Consentire a Lighttpd di generare processi php

Per configurare Lighttpd per la connessione con php e generare processi fastcgi, editare lighttpd.conf. Si consiglia di eseguire le connessioni ai processi fastcgi sul sistema locale tramite socket.

server.modules += ( "mod_fastcgi" )

fastcgi.server = ( ".php" =>
  ((
    "socket" => "/tmp/php.socket",
    "bin-path" => "/usr/local/bin/php-cgi",
    "bin-environment" => (
      "PHP_FCGI_CHILDREN" => "16",
      "PHP_FCGI_MAX_REQUESTS" => "10000"
    ),
    "min-procs" => 1,
    "max-procs" => 1,
    "idle-timeout" => 20
  ))
)

La direttiva bin-path consente a lighttpd di generare processi fastcgi dinamicamente. PHP genererà processi figli in accordo con la variabile di ambiente PHP_FCGI_CHILDREN. La direttiva "bin-environment" imposta l'ambiente per i processi generati. PHP terminerà i processi generati dopo che il numero di richieste specificato in PHP_FCGI_MAX_REQUESTS sia stato raggiunto. L'uso delle direttive "min-procs" e "max-procs" è sconsigliato relativamente a PHP. PHP gestisce autonomamente i propri processi figlio e la cache opcode come APC viene condivisa unicamente tra processi gestiti da PHP. Se "min-procs" è impostata ad un numero maggiore di 1, il numero totale di risponditori di php sarà moltiplicato per PHP_FCGI_CHILDREN (2 min-procs * 16 processi dà come risultato 32 risponditori).

Spawning with spawn-fcgi

Lighttpd fornisce un programma chiamato spawn-fcgi per facilitare la generazione di processi fastcgi.

Impiegare php-cgi

E' possibile generare processi senza spawn-fcgi, ma il procedimento è più complicato. L'impostazione della variabile di ambiente PHP_FCGI_CHILDREN controlla quanti processi figlio saranno generati da PHP per gestire le richieste ricevute. L'impostazione di PHP_FCGI_MAX_REQUESTS determinerà quanto a lungo (in termini di richieste) ogni processo figlio dovrà durare. Segue un semplice script bash per generare risponditori php.

#!/bin/sh

# Location of the php-cgi binary
PHP=/usr/local/bin/php-cgi

# PID File location
PHP_PID=/tmp/php.pid

# Binding to an address
#FCGI_BIND_ADDRESS=10.0.1.1:10000
# Binding to a domain socket
FCGI_BIND_ADDRESS=/tmp/php.sock

PHP_FCGI_CHILDREN=16
PHP_FCGI_MAX_REQUESTS=10000

env -i PHP_FCGI_CHILDREN=$PHP_FCGI_CHILDREN \
       PHP_FCGI_MAX_REQUESTS=$PHP_FCGI_MAX_REQUESTS \
       $PHP -b $FCGI_BIND_ADDRESS &

echo $! > "$PHP_PID"

Connessione a istanze di FCGI remote

Le istanze di Fastcgi possono essere generate su macchine remote multiple per consentire la scalabilità delle applicazioni.

fastcgi.server = ( ".php" =>
   (( "host" => "10.0.0.2", "port" => 1030 ),
    ( "host" => "10.0.0.3", "port" => 1030 ))
)

Testing

If you have built PHP as a CGI program, you may test your build by typing make test. It is always a good idea to test your build. This way you may catch a problem with PHP on your platform early instead of having to struggle with it later.

Using Variables

Some server supplied environment variables are not defined in the current » CGI/1.1 specification. Only the following variables are defined there: AUTH_TYPE, CONTENT_LENGTH, CONTENT_TYPE, GATEWAY_INTERFACE, PATH_INFO, PATH_TRANSLATED, QUERY_STRING, REMOTE_ADDR, REMOTE_HOST, REMOTE_IDENT, REMOTE_USER, REQUEST_METHOD, SCRIPT_NAME, SERVER_NAME, SERVER_PORT, SERVER_PROTOCOL, and SERVER_SOFTWARE. Everything else should be treated as 'vendor extensions'.

Using Binary Packages

Using binary packages to install PHP on OpenBSD is the recommended and simplest method. The core package has been separated from the various modules, and each can be installed and removed independently from the others. The files you need can be found on your OpenBSD CD or on the FTP site.

The main package you need to install is php, which contains the basic engine (plus fpm, gettext and iconv) and might be available in several versions to choose from. Next, take a look at the module packages, such as php-mysqli or php-imap. You need to use the phpxs command to activate and deactivate these modules in your php.ini.

# pkg_add php
# pkg_add php-apache
# pkg_add php-mysqli
  (install the PEAR libraries)
# pkg_add pear

Follow the instructions shown with each package!

  (to remove packages)
# pkg_delete php
# pkg_delete php-apache
# pkg_delete php-mysqli
# pkg_delete pear

Read the » packages(7) manual page for more information about binary packages on OpenBSD.

Using Ports

You can also compile up PHP from source using the » ports tree. However, this is only recommended for users familiar with OpenBSD. The PHP port is split into core and extensions. The extensions generate sub-packages for all of the supported PHP modules. If you find you do not want to create some of these modules, use the no_* FLAVOR. For example, to skip building the imap module, set the FLAVOR to no_imap.

Common Problems

• Apache and Nginx are no longer the default server on OpenBSD, but they can both be easily found in ports and packages. The new default server is also called 'httpd'.
• The default install of httpd runs inside a » chroot(2) jail, which will restrict PHP scripts to accessing files under /var/www. You will therefore need to create a /var/www/tmp directory for PHP session files to be stored, or use an alternative session backend. In addition, database sockets need to be placed inside the jail or listen on the localhost interface. If you use network functions, some files from /etc such as /etc/resolv.conf and /etc/services will need to be moved into /var/www/etc. The OpenBSD PEAR package automatically installs into the correct chroot directories.
• The OpenBSD package for the » gd extension requires Xorg to be installed. Unless already installed at base install by adding the xbase.tgz file set, this can be added at post-installation (see » OpenBSD FAQ#4).

Required software

Solaris installs often lack C compilers and their related tools. Read this FAQ for information on why using GNU versions for some of these tools is necessary.

For unpacking the PHP distribution you need

• tar
• gzip or
• bzip2

For compiling PHP you need

• gcc (recommended, other C compilers may work)
• make
• GNU sed

For building extra extensions or hacking the code of PHP you might also need

• re2c
• bison
• m4
• autoconf
• automake

Using Packages

You can simplify the Solaris install process by using pkgadd to install most of your needed components. The Image Packaging System (IPS) for Solaris 11 Express also contains most of the required components for installation using the pkg command.

Using APT

First, note that other related packages may be desired like libapache-mod-php to integrate with Apache 2, and php-pear for PEAR.

Second, before installing a package, it's wise to ensure the package list is up to date. Typically, this is done by running the command apt update.

# apt install php-common libapache2-mod-php php-cli

APT will automatically install the PHP module for Apache 2 and all of its dependencies, and then activate it. Apache should be restarted in order for the changes take place. For example:

# /etc/init.d/apache2 stop
# /etc/init.d/apache2 start

Better control of configuration

In the last section, PHP was installed with only core modules. It's very likely that additional modules will be desired, such as MySQL, cURL, GD, etc. These may also be installed via the apt command.

# apt-cache search php
# apt search php | grep -i mysql
# aptitude search php

The examples will show a lot of packages including several PHP specific ones like php-cgi, php-cli and php-dev. Determine which are needed and install them like any other with either apt or aptitude. And because Debian performs dependency checks, it'll prompt for those so for example to install MySQL and cURL:

# apt install php-mysql php-curl

APT will automatically add the appropriate lines to the different php.ini related files like /etc/php/7.4/php.ini, /etc/php/7.4/conf.d/*.ini, etc. and depending on the extension will add entries similar to extension=foo.so. However, restarting the web server (like Apache) is required before these changes take affect.

Common Problems

• If the PHP scripts are not parsing via the web server, then it's likely that PHP was not added to the web server's configuration file, which on Debian may be /etc/apache2/apache2.conf or similar. See the Debian manual for further details.
• If an extension was seemingly installed yet the functions are undefined, be sure that the appropriate ini file is being loaded and/or the web server was restarted after installation.
• There are two basic commands for installing packages on Debian (and other linux variants): apt and aptitude. However, explaining the subtle differences between these commands goes beyond the scope of this manual.

PHP Install Tools

» XAMPP, WampServer and BitNami will setup PHP applications for use with Apache on Windows.

Setting up and configuring Nginx on Windows requires a bit more configuration. See the » Nginx documentation for additional setup help.

OpCache

It is highly recommended to enable OpCache. This extension is included with PHP for Windows. It compiles and optimizes PHP scripts and caches them in memory so that they aren't compiled every time the page is loaded.

Set the php.ini to:

opcache.enable=On
opcache.enable_cli=On

WinCache

It is recommended to use WinCache if using IIS, especially if in a shared web hosting environment or using networked file storage (NAS). Note that WinCache is no longer supported as of PHP 8.0.0. All PHP Applications automatically benefit from WinCache's file cache feature. File system operations are cached in memory. WinCache also can cache user objects in memory and share them between php.exe or php-cgi.exe processes (share objects between requests). Many major web applications have a plugin or extension or configuration option to make use of the WinCache user object cache. If you need high performance, you should use the object cache in your applications. See: » http://pecl.php.net/package/WinCache to download a WinCache DLL (or tgz) to your PHP extensions directory (extensions_dir in your php.ini). Set the php.ini to:

extension=php_wincache.dll
wincache.fcenabled=1
wincache.ocenabled=1 ; removed as of wincache 2.0.0.0

IIS Configuration

In IIS Manager, Install FastCGI module and add a handler mapping for `.php` to the path to PHP-CGI.exe (not PHP.exe)

You may use the APPCMD command line tool to script IIS configuration.

Database

You'll probably need a Database Server. Popular databases provide PHP extensions to use them. If your web site doesn't get a lot of traffic, you can run your database server on the same server as your web server. Many popular database servers run on Windows.

PHP includes mysqli and pdo_mysql extensions.

See » https://dev.mysql.com/downloads/windows/

Choose Web Server

@echo off

REM download .ZIP file of PHP build from http://windows.php.net/downloads/

REM path to directory you decompressed PHP .ZIP file into (no trailing \)
set phppath=c:\php


REM Clear current PHP handlers
%windir%\system32\inetsrv\appcmd clear config /section:system.webServer/fastCGI
REM The following command will generate an error message if PHP is not installed. This can be ignored.
%windir%\system32\inetsrv\appcmd set config /section:system.webServer/handlers /-[name='PHP_via_FastCGI']

REM Set up the PHP handler
%windir%\system32\inetsrv\appcmd set config /section:system.webServer/fastCGI /+[fullPath='%phppath%\php-cgi.exe']
%windir%\system32\inetsrv\appcmd set config /section:system.webServer/handlers /+[name='PHP_via_FastCGI',path='*.php',verb='*',modules='FastCgiModule',scriptProcessor='%phppath%\php-cgi.exe',resourceType='Unspecified']
%windir%\system32\inetsrv\appcmd set config /section:system.webServer/handlers /accessPolicy:Read,Script

REM Configure FastCGI Variables
%windir%\system32\inetsrv\appcmd set config -section:system.webServer/fastCgi /[fullPath='%phppath%\php-cgi.exe'].instanceMaxRequests:10000
%windir%\system32\inetsrv\appcmd.exe set config -section:system.webServer/fastCgi /+"[fullPath='%phppath%\php-cgi.exe'].environmentVariables.[name='PHP_FCGI_MAX_REQUESTS',value='10000']"
%windir%\system32\inetsrv\appcmd.exe set config -section:system.webServer/fastCgi /+"[fullPath='%phppath%\php-cgi.exe'].environmentVariables.[name='PHPRC',value='%phppath%\php.ini']"

Choose Build

Windows builds can be downloaded from » http://windows.php.net/download/. All builds are optimized (PGO), and QA and GA releases are thoroughly tested.

There are 4 types of PHP builds:

• Thread-Safe(TS) - for single process web servers, like Apache with mod_php

• Non-Thread-Safe(NTS) - for IIS and other FastCGI web servers (Apache with mod_fastcgi) and recommended for command-line scripts

• x86 - for 32-bits systems.

• x64 - for 64-bits systems.

Installing as an Apache handler

To load the PHP module for Apache 2.x, the following lines in the Apache httpd.conf configuration file must be inserted:

# before PHP 8.0.0 the name of the module was php7_module
LoadModule php_module "c:/php/php8apache2_4.dll"
<FilesMatch \.php$>
    SetHandler application/x-httpd-php
</FilesMatch>
# configure the path to php.ini
PHPIniDir "C:/php"

Nota: The actual path to PHP must be substituted instead of C:/php/ in the above examples. Make sure that the file referenced in the LoadModule directive is at the specified location. Use php7apache2_4.dll for PHP 7, or php8apache2_4.dll for PHP 8.

Running PHP as CGI

It is strongly recommended to consult the » Apache CGI documentation for a more complete understanding of running CGI on Apache.

To run PHP as CGI, the php-cgi files will need to be placed in a directory designated as a CGI directory using the ScriptAlias directive.

A #! line will need to be placed in the PHP files, which point to the location of the PHP binary:

#!C:/php/php.exe
<?php
  phpinfo();
?>

Running PHP under FastCGI

Running PHP under FastCGI has a number of advantages over running it as a CGI. Setting it up this way is fairly straightforward:

Obtain mod_fcgid from » https://www.apachelounge.com. Win32 binaries are available for download from that site. Install the module according to the instructions that will come with it.

Configure your web server as shown below, taking care to adjust any paths to reflect how you have installed things on your particular system:

LoadModule fcgid_module modules/mod_fcgid.so
# Where is your php.ini file?
FcgidInitialEnv PHPRC        "c:/php"
<FilesMatch \.php$>
    SetHandler fcgid-script
</FilesMatch>
FcgidWrapper "c:/php/php-cgi.exe" .php

Check Temp Directory Permissions

WinCache

WinCache è abilitato per impostazione predefinita sui Servizi App di Azure ed è consigliato lasciarlo abilitato. Se si installa una propria build di PHP, si dovrebbe abilitare WinCache anche su di essa.

Build Custom di PHP

Si può effettuare l'upload della propria build PHP sul proprio D:\Home (C:\ non è scrivibile). Quindi nel Portale di Azure, settare SCRIPT_PROCESSOR per .php al path assoluto del file php-cgi.exe nella propria build.

Compiling from sources

In order to enable FPM in your PHP build you need to add --enable-fpm to your configure line.

There are several other FPM-specific configure options (all of them optional):

• --with-fpm-user - set FPM user (default - nobody).

• --with-fpm-group - set FPM group (default - nobody).

• --with-fpm-systemd - Activate systemd integration (default - no).

• --with-fpm-acl - Use POSIX Access Control Lists (default - no).

• --with-fpm-apparmor - Activate AppArmor integration (default - no).

• --with-fpm-selinux - Activate SELinux integration (default - no).

Log delle modifiche

List of global php-fpm.conf directives

pid string

Path to PID file. Default value: none.

error_log string

Path to error log file. Default value: #INSTALL_PREFIX#/log/php-fpm.log. If it's set to "syslog", log is sent to syslogd instead of being written in a local file.

log_level string

Error log level. Possible values: alert, error, warning, notice, debug. Default value: notice.

log_limit int

Log limit for the logged lines which allows to log messages longer than 1024 characters without wrapping. Default value: 1024. Available as of PHP 7.3.0.

log_buffering bool

Experimental logging without extra buffering. Default value: yes. Available as of PHP 7.3.0.

syslog.facility string

used to specify what type of program is logging the message. Default value: daemon.

syslog.ident string

Prepended to every message. If you have multiple FPM instances running on the same server, you can change the default value which must suit common needs. Default value: php-fpm.

emergency_restart_threshold int

If this number of child processes exit with SIGSEGV or SIGBUS within the time interval set by emergency_restart_interval, then FPM will restart. A value of 0 means 'Off'. Default value: 0 (Off).

emergency_restart_interval mixed

Interval of time used by emergency_restart_interval to determine when a graceful restart will be initiated. This can be useful to work around accidental corruptions in an accelerator's shared memory. Available Units: s(econds), m(inutes), h(ours), or d(ays). Default Unit: seconds. Default value: 0 (Off).

process_control_timeout mixed

Time limit for child processes to wait for a reaction on signals from master. Available units: s(econds), m(inutes), h(ours), or d(ays) Default Unit: seconds. Default value: 0.

process.max int

The maximum number of processes FPM will fork. This has been design to control the global number of processes when using dynamic PM within a lot of pools. Use it with caution. Default value: 0.

process.priority int

Specify the nice(2) priority to apply to the master process (only if set). The value can vary from -19 (highest priority) to 20 (lower priority). Default value: not set.

daemonize bool

Send FPM to background. Set to 'no' to keep FPM in foreground for debugging. Default value: yes.

rlimit_files int

Set open file descriptor rlimit for the master process. Default value: system defined value.

rlimit_core int

Set max core size rlimit for the master process. Default value: 0.

events.mechanism string

Specify the event mechanism FPM will use. The following is available: select, pool, epoll, kqueue (*BSD), port (Solaris). Default value: not set (auto detection).

systemd_interval int

When FPM is build with systemd integration, specify the interval, in second, between health report notification to systemd. Set to 0 to disable. Default value: 10.

List of pool directives

With FPM you can run several pools of processes with different setting. These are settings that can be tweaked per pool.

listen string

The address on which to accept FastCGI requests. Valid syntaxes are: 'ip.add.re.ss:port', 'port', '/path/to/unix/socket'. This option is mandatory for each pool.

listen.backlog int

Set listen(2) backlog. A value of -1 means maximum on BSD systems. Default value: -1 (FreeBSD or OpenBSD) or 511 (Linux and other platforms).

listen.allowed_clients string

List of IPv4 or IPv6 addresses of FastCGI clients which are allowed to connect. Equivalent to the FCGI_WEB_SERVER_ADDRS environment variable in the original PHP FastCGI (5.2.2+). Makes sense only with a tcp listening socket. Each address must be separated by a comma. If this value is left blank, connections will be accepted from any ip address. Default value: not set (any ip address accepted).

listen.owner string

Set permissions for unix socket, if one is used. In Linux, read/write permissions must be set in order to allow connections from a web server. Many BSD-derived systems allow connections regardless of permissions. Default values: user and group are set as the running user, mode is set to 0660.

listen.group string

See listen.owner.

listen.mode string

See listen.owner.

listen.acl_users string

When POSIX Access Control Lists are supported you can set them using this option. When set, listen.owner and listen.group are ignored. Value is a comma separated list of user names.

listen.acl_groups string

See listen.acl_users. Value is a comma separated list of group names.

user string

Unix user of FPM processes. This option is mandatory.

group string

Unix group of FPM processes. If not set, the default user's group is used.

pm string

Choose how the process manager will control the number of child processes. Possible values: static, ondemand, dynamic. This option is mandatory.

static - the number of child processes is fixed (pm.max_children).

ondemand - the processes spawn on demand (when requested, as opposed to dynamic, where pm.start_servers are started when the service is started.

dynamic - the number of child processes is set dynamically based on the following directives: pm.max_children, pm.start_servers, pm.min_spare_servers, pm.max_spare_servers.

pm.max_children int

The number of child processes to be created when pm is set to static and the maximum number of child processes to be created when pm is set to dynamic. This option is mandatory.

This option sets the limit on the number of simultaneous requests that will be served. Equivalent to the ApacheMaxClients directive with mpm_prefork and to the PHP_FCGI_CHILDREN environment variable in the original PHP FastCGI.

pm.start_servers int

The number of child processes created on startup. Used only when pm is set to dynamic. Default Value: min_spare_servers + (max_spare_servers - min_spare_servers) / 2.

pm.min_spare_servers int

The desired minimum number of idle server processes. Used only when pm is set to dynamic. Also mandatory in this case.

pm.max_spare_servers int

The desired maximum number of idle server processes. Used only when pm is set to dynamic. Also mandatory in this case.

pm.max_spawn_rate int

The number of rate to spawn child processes at once. Used only when pm is set to dynamic. Default value: 32

pm.process_idle_timeout mixed

The number of seconds after which an idle process will be killed. Used only when pm is set to ondemand. Available units: s(econds)(default), m(inutes), h(ours), or d(ays). Default value: 10s.

pm.max_requests int

The number of requests each child process should execute before respawning. This can be useful to work around memory leaks in 3rd party libraries. For endless request processing specify '0'. Equivalent to PHP_FCGI_MAX_REQUESTS. Default value: 0.

pm.status_listen string

The address on which to accept FastCGI status request. This creates a new invisible pool that can handle requests independently. This is useful if the main pool is busy with long running requests because it is still possible to get the FPM status page before finishing the long running requests. The syntax is the same as for listen directive. Default value: none.

pm.status_path string

The URI to view the FPM status page. This value must start with a leading slash (/). If this value is not set, no URI will be recognized as a status page. Default value: none.

ping.path string

The ping URI to call the monitoring page of FPM. If this value is not set, no URI will be recognized as a ping page. This could be used to test from outside that FPM is alive and responding. Please note that the value must start with a leading slash (/).

ping.response string

This directive may be used to customize the response to a ping request. The response is formatted as text/plain with a 200 response code. Default value: pong.

process.priority int

Specify the nice(2) priority to apply to the worker process (only if set). The value can vary from -19 (highest priority) to 20 (lower priority). Default value: not set.

process.dumpable bool

Set the process dumpable flag (PR_SET_DUMPABLE prctl) even if the process user or group is different than the master process user. It allows to create process core dump and ptrace the process for the pool user. Default Value: no. Since PHP 7.0.29, 7.1.17 and 7.2.5.

prefix string

Specify prefix for path evaluation

request_terminate_timeout mixed

The timeout for serving a single request after which the worker process will be killed. This option should be used when the 'max_execution_time' ini option does not stop script execution for some reason. A value of '0' means 'Off'. Available units: s(econds)(default), m(inutes), h(ours), or d(ays). Default value: 0.

request_terminate_timeout_track_finished bool

The timeout set by request_terminate_timeout is not engaged after a fastcgi_finish_request or when application has finished and internal shutdown functions are being called. This directive will enable timeout limit to be applied unconditionally even in such cases. Default value: no. Since PHP 7.3.0.

request_slowlog_timeout mixed

The timeout for serving a single request after which a PHP backtrace will be dumped to the 'slowlog' file. A value of '0' means 'Off'. Available units: s(econds)(default), m(inutes), h(ours), or d(ays). Default value: 0.

request_slowlog_trace_depth int

The depth of slowlog log stack trace. Default value: 20. Since PHP 7.2.0.

slowlog string

The log file for slow requests. Default value: #INSTALL_PREFIX#/log/php-fpm.log.slow.

rlimit_files int

Set open file descriptor rlimit for child processes in this pool. Default value: system defined value.

rlimit_core int

Set max core size rlimit for child processes in this pool. Possible Values: 'unlimited' or an integer greater or equal to 0. Default value: system defined value.

chroot string

Chroot to this directory at the start. This value must be defined as an absolute path. When this value is not set, chroot is not used.

chdir string

Chdir to this directory at the start. This value must be an absolute path. Default value: current directory or / when chroot.

catch_workers_output bool

Redirect worker stdout and stderr into main error log. If not set, stdout and stderr will be redirected to /dev/null according to FastCGI specs. Default value: no.

decorate_workers_output bool

Enable the output decoration for workers output when catch_workers_output is enabled. Default value: yes. Available as of PHP 7.3.0.

clear_env bool

Clear environment in FPM workers. Prevents arbitrary environment variables from reaching FPM worker processes by clearing the environment in workers before env vars specified in this pool configuration are added. Default value: Yes.

security.limit_extensions string

Limits the extensions of the main script FPM will allow to parse. This can prevent configuration mistakes on the web server side. You should only limit FPM to .php extensions to prevent malicious users to use other extensions to execute php code. Default value: .php .phar

apparmor_hat string

If AppArmor is enabled, it allows to change a hat. Default value: not set

access.log string

The access log file. Default value: not set

access.format string

The access log format. Default value: "%R - %u %t \"%m %r\" %s":

Valid options

Placeholder	Description
%C	%CPU
%d	duration µs
%e	fastcgi env
%f	script
%l	content length
%m	method
%M	memory
%n	pool name
%o	header output
%p	PID
%q	query string
%Q	the glue between %q and %r
%r	request URI
%R	remote IP address
%s	status
%T	time
%t	time
%u	remote user

It's possible to pass additional environment variables and update PHP settings of a certain pool. To do this, you need to add the following options to the pool configuration file.

env[HOSTNAME] = $HOSTNAME
env[PATH] = /usr/local/bin:/usr/bin:/bin
env[TMP] = /tmp
env[TMPDIR] = /tmp
env[TEMP] = /tmp

php_admin_value[sendmail_path] = /usr/sbin/sendmail -t -i -f www@my.domain.com
php_flag[display_errors] = off
php_admin_value[error_log] = /var/log/fpm-php.www.log
php_admin_flag[log_errors] = on
php_admin_value[memory_limit] = 32M

Settings defined with php_admin_value and php_admin_flag cannot be overridden with ini_set().

PHP settings can be set in the webserver configuration.

set $php_value "pcre.backtrack_limit=424242";
set $php_value "$php_value \n pcre.recursion_limit=99999";
fastcgi_param  PHP_VALUE $php_value;

fastcgi_param  PHP_ADMIN_VALUE "open_basedir=/var/www/htdocs";

Nota: Pools are not a security mechanism, because they do not provide full separation; e.g. all pools would use a single OPcache instance.

Where to find an extension?

PHP extensions are usually called php_*.dll (where the star represents the name of the extension), and they are located under the PHP\ext folder.

PHP ships with the extensions most useful to the majority of developers. They are called bundled extensions.

However, if the bundled extensions do not provide the needed functionality, one extension that does may still be found in » PECL. The PHP Extension Community Library (PECL) is a repository for PHP Extensions, providing a directory of all known extensions and hosting facilities for downloading and developing PHP extensions.

If an extension has been developed for particular uses, it may be hosted on PECL so that others with the same needs can benefit from it. A nice side effect is that it's a good chance to receive feedback, (hopefully) thanks, bug reports and even fixes/patches. Before submitting an extension for hosting on PECL, please read » PECL submit.

Which extension to download?

Many times, there will be several versions of each DLL available:

• Different version numbers (at least the first two numbers should match)
• Different thread safety settings
• Different processor architecture (x86, x64, ...)
• Different debugging settings
• etc.

Keep in mind that the extension settings should match all the settings of the PHP executable being used. The following PHP script will tell all about the PHP settings:

Or from the command line, run:

drive:\path\to\php\executable\php.exe -i

Loading an extension

The most common way to load a PHP extension is to include it in the php.ini configuration file. Please note that many extensions are already present in the php.ini and that the semicolon only needs to be removed to activate them.

Note that, as of PHP 7.2.0, the extension name may be used instead of the extension's file name. As this is OS-independent and easier, especially for newcomers, it becomes the recommended way of specifying extensions to load. File names remain supported for compatibility with prior versions.

;extension=php_extname.dll

extension=php_extname.dll

; As of PHP 7.2.0, prefer:
extension=extname
zend_extension=another_extension

However, some web servers are confusing because they do not use the php.ini located alongside the PHP executable. To find out where the actual php.ini resides, look for its path in phpinfo():

Configuration File (php.ini) Path  C:\WINDOWS

Loaded Configuration File   C:\Program Files\PHP\8.2\php.ini

After activating an extension, save php.ini, restart the web server, and check phpinfo() again. The new extension should now have its own section.

Resolving problems

If the extension does not appear in phpinfo(), the logs should be checked to learn where the problem comes from.

If PHP is being used from the command line (CLI), the extension loading error can be read directly on the screen.

If PHP is being used with a web server, the location and format of the logs vary depending on the software. Please read the web server documentation to locate the logs, as it has nothing to do with PHP itself.

Common problems are the location of the DLL and the DLLs it depends on, the value of the "extension_dir" setting inside php.ini and compile-time setting mismatches.

If the problem lies in a compile-time setting mismatch, probably the DLL downloaded is not the right one. Try downloading the extension again with the proper settings. Again, phpinfo() can be of great help.

Scan directories

It is possible to configure PHP to scan for .ini files in a directory after reading php.ini. This can be done at compile time by setting the --with-config-file-scan-dir option. The scan directory can then be overridden at run time by setting the PHP_INI_SCAN_DIR environment variable.

It is possible to scan multiple directories by separating them with the platform-specific path separator (; on Windows, NetWare and RISC OS; : on all other platforms; the value PHP is using is available as the PATH_SEPARATOR constant). If a blank directory is given in PHP_INI_SCAN_DIR, PHP will also scan the directory given at compile time via --with-config-file-scan-dir.

Within each directory, PHP will scan all files ending in .ini in alphabetical order. A list of the files that were loaded, and in what order, is available by calling php_ini_scanned_files(), or by running PHP with the --ini option.

Assuming PHP is configured with --with-config-file-scan-dir=/etc/php.d,
and that the path separator is :...

$ php
  PHP will load all files in /etc/php.d/*.ini as configuration files.

$ PHP_INI_SCAN_DIR=/usr/local/etc/php.d php
  PHP will load all files in /usr/local/etc/php.d/*.ini as
  configuration files.

$ PHP_INI_SCAN_DIR=:/usr/local/etc/php.d php
  PHP will load all files in /etc/php.d/*.ini, then
  /usr/local/etc/php.d/*.ini as configuration files.

$ PHP_INI_SCAN_DIR=/usr/local/etc/php.d: php
  PHP will load all files in /usr/local/etc/php.d/*.ini, then
  /etc/php.d/*.ini as configuration files.

Running PHP as an Apache module

When using PHP as an Apache module, you can also change the configuration settings using directives in Apache configuration files (e.g. httpd.conf) and .htaccess files. You will need "AllowOverride Options" or "AllowOverride All" privileges to do so.

There are several Apache directives that allow you to change the PHP configuration from within the Apache configuration files. For a listing of which directives are INI_ALL, INI_PERDIR, or INI_SYSTEM, have a look at the List of php.ini directives appendix.

php_value name value

Sets the value of the specified directive. Can be used only with INI_ALL and INI_PERDIR type directives. To clear a previously set value use none as the value.

Nota: Don't use php_value to set boolean values. php_flag (see below) should be used instead.

php_flag name on|off

Used to set a boolean configuration directive. Can be used only with INI_ALL and INI_PERDIR type directives.

php_admin_value name value

Sets the value of the specified directive. This can not be used in .htaccess files. Any directive type set with php_admin_value can not be overridden by .htaccess or ini_set(). To clear a previously set value use none as the value.

php_admin_flag name on|off

Used to set a boolean configuration directive. This can not be used in .htaccess files. Any directive type set with php_admin_flag can not be overridden by .htaccess or ini_set().

<IfModule mod_php5.c>
  php_value include_path ".:/usr/local/lib/php"
  php_admin_flag engine on
</IfModule>
<IfModule mod_php4.c>
  php_value include_path ".:/usr/local/lib/php"
  php_admin_flag engine on
</IfModule>

Changing PHP configuration via the Windows registry

When running PHP on Windows, the configuration values can be modified on a per-directory basis using the Windows registry. The configuration values are stored in the registry key HKLM\SOFTWARE\PHP\Per Directory Values, in the sub-keys corresponding to the path names. For example, configuration values for the directory c:\inetpub\wwwroot would be stored in the key HKLM\SOFTWARE\PHP\Per Directory Values\c\inetpub\wwwroot. The settings for the directory would be active for any script running from this directory or any subdirectory of it. The values under the key should have the name of the PHP configuration directive and the string value. PHP constants in the values are not parsed. However, only configuration values changeable in INI_USER can be set this way, INI_PERDIR values can not, because these configuration values are re-read for each request.

Other interfaces to PHP

Regardless of how you run PHP, you can change certain values at runtime of your scripts through ini_set(). See the documentation on the ini_set() page for more information.

If you are interested in a complete list of configuration settings on your system with their current values, you can execute the phpinfo() function, and review the resulting page. You can also access the values of individual configuration directives at runtime using ini_get() or get_cfg_var().

Atomic types

Some atomic types are built-in types which are tightly integrated with the language and cannot be reproduced with user defined types.

The list of base types is:

• Built-in types
  • null type
  • Scalar types:
    • bool type
    • int type
    • float type
    • string type
  • array type
  • object type
  • resource type
  • never type
  • void type
  • Relative class types: self, parent, and static
• Value types
  • false
  • true
• User-defined types (generally referred to as class-types)
  • Interfaces
  • Classes
  • Enumerations
• callable type

Composite types

It is possible to combine multiple atomic types into composite types. PHP allows types to be combined in the following ways:

• Intersection of class-types (interfaces and class names).
• Union of types.

Type aliases

PHP supports two type aliases: mixed and iterable which corresponds to the union type of object|resource|array|string|float|int|bool|null and Traversable|array respectively.

Nota: PHP does not support user-defined type aliases.

Syntax

Esiste solo un valore di tipo null, la costante null, che è invariante, sia essa in maiuscolo o in minuscolo.

Vedere anche le funzioni is_null() e unset().

Casting a null

Effettuare il casting di una variabile a null usando (unset) $var non rimuove la variabile, né cancella il valore. Non fa altro che restituire un valore null.

Syntax

To specify a bool literal, use the constants true or false. Both are case-insensitive.

Typically, the result of an operator which returns a bool value is passed on to a control structure.

Converting to boolean

To explicitly convert a value to bool, use the (bool) cast. Generally this is not necessary because when a value is used in a logical context it will be automatically interpreted as a value of type bool. For more information see the Type Juggling page.

When converting to bool, the following values are considered false:

• the boolean false itself
• the integer 0 (zero)
• the floats 0.0 and -0.0 (zero)
• the empty string "", and the string "0"
• an array with zero elements
• the unit type NULL (including unset variables)
• Internal objects that overload their casting behaviour to bool. For example: SimpleXML objects created from empty elements without attributes.

Every other value is considered true (including resource and NAN).

Syntax

Gli int possono essere specificati nella notazione decimale (base 10), esadecimale (base 16), ottale (base 8) o binaria (base 2). L'operatore di negazione può essere utilizzato per indicare un int negativo.

Per usare la notazione ottale, anteporre uno 0 (zero) al numero. Per usare la notazione esadecimale, anteporre 0x. Per usare la notazione binaria, anteporre 0b.

A partire da PHP 7.4.0, gli interi letterali possono contenere trattini bassi (_) tra le cifre, per una migliore leggibilità dei letterali. Questi trattini bassi vengono rimossi dallo scanner di PHP.

Formalmente, la struttura per gli int letterali è a partire da PHP 7.4.0 (in precedenza, i trattini bassi non erano consentiti):

decimal     : [1-9][0-9]*(_[0-9]+)*
            | 0

hexadecimal : 0[xX][0-9a-fA-F]+(_[0-9a-fA-F]+)*

octal       : 0[0-7]+(_[0-7]+)*

binary      : 0[bB][01]+(_[01]+)*

integer     : decimal
            | hexadecimal
            | octal
            | binary

La dimensione di un int dipende dalla piattaforma, anche se il valore massimo tipico è di circa due miliardi (corrispondente a 32 bit col segno). Le piattaforme a 64 bit hanno normalmente un valore massimo di circa 9E18. PHP non supporta gli int senza segno. La dimensione di un int può essere determinata usando la costante PHP_INT_SIZE, il valore massimo usando la costante PHP_INT_MAX, ed il valore minimo usando la costante PHP_INT_MIN.

Integer overflow

Se PHP incontra un numero oltre i limiti del tipo int, questo verrà interpretato con un float. Allo stesso modo, un'operazione che restituisce un numero oltre i limiti del tipo int restituirà invece un float.

Non esiste un operatore di divisione int in PHP, per ottenere ciò utilizzare la funzione intdiv(). 1/2 produce il float 0.5. Il valore può essere convertito in un int per arrotondarlo verso lo zero, oppure la funzione round() fornisce un controllo più preciso sull'arrotondamento.

Convertire in intero

Per convertire esplicitamente un valore in int, usare o (int) oppure (integer). Comunque, nella maggior parte dei case questo non è necessario, in quanto un valore verrà automaticamente convertito se un operatore, fuinzione o struttura di controllo richiede un argomento int. Un valore può essere convertito in int anche con la funzione intval().

Se un resource è convertito in int, allora il risultato sarà il numero unico di risorsa assegnato al resource da PHP a runtime.

Vedere anche: manipolazione dei tipi.

Conversione a float

Comparare float

Come fatto notare nell'esempio sopra, comparare valori floating point per uguaglianza potrebbe risultare problematico a causa della loro rappresentazione interna. Tuttavia esistono dei metodi per comparare dei valori floating point che aggirano queste limitazioni.

Per confrontare valori floating point per uguaglianza viene scelto un limite superiore all'errore relativo creato dall'arrotondamento. Questo valore è conosciuto come la macchina epsilon, o unità roundoff, ed è la più piccola differenza accettabile nel calcolo.

NaN

Alcune operazioni possono ritornare un valore rappresentato dalla costante NAN. Questo risultato rappresenta un valore indefinito o non presentabile nei calcoli di numeri floating point. Qualsiasi comparazione per uguaglianza o per identicità di questo valore con qualsiasi altro, incluso sé stesso, risulterà false.

Poiché NAN rappresenta un qualsiasi numero di differenti valori, NAN non dovrebbe essere comparato ad altri valori, incluso se stesso, e dovrebbe invece essere verificato tramite la funzione is_nan().

Syntax

A string literal can be specified in four different ways:

• single quoted
• double quoted
• heredoc syntax
• nowdoc syntax

      a
     b
    c

  a
 b
c

PHP Parse error:  Invalid body indentation level (expecting an indentation level of at least 3) in example.php on line 4

PHP Parse error:  Invalid indentation - tabs and spaces cannot be mixed in example.php line 8

array(2) {
  [0] =>
  string(11) "a
  b
    c"
  [1] =>
  string(5) "d e f"
}

PHP Parse error:  syntax error, unexpected identifier "ING", expecting "]" in example.php on line 6

My name is "MyName". I am printing some Foo.
Now, I am printing some Bar2.
This should print a capital 'A': A

Example of string spanning multiple lines
using nowdoc syntax. Backslashes are always treated literally,
e.g. \\ and \'.

My name is "$name". I am printing some $foo->foo.
Now, I am printing some {$foo->bar[1]}.
This should not print a capital 'A': \x41

He drank some apple juice.
He drank some juice made of .
He drank some juice made of apples.

He drank some apple juice.
He drank some orange juice.
He drank some purple juice.
John Smith drank some apple juice.
John Smith then said hello to Jane Smith.
John Smith's wife greeted Robert Paulsen.
Robert Paulsen greeted the two .

The character at index -2 is n.
Changing the character at index -3 to o gives strong.

I am bar.
I am bar.

string(1) "b"
bool(true)

Warning: Illegal string offset '1.0' in /tmp/t.php on line 7
string(1) "b"
bool(false)

Warning: Illegal string offset 'x' in /tmp/t.php on line 9
string(1) "a"
bool(false)
string(1) "b"
bool(false)

Useful functions and operators

Strings may be concatenated using the '.' (dot) operator. Note that the '+' (addition) operator will not work for this. See String operators for more information.

There are a number of useful functions for string manipulation.

See the string functions section for general functions, and the Perl-compatible regular expression functions for advanced find & replace functionality.

There are also functions for URL strings, and functions to encrypt/decrypt strings (Sodium and Hash).

Finally, see also the character type functions.

Converting to string

A value can be converted to a string using the (string) cast or the strval() function. String conversion is automatically done in the scope of an expression where a string is needed. This happens when using the echo or print functions, or when a variable is compared to a string. The sections on Types and Type Juggling will make the following clearer. See also the settype() function.

A bool true value is converted to the string "1". bool false is converted to "" (the empty string). This allows conversion back and forth between bool and string values.

An int or float is converted to a string representing the number textually (including the exponent part for floats). Floating point numbers can be converted using exponential notation (4.1E+6).

Nota:

As of PHP 8.0.0, the decimal point character is always a period ("."). Prior to PHP 8.0.0, the decimal point character is defined in the script's locale (category LC_NUMERIC). See the setlocale() function.

Arrays are always converted to the string "Array"; because of this, echo and print can not by themselves show the contents of an array. To view a single element, use a construction such as echo $arr['foo']. See below for tips on viewing the entire contents.

In order to convert objects to string, the magic method __toString must be used.

Resources are always converted to strings with the structure "Resource id #1", where 1 is the resource number assigned to the resource by PHP at runtime. While the exact structure of this string should not be relied on and is subject to change, it will always be unique for a given resource within the lifetime of a script being executed (ie a Web request or CLI process) and won't be reused. To get a resource's type, use the get_resource_type() function.

null is always converted to an empty string.

As stated above, directly converting an array, object, or resource to a string does not provide any useful information about the value beyond its type. See the functions print_r() and var_dump() for more effective means of inspecting the contents of these types.

Most PHP values can also be converted to strings for permanent storage. This method is called serialization, and is performed by the serialize() function.

Details of the String Type

The string in PHP is implemented as an array of bytes and an integer indicating the length of the buffer. It has no information about how those bytes translate to characters, leaving that task to the programmer. There are no limitations on the values the string can be composed of; in particular, bytes with value 0 (“NUL bytes”) are allowed anywhere in the string (however, a few functions, said in this manual not to be “binary safe”, may hand off the strings to libraries that ignore data after a NUL byte.)

This nature of the string type explains why there is no separate “byte” type in PHP – strings take this role. Functions that return no textual data – for instance, arbitrary data read from a network socket – will still return strings.

Given that PHP does not dictate a specific encoding for strings, one might wonder how string literals are encoded. For instance, is the string "á" equivalent to "\xE1" (ISO-8859-1), "\xC3\xA1" (UTF-8, C form), "\x61\xCC\x81" (UTF-8, D form) or any other possible representation? The answer is that string will be encoded in whatever fashion it is encoded in the script file. Thus, if the script is written in ISO-8859-1, the string will be encoded in ISO-8859-1 and so on. However, this does not apply if Zend Multibyte is enabled; in that case, the script may be written in an arbitrary encoding (which is explicitly declared or is detected) and then converted to a certain internal encoding, which is then the encoding that will be used for the string literals. Note that there are some constraints on the encoding of the script (or on the internal encoding, should Zend Multibyte be enabled) – this almost always means that this encoding should be a compatible superset of ASCII, such as UTF-8 or ISO-8859-1. Note, however, that state-dependent encodings where the same byte values can be used in initial and non-initial shift states may be problematic.

Of course, in order to be useful, functions that operate on text may have to make some assumptions about how the string is encoded. Unfortunately, there is much variation on this matter throughout PHP’s functions:

• Some functions assume that the string is encoded in some (any) single-byte encoding, but they do not need to interpret those bytes as specific characters. This is case of, for instance, substr(), strpos(), strlen() or strcmp(). Another way to think of these functions is that operate on memory buffers, i.e., they work with bytes and byte offsets.
• Other functions are passed the encoding of the string, possibly they also assume a default if no such information is given. This is the case of htmlentities() and the majority of the functions in the mbstring extension.
• Others use the current locale (see setlocale()), but operate byte-by-byte.
• Finally, they may just assume the string is using a specific encoding, usually UTF-8. This is the case of most functions in the intl extension and in the PCRE extension (in the last case, only when the u modifier is used).

Ultimately, this means writing correct programs using Unicode depends on carefully avoiding functions that will not work and that most likely will corrupt the data and using instead the functions that do behave correctly, generally from the intl and mbstring extensions. However, using functions that can handle Unicode encodings is just the beginning. No matter the functions the language provides, it is essential to know the Unicode specification. For instance, a program that assumes there is only uppercase and lowercase is making a wrong assumption.

Strings used in numeric contexts

When a string needs to be evaluated as number (e.g. arithmetic operations, int type declaration, etc.) the following steps are taken to determine the outcome:

1. If the string is numeric, resolve to an int if the string is an integer numeric string and fits into the limits of the int type limits (as defined by PHP_INT_MAX), otherwise resolve to a float.
2. If the context allows leading numeric strings and the string is one, resolve to an int if the leading part of the string is an integer numeric string and fits into the limits of the int type limits (as defined by PHP_INT_MAX), otherwise resolve to a float. Additionally an error of level E_WARNING is raised.
3. The string is not numeric, throw a TypeError.

Behavior prior to PHP 8.0.0

Prior to PHP 8.0.0, a string was considered numeric only if it had leading whitespaces, if it had trailing whitespaces then the string was considered to be leading numeric.

Prior to PHP 8.0.0, when a string was used in a numeric context it would perform the same steps as above with the following differences:

• The usage of a leading numeric string would raise an E_NOTICE instead of an E_WARNING.
• If the string is not numeric, an E_WARNING was raised and the value 0 would be returned.

Syntax

array(
    key  => value,
    key2 => value2,
    key3 => value3,
    ...
)

array(1) {
  [1]=>
  string(1) "d"
}

array(4) {
  ["foo"]=>
  string(3) "bar"
  ["bar"]=>
  string(3) "foo"
  [100]=>
  int(-100)
  [-100]=>
  int(100)
}

array(4) {
  [0]=>
  string(3) "foo"
  [1]=>
  string(3) "bar"
  [2]=>
  string(5) "hello"
  [3]=>
  string(5) "world"
}

array(4) {
  [0]=>
  string(1) "a"
  [1]=>
  string(1) "b"
  [6]=>
  string(1) "c"
  [7]=>
  string(1) "d"
}

array(7) {
  [1]=>
  string(1) "g"
  [-1]=>
  string(1) "d"
  ["01"]=>
  string(1) "e"
  ["1.5"]=>
  string(1) "f"
  [0]=>
  string(1) "h"
  [""]=>
  string(1) "j"
  [2]=>
  string(1) "l"
}

string(3) "bar"
int(24)
string(3) "foo"

$arr[key] = value;
$arr[] = value;
// key may be an int or string
// value may be any value of any type

Useful functions

There are quite a few useful functions for working with arrays. See the array functions section.

Nota:

The unset() function allows removing keys from an array. Be aware that the array will not be reindexed. If a true "remove and shift" behavior is desired, the array can be reindexed using the array_values() function.

<?php
$a = array(1 => 'one', 2 => 'two', 3 => 'three');
unset($a[2]);
/* will produce an array that would have been defined as
$a = array(1 => 'one', 3 => 'three');
and NOT
$a = array(1 => 'one', 2 =>'three');
*/

$b = array_values($a);
// Now $b is array(0 => 'one', 1 =>'three')
?>

The foreach control structure exists specifically for arrays. It provides an easy way to traverse an array.

Array do's and don'ts