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Chapter 3. Configuration

Table of Contents
The configuration file

The configuration file

The configuration file (called php3.ini in PHP 3.0, and simply php.ini as of PHP 4.0) 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 version, it happens on every invocation.

When using PHP as an Apache module, you can also change the configuration settings using directives in Apache configuration files and .htaccess files.

With PHP 3.0, there are Apache directives that correspond to each configuration setting in the php3.ini name, except the name is prefixed by "php3_".

With PHP 4.0, there are just a few Apache directives that allow you to change the PHP configuration settings.

php_value name value

This sets the value of the specified variable.

php_flag name on|off

This is used to set a Boolean configuration option.

php_admin_value name value

This sets the value of the specified variable. "Admin" configuration settings can only be set from within the main Apache configuration files, and not from .htaccess files.

php_admin_flag name on|off

This is used to set a Boolean configuration option.

You can view the settings of the configuration values in the output of phpinfo(). You can also access the values of individial configuration settings using get_cfg_var().

General Configuration Directives

allow_url_fopen boolean

This option enables the URL-aware fopen wrappers that enable accessing URL object like files. Default wrappers are provided for the access of remote files using the ftp or http protocol, some extensions like zlib may register additional wrappers.

Note: This option was introduced immediately after the release of version 4.0.3. For versions up to and including 4.0.3 you can only disable this feature at compile time by using the configuration switch --disable-url-fopen-wrapper.

asp_tags boolean

Enables the use of ASP-like <% %> tags in addition to the usual <?php ?> tags. This includes the variable-value printing shorthand of <%= $value %>. For more information, see Escaping from HTML.

Note: Support for ASP-style tags was added in 3.0.4.

auto_append_file string

Specifies the name of a file that is automatically parsed after the main file. The file is included as if it was called with the include() function, so include_path is used.

The special value none disables auto-appending.

Note: If the script is terminated with exit(), auto-append will not occur.

auto_prepend_file string

Specifies the name of a file that is automatically parsed before the main file. The file is included as if it was called with the include() function, so include_path is used.

The special value none disables auto-prepending.

cgi_ext string

display_errors boolean

This determines whether errors should be printed to the screen as part of the HTML output or not.

doc_root string

PHP's "root directory" on the server. Only used if non-empty. If PHP is configured with safe mode, no files outside this directory are served.

engine boolean

This directive is really only useful in the Apache module version of PHP. It is used by sites that would like to turn PHP parsing on and off on a per-directory or per-virtual server basis. By putting engine off in the appropriate places in the httpd.conf file, PHP can be enabled or disabled.

error_log string

Name of file where script errors should be logged. If the special value syslog is used, the errors are sent to the system logger instead. On UNIX, this means syslog(3) and on Windows NT it means the event log. The system logger is not supported on Windows 95.

error_reporting integer

Set the error reporting level. The parameter is an integer representing a bit field. Add the values of the error reporting levels you want.

Table 3-1. Error Reporting Levels

bit valueenabled reporting
1normal errors
2normal warnings
4parser errors
8non-critical style-related warnings
The default value for this directive is 7 (normal errors, normal warnings and parser errors are shown).

open_basedir string

Limit the files that can be opened by PHP to the specified directory-tree.

When a script tries to open a file with, for example, fopen or gzopen, the location of the file is checked. When the file is outside the specified directory-tree, PHP will refuse to open it. All symbolic links are resolved, so it's not possible to avoid this restriction with a symlink.

The special value . indicates that the directory in which the script is stored will be used as base-directory.

Under Windows, separate the directories with a semicolon. On all other systems, separate the directories with a colon. As an Apache module, open_basedir paths from parent directories are now automatically inherited.

Note: Support for multiple directories was added in 3.0.7.

The default is to allow all files to be opened.

gpc_order string

Set the order of GET/POST/COOKIE variable parsing. The default setting of this directive is "GPC". Setting this to "GP", for example, will cause PHP to completely ignore cookies and to overwrite any GET method variables with POST-method variables of the same name.

ignore_user_abort string

On by default. If changed to Off scripts will be terminated as soon as they try to output something after a client has aborted their connection. ignore_user_abort().

include_path string

Specifies a list of directories where the require(), include() and fopen_with_path() functions look for files. The format is like the system's PATH environment variable: a list of directories separated with a colon in UNIX or semicolon in Windows.

Example 3-1. UNIX include_path


include_path=.:/home/httpd/php-lib 

Example 3-2. Windows include_path


include_path=".;c:\www\phplib" 
The default value for this directive is . (only the current directory).

isapi_ext string

log_errors boolean

Tells whether script error messages should be logged to the server's error log. This option is thus server-specific.

magic_quotes_gpc boolean

Sets the magic_quotes state for GPC (Get/Post/Cookie) operations. When magic_quotes are on, all ' (single-quote), " (double quote), \ (backslash) and NUL's are escaped with a backslash automatically. If magic_quotes_sybase is also on, a single-quote is escaped with a single-quote instead of a backslash.

magic_quotes_runtime boolean

If magic_quotes_runtime is enabled, most functions that return data from any sort of external source including databases and text files will have quotes escaped with a backslash. If magic_quotes_sybase is also on, a single-quote is escaped with a single-quote instead of a backslash.

magic_quotes_sybase boolean

If magic_quotes_sybase is also on, a single-quote is escaped with a single-quote instead of a backslash if magic_quotes_gpc or magic_quotes_runtime is enabled.

max_execution_time integer

This sets the maximum time in seconds a script is allowed to take before it is terminated by the parser. This helps prevent poorly written scripts from tying up the server. The default setting is 30.

memory_limit integer

This sets the maximum amount of memory in bytes that a script is allowed to allocate. This helps prevent poorly written scripts for eating up all available memory on a server.

nsapi_ext string

register_globals boolean

Tells whether or not to register the EGPCS (Environment, GET, POST, Cookie, Server) variables as global variables. You may want to turn this off if you don't want to clutter your scripts' global scope with user data. This makes the most sense when coupled with track_vars - in which case you can access all of the EGPCS variables through the $HTTP_ENV_VARS, $HTTP_GET_VARS, $HTTP_POST_VARS, $HTTP_COOKIE_VARS, and $HTTP_SERVER_VARS arrays in the global scope.

short_open_tag boolean

Tells whether the short form (<? ?>of PHP's open tag should be allowed. If you want to use PHP in combination with XML, you have to disable this option. If disabled, you must use the long form of the open tag (<?php ?>).

sql.safe_mode boolean

track_errors boolean

If enabled, the last error message will always be present in the global variable $php_errormsg.

track_vars boolean

If enabled, then Environment, GET, POST, Cookie, and Server variables can be found in the global associative arrays $HTTP_ENV_VARS, $HTTP_GET_VARS, $HTTP_POST_VARS, $HTTP_COOKIE_VARS, and $HTTP_SERVER_VARS.

Note that as of PHP 4.0.3, track_vars is always turned on.

upload_tmp_dir string

The temporary directory used for storing files when doing file upload. Must be writable by whatever user PHP is running as.

user_dir string

The base name of the directory used on a user's home directory for PHP files, for example public_html.

warn_plus_overloading boolean

If enabled, this option makes PHP output a warning when the plus (+) operator is used on strings. This is to make it easier to find scripts that need to be rewritten to using the string concatenator instead (.).

Mail Configuration Directives

SMTP string

DNS name or IP address of the SMTP server PHP under Windows should use for mail sent with the mail() function.

sendmail_from string

Which "From:" mail address should be used in mail sent from PHP under Windows.

sendmail_path string

Where the sendmail program can be found, usually /usr/sbin/sendmail or /usr/lib/sendmail configure does an honest attempt of locating this one for you and set a default, but if it fails, you can set it here.

Systems not using sendmail should set this directive to the sendmail wrapper/replacement their mail system offers, if any. For example, Qmail users can normally set it to /var/qmail/bin/sendmail.

Safe Mode Configuration Directives

safe_mode boolean

Whether to enable PHP's safe mode. Read the Security chapter for more more information.

safe_mode_exec_dir string

If PHP is used in safe mode, system() and the other functions executing system programs refuse to start programs that are not in this directory.

Debugger Configuration Directives

debugger.host string

DNS name or IP address of host used by the debugger.

debugger.port string

Port number used by the debugger.

debugger.enabled boolean

Whether the debugger is enabled.

Extension Loading Directives

enable_dl boolean

This directive is really only useful in the Apache module version of PHP. You can turn dynamic loading of PHP extensions with dl() on and off per virtual server or per directory.

The main reason for turning dynamic loading off is security. With dynamic loading, it's possible to ignore all the safe_mode and open_basedir restrictions.

The default is to allow dynamic loading, except when using safe-mode. In safe-mode, it's always imposible to use dl().

extension_dir string

In what directory PHP should look for dynamically loadable extensions.

extension string

Which dynamically loadable extensions to load when PHP starts up.

MySQL Configuration Directives

mysql.allow_persistent boolean

Whether to allow persistent MySQL connections.

mysql.default_host string

The default server host to use when connecting to the database server if no other host is specified.

mysql.default_user string

The default user name to use when connecting to the database server if no other name is specified.

mysql.default_password string

The default password to use when connecting to the database server if no other password is specified.

mysql.max_persistent integer

The maximum number of persistent MySQL connections per process.

mysql.max_links integer

The maximum number of MySQL connections per process, including persistent connections.

mSQL Configuration Directives

msql.allow_persistent boolean

Whether to allow persistent mSQL connections.

msql.max_persistent integer

The maximum number of persistent mSQL connections per process.

msql.max_links integer

The maximum number of mSQL connections per process, including persistent connections.

Postgres Configuration Directives

pgsql.allow_persistent boolean

Whether to allow persistent Postgres connections.

pgsql.max_persistent integer

The maximum number of persistent Postgres connections per process.

pgsql.max_links integer

The maximum number of Postgres connections per process, including persistent connections.

SESAM Configuration Directives

sesam_oml string

Name of BS2000 PLAM library containing the loadable SESAM driver modules. Required for using SESAM functions. The BS2000 PLAM library must be set ACCESS=READ,SHARE=YES because it must be readable by the apache server's user id.

sesam_configfile string

Name of SESAM application configuration file. Required for using SESAM functions. The BS2000 file must be readable by the apache server's user id.

The application configuration file will usually contain a configuration like (see SESAM reference manual):


CNF=B NAM=K NOTYPE

sesam_messagecatalog string

Name of SESAM message catalog file. In most cases, this directive is not neccessary. Only if the SESAM message file is not installed in the system's BS2000 message file table, it can be set with this directive.

The message catalog must be set ACCESS=READ,SHARE=YES because it must be readable by the apache server's user id.

Sybase Configuration Directives

sybase.allow_persistent boolean

Whether to allow persistent Sybase connections.

sybase.max_persistent integer

The maximum number of persistent Sybase connections per process.

sybase.max_links integer

The maximum number of Sybase connections per process, including persistent connections.

Sybase-CT Configuration Directives

sybct.allow_persistent boolean

Whether to allow persistent Sybase-CT connections. The default is on.

sybct.max_persistent integer

The maximum number of persistent Sybase-CT connections per process. The default is -1 meaning unlimited.

sybct.max_links integer

The maximum number of Sybase-CT connections per process, including persistent connections. The default is -1 meaning unlimited.

sybct.min_server_severity integer

Server messages with severity greater than or equal to sybct.min_server_severity will be reported as warnings. This value can also be set from a script by calling sybase_min_server_severity(). The default is 10 which reports errors of information severity or greater.

sybct.min_client_severity integer

Client library messages with severity greater than or equal to sybct.min_client_severity will be reported as warnings. This value can also be set from a script by calling sybase_min_client_severity(). The default is 10 which effectively disables reporting.

sybct.login_timeout integer

The maximum time in seconds to wait for a connection attempt to succeed before returning failure. Note that if max_execution_time has been exceeded when a connection attempt times out, your script will be terminated before it can take action on failure. The default is one minute.

sybct.timeout integer

The maximum time in seconds to wait for a select_db or query operation to succeed before returning failure. Note that if max_execution_time has been exceeded when am operation times out, your script will be terminated before it can take action on failure. The default is no limit.

sybct.hostname string

The name of the host you claim to be connecting from, for display by sp_who. The default is none.

Informix Configuration Directives

ifx.allow_persistent boolean

Whether to allow persistent Informix connections.

ifx.max_persistent integer

The maximum number of persistent Informix connections per process.

ifx.max_links integer

The maximum number of Informix connections per process, including persistent connections.

ifx.default_host string

The default host to connect to when no host is specified in ifx_connect() or ifx_pconnect().

ifx.default_user string

The default user id to use when none is specified in ifx_connect() or ifx_pconnect().

ifx.default_password string

The default password to use when none is specified in ifx_connect() or ifx_pconnect().

ifx.blobinfile boolean

Set to true if you want to return blob columns in a file, false if you want them in memory. You can override the setting at runtime with ifx_blobinfile_mode().

ifx.textasvarchar boolean

Set to true if you want to return TEXT columns as normal strings in select statements, false if you want to use blob id parameters. You can override the setting at runtime with ifx_textasvarchar().

ifx.byteasvarchar boolean

Set to true if you want to return BYTE columns as normal strings in select queries, false if you want to use blob id parameters. You can override the setting at runtime with ifx_textasvarchar().

ifx.charasvarchar boolean

Set to true if you want to trim trailing spaces from CHAR columns when fetching them.

ifx.nullformat boolean

Set to true if you want to return NULL columns as the literal string "NULL", false if you want them returned as the empty string "". You can override this setting at runtime with ifx_nullformat().

BC Math Configuration Directives

bcmath.scale integer

Number of decimal digits for all bcmath functions.

Unified ODBC Configuration Directives

uodbc.default_db string

ODBC data source to use if none is specified in odbc_connect() or odbc_pconnect().

uodbc.default_user string

User name to use if none is specified in odbc_connect() or odbc_pconnect().

uodbc.default_pw string

Password to use if none is specified in odbc_connect() or odbc_pconnect().

uodbc.allow_persistent boolean

Whether to allow persistent ODBC connections.

uodbc.max_persistent integer

The maximum number of persistent ODBC connections per process.

uodbc.max_links integer

The maximum number of ODBC connections per process, including persistent connections.

Led