu operacyjnego także serwer (np. Apache na systemach Linux lub IIS na systemach Windows). Możesz także wynająć przestrzeń na serwerze komercyjnym. Tym sposobem nie musisz niczego własnoręcznie konfigurować, a jedynie pisać skrypty, umieszczać je na serwerze i oglądać wyniki w oknie przeglądarki.
Własnoręcznie konfigurując serwer i PHP masz dwie możliwości połączenia PHP z serwerem. Dla wielu serwerów PHP posiada bezpośredni interfejs modułu (zwany także SAPI). Do tych serwerów należą Apache, Microsoft Internet Information Server, Netscape i iPlanet. Przez wiele innych serwerów jest obsługiwane przez ISAPI, interfejs modułów Microsoft (na przykład OmniHTTPd). Jeśli PHP nie ma obsługi modułowej dla twojego serwera, możesz używać go jako procesor CGI lub FastCGI. Oznacza to, że możesz skonfigurować twój serwer tak, aby korzystał z pliku wykonywalnego PHP (php.exe na systemach Windows) do przetwarzania wszystkich plików PHP dostępnych na serwerze.
Jeśli jesteś zainteresowany używaniem PHP do pisania skryptów wywoływanych z linii poleceń (np. pisania skryptów do automatycznego generowania off-line obrazów dla Ciebie lub przetwarzania plików tekstowych zależnie od przekazanych argumentów), potrzebujesz pliku wykonywalnego PHP. Aby uzyskać więcej informacji przeczytaj rozdział Pisanie aplikacji PHP wywoływanych z linii poleceń. W tym przypadku nie potrzebujesz ani serwera ani przeglądarki.
W PHP możesz pisać także aplikacje z interfejsem użytkownika używając rozszerzenia PHP-GTK. Jest to podejście zupełnie inne niż tworzenie stron internetowych, ponieważ nie wysyłasz żadnego wyjścia HTMLowego, ale obsługujesz okienka i obiekty w nich zawarte. Aby uzyskać więcej informacji o PHP-GTK, odwiedź » stronę poświęconą temu rozszerzeniu. PHP-GTK nie jest zawarte w oficjalnej dystrybucji PHP.
Od tego miejsca rozdział dotyczy konfiguracji PHP z serwerami WWW pracującymi pod kontrolą systemów Unix i Windows w postaci modułów serwera lub binariów CGI. W następnych sekcjach znajdziesz informacje o wywoływaniu PHP z linii poleceń.
Kod źródlowy oraz dystrybucje binarne dla Windows, można znaleźć na stronie » http://www.php.net/downloads.php. Zalecane jest korzystanie z jednego z najbliższego » serweru lustrzanego do pobierania dystrybucji PHP.
This section will guide you through the general configuration and installation of PHP on Unix systems. Be sure to investigate any sections specific to your platform or web server before you begin the process.
As our manual outlines in the General Installation Considerations section, we are mainly dealing with web centric setups of PHP in this section, although we will cover setting up PHP for command line usage as well.
There are several ways to install PHP for the Unix platform, either with a compile and configure process, or through various pre-packaged methods. This documentation is mainly focused around the process of compiling and configuring PHP. Many Unix like systems have some sort of package installation system. This can assist in setting up a standard configuration, but if you need to have a different set of features (such as a secure server, or a different database driver), you may need to build PHP and/or your web server. If you are unfamiliar with building and compiling your own software, it is worth checking to see whether somebody has already built a packaged version of PHP with the features you need.
Prerequisite knowledge and software for compiling:
The initial PHP setup and configuration process is controlled by the use of the command line options of the configure script. You could get a list of all available options along with short explanations running ./configure --help. Our manual documents the different options separately. You will find the core options in the appendix, while the different extension specific options are descibed on the reference pages.
When PHP is configured, you are ready to build the module and/or executables. The command make should take care of this. If it fails and you can't figure out why, see the Problems section.
This section contains notes and hints specific to Apache installs of PHP on Unix platforms. We also have instructions and notes for Apache 2 on a separate page.
You can select arguments to add to the configure on line 10 below from the list of core configure options and from extension specific options described at the respective places in the manual. The version numbers have been omitted here, to ensure the instructions are not incorrect. You will need to replace the 'xxx' here with the correct values from your files.
Example #1 Installation Instructions (Apache Shared Module Version) for PHP
1. gunzip apache_xxx.tar.gz 2. tar -xvf apache_xxx.tar 3. gunzip php-xxx.tar.gz 4. tar -xvf php-xxx.tar 5. cd apache_xxx 6. ./configure --prefix=/www --enable-module=so 7. make 8. make install 9. cd ../php-xxx 10. Now, configure your PHP. This is where you customize your PHP with various options, like which extensions will be enabled. Do a ./configure --help for a list of available options. In our example we'll do a simple configure with Apache 1 and MySQL support. Your path to apxs may differ from our example. ./configure --with-mysql --with-apxs=/www/bin/apxs 11. make 12. make install If you decide to change your configure options after installation, you only need to repeat the last three steps. You only need to restart apache for the new module to take effect. A recompile of Apache is not needed. Note that unless told otherwise, 'make install' will also install PEAR, various PHP tools such as phpize, install the PHP CLI, and more. 13. Setup your php.ini file: cp php.ini-dist /usr/local/lib/php.ini You may edit your .ini file to set PHP options. If you prefer your php.ini in another location, use --with-config-file-path=/some/path in step 10. If you instead choose php.ini-recommended, be certain to read the list of changes within, as they affect how PHP behaves. 14. Edit your httpd.conf to load the PHP module. The path on the right hand side of the LoadModule statement must point to the path of the PHP module on your system. The make install from above may have already added this for you, but be sure to check. For PHP 4: LoadModule php4_module libexec/libphp4.so For PHP 5: LoadModule php5_module libexec/libphp5.so 15. And in the AddModule section of httpd.conf, somewhere under the ClearModuleList, add this: For PHP 4: AddModule mod_php4.c For PHP 5: AddModule mod_php5.c 16. Tell Apache to parse certain extensions as PHP. For example, let's have Apache parse the .php extension as PHP. You could have any extension(s) parse as PHP by simply adding more, with each separated by a space. We'll add .phtml to demonstrate. AddType application/x-httpd-php .php .phtml It's also common to setup the .phps extension to show highlighted PHP source, this can be done with: AddType application/x-httpd-php-source .phps 17. Use your normal procedure for starting the Apache server. (You must stop and restart the server, not just cause the server to reload by using a HUP or USR1 signal.)
Alternatively, to install PHP as a static object:
Example #2 Installation Instructions (Static Module Installation for Apache) for PHP
1. gunzip -c apache_1.3.x.tar.gz | tar xf - 2. cd apache_1.3.x 3. ./configure 4. cd .. 5. gunzip -c php-5.x.y.tar.gz | tar xf - 6. cd php-5.x.y 7. ./configure --with-mysql --with-apache=../apache_1.3.x 8. make 9. make install 10. cd ../apache_1.3.x 11. ./configure --prefix=/www --activate-module=src/modules/php5/libphp5.a (The above line is correct! Yes, we know libphp5.a does not exist at this stage. It isn't supposed to. It will be created.) 12. make (you should now have an httpd binary which you can copy to your Apache bin dir if it is your first install then you need to "make install" as well) 13. cd ../php-5.x.y 14. cp php.ini-dist /usr/local/lib/php.ini 15. You can edit /usr/local/lib/php.ini file to set PHP options. Edit your httpd.conf or srm.conf file and add: AddType application/x-httpd-php .php
Informacja: Replace php-5 by php-4 and php5 by php4 in PHP 4.
Depending on your Apache install and Unix variant, there are many possible ways to stop and restart the server. Below are some typical lines used in restarting the server, for different apache/unix installations. You should replace /path/to/ with the path to these applications on your systems.
Example #3 Example commands for restarting Apache
1. Several Linux and SysV variants: /etc/rc.d/init.d/httpd restart 2. Using apachectl scripts: /path/to/apachectl stop /path/to/apachectl start 3. httpdctl and httpsdctl (Using OpenSSL), similar to apachectl: /path/to/httpsdctl stop /path/to/httpsdctl start 4. Using mod_ssl, or another SSL server, you may want to manually stop and start: /path/to/apachectl stop /path/to/apachectl startssl
The locations of the apachectl and http(s)dctl binaries often vary. If your system has locate or whereis or which commands, these can assist you in finding your server control programs.
Different examples of compiling PHP for apache are as follows:
./configure --with-apxs --with-pgsql
This will create a libphp5.so (or libphp4.so in PHP 4) shared library that is loaded into Apache using a LoadModule line in Apache's httpd.conf file. The PostgreSQL support is embedded into this library.
./configure --with-apxs --with-pgsql=shared
This will create a libphp4.so shared library for Apache, but it will also create a pgsql.so shared library that is loaded into PHP either by using the extension directive in php.ini file or by loading it explicitly in a script using the dl() function.
./configure --with-apache=/path/to/apache_source --with-pgsql
This will create a libmodphp5.a library, a mod_php5.c and some accompanying files and copy this into the src/modules/php5 directory in the Apache source tree. Then you compile Apache using --activate-module=src/modules/php5/libphp5.a and the Apache build system will create libphp5.a and link it statically into the httpd binary (replace php5 by php4 in PHP 4). The PostgreSQL support is included directly into this httpd binary, so the final result here is a single httpd binary that includes all of Apache and all of PHP.
./configure --with-apache=/path/to/apache_source --with-pgsql=shared
Same as before, except instead of including PostgreSQL support directly into the final httpd you will get a pgsql.so shared library that you can load into PHP from either the php.ini file or directly using dl().
When choosing to build PHP in different ways, you should consider the advantages and drawbacks of each method. Building as a shared object will mean that you can compile apache separately, and don't have to recompile everything as you add to, or change, PHP. Building PHP into apache (static method) means that PHP will load and run faster. For more information, see the Apache » web page on DSO support.
Informacja: Apache's default httpd.conf currently ships with a section that looks like this:
Unless you change that to "Group nogroup" or something like that ("Group daemon" is also very common) PHP will not be able to open files.User nobody Group "#-1"
Informacja: Make sure you specify the installed version of apxs when using --with-apxs=/path/to/apxs. You must NOT use the apxs version that is in the apache sources but the one that is actually installed on your system.
This section contains notes and hints specific to Apache 2.0 installs of PHP on Unix systems.
Nie zalecamy korzystania z wątkowanego MPM na produkcyjnych serwerach Apache2. Zamiast niego wskazane jest używanie preforkowanego MPM, lub używanie Apache1. Wyjaśnienie powodów można znaleźć w odpowiednim punkcie FAQ, dotyczącym używania Apache2 z wątkowanym MPM
You are highly encouraged to take a look at the » Apache Documentation to get a basic understanding of the Apache 2.0 Server.
Informacja: PHP and Apache 2.0.x compatibility notes
The following versions of PHP are known to work with the most recent version of Apache 2.0.x:These versions of PHP are compatible to Apache 2.0.40 and later.
- PHP 4.3.0 or later available at » http://www.php.net/downloads.php.
- the latest stable development version. Get the source code » http://snaps.php.net/php5-latest.tar.gz or download binaries for Windows » http://snaps.php.net/win32/php5-win32-latest.zip.
- a prerelease version downloadable from » http://qa.php.net/.
- you have always the option to obtain PHP through » anonymous CVS.
Apache 2.0 SAPI-support started with PHP 4.2.0. PHP 4.2.3 works with Apache 2.0.39, don't use any other version of Apache with PHP 4.2.3. However, the recommended setup is to use PHP 4.3.0 or later with the most recent version of Apache2.
All mentioned versions of PHP will work still with Apache 1.3.x.
Download the most recent version of » Apache 2.0 and a fitting PHP version from the above mentioned places. This quick guide covers only the basics to get started with Apache 2.0 and PHP. For more information read the » Apache Documentation. The version numbers have been omitted here, to ensure the instructions are not incorrect. You will need to replace the 'NN' here with the correct values from your files.
Example #1 Installation Instructions (Apache 2 Shared Module Version)
1. gzip -d httpd-2_0_NN.tar.gz 2. tar xvf httpd-2_0_NN.tar 3. gunzip php-NN.tar.gz 4. tar -xvf php-NN.tar 5. cd httpd-2_0_NN 6. ./configure --enable-so 7. make 8. make install Now you have Apache 2.0.NN available under /usr/local/apache2, configured with loadable module support and the standard MPM prefork. To test the installation use your normal procedure for starting the Apache server, e.g.: /usr/local/apache2/bin/apachectl start and stop the server to go on with the configuration for PHP: /usr/local/apache2/bin/apachectl stop. 9. cd ../php-NN 10. Now, configure your PHP. This is where you customize your PHP with various options, like which extensions will be enabled. Do a ./configure --help for a list of available options. In our example we'll do a simple configure with Apache 2 and MySQL support. Your path to apxs may differ, in fact, the binary may even be named apxs2 on your system. ./configure --with-apxs2=/usr/local/apache2/bin/apxs --with-mysql 11. make 12. make install If you decide to change your configure options after installation, you only need to repeat the last three steps. You only need to restart apache for the new module to take effect. A recompile of Apache is not needed. Note that unless told otherwise, 'make install' will also install PEAR, various PHP tools such as phpize, install the PHP CLI, and more. 13. Setup your php.ini cp php.ini-dist /usr/local/lib/php.ini You may edit your .ini file to set PHP options. If you prefer having php.ini in another location, use --with-config-file-path=/some/path in step 10. If you instead choose php.ini-recommended, be certain to read the list of changes within, as they affect how PHP behaves. 14. Edit your httpd.conf to load the PHP module. The path on the right hand side of the LoadModule statement must point to the path of the PHP module on your system. The make install from above may have already added this for you, but be sure to check. For PHP 4: LoadModule php4_module modules/libphp4.so For PHP 5: LoadModule php5_module modules/libphp5.so 15. Tell Apache to parse certain extensions as PHP. For example, let's have Apache parse .php files as PHP. Instead of only using the Apache AddType directive, we want to avoid potentially dangerous uploads and created files such as exploit.php.jpg from being executed as PHP. Using this example, you could have any extension(s) parse as PHP by simply adding them. We'll add .phtml to demonstrate. <FilesMatch \.php$> SetHandler application/x-httpd-php </FilesMatch> Or, if we wanted to allow .php, .php2, .php3, .php4, .php5, .php6, and .phtml files to be executed as PHP, but nothing else, we'd use this: <FilesMatch "\.ph(p[2-6]?|tml)$"> SetHandler application/x-httpd-php </FilesMatch> And to allow .phps files to be executed as PHP source files, add this: <FilesMatch "\.phps$"> SetHandler application/x-httpd-php-source </FilesMatch> 16. Use your normal procedure for starting the Apache server, e.g.: /usr/local/apache2/bin/apachectl start - OR - service httpd restart
Following the steps above you will have a running Apache2 web server with support for PHP as a SAPI module. Of course there are many more configuration options available Apache and PHP. For more information type ./configure --help in the corresponding source tree. If you wish to build a multithreaded version of Apache2, you must overwrite the standard MPM-Module prefork either with worker or perchild. To do so append to your configure line in step 6 above either the option --with-mpm=worker or --with-mpm=perchild. Before doing so, please beware the consequences and have at least a fair understand of what the implications. For more information, read the Apache documentation regarding » MPM-Modules.
Informacja: If you want to use content negotiation, read the Apache MultiViews FAQ.
Informacja: To build a multithreaded version of Apache your system must support threads. This also implies to build PHP with experimental Zend Thread Safety (ZTS). Therefore not all extensions might be available. The recommended setup is to build Apache with the standard prefork MPM-Module.
This section contains notes and hints specific to Lighttpd 1.4 installs of PHP on Unix systems.
Please use the » Lighttpd trac to learn how to install Lighttpd properly before continuing.
Fastcgi is the preferred SAPI to connect PHP and Lighttpd. Fastcgi is automagically enabled in php-cgi in PHP 5.3, but for older versions configure PHP with --enable-fastcgi. To confirm that PHP has fastcgi enabled, php -v should contain PHP 5.2.5 (cgi-fcgi) Before PHP 5.2.3, fastcgi was enabled on the php binary (there was no php-cgi).
To configure Lighttpd to connect to php and spawn fastcgi processes, edit lighttpd.conf. Sockets are preferred to connect to fastcgi processes on the local system.
Example #1 Partial lighttpd.conf
server.modules += ( "mod_fastcgi" ) fastcgi.server = ( ".php" => (( "socket" => "/tmp/php.socket", "bin-path" => "/usr/local/bin/php-cgi", "bin-environment" => ( "PHP_FCGI_CHILDREN" => "16", "PHP_FCGI_MAX_REQUESTS" => "10000" ), "min-procs" => 1, "max-procs" => 1, "idle-timeout" => 20 )) )
The bin-path directive allows lighttpd to spawn fastcgi processes dynamically. PHP will spawn children according to the PHP_FCGI_CHILDREN environment variable. The "bin-environment" directive sets the environment for the spawned processes. PHP will kill a child process after the number of requests specified by PHP_FCGI_MAX_REQUESTS is reached. The directives "min-procs" and "max-procs" should generally be avoided with PHP. PHP manages its own children and opcode caches like APC will only share among children managed by PHP. If "min-procs" is set to something greater than 1, the total number of php responders will be multiplied PHP_FCGI_CHILDREN (2 min-procs * 16 children gives 32 responders).
Lighttpd provides a program called spawn-fcgi to ease the process of spawning fastcgi processes easier.
It is possible to spawn processes without spawn-fcgi, though a bit of heavy-lifting is required. Setting the PHP_FCGI_CHILDREN environment var controls how many children PHP will spawn to handle incoming requests. Setting PHP_FCGI_MAX_REQUESTS will determine how long (in requests) each child will live. Here's a simple bash script to help spawn php responders.
Example #2 Spawning FastCGI Responders
#!/bin/sh # Location of the php-cgi binary PHP=/usr/local/bin/php-cgi # PID File location PHP_PID=/tmp/php.pid # Binding to an address #FCGI_BIND_ADDRESS=10.0.1.1:10000 # Binding to a domain socket FCGI_BIND_ADDRESS=/tmp/php.sock PHP_FCGI_CHILDREN=16 PHP_FCGI_MAX_REQUESTS=10000 env -i PHP_FCGI_CHILDREN=$PHP_FCGI_CHILDREN \ PHP_FCGI_MAX_REQUESTS=$PHP_FCGI_MAX_REQUESTS \ $PHP -b $FCGI_BIND_ADDRESS & echo $! > "$PHP_PID"
Fastcgi instances can be spawned on multiple remote machines in order to scale applications.
Example #3 Connecting to remote php-fastcgi instances
fastcgi.server = ( ".php" => (( "host" => "10.0.0.2", "port" => 1030 ), ( "host" => "10.0.0.3", "port" => 1030 )) )
PHP can be built as a Pike module for the » Caudium webserver. Follow the simple instructions below to install PHP for Caudium.
Example #1 Caudium Installation Instructions
1. Make sure you have Caudium installed prior to attempting to install PHP 4. For PHP 4 to work correctly, you will need Pike 7.0.268 or newer. For the sake of this example we assume that Caudium is installed in /opt/caudium/server/. 2. Change directory to php-x.y.z (where x.y.z is the version number). 3. ./configure --with-caudium=/opt/caudium/server 4. make 5. make install 6. Restart Caudium if it's currently running. 7. Log into the graphical configuration interface and go to the virtual server where you want to add PHP 4 support. 8. Click Add Module and locate and then add the PHP 4 Script Support module. 9. If the documentation says that the 'PHP 4 interpreter isn't available', make sure that you restarted the server. If you did check /opt/caudium/logs/debug/default.1 for any errors related to <filename>PHP4.so</filename>. Also make sure that <filename>caudium/server/lib/[pike-version]/PHP4.so</filename> is present. 10. Configure the PHP Script Support module if needed.
You can of course compile your Caudium module with support for the various extensions available in PHP 4. See the reference pages for extension specific configure options.
Informacja: When compiling PHP 4 with MySQL support you must make sure that the normal MySQL client code is used. Otherwise there might be conflicts if your Pike already has MySQL support. You do this by specifying a MySQL install directory the --with-mysql option.
To build PHP as an fhttpd module, answer "yes" to "Build as an fhttpd module?" (the --with-fhttpd=DIR option to configure) and specify the fhttpd source base directory. The default directory is /usr/local/src/fhttpd. If you are running fhttpd, building PHP as a module will give better performance, more control and remote execution capability.
Informacja: Support for fhttpd is no longer available as of PHP 4.3.0.
This section contains notes and hints specific to Sun Java System Web Server, Sun ONE Web Server, iPlanet and Netscape server installs of PHP on Sun Solaris.
From PHP 4.3.3 on you can use PHP scripts with the NSAPI module to generate custom directory listings and error pages. Additional functions for Apache compatibility are also available. For support in current web servers read the note about subrequests.
You can find more information about setting up PHP for the Netscape Enterprise Server (NES) here: » http://benoit.noss.free.fr/php/install-php4.html
To build PHP with Sun JSWS/Sun ONE WS/iPlanet/Netscape web servers, enter the proper install directory for the --with-nsapi=[DIR] option. The default directory is usually /opt/netscape/suitespot/. Please also read /php-xxx-version/sapi/nsapi/nsapi-readme.txt.
Install the following packages from » http://www.sunfreeware.com/ or another download site:
export PATH
.
gunzip php-x.x.x.tar.gz
(if you have a .gz dist,
otherwise go to 4).
tar xvf php-x.x.x.tar
cd ../php-x.x.x
For the following step, make sure /opt/netscape/suitespot/ is where your netscape server is installed. Otherwise, change to the correct path and run:
./configure --with-mysql=/usr/local/mysql \ --with-nsapi=/opt/netscape/suitespot/ \ --enable-libgcc
After performing the base install and reading the appropriate readme file, you may need to perform some additional configuration steps.
Firstly you may need to add some paths to the LD_LIBRARY_PATH environment for the server to find all the shared libs. This can best done in the start script for your web server. The start script is often located in: /path/to/server/https-servername/start. You may also need to edit the configuration files that are located in: /path/to/server/https-servername/config/.
Add the following line to mime.types (you can do that by the administration server):
type=magnus-internal/x-httpd-php exts=php
Edit magnus.conf (for servers >= 6) or obj.conf (for servers < 6) and add the following, shlib will vary depending on your system, it will be something like /opt/netscape/suitespot/bin/libphp4.so. You should place the following lines after mime types init.
Init fn="load-modules" funcs="php4_init,php4_execute,php4_auth_trans" shlib="/opt/netscape/suitespot/bin/libphp4.so" Init fn="php4_init" LateInit="yes" errorString="Failed to initialize PHP!" [php_ini="/path/to/php.ini"]
Configure the default object in obj.conf (for virtual server classes [version 6.0+] in their vserver.obj.conf):
<Object name="default"> . . . .#NOTE this next line should happen after all 'ObjectType' and before all 'AddLog' lines Service fn="php4_execute" type="magnus-internal/x-httpd-php" [inikey=value inikey=value ...] . . </Object>
This is only needed if you want to configure a directory that only consists of PHP scripts (same like a cgi-bin directory):
<Object name="x-httpd-php"> ObjectType fn="force-type" type="magnus-internal/x-httpd-php" Service fn=php4_execute [inikey=value inikey=value ...] </Object>
Setup of authentication: PHP authentication cannot be used with any other authentication. ALL AUTHENTICATION IS PASSED TO YOUR PHP SCRIPT. To configure PHP Authentication for the entire server, add the following line to your default object:
<Object name="default"> AuthTrans fn=php4_auth_trans . . . </Object>
To use PHP Authentication on a single directory, add the following:
<Object ppath="d:\path\to\authenticated\dir\*"> AuthTrans fn=php4_auth_trans </Object>
Informacja: The stacksize that PHP uses depends on the configuration of the web server. If you get crashes with very large PHP scripts, it is recommended to raise it with the Admin Server (in the section "MAGNUS EDITOR").
Important when writing PHP scripts is the fact that Sun JSWS/Sun ONE WS/iPlanet/Netscape is a multithreaded web server. Because of that all requests are running in the same process space (the space of the web server itself) and this space has only one environment. If you want to get CGI variables like PATH_INFO, HTTP_HOST etc. it is not the correct way to try this in the old PHP way with getenv() or a similar way (register globals to environment, $_ENV). You would only get the environment of the running web server without any valid CGI variables!
Informacja: Why are there (invalid) CGI variables in the environment?
Answer: This is because you started the web server process from the admin server which runs the startup script of the web server, you wanted to start, as a CGI script (a CGI script inside of the admin server!). This is why the environment of the started web server has some CGI environment variables in it. You can test this by starting the web server not from the administration server. Use the command line as root user and start it manually - you will see there are no CGI-like environment variables.
Simply change your scripts to get CGI variables in the correct way for PHP 4.x by using the superglobal $_SERVER. If you have older scripts which use $HTTP_HOST, etc., you should turn on register_globals in php.ini and change the variable order too (important: remove "E" from it, because you do not need the environment here):
variables_order = "GPCS" register_globals = On
You can use PHP to generate the error pages for "404 Not Found" or similar. Add the following line to the object in obj.conf for every error page you want to overwrite:
Error fn="php4_execute" code=XXX script="/path/to/script.php" [inikey=value inikey=value...]
Another possibility is to generate self-made directory listings. Just create a PHP script which displays a directory listing and replace the corresponding default Service line for type="magnus-internal/directory" in obj.conf with the following:
Service fn="php4_execute" type="magnus-internal/directory" script="/path/to/script.php" [inikey=value inikey=value...]
The NSAPI module now supports the nsapi_virtual() function (alias: virtual()) to make subrequests on the web server and insert the result in the web page. This function uses some undocumented features from the NSAPI library. On Unix the module automatically looks for the needed functions and uses them if available. If not, nsapi_virtual() is disabled.
Informacja: But be warned: Support for nsapi_virtual() is EXPERIMENTAL!!!
The default is to build PHP as a CGI program. This creates a command line interpreter, which can be used for CGI processing, or for non-web-related PHP scripting. If you are running a web server PHP has module support for, you should generally go for that solution for performance reasons. However, the CGI version enables users to run different PHP-enabled pages under different user-ids.
Używając instalacji CGI, serwer jest podatny na wiele potencjalnych ataków. Sposoby obrony przed nimi zostały opisane w rozdziale o bezpieczeństwie instalacji CGI.
As of PHP 4.3.0, some important additions have happened to PHP. A new SAPI named CLI also exists and it has the same name as the CGI binary. What is installed at {PREFIX}/bin/php depends on your configure line and this is described in detail in the manual section named Using PHP from the command line. For further details please read that section of the manual.
If you have built PHP as a CGI program, you may test your build by typing make test. It is always a good idea to test your build. This way you may catch a problem with PHP on your platform early instead of having to struggle with it later.
Some server supplied environment variables are not defined in the current » CGI/1.1 specification. Only the following variables are defined there: AUTH_TYPE, CONTENT_LENGTH, CONTENT_TYPE, GATEWAY_INTERFACE, PATH_INFO, PATH_TRANSLATED, QUERY_STRING, REMOTE_ADDR, REMOTE_HOST, REMOTE_IDENT, REMOTE_USER, REQUEST_METHOD, SCRIPT_NAME, SERVER_NAME, SERVER_PORT, SERVER_PROTOCOL, and SERVER_SOFTWARE. Everything else should be treated as 'vendor extensions'.
This section contains notes and hints specific to installing PHP on HP-UX systems.
There are two main options for installing PHP on HP-UX systems. Either compile it, or install a pre-compiled binary.
Official pre-compiled packages are located here: » http://software.hp.com/
Until this manual section is rewritten, the documentation about compiling PHP (and related extensions) on HP-UX systems has been removed. For now, consider reading the following external resource: » Building Apache and PHP on HP-UX 11.11
This section contains notes and hints specific to installing PHP on » OpenBSD 3.6.
Using binary packages to install PHP on OpenBSD is the recommended and simplest method. The core package has been separated from the various modules, and each can be installed and removed independently from the others. The files you need can be found on your OpenBSD CD or on the FTP site.
The main package you need to install is php4-core-4.3.8.tgz, which contains the basic engine (plus gettext and iconv). Next, take a look at the module packages, such as php4-mysql-4.3.8.tgz or php4-imap-4.3.8.tgz. You need to use the phpxs command to activate and deactivate these modules in your php.ini.
Example #1 OpenBSD Package Install Example
# pkg_add php4-core-4.3.8.tgz # /usr/local/sbin/phpxs -s # cp /usr/local/share/doc/php4/php.ini-recommended /var/www/conf/php.ini (add in mysql) # pkg_add php4-mysql-4.3.8.tgz # /usr/local/sbin/phpxs -a mysql (add in imap) # pkg_add php4-imap-4.3.8.tgz # /usr/local/sbin/phpxs -a imap (remove mysql as a test) # pkg_delete php4-mysql-4.3.8 # /usr/local/sbin/phpxs -r mysql (install the PEAR libraries) # pkg_add php4-pear-4.3.8.tgz
Read the » packages(7) manual page for more information about binary packages on OpenBSD.
You can also compile up PHP from source using the » ports tree. However, this is only recommended for users familiar with OpenBSD. The PHP 4 port is split into two sub-directories: core and extensions. The extensions directory generates sub-packages for all of the supported PHP modules. If you find you do not want to create some of these modules, use the no_* FLAVOR. For example, to skip building the imap module, set the FLAVOR to no_imap.
Older releases of OpenBSD used the FLAVORS system to compile up a statically linked PHP. Since it is hard to generate binary packages using this method, it is now deprecated. You can still use the old stable ports trees if you wish, but they are unsupported by the OpenBSD team. If you have any comments about this, the current maintainer for the port is Anil Madhavapeddy (avsm at openbsd dot org).
This section contains notes and hints specific to installing PHP on Solaris systems.
Solaris installs often lack C compilers and their related tools. Read this FAQ for information on why using GNU versions for some of these tools is necessary. The required software is as follows:
In addition, you will need to install (and possibly compile) any additional software specific to your configuration, such as Oracle or MySQL.
You can simplify the Solaris install process by using pkgadd to install most of your needed components.
This section contains notes and hints specific to installing PHP on » Debian GNU/Linux.
While you can just download the PHP source and compile it yourself, using Debian's packaging system is the simplest and cleanest method of installing PHP. If you are not familiar with building software on Linux, this is the way to go.
The first decision you need to make is whether you want to install Apache 1.3.x or Apache 2.x. The corresponding PHP packages are respectively named libapache-mod-php* and libapache2-mod-php*. The steps given below will use Apache 1.3.x. Please note that, as of this writing, there is no official Debian packages of PHP 5. Then the steps given below will install PHP 4.
PHP is available in Debian as CGI or CLI flavour too, named respectively php4-cgi and php4-cli. If you need them, you'll just have to reproduce the following steps with the good package names. Another special package you'd want to install is php4-pear. It contains a minimal PEAR installation and the pear commandline utility.
If you need more recent packages of PHP than the Debian's stable ones or if some PHP modules lacks the Debian official repository, perhaps you should take a look at » http://www.apt-get.org/. One of the results found should be » Dotdeb. This unofficial repository is maintained by » Guillaume Plessis and contains Debian packages of the most recent versions of PHP 4 and PHP 5. To use it, just add the to following two lines to your /etc/apt/sources.lists and run apt-get update :
Example #1 The two Dotdeb related lines
deb http://packages.dotdeb.org stable all deb-src http://packages.dotdeb.org stable all
The last thing to consider is whether your list of packages is up to date. If you have not updated it recently, you need to run apt-get update before anything else. This way, you will be using the most recent stable version of the Apache and PHP packages.
Now that everything is in place, you can use the following example to install Apache and PHP:
Example #2 Debian Install Example with Apache 1.3
# apt-get install libapache-mod-php4
APT will automatically install the PHP 4 module for Apache 1.3, and all its dependencies and then activate it. If you're not asked to restart Apache during the install process, you'll have to do it manually :
Example #3 Stopping and starting Apache once PHP 4 is installed
# /etc/init.d/apache stop # /etc/init.d/apache start
In the last section, PHP was installed with only core modules. This may not be what you want and you will soon discover that you need more activated modules, like MySQL, cURL, GD, etc.
When you compile PHP from source yourself, you need to activate modules via the configure command. With APT, you just have to install additional packages. They're all named 'php4-*' (or 'php5-*' if you installed PHP 5 from a third party repository).
Example #4 Getting the list of PHP additional packages
# dpkg -l 'php4-*'
As you can see from the last output, there's a lot of PHP modules that you can install (excluding the php4-cgi, php4-cli or php4-pear special packages). Look at them closely and choose what you need. If you choose a module and you do not have the proper libraries, APT will automatically install all the dependencies for you.
If you choose to add the MySQL, cURL and GD support to PHP the command will look something like this:
Example #5 Install PHP with MySQL, cURL and GD
# apt-get install php4-mysql php4-curl php4-gd
APT will automatically add the appropriate lines to your different php.ini (/etc/php4/apache/php.ini, /etc/php4/cgi/php.ini, etc).
Example #6 These lines activate MySQL, cURL and GD into PHP
extension=mysql.so extension=curl.so extension=gd.so
You'll only have to stop/start Apache as previously to activate the modules.
Example #7 This line activates PHP 4 into Apache
# Include /etc/apache/conf.d/
This section contains notes and hints specific to installing PHP on Mac OS X. There are two slightly different versions of Mac OS X, Client and Server, our manual deals with installing PHP on both systems. Note that PHP is not available for MacOS 9 and earlier versions.
There are a few pre-packaged and pre-compiled versions of PHP for Mac OS X. This can help in setting up a standard configuration, but if you need to have a different set of features (such as a secure server, or a different database driver), you may need to build PHP and/or your web server yourself. If you are unfamiliar with building and compiling your own software, it's worth checking whether somebody has already built a packaged version of PHP with the features you need.
The following resources offer easy to install packages and precompiled binaries for PHP on Mac OS:
PHP has come standard with Macs since OS X version 10.0.0. Enabling PHP with the default web server requires uncommenting a few lines in the Apache configuration file httpd.conf whereas the CGI and/or CLI are enabled by default (easily accessible via the Terminal program).
Enabling PHP using the instructions below is meant for quickly setting up a local development environment. It's highly recommended to always upgrade PHP to the newest version. Like most live software, newer versions are created to fix bugs and add features and PHP being is no different. See the appropriate MAC OS X installation documentation for further details. The following instructions are geared towards a beginner with details provided for getting a default setup to work. All users are encouraged to compile, or install a new packaged version.
The standard installation type is using mod_php, and enabling the bundled mod_php on Mac OS X for the Apache web server (the default web server, that is accessible via System Preferences) involves the following steps:
Informacja: One way to open this is by using a Unix based text editor in the Terminal, for example nano, and because the file is owned by root we'll use the sudo command to open it (as root) so for example type the following into the Terminal Application (after, it will prompt for a password): sudo nano /etc/httpd/httpd.conf Noteworthy nano commands: ^w (search), ^o (save), and ^x (exit) where ^ represents the Ctrl key.
With a text editor, uncomment the lines (by removing the #) that look similar to the following (these two lines are often not together, locate them both in the file):
# LoadModule php5_module libexec/httpd/libphp5.so # AddModule mod_php5.c
Be sure the desired extensions will parse as PHP (examples: .php .html and .inc)
Due to the following statement already existing in httpd.conf (as of Mac Panther), once PHP is enabled the .php files will automatically parse as PHP.
<IfModule mod_php5.c> # If php is turned on, we respect .php and .phps files. AddType application/x-httpd-php .php AddType application/x-httpd-php-source .phps # Since most users will want index.php to work we # also automatically enable index.php <IfModule mod_dir.c> DirectoryIndex index.html index.php </IfModule> </IfModule>
Informacja: Before OS X 10.5 (Leopard), PHP 4 was bundled instead of PHP 5 in which case the above instructions will differ slightly by changing 5's to 4's.
The phpinfo() function will display information about PHP. Consider creating a file in the DocumentRoot with the following PHP code:
<?php phpinfo(); ?>
The CLI (or CGI in older versions) is appropriately named php and likely exists as /usr/bin/php. Open up the terminal, read the command line section of the PHP manual, and execute php -v to check the PHP version of this PHP binary. A call to phpinfo() will also reveal this information.
Untar them, and run the configure program on Apache like so.
./configure --exec-prefix=/usr \ --localstatedir=/var \ --mandir=/usr/share/man \ --libexecdir=/System/Library/Apache/Modules \ --iconsdir=/System/Library/Apache/Icons \ --includedir=/System/Library/Frameworks/Apache.framework/Versions/1.3/Headers \ --enable-shared=max \ --enable-module=most \ --target=apache
If you want the compiler to do some optimization, you may also want to add this line:
setenv OPTIM=-O2
Next, go to the PHP 4 source directory and configure it.
./configure --prefix=/usr \
--sysconfdir=/etc \
--localstatedir=/var \
--mandir=/usr/share/man \
--with-xml \
--with-apache=/src/apache_1.3.12
Now, reconfigure Apache to build in PHP 4.
./configure --exec-prefix=/usr \ --localstatedir=/var \ --mandir=/usr/share/man \ --libexecdir=/System/Library/Apache/Modules \ --iconsdir=/System/Library/Apache/Icons \ --includedir=/System/Library/Frameworks/Apache.framework/Versions/1.3/Headers \ --enable-shared=max \ --enable-module=most \ --target=apache \ --activate-module=src/modules/php4/libphp4.a
cp php.ini-dist /usr/local/bin/php.ini
or (if your don't have a local directory)
cp php.ini-dist /usr/bin/php.ini
.
The following instructions will help you install a PHP module for the Apache web server included in MacOS X using the MacOS GUI. This version includes MySQL, PostgreSQL, and iODBC database support, cURL, GD, PDFLib, LDAP, and more. These instructions are graciously provided by » Marc Liyanage.
Be sure you know what you're doing before advancing beyond this point! You can cause irreparable harm to your Apache installation otherwise.
Informacja: These instructions will only work with the original Apache web server as shipped by Apple. If you re-built or upgraded your Apache, you will have to build your own PHP module.
To install:
http://www2.entropy.ch/download/entropy-php-5.2.4-1.tar.gz
wget
http://www2.entropy.ch/download/entropy-php-5.2.4-1-apache2.tar.gz
That's all! PHP should now be up and running. You can test it by dropping a file named test.php into your Sites folder in your home directory. Into that file, write this line: <?php phpinfo() ?>.
Now open up 127.0.0.1/~your_username/test.php in your web browser. You should see a status table with information about the PHP module.
This section applies to Windows 98/Me and Windows NT/2000/XP/2003. PHP will not work on 16 bit platforms such as Windows 3.1 and sometimes we refer to the supported Windows platforms as Win32. Windows 95 is no longer supported as of PHP 4.3.0.
Informacja: Windows 98/ME/NT4 is no longer supported as of PHP 5.3.0.
Informacja: Windows 95 is no longer supported as of PHP 4.3.0.
There are two main ways to install PHP for Windows: either manually or by using the installer.
If you have Microsoft Visual Studio, you can also build PHP from the original source code.
Once you have PHP installed on your Windows system, you may also want to load various extensions for added functionality.
There are several all-in-one installers over the Internet, but none of those are endorsed by PHP.net, as we believe that using one of the official windows packages from » http://www.php.net/downloads.php is the best choice to have your system secure and optimized.
The Windows PHP installer is available from the downloads page at » http://www.php.net/downloads.php. This installs the CGI version of PHP and for IIS, PWS, and Xitami, it configures the web server as well. The installer does not include any extra external PHP extensions (php_*.dll) as you'll only find those in the Windows Zip Package and PECL downloads.
Informacja: While the Windows installer is an easy way to make PHP work, it is restricted in many aspects as, for example, the automatic setup of extensions is not supported. Use of the installer isn't the preferred method for installing PHP.
First, install your selected HTTP (web) server on your system, and make sure that it works.
Run the executable installer and follow the instructions provided by the installation wizard. Two types of installation are supported - standard, which provides sensible defaults for all the settings it can, and advanced, which asks questions as it goes along.
The installation wizard gathers enough information to set up the php.ini file, and configure certain web servers to use PHP. One of the web servers the PHP installer does not configure for is Apache, so you'll need to configure it manually.
Once the installation has completed, the installer will inform you if you need to restart your system, restart the server, or just start using PHP.
Be aware, that this setup of PHP is not secure. If you would like to have a secure PHP setup, you'd better go on the manual way, and set every option carefully. This automatically working setup gives you an instantly working PHP installation, but it is not meant to be used on online servers.
The Windows PHP installer for later versions of PHP is built using MSI technology using the Wix Toolkit (» http://wix.sourceforge.net/). It will install and configure PHP and all the built-in and PECL extensions, as well as configure many of the popular web servers such as IIS, Apache, and Xitami.
First, install your selected HTTP (web) server on your system, and make sure that it works. Then proceed with one of the following install types.
Run the MSI installer and follow the instructions provided by the installation wizard. You will be prompted to select the Web Server you wish to configure first, along with any configuration details needed.
You will then be prompted to select which features and extensions you wish to install and enable. By selecting "Will be installed on local hard drive" in the drop-down menu for each item you can trigger whether to install the feature or not. By selecting "Entire feature will be installed on local hard drive", you will be able to install all sub-features of the included feature ( for example by selecting this options for the feature "PDO" you will install all PDO Drivers ).
It is not recommended to install all extensions by default, since many other them require dependencies from outside PHP in order to function properly. Instead, use the Installation Repair Mode that can be triggered thru the 'Add/Remove Programs' control panel to enable or disable extensions and features after installation.
The installer then sets up PHP to be used in Windows and the php.ini file, and configures certain web servers to use PHP. The installer will currently configure IIS, Apache, Xitami, and Sambar Server; if you are using a different web server you'll need to configure it manually.
The installer also supports a silent mode, which is helpful for Systems Administrators to deploy PHP easily. To use silent mode:
msiexec.exe /i php-VERSION-win32-install.msi /q
You can control the install directory by passing it as a parameter to the install. For example, to install to e:\php:
msiexec.exe /i php-VERSION-win32-install.msi /q INSTALLDIR=e:\php
You can also specify what features to install. For example, to install the mysqli extension and the CGI executable:
msiexec.exe /i php-VERSION-win32-install.msi /q ADDLOCAL=cgi,ext_php_mysqli
The current list of Features to install is as follows:
MainExecutable - php.exe executable ScriptExecutable - php-win.exe executable ext_php_* - the various extensions ( for example: ext_php_mysql for MySQL ) apache13 - Apache 1.3 module apache20 - Apache 2.0 module apache22 - Apache 2,2 module apacheCGI - Apache CGI executable iis4ISAPI - IIS ISAPI module iis4CGI - IIS CGI executable iis4FastCGI - IIS CGI executable NSAPI - Sun/iPlanet/Netscape server module netserve - NetServe Web Server CGI executable Xitami - Xitami CGI executable Sambar - Sambar Server ISAPI module CGI - php-cgi.exe executable PEAR - PEAR installer Manual - PHP Manual in CHM Format
For more information on installing MSI installers from the command line, visit » http://msdn.microsoft.com/en-us/library/aa367988.aspx
To upgrade, run the installer either graphically or from the command line as normal. The installer will read your current install options, remove your old installation, and reinstall PHP with the same options as before. It is recommended that you use this method of keeping PHP updated instead of manually replacing the files in the installation directory.
This install guide will help you manually install and configure PHP with a web server on Microsoft Windows. To get started you'll need to download the zip binary distribution from the downloads page at » http://www.php.net/downloads.php.
Although there are many all-in-one installation kits, and we also distribute a PHP installer for Microsoft Windows, we recommend you take the time to setup PHP yourself as this will provide you with a better understanding of the system, and enables you to install PHP extensions easily when needed.
Informacja: Upgrading from a previous PHP version
Previous editions of the manual suggest moving various ini and DLL files into your SYSTEM (i.e. C:\WINDOWS) folder and while this simplifies the installation procedure it makes upgrading difficult. We advise you remove all of these files (like php.ini and PHP related DLLs from the Windows SYSTEM folder) before moving on with a new PHP installation. Be sure to backup these files as you might break the entire system. The old php.ini might be useful in setting up the new PHP as well. And as you'll soon learn, the preferred method for installing PHP is to keep all PHP related files in one directory and have this directory available to your systems PATH.
Informacja: MDAC requirements
If you use Microsoft Windows 98/NT4 download the latest version of the Microsoft Data Access Components (MDAC) for your platform. MDAC is available at » http://msdn.microsoft.com/data/. This requirement exists because ODBC is built into the distributed Windows binaries.
The following steps should be completed on all installations before any server specific instructions are performed:
Extract the distribution file into a directory of your choice. If you are installing PHP 4, extract to C:\, as the zip file expands to a foldername like php-4.3.7-Win32. If you are installing PHP 5, extract to C:\php as the zip file doesn't expand as in PHP 4. You may choose a different location but do not have spaces in the path (like C:\Program Files\PHP) as some web servers will crash if you do.
The directory structure extracted from the zip is different for PHP versions 4 and 5 and look like as follows:
Example #1 PHP 4 package structure
c:\php | +--cli | | | |-php.exe -- CLI executable - ONLY for command line scripting | +--dlls -- support DLLs required by some extensions | | | |-expat.dll | | | |-fdftk.dll | | | |-... | +--extensions -- extension DLLs for PHP | | | |-php_bz2.dll | | | |-php_cpdf.dll | | | |-... | +--mibs -- support files for SNMP | +--openssl -- support files for Openssl | +--pdf-related -- support files for PDF | +--sapi -- SAPI (server module support) DLLs | | | |-php4apache.dll | | | |-php4apache2.dll | | | |-... | +--PEAR -- initial copy of PEAR | | |-go-pear.bat -- PEAR setup script | |-... | |-php.exe -- CGI executable | |-... | |-php.ini-dist -- default php.ini settings | |-php.ini-recommended -- recommended php.ini settings | |-php4ts.dll -- core PHP DLL | |-...
Or:
Example #2 PHP 5 package structure
c:\php | +--dev | | | |-php5ts.lib | +--ext -- extension DLLs for PHP | | | |-php_bz2.dll | | | |-php_cpdf.dll | | | |-... | +--extras | | | +--mibs -- support files for SNMP | | | +--openssl -- support files for Openssl | | | +--pdf-related -- support files for PDF | | | |-mime.magic | +--pear -- initial copy of PEAR | | |-go-pear.bat -- PEAR setup script | |-fdftk.dll | |-... | |-php-cgi.exe -- CGI executable | |-php-win.exe -- executes scripts without an opened command prompt | |-php.exe -- CLI executable - ONLY for command line scripting | |-... | |-php.ini-dist -- default php.ini settings | |-php.ini-recommended -- recommended php.ini settings | |-php5activescript.dll | |-php5apache.dll | |-php5apache2.dll | |-... | |-php5ts.dll -- core PHP DLL | |-...
Notice the differences and similarities. Both PHP 4 and PHP 5 have a CGI executable, a CLI executable, and server modules, but they are located in different folders and/or have different names. While PHP 4 packages have the server modules in the sapi folder, PHP 5 distributions have no such directory and instead they're in the PHP folder root. The supporting DLLs for the PHP 5 extensions are also not in a seperate directory.
Informacja: In PHP 4, you should move all files located in the dll and sapi folders to the main folder (e.g. C:\php).
Here is a list of server modules shipped with PHP 4 and PHP 5:
sapi/php4activescript.dll (php5activescript.dll) - ActiveScript engine, allowing you to embed PHP in your Windows applications.
sapi/php4apache.dll (php5apache.dll) - Apache 1.3.x module.
sapi/php4apache2.dll (php5apache2.dll) - Apache 2.0.x module.
sapi/php5apache2_2.dll - Apache 2.2.x module.
sapi/php4isapi.dll (php5isapi.dll) - ISAPI Module for ISAPI compliant web servers like IIS 4.0/PWS 4.0 or newer.
sapi/php4nsapi.dll (php5nsapi.dll) - Sun/iPlanet/Netscape server module.
sapi/php4pi3web.dll (no equivalent in PHP 5) - Pi3Web server module.
Server modules provide significantly better performance and additional functionality compared to the CGI binary. The CLI version is designed to let you use PHP for command line scripting. More information about CLI is available in the chapter about using PHP from the command line.
The SAPI modules have been significantly improved as of the 4.1 release, however, in older systems you may encounter server errors or other server modules failing, such as ASP.
The CGI and CLI binaries, and the web server modules all require the php4ts.dll (php5ts.dll) file to be available to them. You have to make sure that this file can be found by your PHP installation. The search order for this DLL is as follows:
The same directory from where php.exe is called, or in case you use a SAPI module, the web server's directory (e.g. C:\Program Files\Apache Group\Apache2\bin).
Any directory in your Windows PATH environment variable.
To make php4ts.dll / php5ts.dll available you have three options: copy the file to the Windows system directory, copy the file to the web server's directory, or add your PHP directory, C:\php to the PATH. For better maintenance, we advise you to follow the last option, add C:\php to the PATH, because it will be simpler to upgrade PHP in the future. Read more about how to add your PHP directory to PATH in the corresponding FAQ entry (and then don't forget to restart the computer - logoff isn't enough).
The next step is to set up a valid configuration file for PHP, php.ini. There are two ini files distributed in the zip file, php.ini-dist and php.ini-recommended. We advise you to use php.ini-recommended, because we optimized the default settings in this file for performance, and security. Read this well documented file carefully because it has changes from php.ini-dist that will drastically affect your setup. Some examples are display_errors being off and magic_quotes_gpc being off. In addition to reading these, study the ini settings and set every element manually yourself. If you would like to achieve the best security, then this is the way for you, although PHP works fine with these default ini files. Copy your chosen ini-file to a directory that PHP is able to find and rename it to php.ini. PHP searches for php.ini in the locations described in The configuration file section.
If you are running Apache 2, the simpler option is to use the PHPIniDir directive (read the installation on Apache 2 page), otherwise your best option is to set the PHPRC environment variable. This process is explained in the following FAQ entry.
Informacja: If you're using NTFS on Windows NT, 2000, XP or 2003, make sure that the user running the web server has read permissions to your php.ini (e.g. make it readable by Everyone).
The following steps are optional:
Edit your new php.ini file. If you plan to use OmniHTTPd, do not follow the next step. Set the doc_root to point to your web servers document_root. For example:
doc_root = c:\inetpub\wwwroot // for IIS/PWS doc_root = c:\apache\htdocs // for Apache
PHP is now setup on your system. The next step is to choose a web server, and enable it to run PHP. Choose a web server from the table of contents.
This section contains notes specific to the ActiveScript installation.
ActiveScript is a Windows only SAPI that enables you to use PHP script in any ActiveScript compliant host, like Windows Script Host, ASP/ASP.NET, Windows Script Components or Microsoft Scriptlet control.
As of PHP 5.0.1, ActiveScript has been moved to the » PECL repository. DLL z tym rozszerzeniem PECL można pobrać zarówno ze strony » PHP Downloads lub z » http://pecl4win.php.net/
Informacja: You should read the manual installation steps first!
After installing PHP, you should download the ActiveScript DLL (php5activescript.dll) and place it in the main PHP folder (e.g. C:\php).
After having all the files needed, you must register the DLL on your system. To achieve this, open a Command Prompt window (located in the Start Menu). Then go to your PHP directory by typing something like cd C:\php. To register the DLL just type regsvr32 php5activescript.dll.
To test if ActiveScript is working, create a new file, named test.wsf (the extension is very important) and type:
<job id="test">
<script language="PHPScript">
$WScript->Echo("Hello World!");
</script>
</job>
Informacja: In PHP 4, the engine was named 'ActivePHP', so if you are using PHP 4, you should replace 'PHPScript' with 'ActivePHP' in the above example.
Informacja: ActiveScript doesn't use the default php.ini file. Instead, it will look only in the same directory as the .exe that caused it to load. You should create php-activescript.ini and place it in that folder, if you wish to load extensions, etc.
This section contains notes and hints specific to IIS (Microsoft Internet Information Server).
Używając instalacji CGI, serwer jest podatny na wiele potencjalnych ataków. Sposoby obrony przed nimi zostały opisane w rozdziale o bezpieczeństwie instalacji CGI.
PHP may be installed as a CGI binary, or with the ISAPI module. In either case, you need to start the Microsoft Management Console (may appear as 'Internet Services Manager', either in your Windows NT 4.0 Option Pack branch or the Control Panel=>Administrative Tools under Windows 2000/XP). Then right click on your Web server node (this will most probably appear as 'Default Web Server'), and select 'Properties'.
If you want to use the CGI binary, do the following:
To use the ISAPI module, do the following:
With IIS 6 (2003 Server), open up the IIS Manager, go to Web Service Extensions, choose "Add a new Web service extension", enter in a name such as PHP, choose the Add button and for the value browse to either the ISAPI file (php4isapi.dll or php5isapi.dll) or CGI (php.exe or php-cgi.exe) then check "Set extension status to Allowed" and click OK.
In order to use index.php as a default content page, do the following: From within the Documents tab, choose Add. Type in index.php and click OK. Adjust the order by choosing Move Up or Move Down. This is similar to setting DirectoryIndex with Apache.
The steps above must be repeated for each extension that is to be associated with PHP scripts. .php is the most common although .php3 may be required for legacy applications.
If you experience 100% CPU usage after some time, turn off the IIS setting Cache ISAPI Application.
PWS 4 does not support ISAPI, only PHP CGI should be used.
The recommended method for configuring these servers is to use the REG file included with the distribution (pws-php4cgi.reg in the SAPI folder for PHP 4, or pws-php5cgi.reg in the main folder for PHP 5). You may want to edit this file and make sure the extensions and PHP install directories match your configuration. Or you can follow the steps below to do it manually.
These steps involve working directly with the Windows registry. One error here can leave your system in an unstable state. We highly recommend that you back up your registry first. The PHP Development team will not be held responsible if you damage your registry.
The following steps do not affect the web server installation and only apply if you want your PHP scripts to be executed when they are run from the command line (ex. run C:\myscripts\test.php) or by double clicking on them in a directory viewer window. You may wish to skip these steps as you might prefer the PHP files to load into a text editor when you double click on them.
PWS and IIS 3 users now have a fully operational system. IIS 3 users can use a nifty » tool from Steven Genusa to configure their script maps.
This section contains notes and hints specific to Apache 1.3.x installs of PHP on Microsoft Windows systems. There are also instructions and notes for Apache 2 on a separate page.
Informacja: Please read the manual installation steps first!
There are two ways to set up PHP to work with Apache 1.3.x on Windows. One is to use the CGI binary (php.exe for PHP 4 and php-cgi.exe for PHP 5), the other is to use the Apache Module DLL. In either case you need to edit your httpd.conf to configure Apache to work with PHP, and then restart the server.
It is worth noting here that now the SAPI module has been made more stable under Windows, we recommend it's use above the CGI binary, since it is more transparent and secure.
Although there can be a few variations of configuring PHP under Apache, these are simple enough to be used by the newcomer. Please consult the Apache Documentation for further configuration directives.
After changing the configuration file, remember to restart the server, for example, NET STOP APACHE followed by NET START APACHE, if you run Apache as a Windows Service, or use your regular shortcuts.
Informacja: Nalezy pamiętać, że podając ścieżki w plikach konfiguracyjnych Apache w systemie Windows, wszystkie znaki backslash takie jak na przykład w ścieżce c:\directory\file.ext muszą być zamienione na znaki slash, na przykład c:/directory/file.ext. Zamykające znaki slash mogą być także niezbędne dla katalogów.
You should add the following lines to your Apache httpd.conf file:
Example #1 PHP as an Apache 1.3.x module
This assumes PHP is installed to c:\php. Adjust the path if this is not the case.
For PHP 4:
# Add to the end of the LoadModule section # Don't forget to copy this file from the sapi directory! LoadModule php4_module "C:/php/php4apache.dll" # Add to the end of the AddModule section AddModule mod_php4.c
For PHP 5:
# Add to the end of the LoadModule section LoadModule php5_module "C:/php/php5apache.dll" # Add to the end of the AddModule section AddModule mod_php5.c
For both:
# Add this line inside the <IfModule mod_mime.c> conditional brace AddType application/x-httpd-php .php # For syntax highlighted .phps files, also add AddType application/x-httpd-php-source .phps
If you unzipped the PHP package to C:\php\ as described in the Manual Installation Steps section, you need to insert these lines to your Apache configuration file to set up the CGI binary:
Example #2 PHP and Apache 1.3.x as CGI
ScriptAlias /php/ "c:/php/" AddType application/x-httpd-php .php # For PHP 4 Action application/x-httpd-php "/php/php.exe" # For PHP 5 Action application/x-httpd-php "/php/php-cgi.exe" # specify the directory where php.ini is SetEnv PHPRC C:/php
Note that the second line in the list above can be found in the actual versions of httpd.conf, but it is commented out. Remember also to substitute the c:/php/ for your actual path to PHP.
Używając instalacji CGI, serwer jest podatny na wiele potencjalnych ataków. Sposoby obrony przed nimi zostały opisane w rozdziale o bezpieczeństwie instalacji CGI.
If you would like to present PHP source files syntax highlighted, there is no such convenient option as with the module version of PHP. If you chose to configure Apache to use PHP as a CGI binary, you will need to use the highlight_file() function. To do this simply create a PHP script file and add this code: <?php highlight_file('some_php_script.php'); ?>.
This section contains notes and hints specific to Apache 2.0.x installs of PHP on Microsoft Windows systems. We also have instructions and notes for Apache 1.3.x users on a separate page.
Informacja: You should read the manual installation steps first!
Informacja: Apache 2.2.x Support
Users of Apache 2.2.x may use the documentation below except the appropriate DLL file is named php5apache2_2.dll and it only exists as of PHP 5.2.0. See also » http://snaps.php.net/
Nie zalecamy korzystania z wątkowanego MPM na produkcyjnych serwerach Apache2. Zamiast niego wskazane jest używanie preforkowanego MPM, lub używanie Apache1. Wyjaśnienie powodów można znaleźć w odpowiednim punkcie FAQ, dotyczącym używania Apache2 z wątkowanym MPM
You are highly encouraged to take a look at the » Apache Documentation to get a basic understanding of the Apache 2.0.x Server. Also consider to read the » Windows specific notes for Apache 2.0.x before reading on here.
Informacja: PHP and Apache 2.0.x compatibility notes
The following versions of PHP are known to work with the most recent version of Apache 2.0.x:These versions of PHP are compatible to Apache 2.0.40 and later.
- PHP 4.3.0 or later available at » http://www.php.net/downloads.php.
- the latest stable development version. Get the source code » http://snaps.php.net/php5-latest.tar.gz or download binaries for Windows » http://snaps.php.net/win32/php5-win32-latest.zip.
- a prerelease version downloadable from » http://qa.php.net/.
- you have always the option to obtain PHP through » anonymous CVS.
Apache 2.0 SAPI-support started with PHP 4.2.0. PHP 4.2.3 works with Apache 2.0.39, don't use any other version of Apache with PHP 4.2.3. However, the recommended setup is to use PHP 4.3.0 or later with the most recent version of Apache2.
All mentioned versions of PHP will work still with Apache 1.3.x.
Apache 2.0.x is designed to run on Windows NT 4.0, Windows 2000 or Windows XP. At this time, support for Windows 9x is incomplete. Apache 2.0.x is not expected to work on those platforms at this time.
Download the most recent version of » Apache 2.0.x and a fitting PHP version. Follow the Manual Installation Steps and come back to go on with the integration of PHP and Apache.
There are two ways to set up PHP to work with Apache 2.0.x on Windows. One is to use the CGI binary the other is to use the Apache module DLL. In either case you need to edit your httpd.conf to configure Apache to work with PHP and then restart the server.
Informacja: Nalezy pamiętać, że podając ścieżki w plikach konfiguracyjnych Apache w systemie Windows, wszystkie znaki backslash takie jak na przykład w ścieżce c:\directory\file.ext muszą być zamienione na znaki slash, na przykład c:/directory/file.ext. Zamykające znaki slash mogą być także niezbędne dla katalogów.
You need to insert these three lines to your Apache httpd.conf configuration file to set up the CGI binary:
Example #1 PHP and Apache 2.0 as CGI
ScriptAlias /php/ "c:/php/" AddType application/x-httpd-php .php # For PHP 4 Action application/x-httpd-php "/php/php.exe" # For PHP 5 Action application/x-httpd-php "/php/php-cgi.exe"
Używając instalacji CGI, serwer jest podatny na wiele potencjalnych ataków. Sposoby obrony przed nimi zostały opisane w rozdziale o bezpieczeństwie instalacji CGI.
You need to insert these two lines to your Apache httpd.conf configuration file to set up the PHP module for Apache 2.0:
Example #2 PHP and Apache 2.0 as Module
# For PHP 4 do something like this: LoadModule php4_module "c:/php/php4apache2.dll" # Don't forget to copy the php4apache2.dll file from the sapi directory! AddType application/x-httpd-php .php # For PHP 5 do something like this: LoadModule php5_module "c:/php/php5apache2.dll" AddType application/x-httpd-php .php # configure the path to php.ini PHPIniDir "C:/php"
Informacja: Remember to substitute your actual path to PHP for the c:/php/ in the above examples. Take care to use either php4apache2.dll or php5apache2.dll in your LoadModule directive and not php4apache.dll or php5apache.dll as the latter ones are designed to run with Apache 1.3.x.
Informacja: If you want to use content negotiation, read related FAQ.
Don't mix up your installation with DLL files from different PHP versions. You have the only choice to use the DLL's and extensions that ship with your downloaded PHP version.
This section contains notes and hints specific to Sun Java System Web Server, Sun ONE Web Server, iPlanet and Netscape server installs of PHP on Windows.
From PHP 4.3.3 on you can use PHP scripts with the NSAPI module to generate custom directory listings and error pages. Additional functions for Apache compatibility are also available. For support in current web servers read the note about subrequests.
To install PHP as a CGI handler, do the following:
Make a file association from the command line. Type the following two lines:
assoc .php=PHPScript ftype PHPScript=c:\php\php.exe %1 %*
More details about setting up PHP as a CGI executable can be found here: » http://benoit.noss.free.fr/php/install-php.html
To install PHP with NSAPI, do the following:
Make a file association from the command line. Type the following two lines:
assoc .php=PHPScript ftype PHPScript=c:\php\php.exe %1 %*
Edit magnus.conf (for servers >= 6) or obj.conf (for servers < 6) and add the following: You should place the lines after mime types init.
Init fn="load-modules" funcs="php4_init,php4_execute,php4_auth_trans" shlib="c:/php/sapi/php4nsapi.dll" Init fn="php4_init" LateInit="yes" errorString="Failed to initialise PHP!" [php_ini="c:/path/to/php.ini"]
Configure the default object in obj.conf (for virtual server classes [Sun Web Server 6.0+] in their vserver.obj.conf): In the <Object name="default"> section, place this line necessarily after all 'ObjectType' and before all 'AddLog' lines:
Service fn="php4_execute" type="magnus-internal/x-httpd-php" [inikey=value inikey=value ...]
This is only needed if you want to configure a directory that only consists of PHP scripts (same like a cgi-bin directory):
<Object name="x-httpd-php"> ObjectType fn="force-type" type="magnus-internal/x-httpd-php" Service fn=php4_execute [inikey=value inikey=value ...] </Object>
Informacja: More details about setting up PHP as an NSAPI filter can be found here: » http://benoit.noss.free.fr/php/install-php4.html
Informacja: The stacksize that PHP uses depends on the configuration of the web server. If you get crashes with very large PHP scripts, it is recommended to raise it with the Admin Server (in the section "MAGNUS EDITOR").
Important when writing PHP scripts is the fact that Sun JSWS/Sun ONE WS/iPlanet/Netscape is a multithreaded web server. Because of that all requests are running in the same process space (the space of the web server itself) and this space has only one environment. If you want to get CGI variables like PATH_INFO, HTTP_HOST etc. it is not the correct way to try this in the old PHP way with getenv() or a similar way (register globals to environment, $_ENV). You would only get the environment of the running web server without any valid CGI variables!
Informacja: Why are there (invalid) CGI variables in the environment?
Answer: This is because you started the web server process from the admin server which runs the startup script of the web server, you wanted to start, as a CGI script (a CGI script inside of the admin server!). This is why the environment of the started web server has some CGI environment variables in it. You can test this by starting the web server not from the administration server. Use the command line as root user and start it manually - you will see there are no CGI-like environment variables.
Simply change your scripts to get CGI variables in the correct way for PHP 4.x by using the superglobal $_SERVER. If you have older scripts which use $HTTP_HOST, etc., you should turn on register_globals in php.ini and change the variable order too (important: remove "E" from it, because you do not need the environment here):
variables_order = "GPCS" register_globals = On
You can use PHP to generate the error pages for "404 Not Found" or similar. Add the following line to the object in obj.conf for every error page you want to overwrite:
Error fn="php4_execute" code=XXX script="/path/to/script.php" [inikey=value inikey=value...]
Another possibility is to generate self-made directory listings. Just create a PHP script which displays a directory listing and replace the corresponding default Service line for type="magnus-internal/directory" in obj.conf with the following:
Service fn="php4_execute" type="magnus-internal/directory" script="/path/to/script.php" [inikey=value inikey=value...]
The NSAPI module now supports the nsapi_virtual() function (alias: virtual()) to make subrequests on the web server and insert the result in the web page. The problem is, that this function uses some undocumented features from the NSAPI library.
Under Unix this is not a problem, because the module automatically looks for the needed functions and uses them if available. If not, nsapi_virtual() is disabled.
Under Windows limitations in the DLL handling need the use of a automatic detection of the most recent ns-httpdXX.dll file. This is tested for servers till version 6.1. If a newer version of the Sun server is used, the detection fails and nsapi_virtual() is disabled.
If this is the case, try the following: Add the following parameter to php4_init in magnus.conf/obj.conf:
Init fn=php4_init ... server_lib="ns-httpdXX.dll"
You can check the status by using the phpinfo() function.
Informacja: But be warned: Support for nsapi_virtual() is EXPERIMENTAL!!!
This section contains notes and hints specific to » OmniHTTPd on Windows.
Informacja: You should read the manual installation steps first!
Używając instalacji CGI, serwer jest podatny na wiele potencjalnych ataków. Sposoby obrony przed nimi zostały opisane w rozdziale o bezpieczeństwie instalacji CGI.
You need to complete the following steps to make PHP work with OmniHTTPd. This is a CGI executable setup. SAPI is supported by OmniHTTPd, but some tests have shown that it is not so stable to use PHP as an ISAPI module.
Informacja: Important for CGI users
Read the faq on cgi.force_redirect for important details. This directive needs to be set to 0.
Install OmniHTTPd server.
Right click on the blue OmniHTTPd icon in the system tray and select Properties
Click on Web Server Global Settings
On the 'External' tab, enter: virtual = .php | actual = c:\php\php.exe (use php-cgi.exe if installing PHP 5), and use the Add button.
On the Mime tab, enter: virtual = wwwserver/stdcgi | actual = .php, and use the Add button.
Click OK
Repeat steps 2 - 6 for each extension you want to associate with PHP.
Informacja: Some OmniHTTPd packages come with built in PHP support. You can choose at setup time to do a custom setup, and uncheck the PHP component. We recommend you to use the latest PHP binaries. Some OmniHTTPd servers come with PHP 4 beta distributions, so you should choose not to set up the built in support, but install your own. If the server is already on your machine, use the Replace button in Step 4 and 5 to set the new, correct information.
This section contains notes and hints specific to the » Sambar Server for Windows.
Informacja: You should read the manual installation steps first!
This list describes how to set up the ISAPI module to work with the Sambar server on Windows.
Find the file called mappings.ini (in the config directory) in the Sambar install directory.
Open mappings.ini and add the following line under [ISAPI]:
Example #1 ISAPI configuration of Sambar
#for PHP 4 *.php = c:\php\php4isapi.dll #for PHP 5 *.php = c:\php\php5isapi.dll
(This line assumes that PHP was installed in c:\php.)
Now restart the Sambar server for the changes to take effect.
Informacja: If you intend to use PHP to communicate with resources which are held on a different computer on your network, then you will need to alter the account used by the Sambar Server Service. The default account used for the Sambar Server Service is LocalSystem which will not have access to remote resources. The account can be amended by using the Services option from within the Windows Control Panel Administation Tools.
This section contains notes and hints specific to » Xitami on Windows.
Informacja: You should read the manual installation steps first!
This list describes how to set up the PHP CGI binary to work with Xitami on Windows.
Informacja: Important for CGI users
Read the faq on cgi.force_redirect for important details. This directive needs to be set to 0. If you want to use $_SERVER['PHP_SELF'] you have to enable the cgi.fix_pathinfo directive.
Używając instalacji CGI, serwer jest podatny na wiele potencjalnych ataków. Sposoby obrony przed nimi zostały opisane w rozdziale o bezpieczeństwie instalacji CGI.
Make sure the web server is running, and point your browser to xitamis admin console (usually http://127.0.0.1/admin), and click on Configuration.
Navigate to the Filters, and put the extension which PHP should parse (i.e. .php) into the field File extensions (.xxx).
In Filter command or script put the path and name of your PHP CGI executable i.e. C:\php\php.exe for PHP 4, or C:\php\php-cgi.exe for PHP 5.
Press the 'Save' icon.
Restart the server to reflect changes.
This chapter teaches how to compile PHP from sources on windows, using Microsoft's tools. To compile PHP with cygwin, please refer to Installation on Unix systems.
This step-by-step quick-start guide was written in March of 2008, running Windows XP Service Pack 2 with all the latest updates and building PHP 5.2.5 and PHP 5.3. Experiences using different tools may differ.
Download and install:
+-C:\work | +-bindlib_w32 | | +-Debug | | | +-resolv.lib | | | +-... | | +-... | +-win32build | | +-bin | | +-include | | +-lib | +-php-5.2.5 | | +-build | | +-win32 | | +-...
C:\Program Files\Microsoft Visual Studio 9.0\VC> set "PATH=C:\work\win32build\bin;%PATH%" C:\Program Files\Microsoft Visual Studio 9.0\VC>
To compile and build PHP you need a Microsoft Development Environment. The following environments are supported:
While VC6 (Microsoft Visual C++ 6.0) is used to perform official Windows builds, it can no longer be downloaded from Microsoft's website. New users seeking to build PHP for free must use Microsoft Visual C++ 2005 Express Edition and its auxiliary components.
Informacja: Combined, these components are very large and will require over one gigabyte of disk space.
Setting up Microsoft Visual C++ 2005 Express is rather involved, and requires the installation of three separate packages and various compatibility changes. Be sure to keep track of the paths in which these programs are installed into. Download and install the following programs:
There are a few post-installation steps:
Finally, when using MSVC 2005 Express from the command line, several environment variables must be set up. vsvars32.bat usually found in C:\Program Files\Microsoft Visual Studio 8\Common7\Tools (search for the file if otherwise) contains these declarations. The PATH, INCLUDE and LIB environment variables need the corresponding bin, include and lib directories of the two newly installed SDKs added to them.
Informacja: The .NET SDK paths may already be present in the vsvars32.bat file, as this SDK installs itself into the same directory as Microsoft Visual C++ 2005 Express.
To extract the downloaded files you will also need a ZIP extraction utility. Windows XP and newer already include this functionality built-in.
Before you get started, you have to download:
Finally, you are going to need the source to PHP itself. You can get the latest development version using » anonymous CVS, a » snapshot or the most recent released » source tarball.
After downloading the required packages you have to extract them in a proper place:
Following this steps your directory structure looks like this:
+--C:\work | | | +--bindlib_w32 | | | | | +--arpa | | | | | +--conf | | | | | +--... | | | +--php-5.x.x | | | | | +--build | | | | | +--... | | | | | +--win32 | | | | | +--... | | | +--win32build | | | | | +--bin | | | | | +--include | | | | | +--lib
If you aren't using » Cygwin, you must also create the directories C:\usr\local\lib and then copy bison.simple from C:\work\win32build\bin to C:\usr\local\lib.
Informacja: If you want to use PEAR and the comfortable command line installer, the CLI-SAPI is mandatory. For more information about PEAR and the installer read the documentation at the » PEAR website.
You must build the resolv.lib library. Decide whether you want to have debug symbols available (bindlib - Win32 Debug) or not (bindlib - Win32 Release), but please remember the choice you made, because the debug build will only link with PHP when it is also built in debug mode. Build the appropriate configuration:
At this point, you should have a usable resolv.lib in either your C:\work\bindlib_w32\Debug or Release subdirectories. Copy this file into your C:\work\win32build\lib directory over the file by the same name found in there.
This chapter explains how to compile PHP >=5 using the new build system, which is CLI-based and very similar with the main PHP's Unix build system.
Informacja: This build system isn't available in PHP 4. Please refer to Building from source instead.
Before starting, be sure you have read Building from source and you have built all needed libraries, like » Libxml or » ICU (needed for PHP >= 6).
First you should open a Visual Studio Command Prompt, which should be available under the Start menu. A regular Command Prompt window shouldn't work, as probably it doesn't have the necessary environment variables set. Then type something like cd C:\work\php-5.x.x to enter in the PHP source dir. Now you are ready to start configuring PHP.
The second step is running the buildconf batch file to make the configure script, by scanning the folder for config.w32 files. By default this command will also search in the following directories: pecl; ..\pecl; pecl\rpc; ..\pecl\rpc. Since PHP 5.1.0, you can change this behaviour by using the --add-modules-dir argument (e.g. cscript /nologo win32/build/buildconf.js --add-modules-dir=../php-gtk2 --add-modules-dir=../pecl).
The third step is configuring. To view the list of the available configuration options type cscript /nologo configure.js --help. After choosing the options that you will enable/disable, type something like: cscript /nologo configure.js --disable-foo --enable-fun-ext. Using --enable-foo=shared will attempt to build the 'foo' extension as a shared, dynamically loadable module.
The last step is compiling. To achieve this just issue the command nmake. The generated files (e.g. .exe and .dll) will be placed in either Release_TS or Debug_TS directories (if built with Thread safety), or in the Release or Debug directories otherwise.
Optionally you may also run PHP's test suite, by typing nmake test. If you want to run just a specific test, you may use the 'TESTS' variable (e.g. nmake /D TESTS=ext/sqlite/tests test - will only run sqlite's tests). To delete the files that were created during the compilation, you can use the nmake clean command.
A very useful configure option to build snapshots is --enable-snapshot-build, which add a new compiling mode (nmake build-snap). This tries to build every extension available (as shared, by default), but it will ignore build errors in individual extensions or SAPI.
Compiling PHP using the DSW files isn't supported as of PHP 5, as a much more flexible system was made available. Anyway, you can still use them, but keep in mind that they are not maintained very often, so you can have compiling problems. To compile PHP 4 for windows, this is the only available way though.
The first step is to configure MVC++ to prepare for compiling. Launch Microsoft Visual C++, and from the menu select Tools => Options. In the dialog, select the directories tab. Sequentially change the dropdown to Executables, Includes, and Library files. Your entries should look like this:
The best way to get started is to build the CGI version:
It is possible to do minor customization to the build process by editing the main/config.win32.h file. For example you can change the default location of php.ini, the built-in extensions, and the default location for your extensions.
Next you may want to build the CLI version which is designed to use PHP from the command line. The steps are the same as for building the CGI version, except you have to select the php4ts_cli - Win32 Debug_TS or php4ts_cli - Win32 Release_TS project file. After a successful compiling run you will find the php.exe in either the directory Release_TS\cli\ or Debug_TS\cli\.
In order to build the SAPI module (php4isapi.dll) for integrating PHP with Microsoft IIS, set your active configuration to php4isapi-whatever-config and build the desired dll.
After installing PHP and a web server on Windows, you will probably want to install some extensions for added functionality. You can choose which extensions you would like to load when PHP starts by modifying your php.ini. You can also load a module dynamically in your script using dl().
The DLLs for PHP extensions are prefixed with php_.
Many extensions are built into the Windows version of PHP. This means additional DLL files, and the extension directive, are not used to load these extensions. The Windows PHP Extensions table lists extensions that require, or used to require, additional PHP DLL files. Here's a list of built in extensions:
In PHP 4 (updated PHP 4.3.11): BCMath, Caledar, COM, Ctype, FTP, MySQL, ODBC, Overload, PCRE, Session, Tokenizer, WDDX, XML i Zlib
In PHP 5 (updated PHP 5.0.4), the following changes exist. Built in: DOM, LibXML, Iconv, SimpleXML, SPL i SQLite. And the following are no longer built in: MySQL and Overload.
The default location PHP searches for extensions is C:\php4\extensions in PHP 4 and C:\php5 in PHP 5. To change this setting to reflect your setup of PHP edit your php.ini file:
You will need to change the extension_dir setting to point to the directory where your extensions lives, or where you have placed your php_*.dll files. For example:
extension_dir = C:\php\extensions
Enable the extension(s) in php.ini you want to use by uncommenting the extension=php_*.dll lines in php.ini. This is done by deleting the leading ; from the extension you want to load.
Example #1 Enable Bzip2 extension for PHP-Windows
// change the following line from ... ;extension=php_bz2.dll // ... to extension=php_bz2.dll
Some of the extensions need extra DLLs to work. Couple of them can be found in the distribution package, in the C:\php\dlls\ folder in PHP 4 or in the main folder in PHP 5, but some, for example Oracle (php_oci8.dll) require DLLs which are not bundled with the distribution package. If you are installing PHP 4, copy the bundled DLLs from C:\php\dlls folder to the main C:\php folder. Don't forget to include C:\php in the system PATH (this process is explained in a separate FAQ entry).
Some of these DLLs are not bundled with the PHP distribution. See each extensions documentation page for details. Also, read the manual section titled Installation of PECL extensions for details on PECL. An increasingly large number of PHP extensions are found in PECL, and these extensions require a separate download.
Informacja: If you are running a server module version of PHP remember to restart your web server to reflect your changes to php.ini.
The following table describes some of the extensions available and required additional dlls.
| Extension | Description | Notes |
|---|---|---|
| php_bz2.dll | bzip2 compression functions | None |
| php_calendar.dll | Calendar conversion functions | Built in since PHP 4.0.3 |
| php_crack.dll | Crack functions | None |
| php_ctype.dll | ctype family functions | Built in since PHP 4.3.0 |
| php_curl.dll | CURL, Client URL library functions | Requires: libeay32.dll, ssleay32.dll (bundled) |
| php_dba.dll | DBA: DataBase (dbm-style) Abstraction layer functions | None |
| php_dbase.dll | dBase functions | None |
| php_dbx.dll | dbx functions | |
| php_domxml.dll | DOM XML functions | PHP <= 4.2.0 requires: libxml2.dll (bundled) PHP >= 4.3.0 requires: iconv.dll (bundled) |
| php_dotnet.dll | .NET functions | PHP <= 4.1.1 |
| php_exif.dll | EXIF functions | php_mbstring.dll. And, php_exif.dll must be loaded after php_mbstring.dll in php.ini. |
| php_fbsql.dll | FrontBase functions | PHP <= 4.2.0 |
| php_fdf.dll | FDF: Forms Data Format functions. | Requires: fdftk.dll (bundled) |
| php_filepro.dll | filePro functions | Read-only access |
| php_ftp.dll | FTP functions | Built-in since PHP 4.0.3 |
| php_gd.dll | GD library image functions | Removed in PHP 4.3.2. Also note that truecolor functions are not available in GD1, instead, use php_gd2.dll. |
| php_gd2.dll | GD library image functions | GD2 |
| php_gettext.dll | Gettext functions | PHP <= 4.2.0 requires gnu_gettext.dll (bundled), PHP >= 4.2.3 requires libintl-1.dll, iconv.dll (bundled). |
| php_hyperwave.dll | HyperWave functions | None |
| php_iconv.dll | ICONV characterset conversion | Requires: iconv-1.3.dll (bundled), PHP >=4.2.1 iconv.dll |
| php_ifx.dll | Informix functions | Requires: Informix libraries |
| php_iisfunc.dll | IIS management functions | None |
| php_imap.dll | IMAP POP3 and NNTP functions | None |
| php_ingres.dll | Ingres II functions | Requires: Ingres II libraries |
| php_interbase.dll | InterBase functions | Requires: gds32.dll (bundled) |
| php_java.dll | Java functions | PHP <= 4.0.6 requires: jvm.dll (bundled) |
| php_ldap.dll | LDAP functions | PHP <= 4.2.0 requires libsasl.dll (bundled), PHP >= 4.3.0 requires libeay32.dll, ssleay32.dll (bundled) |
| php_mbstring.dll | Multi-Byte String functions | None |
| php_mcrypt.dll | Mcrypt Encryption functions | Requires: libmcrypt.dll |
| php_mhash.dll | Mhash functions | PHP >= 4.3.0 requires: libmhash.dll (bundled) |
| php_mime_magic.dll | Mimetype functions | Requires: magic.mime (bundled) |
| php_ming.dll | Ming functions for Flash | None |
| php_msql.dll | mSQL functions | Requires: msql.dll (bundled) |
| php_mssql.dll | MSSQL functions | Requires: ntwdblib.dll (bundled) |
| php_mysql.dll | MySQL functions | PHP >= 5.0.0, requires libmysql.dll (bundled) |
| php_mysqli.dll | MySQLi functions | PHP >= 5.0.0, requires libmysql.dll (libmysqli.dll in PHP <= 5.0.2) (bundled) |
| php_oci8.dll | Oracle 8 functions | Requires: Oracle 8.1+ client libraries |
| php_openssl.dll | OpenSSL functions | Requires: libeay32.dll (bundled) |
| php_overload.dll | Object overloading functions | Built in since PHP 4.3.0 |
| php_pdf.dll | PDF functions | None |
| php_pgsql.dll | PostgreSQL functions | None |
| php_printer.dll | Printer functions | None |
| php_shmop.dll | Shared Memory functions | None |
| php_snmp.dll | SNMP get and walk functions | NT only! |
| php_soap.dll | SOAP functions | PHP >= 5.0.0 |
| php_sockets.dll | Socket functions | None |
| php_sybase_ct.dll | Sybase functions | Requires: Sybase client libraries |
| php_tidy.dll | Tidy functions | PHP >= 5.0.0 |
| php_tokenizer.dll | Tokenizer functions | Built in since PHP 4.3.0 |
| php_w32api.dll | W32api functions | None |
| php_xmlrpc.dll | XML-RPC functions | PHP >= 4.2.1 requires: iconv.dll (bundled) |
| php_xslt.dll | XSLT functions | PHP <= 4.2.0 requires sablot.dll, expat.dll (bundled). PHP >= 4.2.1 requires sablot.dll, expat.dll, iconv.dll (bundled). |
| php_yaz.dll | YAZ functions | Requires: yaz.dll (bundled) |
| php_zip.dll | Zip File functions | Read only access |
| php_zlib.dll | ZLib compression functions | Built in since PHP 4.3.0 |
» PECL is a repository of PHP extensions that are made available to you via the » PEAR packaging system. This section of the manual is intended to demonstrate how to obtain and install PECL extensions.
These instructions assume /your/phpsrcdir/ is the path to the PHP source distribution, and that extname is the name of the PECL extension. Adjust accordingly. These instructions also assume a familiarity with the » pear command. The information in the PEAR manual for the pear command also applies to the pecl command.
To be useful, a shared extension must be built, installed, and loaded. The methods described below provide you with various instructions on how to build and install the extensions, but they do not automatically load them. Extensions can be loaded by adding an extension directive. To this php.ini file, or through the use of the dl() function.
When building PHP modules, it's important to have known-good versions of the required tools (autoconf, automake, libtool, etc.) See the » Anonymous CVS Instructions for details on the required tools, and required versions.
There are several options for downloading PECL extensions, such as:
$ cvs -d:pserver:cvsread@cvs.php.net:/repository login
$ cvs -d:pserver:cvsread@cvs.php.net:/repository co pecl/extname
On Windows, you have two ways to load a PHP extension: either compile it into PHP, or load the DLL. Loading a pre-compiled extension is the easiest and preferred way.
To load an extension, you need to have it available as a ".dll" file on your system. All the extensions are automatically and periodically compiled by the PHP Group (see next section for the download).
To compile an extension into PHP, please refer to building from source documentation.
To compile a standalone extension (aka a DLL file), please refer to building from source documentation. If the DLL file is available neither with your PHP distribution nor in PECL, you may have to compile it before you can start using the extension.
PHP extensions are usually called "php_*.dll" (where the star represents the name of the extension) and they are located under the "PHP\ext" ("PHP\extensions" in PHP4) folder.
PHP ships with the extensions most useful to the majority of developers. They are called "core" extensions.
However, if you need functionality not provided by any core extension, you may still be able to find one in PECL. The PHP Extension Community Library (PECL) is a repository for PHP Extensions, providing a directory of all known extensions and hosting facilities for downloading and development of PHP extensions.
If you have developed an extension for your own uses, you might want to think about hosting it on PECL so that others with the same needs can benefit from your time. A nice side effect is that you give them a good chance to give you feedback, (hopefully) thanks, bug reports and even fixes/patches. Before you submit your extension for hosting on PECL, please read http://pecl.php.net/package-new.php.
Many times, you will find several versions of each DLL:
You should keep in mind that your extension settings should match all the settings of the PHP executable you are using. The following PHP script will tell you all about your PHP settings:
<?php phpinfo(); ?>
Or from the command line, run:
drive:\\path\to\php\executable\php.exe -i
The most common way to load a PHP extension is to include it in your php.ini configuration file. Please note that many extensions are already present in your php.ini and that you only need to remove the semicolon to activate them.
;extension=php_extname.dll
extension=php_extname.dll
However, some web servers are confusing because they do not use the php.ini located alongside your PHP executable. To find out where your actual php.ini resides, look for its path in phpinfo():
Configuration File (php.ini) Path C:\WINDOWS
Loaded Configuration File C:\Program Files\PHP\5.2\php.ini
After activating an extension, save php.ini, restart the web server and check phpinfo() again. The new extension should now have its own section.
If the extension does not appear in phpinfo(), you should check your logs to learn where the problem comes from.
If you are using PHP from the command line (CLI), the extension loading error can be read directly on screen.
If you are using PHP with a web server, the location and format of the logs vary depending on your software. Please read your web server documentation to locate the logs, as it does not have anything to do with PHP itself.
Common problems are the location of the DLL, the value of the " extension_dir" setting inside php.ini and compile-time setting mismatches.
If the problem lies in a compile-time setting mismatch, you probably didn't download the right DLL. Try downloading again the extension with the right settings. Again, phpinfo() can be of great help.
PECL makes it easy to create shared PHP extensions. Using the » pecl command, do the following:
$ pecl install extname
This will download the source for extname, compile, and install extname.so into your extension_dir. extname.so may then be loaded via php.ini
By default, the pecl command will not install packages that are marked with the alpha or beta state. If no stable packages are available, you may install a beta package using the following command:
$ pecl install extname-beta
You may also install a specific version using this variant:
$ pecl install extname-0.1
Informacja: After enabling the extension in php.ini, restarting the web service is required for the changes to be picked up.
Sometimes, using the pecl installer is not an option. This could be because you're behind a firewall, or it could be because the extension you want to install is not available as a PECL compatible package, such as unreleased extensions from CVS. If you need to build such an extension, you can use the lower-level build tools to perform the build manually.
The phpize command is used to prepare the build environment for a PHP extension. In the following sample, the sources for an extension are in a directory named extname:
$ cd extname $ phpize $ ./configure $ make # make install
A successful install will have created extname.so and put it into the PHP extensions directory. You'll need to and adjust php.ini and add an extension=extname.so line before you can use the extension.
If the system is missing the phpize command, and precompiled packages (like RPM's) are used, be sure to also install the appropriate devel version of the PHP package as they often include the phpize command along with the appropriate header files to build PHP and its extensions.
Execute phpize --help to display additional usage information.
You might find that you need to build a PECL extension statically into your PHP binary. To do this, you'll need to place the extension source under the php-src/ext/ directory and tell the PHP build system to regenerate its configure script.
$ cd /your/phpsrcdir/ext $ pecl download extname $ gzip -d < extname.tgz | tar -xvf - $ mv extname-x.x.x extname
This will result in the following directory:
/your/phpsrcdir/ext/extname
From here, force PHP to rebuild the configure script, and then build PHP as normal:
$ cd /your/phpsrcdir $ rm configure $ ./buildconf --force $ ./configure --help $ ./configure --with-extname --enable-someotherext --with-foobar $ make $ make install
Informacja: To run the 'buildconf' script you need autoconf 2.13 and automake 1.4+ (newer versions of autoconf may work, but are not supported).
Whether --enable-extname or --with-extname is used depends on the extension. Typically an extension that does not require external libraries uses --enable. To be sure, run the following after buildconf:
$ ./configure --help | grep extname
Niektóre problemy występują częściej niż inne. Tej najczęściej spotykane są wypisane w FAQ PHP, częsci tego podręcznika.
Jeśli w dalszym ciągu nie wiesz co zrobić, być może ktoś z listy dyskusyjnej poświęconej instalacji PHP będzie mógł ci pomóc. Powinienej sprawdzić najpierw archiwum, bo być może ktoś już odpowiedział na twoje pytanie. Archiwa znajdują się w dziale 'Wspracie' na stronie » http://www.php.net/support.php. Aby zapisać się na listę dyskusyjną dotyczącą instalacji PHP, wyślij pusty list na adres » php-install-subscribe@lists.php.net. Adresem listy dyskusyjnej jest » php-install@lists.php.net.
Jeśli chcesz uzyskać pomoc na liście dyskusyjnej, postaraj się być precyzyjny i podaj niezbędne szczegóły dotyczące Twojego środowiska (system operacyjny, wersja PHP, serwer WWW, czy PHP działa jako CGI czy jako moduł, tryb bezpieczny, itp.), i kod, aby inni mogli odtworzyć i sprawdzić Twój problem.
Jeśli uważasz, że znalazłeś błąd w PHP, zgłoś go. Programiści PHP prawdopodobnie nie wiedzą i nim, więc jeśli go nie zgłosisz, to najprawdopodobniej nie będzie usunięty. Możesz zgłaszać błędy korzystając z systemu zgłaszania błędów znajdującego się pod adresem » http://bugs.php.net/. Nie wysyłaj raportów o błędach na listy dyskusyjne lub bezpośrednio do developerów. System śledzenia błędów ma także opcję zgłaszania pomysłów na nowe możliwości.
Przeczytaj dokument » Jak wysyłać raporty o błędach przed wysłaniem jakiegokolwiek raportu o błędzie!
The configuration file (php.ini) is read when PHP starts up. For the server module versions of PHP, this happens only once when the web server is started. For the CGI and CLI version, it happens on every invocation.
php.ini is searched in these locations (in order):
SAPI module specific location (PHPIniDir directive in Apache 2, -c command line option in CGI and CLI, php_ini parameter in NSAPI, PHP_INI_PATH environment variable in THTTPD)
The PHPRC environment variable. Before PHP 5.2.0 this was checked after the registry key mentioned below.
As of PHP 5.2.0, the following registry locations are searched in order: HKEY_LOCAL_MACHINE\SOFTWARE\PHP\x.y.z\IniFilePath, HKEY_LOCAL_MACHINE\SOFTWARE\PHP\x.y\IniFilePath and HKEY_LOCAL_MACHINE\SOFTWARE\PHP\x\IniFilePath, where x, y and z mean the PHP major, minor and release versions.
HKEY_LOCAL_MACHINE\SOFTWARE\PHP\IniFilePath (Windows Registry location)
Current working directory (except CLI)
The web server's directory (for SAPI modules), or directory of PHP (otherwise in Windows)
Windows directory (C:\windows or C:\winnt) (for Windows), or --with-config-file-path compile time option
If php-SAPI.ini exists (where SAPI is used SAPI, so the filename is e.g. php-cli.ini or php-apache.ini), it's used instead of php.ini. SAPI name can be determined by php_sapi_name().
Informacja: The Apache web server changes the directory to root at startup causing PHP to attempt to read php.ini from the root filesystem if it exists.
The php.ini directives handled by extensions are documented respectively on the pages of the extensions themselves. The list of the core directives is available in the appendix. Probably not all PHP directives are documented in the manual though. For a complete list of directives available in your PHP version, please read your well commented php.ini file. Alternatively, you may find the » the latest php.ini from CVS helpful too.
Example #1 php.ini example
; any text on a line after an unquoted semicolon (;) is ignored [php] ; section markers (text within square brackets) are also ignored ; Boolean values can be set to either: ; true, on, yes ; or false, off, no, none register_globals = off track_errors = yes ; you can enclose strings in double-quotes include_path = ".:/usr/local/lib/php" ; backslashes are treated the same as any other character include_path = ".;c:\php\lib"
Since PHP 5.1.0, it is possible to refer to existing .ini variables from within .ini files. Example: open_basedir = ${open_basedir} ":/new/dir".
These modes determine when and where a PHP directive may or may not be set, and each directive within the manual refers to one of these modes. For example, some settings may be set within a PHP script using ini_set(), whereas others may require php.ini or httpd.conf.
For example, the output_buffering setting is PHP_INI_PERDIR therefore it may not be set using ini_set(). However, the display_errors directive is PHP_INI_ALL therefore it may be set anywhere, including with ini_set().
| Mode | Meaning |
|---|---|
| PHP_INI_USER | Entry can be set in user scripts (like with ini_set()) or in the Windows registry |
| PHP_INI_PERDIR | Entry can be set in php.ini, .htaccess or httpd.conf |
| PHP_INI_SYSTEM | Entry can be set in php.ini or httpd.conf |
| PHP_INI_ALL | Entry can be set anywhere |
When using PHP as an Apache module, you can also change the configuration settings using directives in Apache configuration files (e.g. httpd.conf) and .htaccess files. You will need "AllowOverride Options" or "AllowOverride All" privileges to do so.
There are several Apache directives that allow you to change the PHP configuration from within the Apache configuration files. For a listing of which directives are PHP_INI_ALL, PHP_INI_PERDIR, or PHP_INI_SYSTEM, have a look at the List of php.ini directives appendix.
php_value
name
value
Sets the value of the specified directive. Can be used only with PHP_INI_ALL and PHP_INI_PERDIR type directives. To clear a previously set value use none as the value.
Informacja: Don't use
php_valueto set boolean values.php_flag(see below) should be used instead.
php_flag
name
on|off
Used to set a boolean configuration directive. Can be used only with PHP_INI_ALL and PHP_INI_PERDIR type directives.
php_admin_value
name
value
Sets the value of the specified directive.
This can not be used in .htaccess files.
Any directive type set with php_admin_value
can not be overridden by .htaccess or ini_set().
To clear a previously set value use none as the value.
php_admin_flag
name
on|off
Used to set a boolean configuration directive.
This can not be used in .htaccess files.
Any directive type set with php_admin_flag
can not be overridden by .htaccess.
Example #1 Apache configuration example
<IfModule mod_php5.c> php_value include_path ".:/usr/local/lib/php" php_admin_flag safe_mode on </IfModule> <IfModule mod_php4.c> php_value include_path ".:/usr/local/lib/php" php_admin_flag safe_mode on </IfModule>
PHP constants do not exist outside of PHP. For example, in httpd.conf you can not use PHP constants such as E_ALL or E_NOTICE to set the error_reporting directive as they will have no meaning and will evaluate to 0. Use the associated bitmask values instead. These constants can be used in php.ini
When running PHP on Windows, the configuration values can be modified on a per-directory basis using the Windows registry. The configuration values are stored in the registry key HKLM\SOFTWARE\PHP\Per Directory Values, in the sub-keys corresponding to the path names. For example, configuration values for the directory c:\inetpub\wwwroot would be stored in the key HKLM\SOFTWARE\PHP\Per Directory Values\c\inetpub\wwwroot. The settings for the directory would be active for any script running from this directory or any subdirectory of it. The values under the key should have the name of the PHP configuration directive and the string value. PHP constants in the values are not parsed. However, only configuration values changeable in PHP_INI_USER can be set this way, PHP_INI_PERDIR values can not.
Regardless of how you run PHP, you can change certain values at runtime of your scripts through ini_set(). See the documentation on the ini_set() page for more information.
If you are interested in a complete list of configuration settings on your system with their current values, you can execute the phpinfo() function, and review the resulting page. You can also access the values of individual configuration directives at runtime using ini_get() or get_cfg_var().
Kiedy PHP przetwarza plik, szuka otwierających i zamykających znaczników (tagów), które mówią PHP o rozpoczęciu i zakończeniu interpretowania kodu pomiędzy nimi. Przetwarzanie w taki sposób pozwala zagnieżdzać php w dowolnym rodzaju dokumentów, ponieważ wszystko poza parą znaczników, otwierającym i zamykającym jest ignorowane przez parser PHP. Najczęściej zobaczysz php zagnieżdzone w dokumentach HTML, tak jak w tym przykładzie.
<p>To zostanie zignorowane.</p>
<?php echo 'Kiedy to zostanie przetworzone.'; ?>
<p>To również zostanie zignorowane.</p>
Możesz także użyć bardziej zaawansowanej struktury:
Example #1 Zaawansowane wyskakiwanie
<?php
if ($wyrazenie) {
?>
<strong>To jest prawda.</strong>
<?php
} else {
?>
<strong>To jest fałsz.</strong>
<?php
}
?>
To działa jak się spodziewano, ponieważ kiedy PHP natrafi na zamykający znacznik ?>, poprostu zaczyna wyświetlać cokolwiek znajdzie (z wyjątkiem bezpośrednio następującej nowej linii - zobacz oddzielanie instrukcji ) dopóki nie natrafi na kolejny otwierający znacznik. Podany przykład jest oczywiście przekombinowany, ale do wyświetlania dużych bloków tekstu, wychodzenie z trybu przetwarzania PHP jest zasadniczo bardziej efektywne niż wysyłanie całego tekstu przez funkcje echo() lub print().
Mamy cztery różne pary otwierających i zamykających znaczników, które mogą być użyte w php. Dwie z nich, <?php ?> i <script language="php"> </script> są zawsze dostępne. Dwie następne to krótkie znaczniki i znaczniki w stylu ASP, mogą być włączane i wyłączane w pliku konfiguracyjnym php.ini. Część osób postrzega krótkie znaczniki i znaczniki w stylu ASP jako wygodne, jednakże są one mniej przenośne, i zasadniczo nie polecane.
Informacja: Zauważ również, że jeśli zagnieżdzasz PHP w XML lub XHTML musisz stosować znaczniki <?php ?> aby pozostać w zgodzie ze standardami.
Example #2 Znaczniki otwierające i zamykające PHP
1. <?php echo 'jeśli chcesz obsługiwać dokumenty XHTML lub XML, zrób to tak'; ?>
2. <script language="php">
echo 'niektóre edytory (jak FrontPage) nie lubią
instrukcji przetwarzania';
</script>
3. <? echo 'to jest najprostsza instrukcja przetwarzania SGML'; ?>
<?= wyrazenie ?> To jest skrót dla "<? echo wyrazenie ?>"
4. <% echo 'Możesz opcjonalnie użyć znaczników w stylu ASP'; %>
<%= $zmienna; # To jest skrót dla "<% echo . . ." %>
Z pokazanych znaczników, przykłady 1 i 2 są zawsze dostępne, przykład 1 jest najbardziej powszechny i rekomendowany.
Krótkie znaczniki (przykład 3) są dostepne jedynie, kiedy są włączone za pomocą dyrektywy konfiguracyjnej short_open_tag w php.ini lub jeśli php zostało skonfigurowane z opcją --enable-short-tags.
Znaczniki w stylu ASP (przykład 4) są dostępne jedynie gdy zostaną włączone poprzez dyrektywę konfiguracyjną asp_tags w php.ini
Informacja: Powinieneś unikać używania krótkich znaczników, kiedy rozwijasz aplikacje lub biblioteki, które są nastawione na rozpowszechnianie lub pracujesz na serwerach PHP, nad którymi nie masz kontroli, ponieważ krótkie znaczniki mogą nie być obsługiwane na docelowym serwerze. Dla przenośnego, rozpowszechnialnego kodu, miej pewność aby nie użyć krotkich znaczników.
Podobnie jak C i Perl, PHP wymaga aby instrukcje były zakończone średnikiem, na końcu każdego wyrażenia. Zamykający znacznik bloku kodu PHP automatycznie implikuje średnik; nie musisz mieć średnika zamykającego ostatnią linię z bloku PHP. Zamykający znacznik dla bloku będzie zawierać bezpośrednio następującą nową linie jeśli taka istnieje.
<?php
echo 'To jest test';
?>
<?php echo 'To jest test' ?>
<?php echo 'Pomineliśmy ostatni zamykający znacznik';
Informacja: Zamykający znacznik bloku PHP na końcu pliku jest opcjonalny, i w niektórych przypadkach pominięcie jego jest pomocne kiedy używamy include() lub require(), tak więc niechciane białe znaki nie będą znajdować się na końcu pliku, i ciągle będzie możliwe dodanie nagłówków do odpowiedzi. To jest także poręczne jeśli używasz buferowania wyjścia, i nie chciałbyś zobaczyć dodanych niechcianych białych znaków na końcu cześci generowanej przez includowany plik.
PHP obsługuje komentarze w stylu 'C', 'C++' i powłoki Unix (styl Perl\'a). Na przykład:
<?php
echo 'To jest test'; // To jest jednoliniowy komentarz w stylu c++
/* To jest wieloliniowy komentarz
jeszcze inna linia komentarza */
echo 'To jest jeszcze jeden test';
echo 'Ostatni test'; # To jest jednoliniowy komentarz w stylu powłoki
?>
"Jednolinijkowy" styl komentarzy obowiązuje jedynie do konca linii lub bieżącego bloku kodu PHP, cokolwiek wystąpi pierwsze. Co oznacza, że kod HTML za // ... ?> lub # ... ?> ZOSTANIE wyświetlony: ?> przerywa tryb PHP i wraca do trybu HTML, i // lub # nie może wpłynąć na to. Jeśli, dyrektywa konfiguracyjna asp_tags jest włączona, to działa tak samo z // %> i # %>. Jednakże, znacznik </script> nie przerywa trybu PHP w jednolinijkowym komentarzu.
<h1>To jest <?php # echo 'prosty';?> przykład.</h1>
<p>nagłowek powyżej będzie mówił 'To jest przykład'.</p>
Komentarze w stylu 'C' kończą się na pierwszym napotkanym */. Upewnij się, że nie zagnieżdzasz komentarzy w stylu 'C'. Łatwo jest popełnić pomyłkę jeśli próbujesz odkomentować duży blok kodu.
<?php
/*
echo 'To jest test'; /* Ten komentarz będzie przyczyną problemów */
*/
?>
PHP supports eight primitive types.
Four scalar types:
Two compound types:
And finally two special types:
This manual also introduces some pseudo-types for readability reasons:
And the pseudo-variable $... .
Some references to the type "double" may remain in the manual. Consider double the same as float; the two names exist only for historic reasons.
The type of a variable is not usually set by the programmer; rather, it is decided at runtime by PHP depending on the context in which that variable is used.
Informacja: To check the type and value of an expression, use the var_dump() function. To get a human-readable representation of a type for debugging, use the gettype() function. To check for a certain type, do not use gettype(), but rather the is_type functions. Some examples:
<?php
$a_bool = TRUE; // a boolean
$a_str = "foo"; // a string
$a_str2 = 'foo'; // a string
$an_int = 12; // an integer
echo gettype($a_bool); // prints out: boolean
echo gettype($a_str); // prints out: string
// If this is an integer, increment it by four
if (is_int($an_int)) {
$an_int += 4;
}
// If $bool is a string, print it out
// (does not print out anything)
if (is_string($a_bool)) {
echo "String: $a_bool";
}
?>
To forcibly convert a variable to a certain type, either cast the variable or use the settype() function on it.
Note that a variable may be evaluated with different values in certain situations, depending on what type it is at the time. For more information, see the section on Type Juggling. The type comparison tables may also be useful, as they show examples of various type-related comparisons.
This is the simplest type. A boolean expresses a truth value. It can be either TRUE or FALSE.
Informacja: The boolean type was introduced in PHP 4.
To specify a boolean literal, use the keywords TRUE or FALSE. Both are case-insensitive.
<?php
$foo = True; // assign the value TRUE to $foo
?>
Typically, some kind of operator which returns a boolean value, and the value is passed on to a control structure.
<?php
// == is an operator which test
// equality and returns a boolean
if ($action == "show_version") {
echo "The version is 1.23";
}
// this is not necessary...
if ($show_separators == TRUE) {
echo "<hr>\n";
}
// ...because instead, this can be used:
if ($show_separators) {
echo "<hr>\n";
}
?>
To explicitly convert a value to boolean, use the (bool) or (boolean) casts. However, in most cases the cast is unncecessary, since a value will be automatically converted if an operator, function or control structure requires a boolean argument.
See also Type Juggling.
When converting to boolean, the following values are considered FALSE:
Every other value is considered TRUE (including any resource).
-1 is considered TRUE, like any other non-zero (whether negative or positive) number!
<?php
var_dump((bool) ""); // bool(false)
var_dump((bool) 1); // bool(true)
var_dump((bool) -2); // bool(true)
var_dump((bool) "foo"); // bool(true)
var_dump((bool) 2.3e5); // bool(true)
var_dump((bool) array(12)); // bool(true)
var_dump((bool) array()); // bool(false)
var_dump((bool) "false"); // bool(true)
?>
An integer is a number of the set Z = {..., -2, -1, 0, 1, 2, ...}.
See also:
Integers can be specified in decimal (base 10), hexadecimal (base 16), or octal (base 8) notation, optionally preceded by a sign (- or +).
To use octal notation, precede the number with a 0 (zero). To use hexadecimal notation precede the number with 0x.
Example #1 Integer literals
<?php
$a = 1234; // decimal number
$a = -123; // a negative number
$a = 0123; // octal number (equivalent to 83 decimal)
$a = 0x1A; // hexadecimal number (equivalent to 26 decimal)
?>
Formally, the structure for integer literals is:
decimal : [1-9][0-9]*
| 0
hexadecimal : 0[xX][0-9a-fA-F]+
octal : 0[0-7]+
integer : [+-]?decimal
| [+-]?hexadecimal
| [+-]?octal
The size of an integer is platform-dependent, although a maximum value of about two billion is the usual value (that's 32 bits signed). PHP does not support unsigned integers. Integer size can be determined using the constant PHP_INT_SIZE, and maximum value using the constant PHP_INT_MAX since PHP 4.4.0 and PHP 5.0.5.
If an invalid digit is given in an octal integer (i.e. 8 or 9), the rest of the number is ignored.
Example #2 Octal weirdness
<?php
var_dump(01090); // 010 octal = 8 decimal
?>
If PHP encounters a number beyond the bounds of the integer type, it will be interpreted as a float instead. Also, an operation which results in a number beyond the bounds of the integer type will return a float instead.
<?php
$large_number = 2147483647;
var_dump($large_number);
// output: int(2147483647)
$large_number = 2147483648;
var_dump($large_number);
// output: float(2147483648)
// it's true also for hexadecimal specified integers between 2^31 and 2^32-1:
var_dump( 0xffffffff );
// output: float(4294967295)
// this doesn't go for hexadecimal specified integers above 2^32-1:
var_dump( 0x100000000 );
// output: int(2147483647)
$million = 1000000;
$large_number = 50000 * $million;
var_dump($large_number);
// output: float(50000000000)
?>
Unfortunately, there was a bug in PHP which caused this to not always work correctly when negative numbers were involved. For example, the result of -50000 * $million is -429496728. However, when both operands were positive, there was no problem.
This was fixed in PHP 4.1.0.
There is no integer division operator in PHP. 1/2 yields the float 0.5. The value can be casted to an integer to round it downwards, or the round() function provides finer control over rounding.
<?php
var_dump(25/7); // float(3.5714285714286)
var_dump((int) (25/7)); // int(3)
var_dump(round(25/7)); // float(4)
?>
To explicitly convert a value to integer, use either the (int) or (integer) casts. However, in most cases the cast is not needed, since a value will be automatically converted if an operator, function or control structure requires an integer argument. A value can also be converted to integer with the intval() function.
See also: type-juggling.
FALSE will yield 0 (zero), and TRUE will yield 1 (one).
When converting from float to integer, the number will be rounded towards zero.
If the float is beyond the boundaries of integer (usually +/- 2.15e+9 = 2^31), the result is undefined, since the float doesn't have enough precision to give an exact integer result. No warning, not even a notice will be issued when this happens!
Never cast an unknown fraction to integer, as this can sometimes lead to unexpected results.
<?php
echo (int) ( (0.1+0.7) * 10 ); // echoes 7!
?>
See also the warning about float precision.
The behaviour of converting to integer is undefined for other types. Do not rely on any observed behaviour, as it can change without notice.
Floating point numbers (also known as "floats", "doubles", or "real numbers") can be specified using any of the following syntaxes:
<?php
$a = 1.234;
$b = 1.2e3;
$c = 7E-10;
?>
Formally:
LNUM [0-9]+
DNUM ([0-9]*[\.]{LNUM}) | ({LNUM}[\.][0-9]*)
EXPONENT_DNUM [+-]?(({LNUM} | {DNUM}) [eE][+-]? {LNUM})
The size of a float is platform-dependent, although a maximum of ~1.8e308 with a precision of roughly 14 decimal digits is a common value (the 64 bit IEEE format).
It is typical that simple decimal fractions like 0.1 or 0.7 cannot be converted into their internal binary counterparts without a small loss of precision. This can lead to confusing results: for example, floor((0.1+0.7)*10) will usually return 7 instead of the expected 8, since the internal representation will be something like 7.9.
This is due to the fact that it is impossible to express some fractions in decimal notation with a finite number of digits. For instance, 1/3 in decimal form becomes 0.3.
So never trust floating number results to the last digit, and never compare floating point numbers for equality. If higher precision is necessary, the arbitrary precision math functions and gmp functions are available.
For information on converting strings to float, see String conversion to numbers. For values of other types, the conversion is performed by converting the value to integer first and then to float. See Converting to integer for more information. As of PHP 5, a notice is thrown if an object is converted to float.
A string is series of characters. Before PHP 6, a character is the same as a byte. That is, there are exactly 256 different characters possible. This also implies that PHP has no native support of Unicode. See utf8_encode() and utf8_decode() for some basic Unicode functionality.
Informacja: It is no problem for a string to become very large. PHP imposes no boundary on the size of a string; the only limit is the available memory of the computer on which PHP is running.
A string literal can be specified in four different ways:
The simplest way to specify a string is to enclose it in single quotes (the character ').
To specify a literal single quote, escape it with a backslash (\). To specify a literal backslash before a single quote, or at the end of the string, double it (\\). Note that attempting to escape any other character will print the backslash too.
Informacja: Unlike the two other syntaxes, variables and escape sequences for special characters will not be expanded when they occur in single quoted strings.
<?php
echo 'this is a simple string';
echo 'You can also have embedded newlines in
strings this way as it is
okay to do';
// Outputs: Arnold once said: "I'll be back"
echo 'Arnold once said: "I\'ll be back"';
// Outputs: You deleted C:\*.*?
echo 'You deleted C:\\*.*?';
// Outputs: You deleted C:\*.*?
echo 'You deleted C:\*.*?';
// Outputs: This will not expand: \n a newline
echo 'This will not expand: \n a newline';
// Outputs: Variables do not $expand $either
echo 'Variables do not $expand $either';
?>
If the string is enclosed in double-quotes ("), PHP will interpret more escape sequences for special characters:
| Sequence | Meaning |
|---|---|
| \n | linefeed (LF or 0x0A (10) in ASCII) |
| \r | carriage return (CR or 0x0D (13) in ASCII) |
| \t | horizontal tab (HT or 0x09 (9) in ASCII) |
| \v | vertical tab (VT or 0x0B (11) in ASCII) (since PHP 5.2.5) |
| \f | form feed (FF or 0x0C (12) in ASCII) (since PHP 5.2.5) |
| \\ | backslash |
| \$ | dollar sign |
| \" | double-quote |
| \[0-7]{1,3} | the sequence of characters matching the regular expression is a character in octal notation |
| \x[0-9A-Fa-f]{1,2} | the sequence of characters matching the regular expression is a character in hexadecimal notation |
As in single quoted strings, escaping any other character will result in the backslash being printed too. Before PHP 5.1.1, the backslash in \{$var} was not been printed.
The most important feature of double-quoted strings is the fact that variable names will be expanded. See string parsing for details.
A third way to delimit strings is the heredoc syntax: <<<. After this operator, an identifier is provided, then a newline. The string itself follows, and then the same identifier again to close the quotation.
The closing identifier must begin in the first column of the line. Also, the identifier must follow the same naming rules as any other label in PHP: it must contain only alphanumeric characters and underscores, and must start with a non-digit character or underscore.
It is very important to note that the line with the closing identifier must contain no other characters, except possibly a semicolon (;). That means especially that the identifier may not be indented, and there may not be any spaces or tabs before or after the semicolon. It's also important to realize that the first character before the closing identifier must be a newline as defined by the local operating system. This is \n on UNIX systems, including Mac OS X. The closing delimiter (possibly followed by a semicolon) must also be followed by a newline.
If this rule is broken and the closing identifier is not "clean", it will not be considered a closing identifier, and PHP will continue looking for one. If a proper closing identifier is not found before the end of the current file, a parse error will result at the last line.
Heredocs can not be used for initializing class members. Use nowdocs instead.
Example #1 Invalid example
<?php
class foo {
public $bar = <<<EOT
bar
EOT;
}
?>
Heredoc text behaves just like a double-quoted string, without the double quotes. This means that quotes in a heredoc do not need to be escaped, but the escape codes listed above can still be used. Variables are expanded, but the same care must be taken when expressing complex variables inside a heredoc as with strings.
Example #2 Heredoc string quoting example
<?php
$str = <<<EOD
Example of string
spanning multiple lines
using heredoc syntax.
EOD;
/* More complex example, with variables. */
class foo
{
var $foo;
var $bar;
function foo()
{
$this->foo = 'Foo';
$this->bar = array('Bar1', 'Bar2', 'Bar3');
}
}
$foo = new foo();
$name = 'MyName';
echo <<<EOT
My name is "$name". I am printing some $foo->foo.
Now, I am printing some {$foo->bar[1]}.
This should print a capital 'A': \x41
EOT;
?>
Powyższy przykład wyświetli:
My name is "MyName". I am printing some Foo. Now, I am printing some Bar2. This should print a capital 'A': A
Its also possible to use the Heredoc syntax to pass data to function arguments:
Example #3 Heredoc in arguments example
<?php
var_dump(array(<<<EOD
foobar!
EOD
));
?>
Informacja: Heredoc support was added in PHP 4.
Nowdocs are to single-quoted strings what heredocs are to double-quoted strings. A nowdoc is specified similarly to a heredoc, but no parsing is done inside a nowdoc. The construct is ideal for embedding PHP code or other large blocks of text without the need for escaping. It shares some features in common with the SGML <![CDATA[ ]]> construct, in that it declares a block of text which is not for parsing.
A nowdoc is identified with the same <<< seqeuence used for heredocs, but the identifier which follows is enclosed in single quotes, e.g. <<<'EOT'. All the rules for heredoc identifiers also apply to nowdoc identifiers, especially those regarding the appearance of the closing identifier.
Example #4 Nowdoc string quoting example
<?php
$str = <<<'EOD'
Example of string
spanning multiple lines
using nowdoc syntax.
EOD;
/* More complex example, with variables. */
class foo
{
public $foo;
public $bar;
function foo()
{
$this->foo = 'Foo';
$this->bar = array('Bar1', 'Bar2', 'Bar3');
}
}
$foo = new foo();
$name = 'MyName';
echo <<<'EOT'
My name is "$name". I am printing some $foo->foo.
Now, I am printing some {$foo->bar[1]}.
This should not print a capital 'A': \x41
EOT;
?>
Powyższy przykład wyświetli:
My name is "$name". I am printing some $foo->foo. Now, I am printing some {$foo->bar[1]}. This should not print a capital 'A': \x41
Informacja: Unlike heredocs, nowdocs can be used in any static data context. The typical example is initializing class members or constants:
Example #5 Static data example
<?php
class foo {
public $bar = <<<'EOT'
bar
EOT;
}
?>
Informacja: Nowdoc support was added in PHP 5.3.0.
When a string is specified in double quotes or with heredoc, variables are parsed within it.
There are two types of syntax: a simple one and a complex one. The simple syntax is the most common and convenient. It provides a way to embed a variable, an array value, or an object property in a string with a minimum of effort.
The complex syntax was introduced in PHP 4, and can be recognised by the curly braces surrounding the expression.
If a dollar sign ($) is encountered, the parser will greedily take as many tokens as possible to form a valid variable name. Enclose the variable name in curly braces to explicitly specify the end of the name.
<?php
$beer = 'Heineken';
echo "$beer's taste is great"; // works; "'" is an invalid character for variable names
echo "He drank some $beers"; // won't work; 's' is a valid character for variable names but the variable is "$beer"
echo "He drank some ${beer}s"; // works
echo "He drank some {$beer}s"; // works
?>
Similarly, an array index or an object property can be parsed. With array indices, the closing square bracket (]) marks the end of the index. The same rules apply to object properties as to simple variables.
<?php
// These examples are specific to using arrays inside of strings.
// When outside of a string, always quote array string keys and do not use
// {braces}.
// Show all errors
error_reporting(E_ALL);
$fruits = array('strawberry' => 'red', 'banana' => 'yellow');
// Works, but note that this works differently outside a string
echo "A banana is $fruits[banana].";
// Works
echo "A banana is {$fruits['banana']}.";
// Works, but PHP looks for a constant named banana first, as described below.
echo "A banana is {$fruits[banana]}.";
// Won't work, use braces. This results in a parse error.
echo "A banana is $fruits['banana'].";
// Works
echo "A banana is " . $fruits['banana'] . ".";
// Works
echo "This square is $square->width meters broad.";
// Won't work. For a solution, see the complex syntax.
echo "This square is $square->width00 centimeters broad.";
?>
For anything more complex, you should use the complex syntax.
This isn't called complex because the syntax is complex, but because it allows for the use of complex expressions.
In fact, any value in the namespace can be included in a string with this syntax. Simply write the expression the same way as it would appeared outside the string, and then wrap it in { and }. Since { can not be escaped, this syntax will only be recognised when the $ immediately follows the {. Use {\$ to get a literal {$. Some examples to make it clear:
<?php
// Show all errors
error_reporting(E_ALL);
$great = 'fantastic';
// Won't work, outputs: This is { fantastic}
echo "This is { $great}";
// Works, outputs: This is fantastic
echo "This is {$great}";
echo "This is ${great}";
// Works
echo "This square is {$square->width}00 centimeters broad.";
// Works
echo "This works: {$arr[4][3]}";
// This is wrong for the same reason as $foo[bar] is wrong outside a string.
// In other words, it will still work, but only because PHP first looks for a
// constant named foo; an error of level E_NOTICE (undefined constant) will be
// thrown.
echo "This is wrong: {$arr[foo][3]}";
// Works. When using multi-dimensional arrays, always use braces around arrays
// when inside of strings
echo "This works: {$arr['foo'][3]}";
// Works.
echo "This works: " . $arr['foo'][3];
echo "This works too: {$obj->values[3]->name}";
echo "This is the value of the var named $name: {${$name}}";
echo "This is the value of the var named by the return value of getName(): {${getName()}}";
echo "This is the value of the var named by the return value of \$object->getName(): {${$object->getName()}}";
?>
Informacja: Functions and method calls inside {$} work since PHP 5.
Characters within strings may be accessed and modified by specifying the zero-based offset of the desired character after the string using square array brackets, as in $str[42]. Think of a string as an array of characters for this purpose.
Informacja: Strings may also be accessed using braces, as in $str{42}, for the same purpose. However, this syntax is deprecated as of PHP 6. Use square brackets instead.
Writing to an out of range offset pads the string with spaces. Non-integer types are converted to integer. Illegal offset type emits E_NOTICE. Negative offset emits E_NOTICE in write but reads empty string. Only the first character of an assigned string is used. Assigning empty string assigns NUL byte.
Example #6 Some string examples
<?php
// Get the first character of a string
$str = 'This is a test.';
$first = $str[0];
// Get the third character of a string
$third = $str[2];
// Get the last character of a string.
$str = 'This is still a test.';
$last = $str[strlen($str)-1];
// Modify the last character of a string
$str = 'Look at the sea';
$str[strlen($str)-1] = 'e';
?>
Informacja: Accessing variables of other types using [] or {} silently returns NULL.
Strings may be concatenated using the '.' (dot) operator. Note that the '+' (addition) operator will not work for this. See String operators for more information.
There are a number of useful functions for string manipulation.
See the string functions section for general functions, and the regular expression functions or the Perl-compatible regular expression functions for advanced find & replace functionality.
There are also functions for URL strings, and functions to encrypt/decrypt strings (mcrypt and mhash).
Finally, see also the character type functions.
A value can be converted to a string using the (string) cast or the strval() function. String conversion is automatically done in the scope of an expression where a string is needed. This happens when using the echo() or print() functions, or when a variable is compared to a string. The sections on Types and Type Juggling will make the following clearer. See also the settype() function.
A boolean TRUE value is converted to the string "1". Boolean FALSE is converted to "" (the empty string). This allows conversion back and forth between boolean and string values.
An integer or float is converted to a string representing the number textually (including the exponent part for floats). Floating point numbers can be converted using exponential notation (4.1E+6).
Informacja: The decimal point character is defined in the script's locale (category LC_NUMERIC). See the setlocale() function.
Arrays are always converted to the string "Array"; because of this, echo() and print() can not by themselves show the contents of an array. To view a single element, use a construction such as echo $arr['foo']. See below for tips on viewing the entire contents.
Objects in PHP 4 are always converted to the string "Object". To print the values of object members for debugging reasons, read the paragraphs below. To get an object's class name, use the get_class() function. As of PHP 5, the __toString method is used when applicable.
Resources are always converted to strings with the structure "Resource id #1", where 1 is the unique number assigned to the resource by PHP at runtime. Do not rely upon this structure; it is subject to change. To get a resource's type, use the get_resource_type() function.
NULL is always converted to an empty string.
As stated above, directly converting an array, object, or resource to a string does not provide any useful information about the value beyond its type. See the functions print_r() and var_dump() for more effective means of inspecting the contents of these types.
Most PHP values can also be converted to strings for permanent storage. This method is called serialization, and is performed by the serialize() function. If the PHP engine was built with WDDX support, PHP values can also be serialized as well-formed XML text.
When a string is evaluated in a numeric context, the resulting value and type are determined as follows.
The string will be evaluated as a float if it contains any of the characters '.', 'e', or 'E'. Otherwise, it will be evaluated as an integer.
The value is given by the initial portion of the string. If the string starts with valid numeric data, this will be the value used. Otherwise, the value will be 0 (zero). Valid numeric data is an optional sign, followed by one or more digits (optionally containing a decimal point), followed by an optional exponent. The exponent is an 'e' or 'E' followed by one or more digits.
<?php
$foo = 1 + "10.5"; // $foo is float (11.5)
$foo = 1 + "-1.3e3"; // $foo is float (-1299)
$foo = 1 + "bob-1.3e3"; // $foo is integer (1)
$foo = 1 + "bob3"; // $foo is integer (1)
$foo = 1 + "10 Small Pigs"; // $foo is integer (11)
$foo = 4 + "10.2 Little Piggies"; // $foo is float (14.2)
$foo = "10.0 pigs " + 1; // $foo is float (11)
$foo = "10.0 pigs " + 1.0; // $foo is float (11)
?>
For more information on this conversion, see the Unix manual page for strtod(3).
To test any of the examples in this section, cut and paste the examples and insert the following line to see what's going on:
<?php
echo "\$foo==$foo; type is " . gettype ($foo) . "<br />\n";
?>
Do not expect to get the code of one character by converting it to integer, as is done in C. Use the ord() and chr() functions to convert between ASCII codes and characters.
An array in PHP is actually an ordered map. A map is a type that associates values to keys. This type is optimized for several different uses; it can be treated as an array, list (vector), hash table (an implementation of a map), dictionary, collection, stack, queue, and probably more. As array values can be other arrays, trees and multidimensional arrays are also possible.
Explanation of those data structures is beyond the scope of this manual, but at least one example is provided for each of them. For more information, look towards the considerable literature that exists about this broad topic.
An array can be created by the array() language construct. It takes as parameters any number of comma-separated key => value pairs.
array( key => value , ... ) // key may only be an integer or string // value may be any value of any type
<?php
$arr = array("foo" => "bar", 12 => true);
echo $arr["foo"]; // bar
echo $arr[12]; // 1
?>
A key may be either an integer or a string. If a key is the standard representation of an integer, it will be interpreted as such (i.e. "8" will be interpreted as 8, while "08" will be interpreted as "08"). Floats in key are truncated to integer. The indexed and associative array types are the same type in PHP, which can both contain integer and string indices.
A value can be any PHP type.
<?php
$arr = array("somearray" => array(6 => 5, 13 => 9, "a" => 42));
echo $arr["somearray"][6]; // 5
echo $arr["somearray"][13]; // 9
echo $arr["somearray"]["a"]; // 42
?>
If a key is not specified for a value, the maximum of the integer indices is taken and the new key will be that value plus 1. If a key that already has an assigned value is specified, that value will be overwritten.
<?php
// This array is the same as ...
array(5 => 43, 32, 56, "b" => 12);
// ...this array
array(5 => 43, 6 => 32, 7 => 56, "b" => 12);
?>
Before PHP 4.3.0, appending to an array in which the current maximum key was negative would create a new key as described above. Since PHP 4.3.0, the new key will be 0.
Using TRUE as key will evaluate to integer 1 as a key. Using FALSE as key will evaluate to integer 0 as a key. Using NULL as a key will evaluate to the empty string. Using the empty string as a key will create (or overwrite) a key with the empty string and its value; it is not the same as using empty brackets.
Arrays and objects can not be used as keys. Doing so will result in a warning: Illegal offset type.
An existing array can be modified by explicitly setting values in it.
This is done by assigning values to the array, specifying the key in brackets. The key can also be omitted, resulting in an empty pair of brackets ([]).
$arr[key] = value; $arr[] = value; // key may be an integer or string // value may be any value of any type
If $arr doesn't exist yet, it will be created, so this is also an alternative way to create an array. To change a certain value, assign a new value to that element using its key. To remove a key/value pair, call the unset() function on it.
<?php
$arr = array(5 => 1, 12 => 2);
$arr[] = 56; // This is the same as $arr[13] = 56;
// at this point of the script
$arr["x"] = 42; // This adds a new element to
// the array with key "x"
unset($arr[5]); // This removes the element from the array
unset($arr); // This deletes the whole array
?>
Informacja: As mentioned above, if no key is specified, the maximum of the existing integer indices is taken, and the new key will be that maximum value plus 1. If no integer indices exist yet, the key will be 0 (zero). If a key that already has a value is specified, that value will be overwritten.
Note that the maximum integer key used for this need not currently exist in the array. It need only have existed in the array at some time since the last time the array was re-indexed. The following example illustrates:
<?php
// Create a simple array.
$array = array(1, 2, 3, 4, 5);
print_r($array);
// Now delete every item, but leave the array itself intact:
foreach ($array as $i => $value) {
unset($array[$i]);
}
print_r($array);
// Append an item (note that the new key is 5, instead of 0).
$array[] = 6;
print_r($array);
// Re-index:
$array = array_values($array);
$array[] = 7;
print_r($array);
?>Powyższy przykład wyświetli:
Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 ) Array ( ) Array ( [5] => 6 ) Array ( [0] => 6 [1] => 7 )
There are quite a few useful functions for working with arrays. See the array functions section.
Informacja: The unset() function allows removing keys from an array. Be aware that the array will not be reindexed. If a true "remove and shift" behavior is desired, the array can be reindexed using the array_values() function.
<?php
$a = array(1 => 'one', 2 => 'two', 3 => 'three');
unset($a[2]);
/* will produce an array that would have been defined as
$a = array(1 => 'one', 3 => 'three');
and NOT
$a = array(1 => 'one', 2 =>'three');
*/
$b = array_values($a);
// Now $b is array(0 => 'one', 1 =>'three')
?>
The foreach control structure exists specifically for arrays. It provides an easy way to traverse an array.
Always use quotes around a string literal array index. For example, $foo['bar'] is correct, while $foo[bar] is not. But why? It is common to encounter this kind of syntax in old scripts:
<?php
$foo[bar] = 'enemy';
echo $foo[bar];
// etc
?>
This is wrong, but it works. The reason is that this code has an undefined constant (bar) rather than a string ('bar' - notice the quotes). PHP may in future define constants which, unfortunately for such code, have the same name. It works because PHP automatically converts a bare string (an unquoted string which does not correspond to any known symbol) into a string which contains the bare string. For instance, if there is no defined constant named bar, then PHP will substitute in the string 'bar' and use that.
Informacja: This does not mean to always quote the key. Do not quote keys which are constants or variables, as this will prevent PHP from interpreting them.
Powyższy przykład wyświetli:<?php
error_reporting(E_ALL);
ini_set('display_errors', true);
ini_set('html_errors', false);
// Simple array:
$array = array(1, 2);
$count = count($array);
for ($i = 0; $i < $count; $i++) {
echo "\nChecking $i: \n";
echo "Bad: " . $array['$i'] . "\n";
echo "Good: " . $array[$i] . "\n";
echo "Bad: {$array['$i']}\n";
echo "Good: {$array[$i]}\n";
}
?>
Checking 0: Notice: Undefined index: $i in /path/to/script.html on line 9 Bad: Good: 1 Notice: Undefined index: $i in /path/to/script.html on line 11 Bad: Good: 1 Checking 1: Notice: Undefined index: $i in /path/to/script.html on line 9 Bad: Good: 2 Notice: Undefined index: $i in /path/to/script.html on line 11 Bad: Good: 2
More examples to demonstrate this behaviour:
<?php
// Show all errors
error_reporting(E_ALL);
$arr = array('fruit' => 'apple', 'veggie' => 'carrot');
// Correct
print $arr['fruit']; // apple
print $arr['veggie']; // carrot
// Incorrect. This works but also throws a PHP error of level E_NOTICE because
// of an undefined constant named fruit
//
// Notice: Use of undefined constant fruit - assumed 'fruit' in...
print $arr[fruit]; // apple
// This defines a constant to demonstrate what's going on. The value 'veggie'
// is assigned to a constant named fruit.
define('fruit', 'veggie');
// Notice the difference now
print $arr['fruit']; // apple
print $arr[fruit]; // carrot
// The following is okay, as it's inside a string. Constants are not looked for
// within strings, so no E_NOTICE occurs here
print "Hello $arr[fruit]"; // Hello apple
// With one exception: braces surrounding arrays within strings allows constants
// to be interpreted
print "Hello {$arr[fruit]}"; // Hello carrot
print "Hello {$arr['fruit']}"; // Hello apple
// This will not work, and will result in a parse error, such as:
// Parse error: parse error, expecting T_STRING' or T_VARIABLE' or T_NUM_STRING'
// This of course applies to using superglobals in strings as well
print "Hello $arr['fruit']";
print "Hello $_GET['foo']";
// Concatenation is another option
print "Hello " . $arr['fruit']; // Hello apple
?>
When error_reporting is set to show E_NOTICE level errors (by setting it to E_ALL, for example), such uses will become immediately visible. By default, error_reporting is set not to show notices.
As stated in the syntax section, what's inside the square brackets ('[' and ']') must be an expression. This means that code like this works:
<?php
echo $arr[somefunc($bar)];
?>
This is an example of using a function return value as the array index. PHP also knows about constants:
<?php
$error_descriptions[E_ERROR] = "A fatal error has occured";
$error_descriptions[E_WARNING] = "PHP issued a warning";
$error_descriptions[E_NOTICE] = "This is just an informal notice";
?>
Note that E_ERROR is also a valid identifier, just like bar in the first example. But the last example is in fact the same as writing:
<?php
$error_descriptions[1] = "A fatal error has occured";
$error_descriptions[2] = "PHP issued a warning";
$error_descriptions[8] = "This is just an informal notice";
?>
because E_ERROR equals 1, etc.
At some point in the future, the PHP team might want to add another constant or keyword, or a constant in other code may interfere. For example, it is already wrong to use the words empty and default this way, since they are reserved keywords.
Informacja: To reiterate, inside a double-quoted string, it's valid to not surround array indexes with quotes so "$foo[bar]" is valid. See the above examples for details on why as well as the section on variable parsing in strings.
For any of the types: integer, float, string, boolean and resource, converting a value to an array results in an array with a single element with index zero and the value of the scalar which was converted. In other words, (array)$scalarValue is exactly the same as array($scalarValue).
If an object is converted to an array, the result is an array whose elements are the object's properties. The keys are the member variable names, with a few notable exceptions: integer properties are unaccessible; private variables have the class name prepended to the variable name; protected variables have a '*' prepended to the variable name. These prepended values have null bytes on either side. This can result in some unexpected behaviour:
<?php
class A {
private $A; // This will become '\0A\0A'
}
class B extends A {
private $A; // This will become '\0B\0A'
public $AA; // This will become 'AA'
}
var_dump((array) new B());
?>
The above will appear to have two keys named 'AA', although one of them is actually named '\0A\0A'.
It is possible to compare arrays with the array_diff() function and with array operators.
The array type in PHP is very versatile. Here are some examples:
<?php
// This:
$a = array( 'color' => 'red',
'taste' => 'sweet',
'shape' => 'round',
'name' => 'apple',
4 // key will be 0
);
$b = array('a', 'b', 'c');
// . . .is completely equivalent with this:
$a = array();
$a['color'] = 'red';
$a['taste'] = 'sweet';
$a['shape'] = 'round';
$a['name'] = 'apple';
$a[] = 4; // key will be 0
$b = array();
$b[] = 'a';
$b[] = 'b';
$b[] = 'c';
// After the above code is executed, $a will be the array
// array('color' => 'red', 'taste' => 'sweet', 'shape' => 'round',
// 'name' => 'apple', 0 => 4), and $b will be the array
// array(0 => 'a', 1 => 'b', 2 => 'c'), or simply array('a', 'b', 'c').
?>
Example #1 Using array()
<?php
// Array as (property-)map
$map = array( 'version' => 4,
'OS' => 'Linux',
'lang' => 'english',
'short_tags' => true
);
// strictly numerical keys
$array = array( 7,
8,
0,
156,
-10
);
// this is the same as array(0 => 7, 1 => 8, ...)
$switching = array( 10, // key = 0
5 => 6,
3 => 7,
'a' => 4,
11, // key = 6 (maximum of integer-indices was 5)
'8' => 2, // key = 8 (integer!)
'02' => 77, // key = '02'
0 => 12 // the value 10 will be overwritten by 12
);
// empty array
$empty = array();
?>
Example #2 Collection
<?php
$colors = array('red', 'blue', 'green', 'yellow');
foreach ($colors as $color) {
echo "Do you like $color?\n";
}
?>
Powyższy przykład wyświetli:
Do you like red? Do you like blue? Do you like green? Do you like yellow?
Changing the values of the array directly is possible since PHP 5 by passing them by reference. Before that, a workaround is necessary:
Example #3 Collection
<?php
// PHP 5
foreach ($colors as &$color) {
$color = strtoupper($color);
}
unset($color); /* ensure that following writes to
$color will not modify the last array element */
// Workaround for older versions
foreach ($colors as $key => $color) {
$colors[$key] = strtoupper($color);
}
print_r($colors);
?>
Powyższy przykład wyświetli:
Array ( [0] => RED [1] => BLUE [2] => GREEN [3] => YELLOW )
This example creates a one-based array.
Example #4 One-based index
<?php
$firstquarter = array(1 => 'January', 'February', 'March');
print_r($firstquarter);
?>
Powyższy przykład wyświetli:
Array ( [1] => 'January' [2] => 'February' [3] => 'March' )
Example #5 Filling an array
<?php
// fill an array with all items from a directory
$handle = opendir('.');
while (false !== ($file = readdir($handle))) {
$files[] = $file;
}
closedir($handle);
?>
Arrays are ordered. The order can be changed using various sorting functions. See the array functions section for more information. The count() function can be used to count the number of items in an array.
Example #6 Sorting an array
<?php
sort($files);
print_r($files);
?>
Because the value of an array can be anything, it can also be another array. This enables the creation of recursive and multi-dimensional arrays.
Example #7 Recursive and multi-dimensional arrays
<?php
$fruits = array ( "fruits" => array ( "a" => "orange",
"b" => "banana",
"c" => "apple"
),
"numbers" => array ( 1,
2,
3,
4,
5,
6
),
"holes" => array ( "first",
5 => "second",
"third"
)
);
// Some examples to address values in the array above
echo $fruits["holes"][5]; // prints "second"
echo $fruits["fruits"]["a"]; // prints "orange"
unset($fruits["holes"][0]); // remove "first"
// Create a new multi-dimensional array
$juices["apple"]["green"] = "good";
?>
Array assignment always involves value copying. Use the reference operator to copy an array by reference.
<?php
$arr1 = array(2, 3);
$arr2 = $arr1;
$arr2[] = 4; // $arr2 is changed,
// $arr1 is still array(2, 3)
$arr3 = &$arr1;
$arr3[] = 4; // now $arr1 and $arr3 are the same
?>
To create a new object, use the new statement to instantiate a class:
<?php
class foo
{
function do_foo()
{
echo "Doing foo.";
}
}
$bar = new foo;
$bar->do_foo();
?>
For a full discussion, see the Classes and Objects chapter.
If an object is converted to an object, it is not modified. If a value of any other type is converted to an object, a new instance of the stdClass built-in class is created. If the value was NULL, the new instance will be empty. Arrays convert to an object with properties named by keys, and corresponding values. For any other value, a member variable named scalar will contain the value.
<?php
$obj = (object) 'ciao';
echo $obj->scalar; // outputs 'ciao'
?>
A resource is a special variable, holding a reference to an external resource. Resources are created and used by special functions. See the appendix for a listing of all these functions and the corresponding resource types.
Informacja: The resource type was introduced in PHP 4
See also the get_resource_type() function.
As resource variables hold special handlers to opened files, database connections, image canvas areas and the like, converting to a resource makes no sense.
Thanks to the reference-counting system introduced with PHP 4's Zend Engine, a resource with no more references to it is detected automatically, and it is freed by the garbage collector. For this reason, it is rarely necessary to free the memory manually.
Informacja: Persistent database links are an exception to this rule. They are not destroyed by the garbage collector. See the persistent connections section for more information.
The special NULL value represents a variable with no value. NULL is the only possible value of type NULL.
Informacja: The null type was introduced in PHP 4.
A variable is considered to be null if:
it has been assigned the constant NULL.
it has not been set to any value yet.
it has been unset().
There is only one value of type null, and that is the case-insensitive keyword NULL.
<?php
$var = NULL;
?>
Casting a variable to null will remove the variable and unset its value.
mixed indicates that a parameter may accept multiple (but not necessarily all) types.
gettype() for example will accept all PHP types, while str_replace() will accept strings and arrays.
Some functions like call_user_func() or usort() accept user-defined callback functions as a parameter. Callback functions can not only be simple functions, but also object methods, including static class methods.
A PHP function is passed by its name as a string. Any built-in or user-defined function can be used, except language constructs such as: array(), echo(), empty(), eval(), exit(), isset(), list(), print() or unset().
A method of an instantiated object is passed as an array containing an object at index 0 and the method name at index 1.
Static class methods can also be passed without instantiating an object of that class by passing the class name instead of an object at index 0.
Apart from common user-defined function, create_function() can also be used to create an anonymous callback function.
Example #1 Callback function examples
<?php
// An example callback function
function my_callback_function() {
echo 'hello world!';
}
// An example callback method
class MyClass {
static function myCallbackMethod() {
echo 'Hello World!';
}
}
// Type 1: Simple callback
call_user_func('my_callback_function');
// Type 2: Static class method call
call_user_func(array('MyClass', 'myCallbackMethod'));
// Type 3: Object method call
$obj = new MyClass();
call_user_func(array($obj, 'myCallbackMethod'));
// Type 4: Static class method call (As of PHP 5.2.3)
call_user_func('MyClass::myCallbackMethod');
// Type 5: Relative static class method call (As of PHP 5.3.0)
class A {
public static function who() {
echo "A\n";
}
}
class B extends A {
public static function who() {
echo "B\n";
}
}
call_user_func(array('B', 'parent::who')); // A
?>
Informacja: In PHP4, it was necessary to use a reference to create a callback that points to the actual object, and not a copy of it. For more details, see References Explained.
void as a return type means that the return value is useless. void in a parameter list means that the function doesn't accept any parameters.
$... in function prototypes means and so on. This variable name is used when a function can take an endless number of arguments.
PHP does not require (or support) explicit type definition in variable declaration; a variable's type is determined by the context in which the variable is used. That is to say, if a string value is assigned to variable $var, $var becomes a string. If an integer value is then assigned to $var, it becomes an integer.
An example of PHP's automatic type conversion is the addition operator '+'. If either operand is a float, then both operands are evaluated as floats, and the result will be a float. Otherwise, the operands will be interpreted as integers, and the result will also be an integer. Note that this does not change the types of the operands themselves; the only change is in how the operands are evaluated and what the type of the expression itself is.
<?php
$foo = "0"; // $foo is string (ASCII 48)
$foo += 2; // $foo is now an integer (2)
$foo = $foo + 1.3; // $foo is now a float (3.3)
$foo = 5 + "10 Little Piggies"; // $foo is integer (15)
$foo = 5 + "10 Small Pigs"; // $foo is integer (15)
?>
If the last two examples above seem odd, see String conversion to numbers.
To force a variable to be evaluated as a certain type, see the section on Type casting. To change the type of a variable, see the settype() function.
To test any of the examples in this section, use the var_dump() function.
Informacja: The behaviour of an automatic conversion to array is currently undefined.
Also, because PHP supports indexing into strings via offsets using the same syntax as array indexing, the following example holds true for all PHP versions:
See the section titled String access by character for more information.<?php
$a = 'car'; // $a is a string
$a[0] = 'b'; // $a is still a string
echo $a; // bar
?>
Type casting in PHP works much as it does in C: the name of the desired type is written in parentheses before the variable which is to be cast.
<?php
$foo = 10; // $foo is an integer
$bar = (boolean) $foo; // $bar is a boolean
?>
The casts allowed are:
(binary) casting and b prefix forward support was added in PHP 5.2.1
Note that tabs and spaces are allowed inside the parentheses, so the following are functionally equivalent:
<?php
$foo = (int) $bar;
$foo = ( int ) $bar;
?>
Casting literal strings and variables to binary strings:
<?php
$binary = (binary)$string;
$binary = b"binary string";
?>
Informacja: Instead of casting a variable to a string, it is also possible to enclose the variable in double quotes.
<?php
$foo = 10; // $foo is an integer
$str = "$foo"; // $str is a string
$fst = (string) $foo; // $fst is also a string
// This prints out that "they are the same"
if ($fst === $str) {
echo "they are the same";
}
?>
It may not be obvious exactly what will happen when casting between certain types. For more information, see these sections:
Każdą zmienną w PHP zapisuje się, poprzedzając jej nazwę znakiem dolara "$". Wielkość liter w nazwie zmiennej jest rozróżniana.
Nazw zmiennych dotyczą te same reguły, co innych rodzajów nazw w PHP. Poprawna nazwa zmiennej zaczyna się od litery lub znaku podkreślenia "_", po których może wystąpić dowolna ilość liter, cyfr lub znaków podkreślenia. Jako wyrażenie regularne, można to zapisać tak: '[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*'
Informacja: W naszym rozumieniu, litery to znaki a-z, A-Z i symbole ASCII od 127 do 255 (0x7f-0xff).
Informacja: $this to specialna zmienna, której nie można definiować.
Zobacz także Userland Naming Guide.
Aby uzyskać więcej informacji na temat funkcji powiązanych ze zmiennymi, zobacz Funkcje Obsługi Zmiennych.
<?php
$zmienna = 'Pan';
$Zmienna = 'Jan';
echo "$zmienna, $Zmienna"; // wyświetla "Pan, Jan"
$7dni = 'tydzień'; // niepoprawna nazwa - zaczyna się od cyfry
$_7dni = 'tydzień'; // poprawna nazwa - zaczyna się znakiem podkreślenia
$jaźń = 'osobowość'; // poprawna nazwa - "ń" i "ź" należą do ASCII 127-255
?>
Domyślnie, zmienne zawsze są zawsze przypisywane przez wartość. Innymi słowy, jeśli przypiszesz do zmiennej jakieś wyrażenie, wartość tego wyrażenia zostanie skopiowana do zmiennej. Oznacza to, że po przypisaniu wartości jednej zmiennej do drugiej, późniejsza zmiana wartości jednej z nich nie spowoduje zmiany wartości drugiej. Więcej informacji na ten temat w rozdziale Wyrażenia.
PHP oferuje jeszcze jeden sposób przypisywania wartości do zmiennych: przypisanie przez referencję. Oznacza to, że nowa zmienna tylko odnosi się (innymi słowy, "staje się aliasem" lub "wskazuje na") do pierwotnej zmiennej. Zmiany wykonane na nowej zmiennej oddziałują także na pierwotną zmienną i vice versa.
Aby przypisać przez referencję, postaw znak ampersand (&) przed nazwą zmiennej przypisywanej (zmiennej od której pobierasz wartość). Na przykład poniższy kod wyświetla "To jest PHP" dwa razy:
<?php
$foo = "PHP"; // Przypisz wartość "PHP" do $foo.
$bar = &$foo; // Przypisz referencyjnie $foo do $bar.
$bar = "To jest $bar"; // Zmień $bar...
echo $bar;
echo $foo; // $foo też się zmieniło.
?>
Należy pamiętać, że tylko wyrażenia posiadające nazwę mogą być przypisane przez referencję.
<?php
$foo = 25;
$bar = &$foo; // Przypisanie poprawne.
$bar = &(24 * 7); // Przypisanie niepoprawne - do nienazwanego wyrażenia.
function test()
{
return 25;
}
$bar = &test(); // Niepoprawne.
?>
W PHP nie jest konieczne inicjowanie zmiennych, jednak jest to bardzo dobry nawyk. Niezainicjowane zmienne mają domyślne wartości w zależności od ich typu - FALSE, zero, pusty łańcuch lub niewypełnioną tablicę.
Example #1 Domyślne wartości niezainicjowanych zmiennych
<?php
echo ($nieinicjowana_zmiena_bool ? "true" : "false"); // false
$nieinicjowana_zmienna_int += 25; // 0 + 25 => 25
echo $nieinicjowany_lancuch . "abc"; // "" . "abc" => "abc"
$nieinicjowana_tablica[3] = "def"; // array() + array(3 => "def") => array(3 => "def")
?>
Poleganie na domyślnej wartości niezainicjowanej zmiennej jest problematyczne, w razie zawarcia jednego pliku wewnątrz innego, posiadającego tak samo nazwane zmienne. Jest to również poważne zagrożenie dla bezpieczeństwa przy włączonej opcji register_globals. Ostrzeżenie klasy E_NOTICE pojawi się podczas pracy z niezainicjowanymi zmiennymi, jednak w przypadku przypisywania elentów do niezainicjowanych tablic - już nie. Funkcja isset() może zostać użyta w celu wykrycia, czy zmienna została już zainicjowana.
PHP udostępnia dla każdego pracującego skryptu dużą ilość predefiniowanych zmiennych. Jednakże wiele spośród tych zmiennych nie może być w pełni objaśnionych, gdyż są zależne od rodzaju serwera, jego wersji, ustawień i innych czynników. Niektóre z tych zmiennych nie będą dostępne dla skryptów PHP uruchomionych z Linii Poleceń. Lista tych zmiennych znajduje się w rozdziale Predefiniowane Zmienne.
W PHP 4.2.0 i późniejszych, domyślne ustawienie dla instrukcji PHP register_globals jest wyłączone. Jest to bardzo istotna zmiana w PHP. Mając opcję register_globals wyłączoną wpływamy na ustawienie zmiennych predefiniowanych, dostępnych globalnie. Na przykład, aby poznać wartość DOCUMENT_ROOT użyjesz $_SERVER['DOCUMENT_ROOT'] zamiast $DOCUMENT_ROOT, lub $_GET['id'] z adresu URL http://www.example.com/test.php?id=3 zamiast $id, albo $_ENV['HOME'] a nie $HOME.
Aby uzyskać informacje powiązane z tą zmianą, przeczytaj część o konfiguracji register_globals, rozdziału o bezpieczeństwie Używanie Register Globals , oraz w informacjach o wydaniu (ang. Release Announcements) PHP » 4.1.0 jak i » 4.2.0
Używanie dostępnych zmiennych predefiniowanych, jak tablice superglobalne, jest zalecane.
Począwszy od wersji 4.1.0, PHP udostępnia dodatkowo zestaw predefiniowanych tablic, które zawierają zmienne serwera, zmienne środowiskowe oraz zmienne użytkownika. Tablice te są dość specyficzne, gdyż są one automatycznie globalne, tzn. automatycznie dostępne w każdym miejscu. Dlatego nazywa się je "superglobalami". (W PHP nie ma mechanizmu pozwalającego użytkownikowi na definiowanie własnych superglobali.) Superglobale PHP wymienione są poniżej; jednakże wykaz ich zawartości i głębsze omówienie prefiniowanych zmiennych PHP oraz ich natury znajduje się w rozdziale predefiniowane zmienne. Zauważ także, że starsze zmienne predefiniowane ($HTTP_*_VARS) wciąż funkcjonują. Od PHP 5.0.0, długie tablice zmiennych predefiniowanych mogą być wyłączone dyrektywą konfiguracji register_long_arrays.
Informacja: Zmienne zmienne
Zmienne superglobale nie mogą być użyte jako zmienne zmienne wewnątrz funkcji, ani jako metody klasy.
Informacja: Nawet pomimo tego, że zmienne superglobalne i HTTP_*_VARS mogą istnieć w tym samym czasie; nie są one tożsame, czyli zmiana jednej nie zmieni drugiej.
Jeśli pewne zmienne w variables_order nie są ustawione, to ich odpowiedniki zmiennych predefiniowanych PHP również są puste.
Zasięg zmiennej zależy od miejsca, w jakim ją zdefiniowano. Najczęściej zmienne PHP widoczne są tylko w jednym zasięgu. Taki zasięg obejmuje również pliki dołączone funkcjami include i require. Na przykład:
<?php
$a = 1;
include 'b.inc';
?>
Tutaj zmienna $a będzie dostępna także wewnątrz dołączonego funkcją include pliku b.inc w skrypcie. Jednakże wewnątrz funkcji zdefiniowanych samodzielnie zmienne mają zasięg lokalny. Każda zmienna użyta wewnątrz funkcji jest domyślnie ograniczona do zasięgu lokalnego funkcji. Na przykład:
<?php
$a = 1; /* zasięg globalny */
function Test()
{
echo $a; /* odwołanie do zmiennej o zasięgu lokalnym */
}
Test();
?>
Ten skrypt nie wyświetli niczego, ponieważ instrukcja echo odwołuje się do zmiennej lokalnej $a, której jak dotąd nie została przypisana żadna wartość. Można tu zauważyć różnicę w stosunku do języka C, gdzie zmienne globalne są zawsze dostępne wewnątrz definicji funkcji, o ile nie zostały nadpisane przez lokalną definicję zmiennej. Może to spowodować problem, że ktoś może nieodwracalnie zmienić wartość zmiennej globalnej. W PHP zmienne globalne muszą być jawnie określone jako globalne wewnątrz funkcji, w której mają być użyte, do czego używamy słowa kluczowego global.
Najpierw, przykład użycia global:
Example #1 Używanie polecenia global
<?php
$a = 1;
$b = 2;
function Suma()
{
global $a, $b;
$b = $a + $b;
}
Suma();
echo $b;
?>
Powyższy skrypt wyświetli wynik "3". Przez zadeklarowanie wewnątrz funkcji globalności zmiennych $a i $b, wszystkie odwołania do tych zmiennych będą odnosiły się do ich globalnych wersji. Nie ma żadnych ograniczeń w ilości zmiennych globalnych, na których chcemy operować wewnątrz funkcji.
Drugim sposobem uzyskania dostępu do zmiennych globalnych wewnątrz funkcji jest użycie specjalnej, zdefiniowanej przez PHP tablicy $GLOBALS. Powyższy przykład można zatem przepisać tak:
Example #2 Używanie $GLOBALS zamiast polecenia global
<?php
$a = 1;
$b = 2;
function Suma()
{
$GLOBALS['b'] = $GLOBALS['a'] + $GLOBALS['b'];
}
Suma();
echo $b;
?>
Tablica $GLOBALS jest asocjacyjną tablicą, w której nazwa zmiennej jest kluczem, a zawartość zmiennej wartością komórki tablicy. Zauważ, że $GLOBALS jest dostępna z każdego miejsca, ponieważ $GLOBALS jest tablicą superglobalną. Poniżej przykład demonstrujący moc superglobali:
Example #3 Przykład demonstrujący superglobale i zasięg zmiennych
<?php
function test_global()
{
// Większość predefiniowanych zmiennych nie jest "super i wymaga
// 'global', by być dostępnymi w zasięgu lokalnym funkcji.
global $HTTP_POST_VARS;
echo $HTTP_POST_VARS['name'];
// Superglobale są dostępne z każdego miejsca
// i nie wymagają 'global'. Superglobale udostępniono
// wraz z PHP 4.1.0, a HTTP_POST_VARS jest
// uważane za przestarzałe.
echo $_POST['name'];
}
?>
Jeszcze jedną ważną rzeczą, związaną z zasięgiem zmiennych jest zmienna statyczna (ang. static variable). Zmienna statyczna może mieć wyłącznie zasięg lokalny, ale nie traci swojej wartości, kiedy program opuści ten zasięg lokalny, w którym dana zmienna statyczna się znajduje. Rozważmy poniższy przykład:
Example #4 Przykład ukazujący przydatność zmiennych statycznych
<?php
function Test()
{
$a = 0;
echo $a;
$a++;
}
?>
Ta funkcja jest bezużyteczna, gdyż przy każdym jej wywołaniu zmienna $a otrzymuje wartość 0, w związku z czym funkcja stale wyświetla "0". Występująca potem inkrementacja $a++ nie ma żadnego znaczenia, gdyż funkcja się kończy i zmienna $a znika. Aby powyższa funkcja miała jakiś sens, należy zapobiec gubieniu wartości $a, do czego używamy słowa kluczowego static:
Example #5 Przykład użycia zmiennych statycznych
<?php
function Test()
{
static $a = 0;
echo $a;
$a++;
}
?>
Teraz, za każdym wywołaniem funkcji test, zostanie wyświetlona wartość zmiennej $a, po czym ta zmienna zostanie inkrementowana.
Zmienne statyczne pozwalają też na wykorzystanie funkcji rekurencyjnych, czyli takich, które wywołują same siebie. Funkcje rekurencyjne należy pisać ostrożnie, gdyż łatwo jest wywołać nieskończoną rekurencję. Musisz być pewny, że masz odpowiednie mechanizmy do zatrzymania rekurencji w jakimś momencie. Poniższa, prosta funkcja rekurencyjnie liczy do 10, używając zmiennej statycznej $licznik, aby wiedzieć, kiedy się zatrzymać:
Example #6 Zmienne statyczne w funkcjach rekurencyjnych
<?php
function Test()
{
static $licznik = 0;
$licznik++;
echo $licznik;
if ($licznik < 10) {
Test();
}
$licznik--;
}
?>
Informacja: Zmienne statyczne mogą być deklarowane, tak jak w powyższym przykładzie. Próba przypisania wartości do tego typu zmiennych, poprzez wynik jakiegoś wyrażenia, spowoduje błąd składni (ang. Parse error).
Example #7 Deklaracja zmiennych statycznych
<?php
function foo(){
static $int = 0; // prawidłowo
static $int = 1+2; // błąd (w rzeczywistości to jest wyrażenie)
static $int = sqrt(121); // błąd (to również jest wyrażenie)
$int++;
echo $int;
}
?>
Silnik Zend 1 (ang. Zend Engine 1) napędzający PHP4, implementuje modyfikatory statyczny oraz globalny dla zmiennych, pod względem referencji. Na przykład, w rzeczywistości globalna zmienna wprowadzona wewnątrz zasięgu funkcji z wyrażeniem global na dziś dzień tworzy referencję do zmiennej globalnej. Takie zachowanie może prowadzić do nieoczekiwanych sytuacji, czego dowodzi poniższy przykład:
<?php
function test_global_ref() {
global $obj;
$obj = &new stdclass;
}
function test_global_noref() {
global $obj;
$obj = new stdclass;
}
test_global_ref();
var_dump($obj);
test_global_noref();
var_dump($obj);
?>
Wykonanie tego przykładu da następujące wyniki:
NULL
object(stdClass)(0) {
}
Podobna sytuacja dotyczy deklaracji static. Referencje nie są magazynowane statycznie:
<?php
function &get_instance_ref() {
static $obj;
echo 'Obiekt statyczny: ';
var_dump($obj);
if (!isset($obj)) {
// Przypisanie referencji do zmiennej statycznej.
$obj = &new stdclass;
}
$obj->property++;
return $obj;
}
function &get_instance_noref() {
static $obj;
echo 'Obiekt statyczny: ';
var_dump($obj);
if (!isset($obj)) {
// Przypisanie do obiektu zmiennej statycznej
$obj = new stdclass;
}
$obj->property++;
return $obj;
}
$obj1 = get_instance_ref();
$still_obj1 = get_instance_ref();
echo "\n";
$obj2 = get_instance_noref();
$still_obj2 = get_instance_noref();
?>
Wykonanie tego przykładu da następujące wyniki:
Obiekt statyczny: NULL
Obiekt statyczny: NULL
Obiekt statyczny: NULL
Obiekt statyczny: object(stdClass)(1) {
["property"]=>
int(1)
}
Ten przykład pokazuje, że podczas przypisywania referencji do zmiennej statycznej, nie następuje zapamiętanie, gdy wywołasz funkcję &get_instance_ref() po raz drugi.
W niektórych przypadkach jest wygodne, by móc użyć zmiennej o zmiennej nazwie. To znaczy zmiennej, której nazwa może być zmieniana dynamicznie. Zwykła zmienna jest ustawiana wyrażeniem jak poniżej:
<?php
$a = "witaj";
?>
Zmienna zmienna pobiera wartość jednej zmiennej i traktuje ją jako nazwę innej. W powyższym przykładzie, witaj, może stać się nazwą zmiennej, dzięki użyciu dwóch znaków dolara, tzn.
<?php
$$a = "świecie";
?>
W tym momencie dwie zmienne zostały zdefiniowane i umieszczone w drzewie symbolicznym PHP: $a zawierająca "witaj" i $witaj zawierająca "świecie". Zatem poniższy zapis:
<?php
echo "$a ${$a}";
?>
znaczy to samo, co:
<?php
echo "$a $witaj";
?>
tzn. obydwa wyświetlą: witaj świecie.
Aby używać zmiennych zmiennych jako tablic, trzeba wyjaśnić pewną niejasność. Mianowicie, jeśli napiszesz $$a[1], parser musi wiedzieć, czy chesz użyć $a[1] jako nazwy zmiennej, czy $$a jako nazwy tablicy, której rekord [1] cię interesuje. W tym przypadku należy zastosować odrębną składnię: ${$a[1]} dla pierwszego przypadku a ${$a}[1] dla drugiego.
Zauważ, że zmienne zmienne nie mogą być używane z Tablicami superglobalnymi PHP, wewnątrz funkcji, czy metod klas. Zmienna $this jest także specjalną zmienną, dla której referencje dynamiczne nie są dozwolone.
Kiedy do skryptu PHP zostanie wysłany formularz, informacja z niego jest automatycznie dostępna w skrypcie. Istnieje wiele sposobów na uzyskanie tych informacji, dla przykładu:
Example #1 Prosty formularz HTML
<form action="foo.php" method="post">
Imie: <input type="text" name="imie" /><br />
Email: <input type="text" name="email" /><br />
<input type="submit" name="submit" value="Wyslij!" />
</form>
W zależności od twoich szczególnych ustawień i osobistych upodobań, istnieje wiele sposobów dostępu do danych z twoich formularzy HTML. Oto kilka przykładów:
Example #2 Dostęp do informacji z prostego formularza HTML (wysłanego metodą POST)
<?php
// Możliwe od PHP 4.1.0
echo $_POST['imie'];
echo $_REQUEST['imie'];
import_request_variables('p', 'p_');
echo $p_imie;
// Niedostępne od PHP 6. Od PHP 5.0.0, te długie predefiniowane
// zmienne mogą być niedostępne z włączoną opcją register_long_arrays.
echo $HTTP_POST_VARS['imie'];
// Dostępne, jeśli opcja register_globals jest włączona - "on". Począwszy od
// PHP 4.2.0 domyślna wartość opcji register_globals to off.
// Nie jest zalecane poleganie na tej metodzie.
echo $imie;
?>
Przesyłanie danych z formularza metodą GET jest podobne, z takim wyjątkiem, że użyjesz zmienną predefiniowaną odpowiednią dla tej metody, zamiast poprzedniej. GET także odnosi się do tzw. QUERY_STRING (informacje w adresie URL, po znaku '?'). Tak więc, dla przykładu, http://www.example.com/test.php?id=3 zawiera dane dla metody GET, dostępne poprzez $_GET['id']. Zobacz także $_REQUEST oraz import_request_variables().
Informacja: Tablice superglobalne, takie jak $_POST i $_GET, zostały udostępnione w PHP 4.1.0
Jak widać, przed PHP 4.2.0 domyślną wartością opcji register_globals było on. Społeczność PHP jest całkowiie przekonana, by nie polegać na tej opcji; i rzeczywiście najlepiej jest nadać jej wartość off, oraz przystosować do tego kod.
Informacja: Dyrektywa konfiguracyjna magic_quotes_gpc oddziałuje na zmienne z Get, Post i Cookie. Jeśli jest włączona, tekst (It's "PHP!") automagicznie zmieni się w (It\'s \"PHP!\"). Jest to potrzebne przy wpisywaniu danych do baz danych. Zobacz także addslashes(), stripslashes() i magic_quotes_sybase.
PHP obsługuje także tablice w kontekście zmiennych z formularzy (zajrzyj do FAQ). Można na przykład pogrupować razem powiązane zmienne lub użyć tej możliwości do pobrania wartości z pola wyboru (select). Na przykład, wyślijmy formularz z pliku metodą POST do samego siebie i wyświetlmy te dane:
Example #3 Bardziej złożone zmienne w formularzach
<?php
if ($_POST) {
echo '<pre>';
echo htmlspecialchars(print_r($_POST, true));
echo '</pre>';
}
?>
<form action="" method="post">
Nazwisko: <input type="text" name="personal[nazwisko]"><br />
Email: <input type="text" name="personal[email]"><br />
Piwo: <br />
<select multiple name="piwo[]">
<option value="zywiec">Żywiec</option>
<option value="tyskie">Tyskie</option>
<option value="lech">Lech</option>
</select><br />
<input type="submit" value="Wyślij mnie!" />
</form>
Przy tworzeniu formularza, można użyć obrazka, zamiast standardowego przycisku Wyślij, za pomocą takiego znacznika:
<input type="image" src="obrazek.gif" name="sub" />
Kiedy użytkownik kliknie gdzieś na obrazku, formularz, którego to dotyczy, zostanie wysłany do serwera z dwiema dodatkowymi zmiennymi, sub_x i sub_y. Zawierają one współrzędne miejsca kliknięcia na obrazek. Można przy tym zauważyć, że na razie w nazwach zmiennych znajduje się kropka zamiast podkreślnika, ale PHP konwertuje kropkę na podkreślnik automatycznie.
PHP normalnie nie zmienia nazw zmiennych podczas przekazywania ich do skryptu. Jednakże należy pamiętać, że kropka "." nie jest poprawnym znakiem w nazwie zmiennej PHP. Dlaczego? Proszę spojrzeć na to:
<?php
$varname.ext; /* niepoprawna nazwa zmiennej */
?>
Warto zatem wiedzieć, że PHP automatycznie zastąpi podkreślnikiem "_" każdą kropkę w nazwie każdej odebranej zmiennej.
Ponieważ PHP samodzielnie określa typy zmiennych i konwertuje je (zasadniczo) jak potrzeba, nie zawsze jest jasne, jakiego typu jest dana zmienna w danym momencie. PHP zawiera kilka funkcji do określania typów zmiennych, takich jak: gettype(), is_array(), is_float(), is_int(), is_object() i is_string(). Zobacz także rozdział o Typach.
Stałe są to nazwy, identyfikujące proste wartości. Jak sama nazwa wskazuje, nie mogą się one zmieniać w trakcie wykonywania skryptu (wyjątkiem są magiczne stałe, które własciwie nie sa stałymi). W nazwach stałych domyślnie rozróżniana jest wielkość liter. Zgodnie z ogólnie przyjętą konwencją, nazwy stałych zawsze pisane sa wielkimi literami.
Nazwy stałych obowiązują identyczne zasady, jak w przypadku wszystkich innych etykiet. Poprawna nazwa stałej zaczyna się od litery lub podkreślnika, po których następuje dowolna ilość liter, cyfr i podkreślników. Jako wyrażenie regularne, określone zostałoby to następująco: [a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*
Zobacz także Userland Naming Guide.
Example #1 Poprawne i niepoprawne nazwy stałych
<?php
// Poprawne nazwy stałych
define("FOO", "something");
define("FOO2", "something else");
define("FOO_BAR", "something more");
// Niepoprawne nazwy stałych
define("2FOO", "something");
// Pomimo tego, że poniższy zapis jest poprawny, powinno się go unikać:
// PHP może kiedyś zawierać magiczną stałą,
// która zepsuje Twój skrypt
define("__FOO__", "something");
?>
Informacja: Dla naszych celów, literami są a-z, A-Z, oraz znaki ASCII z przedziału od 127 do 255 (0x7f-0xff).
Podobnie jak superglobals, zasięg stałych jest globalny. Można sie odwoływać do nich w każdym miejscu pliku, nie przejmując sie zasięgiem. Więcej informacji na ten temat znajdziesz w rozdziale pt. zasięg zmiennych.
Możesz zdefiniować stałą, używając funkcji define(). Raz zdefiniowana stała nie może byc zmieniona ani usunięta.
Stałe mogą zawierać jedynie dane skalarne (boolean, integer, float oraz string) Stałe nie mogą być typu resource.
Wartość stałej otrzymujemy, używając jej nazwy. W przeciwieństwie do zmiennych, nazw stałych nie poprzedzamy znakiem $. Możesz także użyć funkcji constant() do odczytania wartości stałej, jeśli chcesz wygenerować jej nazwę dynamicznie. Aby uzyskać listę wszystkich zdefiniowanych stałych, użyj get_defined_constants().
Informacja: Stałe i zmienne globalne operują w różnych przestrzeniach nazw. Oznacza to, że na przykład TRUE i $TRUE oznaczają co innego.
Jeśli używasz niezdefiniowanej stałej, PHP traktuje to, jak gdybyś chciał użyć nazwy stałej jako wartości typu string (STAŁA a "STAŁA"). Błąd typu E_NOTICE zostanie wywołany, kiedy to się stanie. Przeczytaj także, dlaczego $foo[bar] jest niepoprawne (jeśli nie zdefiniujesz bar jako stałej). Chcąc sprawdzić, czy dana stała istnieje, użyj funkcji defined().
Oto różnice pomiędzy stałymi i zmiennymi:
Example #1 Definiowanie stałych
<?php
define("CONSTANT", "Hello world.");
echo CONSTANT; // wypisuje "Hello world."
echo Constant; // wypisuje "Constant" i wywoułuje ostrzeżenie.
?>
Zobacz także Stałe Klas.
PHP zapewnia szeroki zakres predefiniowanych stałych każdemu skryptowi, który jest uruchamiany. Wiele z tych stałych jest jednak dostępnych dzieki różnym rozszerzeniom i można z nich korzystać jedynie, kiedy te rozszerzenia sa dostępne przez dynamiczne załadowanie, badź też zostały wkompilowane.
Istnieje siedem magicznych stałych, które zmieniają sie w zależności od tego, gdzie są użyte. Na przykład, wartość __LINE__ zależy od linii, w której ta stała została użyta. Nazwy tych magicznych stałych są niezależne od wielkości liter:
| Nazwa | Opis |
|---|---|
| __LINE__ | Aktualna linia pliku. |
| __FILE__ | Pełna scieżka i nazwa pliku. Jeśli użyta wewnątrz dołączonego pliku, jego nazwa jest zwracana. Od PHP 4.0.2, __FILE__zawsze zawiera bezwzględną scieżkę z rozwiązanymi dowiązaniami symbolicznymi, podczas kiedy w starszych wersjach czasem zawierała scieżkę względną. |
| __DIR__ | Nazwa katalogu pliku. Jeśli użyta wewnątrz dołączonego pliku, zwraca nazwę jego katalogu. Odpowiada dirname(__FILE__). Zwracana nazwa nie zawiera końcowego ukośnika, chyba że jest to katalog root. (Dodano w PHP 5.3.0.) |
| __FUNCTION__ | Nazwa funkcji. (Dodano w PHP 4.3.0) W PHP 5 ta stała zwraca nazwę funkcji tak jak ją zadeklarowano (z uwzględnieniem wielkości liter), podczas kiedy w PHP 4 zwracana wartość zawiera jedynie małe litery. |
| __CLASS__ | Nazwa klasy. (Dodano w PHP 4.3.0) W PHP 5 ta stała zwraca nazwę klasy tak jak ją zadeklarowano (z uwzględnieniem wielkości liter), podczas kiedy w PHP 4 zwracana wartość zawiera jedynie małe litery. |
| __METHOD__ | Nazwa metody. (Dodano w PHP 5.0.0) Nazwa metody zwracana jest tak jak ją zadeklarowano (z uwzględnieniem wielkości liter). |
| __NAMESPACE__ | Nazwa aktualnej przestrzeni nazw (z uwzględnieniem wielkości liter). Ta stała definiowana jest w czasie kompilacji (Dodano w PHP 5.3.0). |
Zobacz także get_class(), get_object_vars(), file_exists() i function_exists().
Wyrażenia są naważniejszymi elementami składowymi PHP. W PHP prawie wszystko co napiszesz jest wyrażeniem. Najprostszą i najdokładniejszą definicją wyrażenia jest "wszystko co ma wartość".
Najbardziej podstawową formą wyrażeń są stałe i zmienna. Jeśli napiszesz "$a = 5" przypisujesz '5' do '$a'. '5' ma oczywiście wartość 5, lub innymi słowy '5' jest wyrażeniem o wartości 5 (w tym przypadku, '5' jest stałą liczbą całkowitą).
Po tym przypisaniu możesz się spodziwać, że wartością $a jest także 5, więc jeśli napiszesz "$b = $a" możesz się spodziewać, że będzie to równoznaczne z napisaniem "$b = 5". Innymi słowy, $a jest wyrażeniem o wartości 5. Jeśli wszystko działa prawidłowo, wszystko będzie się dziać tak jak napisano wyżej.
Trochę bardziej złożonymi przykładami wyrażeń są funkcje. Przyjrzyj się poniższej funkcji:
<?php
function foo ()
{
return 5;
}
?>
Zakładając że oswoiłeś się z koncepcją funkcji (jeśli nie, przejrzyj najpierw rozdział o funkcjach), możesz założyć, że napisanie $c = foo() jest równoznaczne z napisaniem $c = 5, i masz racię. Funkcje są wyrażeniami o wartości którą zwracają. Ponieważ foo() zwraca 5, wartością wyrażenia 'foo()' jest 5. Zazwyczaj funkcje nie zwracają statycznej wartości, ale coś obliczają.
Oczywiście wartości w PHP nie muszą być liczbami całkowitymi, i bardzo często nie są nimi. PHP obsługuje 3 skalarne warotści danych: wartości całkowite (integer), wartości rzeczywiste (float i ciągi znaków (string) (wartości skalarne to takie, których nie możesz 'rozbić' na mniejsze kawałki, w przeciwieństwie do np. tablic). PHP obsługuje także dwa złożone (nieskalarne) typy danych: tablice i obiekty. Każdą z tych wartości można przypisać do zmiennych lub może być zwrócona przez funkcję.
PHP rozwija wyrażenia znacznie bardziej, podobnie jak wiele innych języków programowania. PHP jest językiem zorientowanym na wyrażenia, co oznacza że prawie wszystko jest wyrażeniem. Przyjrzyj się przykładowi który już analizowaliśmy, '$a = 5'. Łatwo jest zauważyć, że są tu dwie wartości. Wartość stałej całkowitej '5', a także wartość $a, która zostanie zamieniona na 5. Ale tak naprawdę jest tu jeszcze jedna wartość, którą jest wartość operacji przypisania. Przypisanie przyjmuje wartość przypisywanej wartości, w tym przypadku 5. W praktyce oznacza to, że '$a = 5', niezależnie co to robi, jest wyrażeniem o wartości 5. Wynika z tego, że napisanie '$b = ($a = 5)' jest równoznaczne napisaniu '$a = 5; $b = 5;' (średnik oznacza koniec instrukcji). Ponieważ przypisania są przetwarzane od prawej do lewej, możesz także napisać '$b = $a = 5'.
Kolejnym dobrym przykładem orientacji wyrażeniowej jest pre- i postinkrementacja i dekrementacja. Użytkownicy PHP i wielu innych języków mogą być już zaznajomieni z notacją zmienna++ i zmienna--. Są to operatory inkrementacji i dekrementacji. W PHP/FI 2 instrukcja '$a++' nie ma wartości (nie jest wyrażeniem), więc nie możesz jej przypisać lub użyć w jakikolwiek sposób. PHP rozszerza możliwości inkrementacji/dekrementacji robiąc także z nich wyrażenia, podobnie jak w C. W PHP, tak jak w C, sa dwa typy inkrementacji: preinkrementacja i postinkrementacja. I pre- i postinkrementacja zwiększają wartość zmiannej, więc efekt w stosunku do zmiennej jest taki sam. Różnica jest w wartości wyrażenia inkrementacji. Preinkrementacja, która jest oznaczana jako '++$zmienna', zwraca zwiększoną wartość (PHP zwiększa zmienną przed odczytaniem wartości, dlatego nazywa się to 'pre-inkrementacją'). Postinkrementacja, która jest oznaczana jako '$zmienna++', zwraca orginalną wartość $zmienna przed zwiększeniem jej wartości (PHP zwiększa wartość po odczytaniu jej wartości, stąd nazwa 'post-inkrementacja').
Popularnym typem wyrażeń są porównania. Wyrażenia te zwracają wartość FALSE lub TRUE. PHP obsługuje > (większy), >= (większy lub równy), == (równy), != (nie równy), < (mniejszy) i <= (mniejszy lub równy). Język obsługuje także zbiór operatorów ścisłego porównania: === (równy i tego samego typu) i !== (nie równy lub różnego typu). Wyrażenia te są powszechnie używane przy sprawdzaniu warunków, jak na przykład instrukcje if.
Ostatnim przykładem, którym będziemy się tu zajmować są połączone wyrażenia operacji i przypisania. Już wiesz, że jeśli chcesz zwiększyć wartość zmiennej $a o 1, możesz po prostu napisać '$a++' lub '++$a'. Ale co jeśli chcesz dodać do niej więcej niż jeden, na przykład 3? Mógłbyś napisać wielokrotnie '$a++', ale nie jest to sposób ani efektywny ani wygodny. Częściej spotykane jest używanie instrukcji '$a = $a + 3'. '$a + 4' zwraca wartość zmiennej $a plus 3, która jest przypisywana z powrotem do $a, co oznacza zwiększenie wartości zmiennej $a o 3. W PHP, tak jak kilku innych językach jak na przykład C, możesz napisać to krócej, co z czasem stanie się także bardziej przejrzyste i łatwiejsze do zrozumienia. Dodanie 4 do bieżącej wartości $a może być zapisane jako '$a += 4'. Oznacza to dokładnie "weź wartość $a, dodaj do niej 3 i przypisz ją z powrotem do $a". Oprócz bycia krótszą i bardziej przejrzystą, instrukcja ta jest także szybsza w wykonaniu. Wartość '$a += 5', tak jak wartość zwykłego przypisania, jest przypisywaną wartością. Zauważ, że NIE jest to 4, ale połączona warotść $a i 4 (jest to wartość która jest przypisywana do $a). Dowolne dwuoperandowe operatory mogą być użyte w trybie operacji-przypisania, na przykład '$a -= 5' (odejmij 5 od wartości $a), '$b *= 7' (pomnóż wartość $b przez 7), itp.
Jest jeszcze jedno wyrażenie, które może się wydać dziwne jeśli nie widziałeś go w innych językac, trójoperandowy operator warunkowy:
<?php
$pierwsze ? $drugie : $trzecie
?>
Jeśli wartością pierwszego podwyrażenia jest TRUE (rózna od zera), to zwracany jest drugie podwyrażanie, i jest to wynik wyrażenia warunkowego. W przeciwnym wypadku, zwracana jest wartość trzeciego podwyrażenia.
Poniższy przykład powinien pomóc w lepszym zrozumieniu pre- i postinkrementacji i ogólnie koncepcji wyrażeń:
<?php
function double($i)
{
return $i*2;
}
$b = $a = 5; /* przypisz wartość pięc do zmiennej $a i $b */
$c = $a++; /* postinkrementuj, przypisz początkową wartość
$a (5) do $c */
$e = $d = ++$b; /* preinkrementuj, przypisz zwiększoną wartość
$b (6) to $d i $e */
/* w tym momencie i $d i $e są równe 6 */
$f = double($d++); /* przypisz podwojoną wartość $d przed
inkrementacji, 2*6 = 12 do $f */
$g = double(++$e); /* przypisz podwojoną wartość $e po
inkrementacji, 2*7 = 14 do $g */
$h = $g += 10; /* na początku $g jest zwiększane o 10 i przyjmuje
wartość 24; wartość przypisania (24) jest później
przypisywana do $h, które przyjmuje wartość 24. */
?>
Na początku rozdziału powiedzieliśmy, że będziemy opisywać różne typy instrukcji, i tak jak obiecywaliśmy, wyrażenia mogą być instrukcjami. Jednakże nie każde wyrażenie jest instrukcją. Niektóre wyrażenia mogą być instrukcjami. Ten przypadek ma postać 'wyrażenie' ';', czyli wyrażenie a po nim średnik. W '$b=$a=5;', $a=5 jest poprawnym wyrażeniem, ale nie jest instrukcją. Jednakże '$b=$a=$b;' jest poprawną intrukcją.
Ostatnią rzeczą wartą uwagi jest wartość prawdy wyrażeń. W wielu przypadkach, głównie przy sprawdzaniu warunkow i w pętlach, nie interesuje cię wartość wyrażenia, ale tylko czy oznacza TRUE czy FALSE. Stałe TRUE i FALSE (niezależne od wielkości znaków) są dwiema możliwymi wartościami logicznymi. Kiedy to konieczne, wyrażenie jest automatycznie konwertowane na typ boolean. Zobacz rozdział o rzutowaniu typów jeśli interesują cię szczegóły jak to jest przeprowadzane.
PHP dostarcza pełnej i potężnej implementacji wyrażeń i całkowita ich dokumentacja przekracza ramy tego podręcznika. Powyższe przykłady powinny dać ci ogólne pojęcie czym są wyrażenia i jak możesz konstruować przydatne wyrażenia. Przez resztę podręcznika będziemy pisać expr aby oznaczyć dowolne poprawne wyrażenie PHP.
An operator is something that you feed with one or more values (or expressions, in programming jargon) which yields another value (so that the construction itself becomes an expression). So you can think of functions or constructions that return a value (like print) as operators and those that return nothing (like echo) as any other thing.
There are three types of operators. Firstly there is the unary operator which operates on only one value, for example ! (the negation operator) or ++ (the increment operator). The second group are termed binary operators; this group contains most of the operators that PHP supports, and a list follows below in the section Operator Precedence.
The third group is the ternary operator: ?:. It should be used to select between two expressions depending on a third one, rather than to select two sentences or paths of execution. Surrounding ternary expressions with parentheses is a very good idea.
The precedence of an operator specifies how "tightly" it binds two expressions together. For example, in the expression 1 + 5 * 3, the answer is 16 and not 18 because the multiplication ("*") operator has a higher precedence than the addition ("+") operator. Parentheses may be used to force precedence, if necessary. For instance: (1 + 5) * 3 evaluates to 18. If operator precedence is equal, left to right associativity is used.
The following table lists the precedence of operators with the highest-precedence operators listed at the top of the table. Operators on the same line have equal precedence, in which case their associativity decides which order to evaluate them in.
| Associativity | Operators | Additional Information |
|---|---|---|
| non-associative | clone new | clone and new |
| left | [ | array() |
| non-associative | ++ -- | increment/decrement |
| non-associative | ~ - (int) (float) (string) (array) (object) (bool) @ | types |
| non-associative | instanceof | types |
| right | ! | logical |
| left | * / % | arithmetic |
| left | + - . | arithmetic i string |
| left | << >> | bitwise |
| non-associative | < <= > >= <> | comparison |
| non-associative | == != === !== | comparison |
| left | & | bitwise i references |
| left | ^ | bitwise |
| left | | | bitwise |
| left | && | logical |
| left | || | logical |
| left | ? : | ternary |
| right | = += -= *= /= .= %= &= |= ^= <<= >>= | assignment |
| left | and | logical |
| left | xor | logical |
| left | or | logical |
| left | , | many uses |
Left associativity means that the expression is evaluated from left to right, right associativity means the opposite.
Example #1 Associativity
<?php
$a = 3 * 3 % 5; // (3 * 3) % 5 = 4
$a = true ? 0 : true ? 1 : 2; // (true ? 0 : true) ? 1 : 2 = 2
$a = 1;
$b = 2;
$a = $b += 3; // $a = ($b += 3) -> $a = 5, $b = 5
?>
Use parentheses to increase readability of the code.
Informacja: Although = has a lower precedence than most other operators, PHP will still allow expressions similar to the following: if (!$a = foo()), in which case the return value of foo() is put into $a.
Remember basic arithmetic from school? These work just like those.
| Example | Name | Result |
|---|---|---|
| -$a | Negation | Opposite of $a. |
| $a + $b | Addition | Sum of $a and $b. |
| $a - $b | Subtraction | Difference of $a and $b. |
| $a * $b | Multiplication | Product of $a and $b. |
| $a / $b | Division | Quotient of $a and $b. |
| $a % $b | Modulus | Remainder of $a divided by $b. |
The division operator ("/") returns a float value unless the two operands are integers (or strings that get converted to integers) and the numbers are evenly divisible, in which case an integer value will be returned.
Operands of modulus are converted to integers (by stripping the decimal part) before processing.
Informacja: Remainder $a % $b is negative for negative $a.
See also the manual page on Math functions.
The basic assignment operator is "=". Your first inclination might be to think of this as "equal to". Don't. It really means that the left operand gets set to the value of the expression on the rights (that is, "gets set to").
The value of an assignment expression is the value assigned. That is, the value of "$a = 3" is 3. This allows you to do some tricky things:
<?php
$a = ($b = 4) + 5; // $a is equal to 9 now, and $b has been set to 4.
?>
In addition to the basic assignment operator, there are "combined operators" for all of the binary arithmetic, array union and string operators that allow you to use a value in an expression and then set its value to the result of that expression. For example:
<?php
$a = 3;
$a += 5; // sets $a to 8, as if we had said: $a = $a + 5;
$b = "Hello ";
$b .= "There!"; // sets $b to "Hello There!", just like $b = $b . "There!";
?>
Note that the assignment copies the original variable to the new one (assignment by value), so changes to one will not affect the other. This may also have relevance if you need to copy something like a large array inside a tight loop. Assignment by reference is also supported, using the $var = &$othervar; syntax. 'Assignment by reference' means that both variables end up pointing at the same data, and nothing is copied anywhere. To learn more about references, please read References explained. As of PHP 5, objects are assigned by reference unless explicitly told otherwise with the new clone keyword.
Bitwise operators allow you to turn specific bits within an integer on or off. If both the left- and right-hand parameters are strings, the bitwise operator will operate on the characters' ASCII values.
<?php
echo 12 ^ 9; // Outputs '5'
echo "12" ^ "9"; // Outputs the Backspace character (ascii 8)
// ('1' (ascii 49)) ^ ('9' (ascii 57)) = #8
echo "hallo" ^ "hello"; // Outputs the ascii values #0 #4 #0 #0 #0
// 'a' ^ 'e' = #4
echo 2 ^ "3"; // Outputs 1
// 2 ^ ((int)"3") == 1
echo "2" ^ 3; // Outputs 1
// ((int)"2") ^ 3 == 1
?>
| Example | Name | Result |
|---|---|---|
| $a & $b | And | Bits that are set in both $a and $b are set. |
| $a | $b | Or | Bits that are set in either $a or $b are set. |
| $a ^ $b | Xor | Bits that are set in $a or $b but not both are set. |
| ~ $a | Not | Bits that are set in $a are not set, and vice versa. |
| $a << $b | Shift left | Shift the bits of $a $b steps to the left (each step means "multiply by two") |
| $a >> $b | Shift right | Shift the bits of $a $b steps to the right (each step means "divide by two") |
Don't right shift for more than 32 bits on 32 bits systems. Don't left shift in case it results to number longer than 32 bits.
Comparison operators, as their name implies, allow you to compare two values. You may also be interested in viewing the type comparison tables, as they show examples of various type related comparisons.
| Example | Name | Result |
|---|---|---|
| $a == $b | Equal | TRUE if $a is equal to $b. |
| $a === $b | Identical | TRUE if $a is equal to $b, and they are of the same type. (introduced in PHP 4) |
| $a != $b | Not equal | TRUE if $a is not equal to $b. |
| $a <> $b | Not equal | TRUE if $a is not equal to $b. |
| $a !== $b | Not identical | TRUE if $a is not equal to $b, or they are not of the same type. (introduced in PHP 4) |
| $a < $b | Less than | TRUE if $a is strictly less than $b. |
| $a > $b | Greater than | TRUE if $a is strictly greater than $b. |
| $a <= $b | Less than or equal to | TRUE if $a is less than or equal to $b. |
| $a >= $b | Greater than or equal to | TRUE if $a is greater than or equal to $b. |
If you compare an integer with a string, the string is converted to a number. If you compare two numerical strings, they are compared as integers. These rules also apply to the switch statement.
<?php
var_dump(0 == "a"); // 0 == 0 -> true
var_dump("1" == "01"); // 1 == 1 -> true
var_dump("1" == "1e0"); // 1 == 1 -> true
switch ("a") {
case 0:
echo "0";
break;
case "a": // never reached because "a" is already matched with 0
echo "a";
break;
}
?>
For various types, comparison is done according to the following table (in order).
| Type of Operand 1 | Type of Operand 2 | Result |
|---|---|---|
| null or string | string | Convert NULL to "", numerical or lexical comparison |
| bool or null | anything | Convert to bool, FALSE < TRUE |
| object | object | Built-in classes can define its own comparison, different classes are uncomparable, same class - compare properties the same way as arrays (PHP 4), PHP 5 has its own explanation |
| string, resource or number | string, resource or number | Translate strings and resources to numbers, usual math |
| array | array | Array with fewer members is smaller, if key from operand 1 is not found in operand 2 then arrays are uncomparable, otherwise - compare value by value (see following example) |
| array | anything | array is always greater |
| object | anything | object is always greater |
Example #1 Transcription of standard array comparison
<?php
// Arrays are compared like this with standard comparison operators
function standard_array_compare($op1, $op2)
{
if (count($op1) < count($op2)) {
return -1; // $op1 < $op2
} elseif (count($op1) > count($op2)) {
return 1; // $op1 > $op2
}
foreach ($op1 as $key => $val) {
if (!array_key_exists($key, $op2)) {
return null; // uncomparable
} elseif ($val < $op2[$key]) {
return -1;
} elseif ($val > $op2[$key]) {
return 1;
}
}
return 0; // $op1 == $op2
}
?>
See also strcasecmp(), strcmp(), Array operators, and the manual section on Types.
Another conditional operator is the "?:" (or ternary) operator.
Example #2 Assigning a default value
<?php
// Example usage for: Ternary Operator
$action = (empty($_POST['action'])) ? 'default' : $_POST['action'];
// The above is identical to this if/else statement
if (empty($_POST['action'])) {
$action = 'default';
} else {
$action = $_POST['action'];
}
?>
The expression (expr1) ? (expr2) : (expr3) evaluates to expr2 if expr1 evaluates to TRUE, and expr3 if expr1 evaluates to FALSE.
Informacja: Please note that the ternary operator is a statement, and that it doesn't evaluate to a variable, but to the result of a statement. This is important to know if you want to return a variable by reference. The statement return $var == 42 ? $a : $b; in a return-by-reference function will therefore not work and a warning is issued in later PHP versions.
Informacja: Is is recommended that you avoid "stacking" ternary expressions. PHP's behaviour when using more than one ternary operator within a single statement is non-obvious:
Example #3 Non-obvious Ternary Behaviour
<?php
// on first glance, the following appears to output 'true'
echo (true?'true':false?'t':'f');
// however, the actual output of the above is 't'
// this is because ternary expressions are evaluated from left to right
// the following is a more obvious version of the same code as above
echo ((true ? 'true' : 'false') ? 't' : 'f');
// here, you can see that the first expression is evaluated to 'true', which
// in turn evaluates to (bool)true, thus returning the true branch of the
// second ternary expression.
?>
PHP supports one error control operator: the at sign (@). When prepended to an expression in PHP, any error messages that might be generated by that expression will be ignored.
If the track_errors feature is enabled, any error message generated by the expression will be saved in the variable $php_errormsg. This variable will be overwritten on each error, so check early if you want to use it.
<?php
/* Intentional file error */
$my_file = @file ('non_existent_file') or
die ("Failed opening file: error was '$php_errormsg'");
// this works for any expression, not just functions:
$value = @$cache[$key];
// will not issue a notice if the index $key doesn't exist.
?>
Informacja: The @-operator works only on expressions. A simple rule of thumb is: if you can take the value of something, you can prepend the @ operator to it. For instance, you can prepend it to variables, function and include() calls, constants, and so forth. You cannot prepend it to function or class definitions, or conditional structures such as if and foreach, and so forth.
See also error_reporting() and the manual section for Error Handling and Logging functions.
Currently the "@" error-control operator prefix will even disable error reporting for critical errors that will terminate script execution. Among other things, this means that if you use "@" to suppress errors from a certain function and either it isn't available or has been mistyped, the script will die right there with no indication as to why.
PHP supports one execution operator: backticks (``). Note that these are not single-quotes! PHP will attempt to execute the contents of the backticks as a shell command; the output will be returned (i.e., it won't simply be dumped to output; it can be assigned to a variable). Use of the backtick operator is identical to shell_exec().
<?php
$output = `ls -al`;
echo "<pre>$output</pre>";
?>
Informacja: The backtick operator is disabled when tryb bezpieczny is enabled or shell_exec() is disabled.
See also the manual section on Program Execution functions, popen() proc_open(), and Using PHP from the commandline.
PHP supports C-style pre- and post-increment and decrement operators.
Informacja: The increment/decrement operators do not affect boolean values. Decrementing NULL values has no effect too, but incrementing them results in 1.
| Example | Name | Effect |
|---|---|---|
| ++$a | Pre-increment | Increments $a by one, then returns $a. |
| $a++ | Post-increment | Returns $a, then increments $a by one. |
| --$a | Pre-decrement | Decrements $a by one, then returns $a. |
| $a-- | Post-decrement | Returns $a, then decrements $a by one. |
Here's a simple example script:
<?php
echo "<h3>Postincrement</h3>";
$a = 5;
echo "Should be 5: " . $a++ . "<br />\n";
echo "Should be 6: " . $a . "<br />\n";
echo "<h3>Preincrement</h3>";
$a = 5;
echo "Should be 6: " . ++$a . "<br />\n";
echo "Should be 6: " . $a . "<br />\n";
echo "<h3>Postdecrement</h3>";
$a = 5;
echo "Should be 5: " . $a-- . "<br />\n";
echo "Should be 4: " . $a . "<br />\n";
echo "<h3>Predecrement</h3>";
$a = 5;
echo "Should be 4: " . --$a . "<br />\n";
echo "Should be 4: " . $a . "<br />\n";
?>
PHP follows Perl's convention when dealing with arithmetic operations on character variables and not C's. For example, in Perl 'Z'+1 turns into 'AA', while in C 'Z'+1 turns into '[' ( ord('Z') == 90, ord('[') == 91 ). Note that character variables can be incremented but not decremented and even so only plain ASCII characters (a-z and A-Z) are supported.
Example #1 Arithmetic Operations on Character Variables
<?php
$i = 'W';
for ($n=0; $n<6; $n++) {
echo ++$i . "\n";
}
?>
Powyższy przykład wyświetli:
X Y Z AA AB AC
Incrementing or decrementing booleans has no effect.
| Example | Name | Result |
|---|---|---|
| $a and $b | And | TRUE if both $a and $b are TRUE. |
| $a or $b | Or | TRUE if either $a or $b is TRUE. |
| $a xor $b | Xor | TRUE if either $a or $b is TRUE, but not both. |
| ! $a | Not | TRUE if $a is not TRUE. |
| $a && $b | And | TRUE if both $a and $b are TRUE. |
| $a || $b | Or | TRUE if either $a or $b is TRUE. |
The reason for the two different variations of "and" and "or" operators is that they operate at different precedences. (See Operator Precedence.)
Example #1 Logical operators illustrated
<?php
// foo() will never get called as those operators are short-circuit
$a = (false && foo());
$b = (true || foo());
$c = (false and foo());
$d = (true or foo());
// "||" has a greater precedence than "or"
$e = false || true; // $e will be assigned to (false || true) which is true
$f = false or true; // $f will be assigned to false
var_dump($e, $f);
// "&&" has a greater precedence than "and"
$g = true && false; // $g will be assigned to (true && false) which is false
$h = true and false; // $h will be assigned to true
var_dump($g, $h);
?>
Powyższy przykład wyświetli coś podobnego do:
bool(true) bool(false) bool(false) bool(true)
There are two string operators. The first is the concatenation operator ('.'), which returns the concatenation of its right and left arguments. The second is the concatenating assignment operator ('.='), which appends the argument on the right side to the argument on the left side. Please read Assignment Operators for more information.
<?php
$a = "Hello ";
$b = $a . "World!"; // now $b contains "Hello World!"
$a = "Hello ";
$a .= "World!"; // now $a contains "Hello World!"
?>
See also the manual sections on the String type and String functions.
| Example | Name | Result |
|---|---|---|
| $a + $b | Union | Union of $a and $b. |
| $a == $b | Equality | TRUE if $a and $b have the same key/value pairs. |
| $a === $b | Identity | TRUE if $a and $b have the same key/value pairs in the same order and of the same types. |
| $a != $b | Inequality | TRUE if $a is not equal to $b. |
| $a <> $b | Inequality | TRUE if $a is not equal to $b. |
| $a !== $b | Non-identity | TRUE if $a is not identical to $b. |
The + operator appends elements of remaining keys from the right handed array to the left handed, whereas duplicated keys are NOT overwritten.
<?php
$a = array("a" => "apple", "b" => "banana");
$b = array("a" => "pear", "b" => "strawberry", "c" => "cherry");
$c = $a + $b; // Union of $a and $b
echo "Union of \$a and \$b: \n";
var_dump($c);
$c = $b + $a; // Union of $b and $a
echo "Union of \$b and \$a: \n";
var_dump($c);
?>
When executed, this script will print the following:
Union of $a and $b: array(3) { ["a"]=> string(5) "apple" ["b"]=> string(6) "banana" ["c"]=> string(6) "cherry" } Union of $b and $a: array(3) { ["a"]=> string(4) "pear" ["b"]=> string(10) "strawberry" ["c"]=> string(6) "cherry" }
Elements of arrays are equal for the comparison if they have the same key and value.
Example #1 Comparing arrays
<?php
$a = array("apple", "banana");
$b = array(1 => "banana", "0" => "apple");
var_dump($a == $b); // bool(true)
var_dump($a === $b); // bool(false)
?>
See also the manual sections on the Array type and Array functions.
instanceof is used to determine whether a PHP variable is an instantiated object of a certain class:
Example #1 Using instanceof with classes
<?php
class MyClass
{
}
class NotMyClass
{
}
$a = new MyClass;
var_dump($a instanceof MyClass);
var_dump($a instanceof NotMyClass);
?>
Powyższy przykład wyświetli:
bool(true) bool(false)
instanceof can also be used to determine whether a variable is an instantiated object of a class that inherits from a parent class:
Example #2 Using instanceof with inherited classes
<?php
class ParentClass
{
}
class MyClass extends ParentClass
{
}
$a = new MyClass;
var_dump($a instanceof MyClass);
var_dump($a instanceof ParentClass);
?>
Powyższy przykład wyświetli:
bool(true) bool(true)
To check if an object is not an instanceof a class, the logical not operator can be used.
Example #3 Using instanceof to check if object is not an instanceof a class
<?php
class MyClass
{
}
$a = new MyClass;
var_dump(!($a instanceof stdClass));
?>
Powyższy przykład wyświetli:
bool(true)
Lastly, instanceof can also be used to determine whether a variable is an instantiated object of a class that implements an interface:
Example #4 Using instanceof for class
<?php
interface MyInterface
{
}
class MyClass implements MyInterface
{
}
$a = new MyClass;
var_dump($a instanceof MyClass);
var_dump($a instanceof MyInterface);
?>
Powyższy przykład wyświetli:
bool(true) bool(true)
Although instanceof is usually used with a literal classname, it can also be used with another object or a string variable:
Example #5 Using instanceof with other variables
<?php
interface MyInterface
{
}
class MyClass implements MyInterface
{
}
$a = new MyClass;
$b = new MyClass;
$c = 'MyClass';
$d = 'NotMyClass';
var_dump($a instanceof $b); // $b is an object of class MyClass
var_dump($a instanceof $c); // $c is a string 'MyClass'
var_dump($a instanceof $d); // $d is a string 'NotMyClass'
?>
Powyższy przykład wyświetli:
bool(true) bool(true) bool(false)
There are a few pitfalls to be aware of. Before PHP version 5.1.0, instanceof would call __autoload() if the class name did not exist. In addition, if the class was not loaded, a fatal error would occur. This can be worked around by using a dynamic class reference, or a string variable containing the class name:
Example #6 Avoiding classname lookups and fatal errors with instanceof in PHP 5.0
<?php
$d = 'NotMyClass';
var_dump($a instanceof $d); // no fatal error here
?>
Powyższy przykład wyświetli:
bool(false)
The instanceof operator was introduced in PHP 5. Before this time is_a() was used but is_a() has since been deprecated in favor of instanceof. Note that as of PHP 5.3.0, is_a() is no longer deprecated.