Vad är PHP?

PHP (rekursiv akronym för "PHP: Hypertext Preprocessor") är ett vida spritt Open Source-scriptspråk med brett användningsområde. Det lämpar sig speciellt för webbutveckling och kan bäddas in i HTML.

Enkelt svar, men vad betyder det? Ett exempel:

Notera hur PHP skiljer sig från ett script skrivet i andra språk, som t.ex. Perl eller C - istället för att skriva ett program med massor av kommandon som i sin tur skriver ut HTML, skriver du istället HTML med inbäddad PHP-kod som utför något (i det här fallet; skriver ut lite text). PHP-koden omsluts av speciella start- och slut-taggar som gör det möjligt att växla mellan PHP-kod och HTML.

Det som utmärker PHP från något som t.ex. JavaScript är att koden exekveras på servern istället för hos användaren. Om du skulle använda ett script liknande det ovan på din server, skulle klienten få resultatet av exekveringen men utan någon möjlighet att ta reda på vilken kod som ligger bakom den. Du kan till och med konfigurera din webbserver att tolka alla dina HTML-filer genom PHP-motorn, och då finns verkligen inget sätt för användaren att se vad som finns bakom.

Det bästa med PHP är att det är oerhört enkelt att lära sig, men ändå erbjuder avancerade funktioner för professionella programmerare. Bli inte avskräckt av den långa listan med funktioner, från det att man börjar lära sig PHP tar det inte längre än några timmar innan man kan skriva enkla script.

Även om PHP's utveckling fokuseras på server-side-scripting kan du göra mycket mer med PHP. Läs vidare, och se mer under rubriken Vad kan PHP göra?.

Vad kan PHP göra?

Vad som helst. PHP's fokus ligger på server-side-scripting, vilket betyder att du kan göra allt som andra CGI-program kan göra, såsom att samla in data, generera dynamiska webbsidor eller skicka och ta emot cookies. Men PHP kan göra mer än så.

Det finns tre huvudområden där PHP-script används.

• Server-side-scripting. Det här är det mest traditionella och huvudsakliga användningsområdet för PHP. Du behöver tre saker för att det ska fungera: PHP-motorn (CGI- eller server-modul), en webbserver och en webbläsare. Du måste köra webbservern med aktiverat PHP-stöd. Du kan se utdatan från PHP-motorn med en webbläsare genom att titta på sidan skickad från webbservern. Se installationsinstruktionerna för mer information.
• Kommandoradsscripting. Du kan skapa ett PHP-script som varken kräver webbserver eller webbläsare. Det enda du behöver är PHP-motorn. Den här typen av användning är idealisk för script som exekveras regelbundet med hjälp av cron (under *nix eller Linux) eller Schemaläggaren (under Windows). Den här typen av script kan också användas för enklare textmanipulering. Mer information finns under rubriken PHP i kommandoraden.
• Skriva klient-side-applikationer med grafiskt användargränssnitt. PHP är antagligen inte det bästa språket att skriva fönsterapplikationer med, men om du kan PHP bra och skulle vilja utnyttja några av PHP's avancerade funktioner i dina applikationer kan du använda PHP-GTK för att skriva sådana program. Genom PHP-GTK ges du också möjligheten att skriva plattformsoberoende program. PHP-GTK är ett tillägg till PHP, som inte finns tillgängligt i huvuddistributionen. Om du är intresserad av att veta mer om PHP-GTK, besök » dess hemsida.

PHP kan användas på alla större operativsystem; Linux, många Unix-varianter (t.ex. HP-UX, Solaris och OpenBSD), Microsoft Windows, Mac OS X, RISC OS och antagligen ännu fler. PHP har också stöd för de flesta av webbservrarna som finns på marknaden idag, inkluderat Apache, Microsoft Internet Information Server, Personal Web Server, Netscape- och iPlanet-servrar, Oreilly Website Pro server, Caudium, Xitami, OmniHTTPd, och många fler. För majoriteten av webbservrarna kan PHP köras som en modul, för de som stöder CGI-standarden kan PHP köras som CGI-processor.

Med PHP har du med andra ord friheten att välja både operativsystem och webbserver. Vidare kan du även välja om du vill använda procedur-programmering eller objekt-orienterad programmering, eller en mix av dem. Även om inte alla OOP-funktioner finns implementerade i den nuvarande versionen av PHP är många kodbibliotek och större applikationer (t.ex. PEAR-biblioteket) skrivet endast med hjälp av OOP-kod.

Med PHP är du heller inte begränsad till att skriva ut HTML. PHP kan också generera bilder, PDF-filer och till och med Flash-filmer (med hjälp av libswf och Ming) i realtid. Du kan dessutom med enkelhet skriva ut vilken text som helst, t.ex. XHTML- och XML-filer. PHP kan skapa dessa filer automatiskt och spara dem i filsystemet, istället för att skicka dem till webbläsaren och på så vis bilda ett server-side-cache-system för ditt dynamiska innehåll.

En av de viktigaste och mest intressanta funktionerna i PHP är dess omfattande databasstöd. Att skriva webbsidor som använder databaser är oerhört enkelt. Följande databaser stöds för tillfället:

• Adabas D
• dBase
• Empress
• FilePro (endast läsning)
• Hyperwave
• IBM DB2
• Informix
• Ingres
• InterBase
• FrontBase
• mSQL
• Direct MS-SQL
• MySQL
• ODBC
• Oracle (OCI7 och OCI8)
• Ovrimos
• PostgreSQL
• Solid
• Sybase
• Velocis
• Unix dbm

PHP har också stöd för att kommunicera med andra tjänster med hjälp av protokoll såsom LDAP, IMAP, SNMP, NNTP, POP3, HTTP, COM (under Windows) och otaliga andra. Du kan också öppna direkta socket-anslutningar och interaktera genom andra protokoll. PHP har stöd för WDDX complex data exchange mellan praktiskt taget alla webbspråk. På tal om sammanlänkning har PHP stöd för instansiering av Java-objekt och möjlighet att använda dem som PHP-objekt. Du kan också använda COBRA-tillägget för att använda externa objekt.

PHP har mycket användbara textmanipuleringsfunktioner, allt från POSIX Extended och Perls reguljära uttryck till tolkning av XML-dokument. För tolkning och åtkomst av XML-dokument, stöds SAX- och DOM-standarderna. Du kan använda XSLT-tillägget för att omvandla XML-dokument.

Om du planerar att använda PHP till e-handel, kommer du antagligen finna Cybercash-betalning, CyberMUT, VeriSign Payflow Pro och CCVS-funktioner användbara för dina betalningsprogram.

Sist men inte minst, finns många andra intressanta tillägg: mgnGoSearch's sökmotor-funktioner, IRC Gateway-funktioner, många kompressionsverktyg (gzip, bz2), datumomvandligsfunktioner, översättning..

Som du märker är inte denna sida tillräcklig för att räkna upp alla funktioner och fördelar som PHP kan erbjuda. Du kan fortsätta att läsa under sektionen som behandlar installation, och funktionsreferensen för förklaringar av tidigare nämnda tillägg.

Vad behöver jag?

Den här texten förutsätter att du har en webbserver med PHP-stöd installerad och aktiverad samt att alla filer som har filtillägget .php behandlas av PHP. På de flesta webbservrar är detta standardtillägget för PHP-filer, men fråga din systemadministratör om du är osäker. Om din webbserver har stöd för PHP behöver du inte göra någonting mer, skapa bara dina .php-filer och lägg dem i rätt katalog och sedan tar webbservern och PHP-motorn hand om resten. Det finns ingen anledning att kompilera något eller installera några extra verktyg. Föreställ dig PHP-filer som vanliga HTML-filer med en serie magiska taggar som ger dig nya möjligheter i ditt webbskapande.

Din första PHP-sida

Skapa en fil och döp den till hello.php, lägg den sedan i din webbkatalog. Innehållet i filen ska vara följande:

<html>
  <head>
    <title>PHP Test</title>
  </head>
  <body>
    <p>Hello World</p>
  </body>
</html>

      

Notera att PHP-scriptet inte fungerar på samma sätt som ett CGI-script. Filen behöver inte vara exekverbar eller skilja sig från vanliga HTML-filer på något sätt vad det gäller rättigheter eller ägarskap. Du kan tänka dig PHP-filen som en vanlig HTML-fil fast med ett antal specialtaggar med vilka du kan utföra massor av intressanta saker.

Det här programmet är egentligen så simpelt att du inte skulle behöva PHP för dess funktion. Allt scriptet gör är att visa texten Hello World genom att anropa PHP-funktionen echo().

Om du prövar det här exemplet och det inte skriver ut något, eller du blir tillfrågad om du vill ladda ner filen, eller om du helt enkelt ser hela filen som vanlig text finns det risk att din webbserver inte har PHP inlagt. Du kan då fråga din administratör om han kan installera det åt dig, vägledning finns i kapitlet som behandlar installation. Om du vill utveckla PHP-script lokalt behöver du » ladda ner PHP. Du kan utveckla dina script på vilket operativsystem som helst, om du installerar en webbserver som fungerar med PHP.

Poängen med scriptet ovan är att demonstrera hur PHP-taggar fungerar. I det här exemplet använde vi <?php för att inleda PHP-koden. Sedan skrev vi vår kod och avslutade med ?>. Du kan utan problem växla mellan HTML- och PHP-kod hur mycket du vill i ditt dokument.

Något användbart

Nu ska vi göra något lite mer användbart än det tidigare; vi ska kontrollera vilken webbläsare besökaren av webbsidan använder. För att göra det undersöker vi "user agent"-strängen som skickas till webbservern av webbläsaren som en del av HTTP-förfrågan. Den informationen finns lagrad i en variabel. Variabler inleds i PHP alltid med ett dollar-tecken. Variabeln vi behöver nu är $_SERVER["HTTP_USER_AGENT"].

Note: PHP Autoglobals-not $_SERVER är en speciell, reserverad variabel i PHP som innehåller all webbserverinformation. Den typen av variabel kallas för en "autoglobal" (eller superglobal). Läs mer under sektionen Autoglobals (även kallade superglobals). Dessa specialvariabler introducerades i version 4.1.0 av PHP. Förut användes istället $HTTP_*_VARS-arrayer såsom t.ex. $HTTP_SERVER_VARS. Trots att anvädningen av dessa variabler inte rekommenderas finns de fortfarande kvar. (Se även noten som behandlar gammal kod.)

För att skriva ut variabeln, skriver vi helt enkelt:

Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)
     

Det finns många olika typer av variabler i PHP. I ovanstående exempel skrev vi ut ett element från en array. Arrayer kan vara väldigt användbara.

$_SERVER är bara en av de variabler som automatiskt finns tillgängliga i PHP. En lista på alla återfinns i kapitlet Reserverade variabler, eller så kan du skapa en lista med hjälp av följande PHP-kod:

Om du tittar på den här filen i din webbläsare kommer du se en sida full av information om PHP samt en lista med de variabler som finns tillgängliga.

Du kan ha flera PHP-kommandon inom en PHP-tagg och skapa små block av kod som gör mer än bara skriver ut text. Om vi till exempel skulle vilja kontrollera om användaren kör Internet Explorer skulle vi kunna göra så här:

You are using Internet Explorer<br />

      

Här ovan introducerade vi ett par nya begrepp. Det finns bland annat en if-sats. Om du är bekant med den grundläggande syntaxen i C bör det här se logiskt ut. Om du inte kan C eller något språk med en liknande syntax som den ovan bör du antagligen införskaffa en PHP-bok för nybörjare och läsa åtminstone de första kapitlen. Alternativt kan du läsa Språkreferens-delen av manualen. En förteckning över PHP-böcker finner du på adressen » http://www.php.net/books.php.

Det andra begreppet vi nu introducerat är funktionsanropet till strstr(). strstr() är en inbyggd funktion i PHP som söker i en sträng efter en annan sträng, i det här fallet letar vi efter "MSIE" inuti $_SERVER["HTTP_USER_AGENT"]. Om strängen hittas returnerar funktionen TRUE och om den inte hittas returneras FALSE. Om funktionen returnerar TRUE blir även if-satsen TRUE och därmed körs PHP-koden som omsluts av dess "måstecken", det vill säga { och }. Om inte, körs inte PHP-koden inom nämnda. Skapa gärna egna if-satser som även kan innehålla else, och bekanta dig med funktioner som strtoupper() och strlen(). Dess sidor i manualen innehåller alla exempel på hur funktionerna används.

Vi ska nu gå ännu längre och demonstrera hur du kan växla mellan PHP och HTML mitt i ett PHP-block:

<h3>strstr must have returned true</h3>
<center><b>You are using Internet Explorer</b></center>

      

Istället för att använda PHP-funktionen echo för att skriva ut något, växlade vi till HTML-läge och skrev vanlig HTML. Observera dock att logiken i scriptet fortfarande finns kvar, bara ett av HTML-blocken visas för användaren beroende på om strstr() returnerade TRUE eller FALSE, med andra ord om strängen MSIE hittades eller inte.

Skapa formulär

Av PHP's alla egenskaper är en av de mest kraftfulla dess hantering av HTML-formulär. Grunden är att förstå att varje element i ett HTML-formulär blir tillgängligt i ditt PHP-script. Läs gärna kapitlet om Externa variabler i PHP för mer information om hur man använder formulär med PHP. Här är ett exempel med HTML-formulär:

<form action="action.php" method="POST">
 Your name: <input type="text" name="name" />
 Your age: <input type="text" name="age" />
 <input type="submit">
</form>

Det är inget speciellt med det här formuläret. Det är ett vanligt HTML-formulär utan några special-taggar. När användaren fyller i det här formuläret och trycker på Skicka anropas action.php. I den filen skulle du kunna ha något liknande följande:

Hi Joe.
You are 22 years old.

      

Det borde vara uppenbart vad ovanstående gör. Det är inte mer med det. Variablerna $_POST["name"] och $_POST["age"] defineras automatiskt åt dig av PHP. Tidigare använde vi autoglobalen $_SERVER, nu använde vi istället autoglobalen $_POST som innehåller all POST-data. Notera att metoden i HTML-formuläret är satt till POST. Om vi istället skulle använt metoden GET skulle formulär-datan finnas i autoglobalen $_GET. Du kan också använda $_REQUEST om du inte bryr dig om varifrån din data kommer. Den innehåller en mix av GET-, POST-, COOKIE-, och FILE-data. Se även funktionen import_request_variables().

Använda gammal kod i nyare versioner av PHP

Nu när PHP har växt och blivit ett populärt scriptspråk har det medfört att det finns många källor till PHP-kod på internet, från vilka du kan hämta kod som du kan använda i dina egna script. För det mesta har utvecklarna av PHP försökt att göra språket bakåt-kompatibelt så att script skrivna i äldre versioner av PHP även ska kunna köras utan förändringar i nyare versioner, tyvärr är det inte alltid så idealiskt utan några förändringar behövs oftast.

De två viktigaste av de senaste förändringarna som påverkar äldre kod är:

• Du rekommenderas inte längre att använda de äldre $HTTP_*_VARS-arrayerna (som behövde deklareras som globala om de användes i en funktion). Följande autoglobala arrayer introducerades i PHP » 4.1.0: $_GET, $_POST, $_COOKIE, $_SERVER, $_ENV, $_REQUEST, and $_SESSION. De äldre $HTTP_*_VARS-arrayerna, t.ex. $HTTP_POST_VARS, existerar fortfarande såsom de gjort sen PHP 3.
• Externa variabeler registreras inte längre med automatik i det globala "variabelscopet". Med andra ord, från PHP » 4.2.0 har PHP-direktivet register_globals satts till off som standard i php.ini. Du bör istället använda de autoglobaler som nämnts ovan för att komma åt datan. Äldre script, böcker och lektioner kan bygga på att register_globals är påslaget. Om så är fallet kan du, t.ex. med adressen http://www.example.com/foo.php?id=42 använda $_GET['id'] istället för $id för att komma åt värdet på id. $_GET['id'] sätts oavsett om register_globals är påslaget eller inte.

Vad händer nu?

Med det du nu vet bör du kunna förstå det mesta av manualen och även många av de exempel som finns tillgängliga i scriptarkiven. Du kan också hitta andra exempel under länksektionen på adressen » http://www.php.net/links.php.

Apache 1.3.x on Unix systems

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.

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:

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

      

Note: 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.

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.

Note: Apache's default httpd.conf currently ships with a section that looks like this:

User nobody
Group "#-1"

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.

Note: 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.

Apache 2.0 on Unix systems

This section contains notes and hints specific to Apache 2.0 installs of PHP on Unix systems.

You are highly encouraged to take a look at the » Apache Documentation to get a basic understanding of the Apache 2.0 Server.

Note: 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:

• 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.

These versions of PHP are compatible to Apache 2.0.40 and later.
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.

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 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
 
16. Use your normal procedure for starting the Apache server, e.g.:
   
      /usr/local/apache2/bin/apachectl start
   


      

Following the steps above you will have a running Apache 2.0 with support for PHP as SAPI module. Of course there are many more configuration options available for both, Apache and PHP. For more information use ./configure --help in the corresponding source tree. In case you wish to build a multithreaded version of Apache 2.0 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. Take care about the consequences and understand what you are doing. For more information read the Apache documentation about the » MPM-Modules.

Note: If you want to use content negotiation, read the Apache MultiViews FAQ.

Note: 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.

Caudium

PHP 4 can be built as a Pike module for the » Caudium webserver. Note that this is not supported with PHP 3. Follow the simple instructions below to install PHP 4 for Caudium.

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.

Note: 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.

fhttpd related notes

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.

Note: Support for fhttpd is no longer available as of PHP 4.3.0.

Sun, iPlanet and Netscape servers on Sun Solaris

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.

1. Install the following packages from » http://www.sunfreeware.com/ or another download site:

   • autoconf-2.13
   • automake-1.4
   • bison-1_25-sol26-sparc-local
   • flex-2_5_4a-sol26-sparc-local
   • gcc-2_95_2-sol26-sparc-local
   • gzip-1.2.4-sol26-sparc-local
   • m4-1_4-sol26-sparc-local
   • make-3_76_1-sol26-sparc-local
   • mysql-3.23.24-beta (if you want mysql support)
   • perl-5_005_03-sol26-sparc-local
   • tar-1.13 (GNU tar)

2. Make sure your path includes the proper directories PATH=.:/usr/local/bin:/usr/sbin:/usr/bin:/usr/ccs/bin and make it available to your system export PATH .
3. gunzip php-x.x.x.tar.gz (if you have a .gz dist, otherwise go to 4).
4. tar xvf php-x.x.x.tar
5. Change to your extracted PHP directory: cd ../php-x.x.x

6. 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
   

7. Run make followed by make install.

After performing the base install and reading the appropriate readme file, you may need to perform some additional configuration steps.

Configuration Instructions for Sun/iPlanet/Netscape

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/.

1. Add the following line to mime.types (you can do that by the administration server):

   type=magnus-internal/x-httpd-php exts=php
   
            

2. 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"]
   

   (PHP >= 4.3.3) The php_ini parameter is optional but with it you can place your php.ini in your web server config directory.

3. 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>
   

   (PHP >= 4.3.3) As additional parameters you can add some special php.ini-values, for example you can set a docroot="/path/to/docroot" specific to the context php4_execute is called. For boolean ini-keys please use 0/1 as value, not "On","Off",... (this will not work correctly), e.g. zlib.output_compression=1 instead of zlib.output_compression="On"

4. 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>
   

   After that you can configure a directory in the Administration server and assign it the style x-httpd-php. All files in it will get executed as PHP. This is nice to hide PHP usage by renaming files to .html.

5. 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>
   

6. To use PHP Authentication on a single directory, add the following:

   <Object ppath="d:\path\to\authenticated\dir\*">
   AuthTrans fn=php4_auth_trans
   </Object>
   

Note: 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").

variables_order = "GPCS"
register_globals = On

Error fn="php4_execute" code=XXX script="/path/to/script.php" [inikey=value inikey=value...]

Service fn="php4_execute" type="magnus-internal/directory" script="/path/to/script.php" [inikey=value inikey=value...]

CGI and command line setups

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.

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.

HP-UX specific installation notes

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

OpenBSD installation notes

This section contains notes and hints specific to installing PHP on » OpenBSD 3.6.

# 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

Solaris specific installation tips

This section contains notes and hints specific to installing PHP on Solaris systems.

Debian GNU/Linux installation notes

This section contains notes and hints specific to installing PHP on » Debian GNU/Linux.

deb http://packages.dotdeb.org stable all
deb-src http://packages.dotdeb.org stable all

# apt-get install libapache-mod-php4

# /etc/init.d/apache stop
# /etc/init.d/apache start

# dpkg -l 'php4-*'

# apt-get install php4-mysql php4-curl php4-gd

extension=mysql.so
extension=curl.so
extension=gd.so

Using Packages

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:

• MacPorts: » http://www.macports.org/
• Entropy: » http://www.entropy.ch/software/macosx/php/
• Fink: » http://fink.sourceforge.net/

Using the bundled PHP

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:

1. Locate and open the Apache configuration file. By default, the location is as follows: /etc/httpd/httpd.conf Using Finder or Spotlight to find this file may prove difficult as by default it's private and owned by the root user.

   Note: 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.

2. 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 php4_module libexec/httpd/libphp4.so
   
   # AddModule mod_php4.c
   
        

   Notice the location/path. When building PHP in the future, the above files should be replaced or commented out.

3. 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_php4.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>
   
        

4. Be sure the DirectoryIndex loads the desired default index file This is also set in httpd.conf. Typically index.php and index.html are used. By default index.php is enabled because it's also in the PHP check shown above. Adjust accordingly.
5. Set the php.ini location or use the default A typical default location on Mac OS X is /usr/local/php/php.ini and a call to phpinfo() will reveal this information. If a php.ini is not used, PHP will use all default values. See also the related FAQ on finding php.ini.
6. Locate or set the DocumentRoot This is the root directory for all the web files. Files in this directory are served from the web server so the PHP files will parse as PHP before outputting them to the browser. A typical default path is /Library/WebServer/Documents but this can be set to anything in httpd.conf. Alternatively, the default DocumentRoot for individual users is /Users/yourusername/Sites
7. Create a phpinfo() file

   The phpinfo() function will display information about PHP. Consider creating a file in the DocumentRoot with the following PHP code:

   <?php phpinfo(); ?>

8. Restart Apache, and load the PHP file created above To restart, either execute sudo apachectl graceful in the shell or stop/start the "Personal Web Server" option in the OS X System Preferences. By default, loading local files in the browser will have an URL like so: http://localhost/info.php Or using the DocumentRoot in the user directory is another option and would end up looking like: http://localhost/~yourusername/info.php

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.

Compiling for OS X Server

Mac OS X Server install

1. Get the latest distributions of Apache and PHP.

2. 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
   

3. If you want the compiler to do some optimization, you may also want to add this line:

   setenv OPTIM=-O2
   

4. 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
   

   If you have any other additions (MySQL, GD, etc.), be sure to add them here. For the --with-apache string, put in the path to your apache source directory, for example /src/apache_1.3.12.

5. Type make and make install. This will add a directory to your Apache source directory under src/modules/php4.

6. 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
   

   You may get a message telling you that libmodphp4.a is out of date. If so, go to the src/modules/php4 directory inside your Apache source directory and run this command: ranlib libmodphp4.a. Then go back to the root of the Apache source directory and run the above configure command again. That'll bring the link table up to date. Run make and make install again.

7. Copy and rename the php.ini-dist file to your bin directory from your PHP 4 source directory: 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 .

Compiling for MacOS X Client

The following instructions will help you install a PHP module for the Apache web server included in MacOS X. This version includes support for the MySQL and PostgreSQL databases. These instructions are graciously provided by » Marc Liyanage.

Do this to install:

1. Open a terminal window.
2. Type wget http://www.diax.ch/users/liyanage/software/macosx/libphp4.so.gz , wait for the download to finish.
3. Type gunzip libphp4.so.gz .
4. Type sudo apxs -i -a -n php4 libphp4.so

5. Now type sudo open -a TextEdit /etc/httpd/httpd.conf . TextEdit will open with the web server configuration file. Locate these two lines towards the end of the file: (Use the Find command)

   #AddType application/x-httpd-php .php 
   #AddType application/x-httpd-php-source .phps
   

   Remove the two hash marks (#), then save the file and quit TextEdit.

6. Finally, type sudo apachectl graceful to restart the web server.

PHP should now be up and running. You can test it by dropping a file into your Sites folder which is called test.php. 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.

Windows Installer (PHP 5.2 and later)

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.

       
msiexec.exe /i php-VERSION-win32-install.msi /q
     
      

       
msiexec.exe /i php-VERSION-win32-install.msi /q INSTALLDIR=e:\php
     
      

       
msiexec.exe /i php-VERSION-win32-install.msi /q ADDLOCAL=cgi,ext_php_mysqli
     
      

 
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
NSAPI - Sun/iPlanet/Netscape server module
Xitami - Xitami CGI executable
Sambar - Sambar Server ISAPI module
CGI - php-cgi.exe executable
PEAR - PEAR installer
Manual - PHP Manual in CHM Format

      

Windows Installer (PHP 5.1.0 and earlier)

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.

Note: 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.

Manual Installation Steps

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.

Note: 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.

Note: 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:

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:

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.

Note: 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 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 Runtime Configuration 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.

Note: 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
  

• Choose the extensions you would like to load when PHP starts. See the section about Windows extensions, about how to set up one, and what is already built in. Note that on a new installation it is advisable to first get PHP working and tested without any extensions before enabling them in php.ini.
• On PWS and IIS, you can set the browscap configuration setting to point to: c:\windows\system\inetsrv\browscap.ini on Windows 9x/Me, c:\winnt\system32\inetsrv\browscap.ini on NT/2000, and c:\windows\system32\inetsrv\browscap.ini on XP. For an up-to-date browscap.ini, read the following FAQ.

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.

ActiveScript

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. The DLL for this PECL extension may be downloaded from either the » PHP Downloads page or from » http://pecl4win.php.net/

Note: 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>

Note: 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.

Note: 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.

Microsoft IIS / PWS

This section contains notes and hints specific to IIS (Microsoft Internet Information Server).

Apache 1.3.x on Microsoft Windows

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.

Note: 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.

Note: Remember that when adding path values in the Apache configuration files on Windows, all backslashes such as c:\directory\file.ext must be converted to forward slashes, as c:/directory/file.ext. A trailing slash may also be necessary for directories.

# 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

# 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

# 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

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

Apache 2.0.x on Microsoft Windows

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.

Note: You should read the manual installation steps first!

Note: 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/

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.

Note: 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:

• 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.

These versions of PHP are compatible to Apache 2.0.40 and later.
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.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.

Note: Remember that when adding path values in the Apache configuration files on Windows, all backslashes such as c:\directory\file.ext must be converted to forward slashes, as c:/directory/file.ext. A trailing slash may also be necessary for directories.

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"

# 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"

Sun, iPlanet and Netscape servers on Microsoft Windows

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.

variables_order = "GPCS"
register_globals = On

Error fn="php4_execute" code=XXX script="/path/to/script.php" [inikey=value inikey=value...]

Service fn="php4_execute" type="magnus-internal/directory" script="/path/to/script.php" [inikey=value inikey=value...]

Init fn=php4_init ... server_lib="ns-httpdXX.dll"

OmniHTTPd Server

This section contains notes and hints specific to » OmniHTTPd on Windows.

Note: You should read the manual installation steps first!

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.

Note: Important for CGI users Read the faq on cgi.force_redirect for important details. This directive needs to be set to 0.

1. Install OmniHTTPd server.

2. Right click on the blue OmniHTTPd icon in the system tray and select Properties

3. Click on Web Server Global Settings

4. 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.

5. On the Mime tab, enter: virtual = wwwserver/stdcgi | actual = .php, and use the Add button.

6. Click OK

Repeat steps 2 - 6 for each extension you want to associate with PHP.

Note: 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.

Sambar Server on Microsoft Windows

This section contains notes and hints specific to the » Sambar Server for Windows.

Note: 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.

Note: 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.

Xitami on Microsoft Windows

This section contains notes and hints specific to » Xitami on Windows.

Note: 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.

Note: 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.

• 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.

Building from source

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.

+--C:\work
|  |
|  +--bindlib_w32
|  |  |
|  |  +--arpa
|  |  |
|  |  +--conf
|  |  |
|  |  +--...
|  |
|  +--php-5.x.x
|  |  |
|  |  +--build
|  |  |
|  |  +--...
|  |  |
|  |  +--win32
|  |  |
|  |  +--...
|  |
|  +--win32build
|  |  |
|  |  +--bin
|  |  |
|  |  +--include
|  |  |
|  |  +--lib

   

Installation of extensions on Windows

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 and Zlib

In PHP 5 (updated PHP 5.0.4), the following changes exist. Built in: DOM, LibXML, Iconv, SimpleXML, SPL and 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.

Note: 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.

Introduction to PECL Installations

» 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.

Downloading PECL extensions

There are several options for downloading PECL extensions, such as:

• » http://pecl.php.net/ The PECL web site contains information about the different extensions that are offered by the PHP Development Team. The information available here includes: ChangeLog, release notes, requirements and other similar details.
• pecl download extname PECL extensions that have releases listed on the PECL web site are available for download and installation using the » pecl command. Specific revisions may also be specified.
• CVS Most PECL extensions also reside in CVS. A web-based view may be seen at » http://cvs.php.net/pecl/. To download straight from CVS, the following sequence of commands may be used. Note that phpfi is the password for user cvsread:

  $ cvs -d:pserver:cvsread@cvs.php.net:/repository login 
  $ cvs -d:pserver:cvsread@cvs.php.net:/repository co pecl/extname
       

• Windows downloads Windows users may find compiled PECL binaries by downloading the Collection of PECL modules from the » PHP Downloads page, or by retrieving a » PECL Snapshot or an extension DLL on » PECL4WIN. To compile PHP under Windows, read the appropriate chapter.

PECL for Windows users

As with any other PHP extension DLL, installation is as simple as copying the PECL extension DLLs into the extension_dir folder and loading them from php.ini. For example, add the following line to your php.ini:

extension=php_extname.dll
   

After doing this, restart the web service.

Compiling shared PECL extensions with the pecl command

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
   

Note: After enabling the extension in php.ini, restarting the web service is required for the changes to be picked up.

Compiling shared PECL extensions with phpize

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.

Compiling PECL extensions statically into PHP

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
   

Note: 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
   

Read the FAQ

Some problems are more common than others. The most common ones are listed in the PHP FAQ, part of this manual.

Other problems

If you are still stuck, someone on the PHP installation mailing list may be able to help you. You should check out the archive first, in case someone already answered someone else who had the same problem as you. The archives are available from the support page on » http://www.php.net/support.php. To subscribe to the PHP installation mailing list, send an empty mail to » php-install-subscribe@lists.php.net. The mailing list address is » php-install@lists.php.net.

If you want to get help on the mailing list, please try to be precise and give the necessary details about your environment (which operating system, what PHP version, what web server, if you are running PHP as CGI or a server module, safe mode, etc...), and preferably enough code to make others able to reproduce and test your problem.

Bug reports

If you think you have found a bug in PHP, please report it. The PHP developers probably don't know about it, and unless you report it, chances are it won't be fixed. You can report bugs using the bug-tracking system at » http://bugs.php.net/. Please do not send bug reports in mailing list or personal letters. The bug system is also suitable to submit feature requests.

Read the » How to report a bug document before submitting any bug reports!

The configuration file

The configuration file (called php3.ini in PHP 3, and simply php.ini as of PHP 4) 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().

Note: 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.

; 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".

How to change configuration settings

<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>
<IfModule mod_php3.c>
  php3_include_path ".:/usr/local/lib/php"
  php3_safe_mode on
</IfModule>

Escaping from HTML

When PHP parses a file, it looks for opening and closing tags, which tell PHP to start and stop interpreting the code between them. Parsing in this manner allows php to be embedded in all sorts of different documents, as everything outside of a pair of opening and closing tags is ignored by the PHP parser. Most of the time you will see php embedded in HTML documents, as in this example.

You can also use more advanced structures:

There are four different pairs of opening and closing tags which can be used in php. Two of those, <?php ?> and <script language="php"> </script>, are always available. The other two are short tags and ASP style tags, and can be turned on and off from the php.ini configuration file. As such, while some people find short tags and ASP style tags convenient, they are less portable, and generally not recommended.

Note: Also note that if you are embedding PHP within XML or XHTML you will need to use the <?php ?> tags to remain compliant with standards.

While the tags seen in examples one and two are both always available, example one is the most commonly used, and recommended, of the two.

Short tags (example three) are only available when they are enabled via the short_open_tag php.ini configuration file directive, or if php was configured with the --enable-short-tags option.

Note: If you are using PHP 3 you may also enable short tags via the short_tags() function. This is only available in PHP 3!

ASP style tags (example four) are only available when they are enabled via the asp_tags php.ini configuration file directive.

Note: Support for ASP tags was added in 3.0.4.

Note: Using short tags should be avoided when developing applications or libraries that are meant for redistribution, or deployment on PHP servers which are not under your control, because short tags may not be supported on the target server. For portable, redistributable code, be sure not to use short tags.

Instruction separation

As in C or Perl, PHP requires instructions to be terminated with a semicolon at the end of each statement. The closing tag of a block of PHP code automatically implies a semicolon; you do not need to have a semicolon terminating the last line of a PHP block. The closing tag for the block will include the immediately trailing newline if one is present.

Note: The closing tag of a PHP block at the end of a file is optional, and in some cases omitting it is helpful when using include() or require(), so unwanted whitespace will not occur at the end of files, and you will still be able to add headers to the response later. It is also handy if you use output buffering, and would not like to see added unwanted whitespace at the end of the parts generated by the included files.

Comments

PHP supports 'C', 'C++' and Unix shell-style (Perl style) comments. For example:

The "one-line" comment styles only comment to the end of the line or the current block of PHP code, whichever comes first. This means that HTML code after // ... ?> or # ... ?> WILL be printed: ?> breaks out of PHP mode and returns to HTML mode, and // or # cannot influence that. If the asp_tags configuration directive is enabled, it behaves the same with // %> and # %>. However, the </script> tag doesn't break out of PHP mode in a one-line comment.

'C' style comments end at the first */ encountered. Make sure you don't nest 'C' style comments. It is easy to make this mistake if you are trying to comment out a large block of code.

Introduction

PHP supports eight primitive types.

Four scalar types:

• boolean
• integer
• float (floating-point number, aka 'double')
• string

• array
• object

• resource
• NULL

• mixed
• number
• callback

You may also find some references to the type "double". Consider double the same as float, the two names exist only for historic reasons.

The type of a variable is usually not set by the programmer; rather, it is decided at runtime by PHP depending on the context in which that variable is used.

Note: If you want to check out the type and value of a certain expression, use var_dump(). If you simply want a human-readable representation of the type for debugging, use gettype(). To check for a certain type, do not use gettype(), but use 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";
}
?>

If you would like to force a variable to be converted to a certain type, you may 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. Also, you may be interested in viewing the type comparison tables, as they show examples of various type related comparisons.

Booleans

This is the easiest type. A boolean expresses a truth value. It can be either TRUE or FALSE.

Note: The boolean type was introduced in PHP 4.

Integers

An integer is a number of the set Z = {..., -2, -1, 0, 1, 2, ...}.

See also: Arbitrary length integer / GMP, Floating point numbers, and Arbitrary precision / BCMath

decimal     : [1-9][0-9]*
            | 0

hexadecimal : 0[xX][0-9a-fA-F]+

octal       : 0[0-7]+

integer     : [+-]?decimal
            | [+-]?hexadecimal
            | [+-]?octal

Floating point numbers

Floating point numbers (AKA "floats", "doubles" or "real numbers") can be specified using any of the following syntaxes:

Strings

A string is series of characters. In PHP, 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 Unicode support.

Note: It is no problem for a string to become very large. There is no practical bound to the size of strings imposed by PHP, so there is no reason at all to worry about long strings.

Arrays

An array in PHP is actually an ordered map. A map is a type that maps values to keys. This type is optimized in several ways, so you can use it as a real array, or a list (vector), hashtable (which is an implementation of a map), dictionary, collection, stack, queue and probably more. Because you can have another PHP array as a value, you can also quite easily simulate trees.

Explanation of those data structures is beyond the scope of this manual, but you'll find at least one example for each of them. For more information we refer you to external literature about this broad topic.

array(  key =>  value
     , ...
     )
// key may be an integer or string
// value may be any value
      

$arr[key] = value;
$arr[] = value;
// key may be an integer or string
// value may be any value
      

Do you like red?
Do you like blue?
Do you like green?
Do you like yellow?

     

Array
(
    [0] => RED
    [1] => BLUE
    [2] => GREEN
    [3] => YELLOW
)

      

Array 
(
    [1] => 'January'
    [2] => 'February'
    [3] => 'March'
)
   
      

Objects

Resource

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.

Note: The resource type was introduced in PHP 4

See also get_resource_type().

NULL

The special NULL value represents that a variable has no value. NULL is the only possible value of type NULL.

Note: 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().

Pseudo-types and variables used in this documentation

Type Juggling

PHP does not require (or support) explicit type definition in variable declaration; a variable's type is determined by the context in which that variable is used. That is to say, if you assign a string value to variable $var , $var becomes a string. If you then assign an integer value to $var , it becomes an integer.

An example of PHP's automatic type conversion is the addition operator '+'. If any of the operands is a float, then all 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.

If the last two examples above seem odd, see String conversion to numbers.

If you wish to force a variable to be evaluated as a certain type, see the section on Type casting. If you wish to change the type of a variable, see settype().

If you would like to test any of the examples in this section, you can use the var_dump() function.

Note: 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:

<?php
$a    = 'car'; // $a is a string
$a[0] = 'b';   // $a is still a string
echo $a;       // bar
?>

See the section titled String access by character for more information.

Basics

Variables in PHP are represented by a dollar sign followed by the name of the variable. The variable name is case-sensitive.

Variable names follow the same rules as other labels in PHP. A valid variable name starts with a letter or underscore, followed by any number of letters, numbers, or underscores. As a regular expression, it would be expressed thus: '[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*'

Note: For our purposes here, a letter is a-z, A-Z, and the ASCII characters from 127 through 255 (0x7f-0xff).

Note: $this is a special variable that can't be assigned.

For information on variable related functions, see the Variable Functions Reference.

In PHP 3, variables are always assigned by value. That is to say, when you assign an expression to a variable, the entire value of the original expression is copied into the destination variable. This means, for instance, that after assigning one variable's value to another, changing one of those variables will have no effect on the other. For more information on this kind of assignment, see the chapter on Expressions.

As of PHP 4, PHP offers another way to assign values to variables: assign by reference. This means that the new variable simply references (in other words, "becomes an alias for" or "points to") the original variable. Changes to the new variable affect the original, and vice versa.

To assign by reference, simply prepend an ampersand (&) to the beginning of the variable which is being assigned (the source variable). For instance, the following code snippet outputs 'My name is Bob' twice:

One important thing to note is that only named variables may be assigned by reference.

It is not necessary to initialize variables in PHP however it is a very good practice. Uninitialized variables have a default value of their type - FALSE, zero, empty string or an empty array.

Relying on the default value of an uninitialized variable is problematic in the case of including one file into another which uses the same variable name. It is also a major security risk with register_globals turned on. E_NOTICE level error is issued in case of working with uninitialized variables, however not in the case of appending elements to the uninitialized array. isset() language construct can be used to detect if a variable has been already initialized.

Predefined variables

PHP provides a large number of predefined variables to any script which it runs. Many of these variables, however, cannot be fully documented as they are dependent upon which server is running, the version and setup of the server, and other factors. Some of these variables will not be available when PHP is run on the command line. For a listing of these variables, please see the section on Reserved Predefined Variables.

From version 4.1.0 onward, PHP provides an additional set of predefined arrays containing variables from the web server (if applicable), the environment, and user input. These new arrays are rather special in that they are automatically global--i.e., automatically available in every scope. For this reason, they are often known as "superglobals". (There is no mechanism in PHP for user-defined superglobals.) The superglobals are listed below; however, for a listing of their contents and further discussion on PHP predefined variables and their natures, please see the section Reserved Predefined Variables. Also, you'll notice how the older predefined variables ($HTTP_*_VARS) still exist. As of PHP 5.0.0, the long PHP predefined variable arrays may be disabled with the register_long_arrays directive.

Note: Variable variables Superglobals cannot be used as variable variables inside functions or class methods.

Note: Even though both the superglobal and HTTP_*_VARS can exist at the same time; they are not identical, so modifying one will not change the other.

If certain variables in variables_order are not set, their appropriate PHP predefined arrays are also left empty.

PHP Superglobals

$GLOBALS

Contains a reference to every variable which is currently available within the global scope of the script. The keys of this array are the names of the global variables. $GLOBALS has existed since PHP 3.

$_SERVER

Variables set by the web server or otherwise directly related to the execution environment of the current script. Analogous to the old $HTTP_SERVER_VARS array (which is still available, but deprecated).

$_GET

Variables provided to the script via URL query string. Analogous to the old $HTTP_GET_VARS array (which is still available, but deprecated).

$_POST

Variables provided to the script via HTTP POST. Analogous to the old $HTTP_POST_VARS array (which is still available, but deprecated).

$_COOKIE

Variables provided to the script via HTTP cookies. Analogous to the old $HTTP_COOKIE_VARS array (which is still available, but deprecated).

$_FILES

Variables provided to the script via HTTP post file uploads. Analogous to the old $HTTP_POST_FILES array (which is still available, but deprecated). See POST method uploads for more information.

$_ENV

Variables provided to the script via the environment. Analogous to the old $HTTP_ENV_VARS array (which is still available, but deprecated).

$_REQUEST

Variables provided to the script via the GET, POST, and COOKIE input mechanisms, and which therefore cannot be trusted. The presence and order of variable inclusion in this array is defined according to the PHP variables_order configuration directive. This array has no direct analogue in versions of PHP prior to 4.1.0. See also import_request_variables().

Caution

Since PHP 4.3.0, FILE information from $_FILES does not exist in $_REQUEST.

Note: When running on the command line , this will not include the argv and argc entries; these are present in the $_SERVER array.

$_SESSION

Variables which are currently registered to a script's session. Analogous to the old $HTTP_SESSION_VARS array (which is still available, but deprecated). See the Session handling functions section for more information.

Variable scope

The scope of a variable is the context within which it is defined. For the most part all PHP variables only have a single scope. This single scope spans included and required files as well. For example:

Here the $a variable will be available within the included b.inc script. However, within user-defined functions a local function scope is introduced. Any variable used inside a function is by default limited to the local function scope. For example:

This script will not produce any output because the echo statement refers to a local version of the $a variable, and it has not been assigned a value within this scope. You may notice that this is a little bit different from the C language in that global variables in C are automatically available to functions unless specifically overridden by a local definition. This can cause some problems in that people may inadvertently change a global variable. In PHP global variables must be declared global inside a function if they are going to be used in that function.

NULL
object(stdClass)(0) {
}