The Zend_Config component provides a standardized solution for managing and accessing your application's configuration data. This configuration data is most commonly managed within files using INI and XML syntax formats, however it's also possible to access configuration data stored within an array, meaning you could just as easily manage the data within a database and populate the configuration array as necessary. Because the INI file is not only easy to understand but also seems to be the most widely used within Zend Framework applications, I'll use that as the basis for the examples throughout this tutorial, although applying what you learn to the other available formats should be straightforward.

Managing Your Configuration Data

Presuming you use Zend_Tool to create your Zend Framework projects, in your project directory you'll find a directory named configs. This is the default location for storing configuration data related to your project. Within the configs directory you'll find a file named application.ini which contains several default configuration settings. The original file looks like this:

  [production]
phpSettings.display_startup_errors = 0
phpSettings.display_errors = 0
includePaths.library = APPLICATION_PATH "/../library"
bootstrap.path = APPLICATION_PATH "/Bootstrap.php"
bootstrap.class = "Bootstrap"
resources.frontController.controllerDirectory = APPLICATION_PATH "/controllers"
[staging : production]
[testing : production]
phpSettings.display_startup_errors = 1
phpSettings.display_errors = 1
[development : production]
phpSettings.display_startup_errors = 1
phpSettings.display_errors = 1

As you can see, a dotted naming convention is used. Some of the naming prefixes such as phpSettings and bootstrap are of special significance to the Zend Framework. For instance, using the phpSettings prefix allows you to assign an application-specific value to one of PHP's configuration directives. In the above listing you'll see the display_errors directive has been set to 0, meaning any errors generated during the application's execution will not be displayed to the browser. For organizational purposes you are free to create your own prefixes. For instance when organizing the e-mail addresses used throughout a Web site I use the logical prefix email:

  email.support = "support@example.com"
email.admin = "admin@example.com"
email.sales = "sales@example.com"

You probably also noticed certain configuration variables are repeated throughout the configuration file. This is because the Zend_Config component allows you to manage stage-specific configuration variables. For instance, you'll in all likelihood use several databases in conjunction with your application; one for development, another for staging, and still another for production. To accommodate the various stages, you'll see the configuration file is separated into sections titled production, staging, testing, and development. By default the staging, testing, and development sections inherit from the production section, as indicated by the colon which denotes inheritance. By taking advantage of this feature, you won't have to worry about redundantly listing configuration variables whose values do not change as the application is migrated from one stage to another.

But how does the application know which set of configuration variables to use? The stage can be configured in a number of ways, however the most commonplace is within the .htaccess file, located within your application's public directory. Open .htaccess and you'll find that a variable named APPLICATION_ENV has been assigned the value development, meaning the variables found within the application.ini's [development] section will be used.

Accessing the Configuration Data

With the configuration data neatly organized within the application.ini file, we'll want to begin accessing that data within the application's controllers. To access this data throughout a controller's actions, add the following three lines to your controller's init method:

  $bootstrap = $this->getInvokeArg('bootstrap');
$configArray = $bootstrap->getOptions();
$this->config = new Zend_Config($configArray);

Now suppose you wanted to access the sales e-mail address configuration variable I had presented earlier in the tutorial, which looked like this:

  email.sales = "sales@example.com"

The $this->config variable is actually an object, with all of the configuration variables having been associated with this object as attributes. Therefore to retrieve the sales e-mail address, you'll use the following syntax:

$email = $this->config->email->sales;

Where to From Here?

The Zend Framework's Zend_Config component makes it trivial to manage your application's configuration data within a central location. In taking advantage of this great feature, you'll remove yet another tedious task from your TODO list, freeing up additional time to think about what counts the most: creating a great Web application!

Original Article