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Introduction

Zend_Config is designed to simplify the access to, and the use of, configuration data within applications. It provides a nested object property based user interface for accessing this configuration data within application code. The configuration data may come from a variety of media supporting hierarchical data storage. Currently Zend_Config provides adapters for configuration data that are stored in text files with Zend_Config_Ini and Zend_Config_Xml.

Example 118. Using Zend_Config

Normally it is expected that users would use one of the adapter classes such as Zend_Config_Ini or Zend_Config_Xml, but if configuration data are available in a PHP array, one may simply pass the data to the Zend_Config constructor in order to utilize a simple object-oriented interface: 

// Given an array of configuration data
$configArray = array(
    'webhost'  => 'www.example.com',
    'database' => array(
        'adapter' => 'pdo_mysql',
        'params'  => array(
            'host'     => 'db.example.com',
            'username' => 'dbuser',
            'password' => 'secret',
            'dbname'   => 'mydatabase'
        )
    )
);

// Create the object-oriented wrapper upon the configuration data
$config = new Zend_Config($configArray);

// Print a configuration datum (results in 'www.example.com')
echo $config->webhost;

// Use the configuration data to connect to the database
$db = Zend_Db::factory($config->database->adapter,
                       $config->database->params->toArray());

// Alternative usage: simply pass the Zend_Config object.
// The Zend_Db factory knows how to interpret it.
$db = Zend_Db::factory($config->database);

As illustrated in the example above, Zend_Config provides nested object property syntax to access configuration data passed to its constructor.

Along with the object oriented access to the data values, Zend_Config also has get() which will return the supplied default value if the data element doesn't exist. For example: 

$host = $config->database->get('host', 'localhost');

Example 119. Using Zend_Config with a PHP Configuration File

It is often desirable to use a pure PHP-based configuration file. The following code illustrates how easily this can be accomplished: 

// config.php
return array(
    'webhost'  => 'www.example.com',
    'database' => array(
        'adapter' => 'pdo_mysql',
        'params'  => array(
            'host'     => 'db.example.com',
            'username' => 'dbuser',
            'password' => 'secret',
            'dbname'   => 'mydatabase'
        )
    )
);

// Configuration consumption
$config = new Zend_Config(require 'config.php');

// Print a configuration datum (results in 'www.example.com')
echo $config->webhost;

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