PHP Error Handling Reading Configuration Variables

PHP Error Handling

Reading Configuration Variables

Problem

You want to get the value of a PHP configuration setting.

Solution

Use ini_get():

       // find out the include path:

       $include_path = ini_get('include_path');

Discussion

To get all the configuration variable values in one step, call ini_get_all(). It returns the variables in an associative array, and each array element is itself an associative array. The second array has three elements: a global value for the setting, a local value, and an access code:

       // Put all config values in an associative array

       $vars = ini_get_all();

       print_r($vars['date.timezone']);

This prints:

       Array

       (

            [global_value] => UTC

            [local_value] => UTC

            [access] => 7

       )

The global_value is the value set from the php.ini file; the local_value is adjusted to account for any changes made in the web server’s configuration file, any relevant .htaccess files, and the current script. The value of access is a numeric constant representing the places where this value can be altered.

Note that the name access is a little misleading in this respect because the value of the setting can always be checked, but not always adjusted.

Table Access values

Value    PHP constant               Meaning                                                                                                                   

1            PHP_INI_USER          Any script, using ini_set()

2           PHP_INI_PERDIR      Directory level, using .htaccess

4           PHP_INI_SYSTEM     System level, using php.ini or httpd.conf

7           PHP_INI_ALL              Everywhere: scripts, directories, and the system

_____________________________________________________________________

A value of 6 means the setting can be changed in both the directory and system level, as 2 + 4 = 6. In practice, there are no variables modifiable only in PHP_INI_USER or PHP_INI_PERDIR, and all variables are modifiable in PHP_INI_SYSTEM, so everything has a value of 4, 6, or 7.

You can also get variables belonging to a specific extension by passing the extension name to ini_get_all():

       // return just the session module specific variables

       $session = ini_get_all('session');

By convention, the variables for an extension are prefixed with the extension name and a period. So all the session variables begin with session. and all the PDO variables begin with pdo, for example.

Because ini_get() returns the current value for a configuration directive, if you want to check the original value from the php.ini file, use get_cfg_var():

       $original = get_cfg_var('sendmail_from'); // have we changed our address?

The value returned by get_cfg_var() is the same as what appears in the global_value element of the array returned by ini_get_all().