PHP Zend Framework - Zend_Config and global state

Question

I'm in the process of evaluating the benefits of Zend_Config_Ini versus using a simple constant file.

e.g. -

define('DB_HOST',localhost);

//versus

$config = new Zend_Config_Ini('/path/to/config.ini', 'staging');
echo $config->database->params->host;   // prints "dev.example.com"

The only thing is that the $config is not globally accessible. So then you need to use Zend_Registry to store for application usage, without having to initiate each time.

This seems to add more complexity than needed.... am I missing something or is Zend_Config + Zend_Registry a technique that is better in the long run as an app grows?

Answer 1

The main advantage of using the Registry with a config is to avoid polluting the global namespace. Say, you want to include a third party lib and your app and the lib both define a constant DB_HOST. No good.

In addition, many of the factories in Zend Framework utilize the config object to create instances. Zend_Db is a good example of this. You just pass it $this->database and it will take what it needs to instantiate your adapter.

You can also extend the registry with custom functionality, e.g. finder methods or stuff like that. Check the pattern description by Fowler.