Introduction - Zend_Config
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 #1 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,
- // 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 #2 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: