gnu-social/vendor/zendframework/zend-config/doc/book/intro.md

Introduction

zend-config is designed to simplify access to 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 formats supporting hierarchical data storage. Currently, zend-config provides adapters that read and write configuration data stored in INI, JSON, YAML, and XML files.

Using Reader Classes

Normally, users will use one of the reader classes to read a configuration file, but if configuration data is available in a PHP array, one may simply pass the data to Zend\Config\Config's constructor in order to utilize a simple object-oriented interface:

// An array of configuration data is given
$configArray = [
    'webhost'  => 'www.example.com',
    'database' => [
        'adapter' => 'pdo_mysql',
        'params'  => [
            'host'     => 'db.example.com',
            'username' => 'dbuser',
            'password' => 'secret',
            'dbname'   => 'mydatabase',
        ],
    ],
];

// Create the object-oriented wrapper using the configuration data
$config = new Zend\Config\Config($configArray);

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

As illustrated in the example above, Zend\Config\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\Config also has a get() method that accepts a default value to return if the data element requested doesn't exist in the configuration array. For example:

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

Using PHP Configuration Files

PHP-basd configuration files are often recommended due to the speed with which they are parsed, and the fact that they can be cached by opcode caches.

The following code illustrates how to use PHP configuration files:

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

// Consumes the configuration array
$config = new Zend\Config\Config(include 'config.php');

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