Sunday 28 August 2011

Accessing HTTP Header Information With Zend Framework

By Chris Channing


Getting the current URL in a Zend Application is useful for when building templates and navigations. Luckily the designers of Zend Framework have made the process as simple as calling several different methods from your Zend application.

The front controller of Zend is what is called a singleton. It's easy to think of it as a global variable that can be accessed at will, no matter where you are in the development stack. The first lesson is simple: just because you have this power does not mean you should use it. Singleton patterns are not very popular because they lead to confusion. If you are working in the view, you should not be accessing the front controller directly, as dictated in MVC design.

If you do intend on getting URL parameters in a view, you have two options. The easiest is to use a view helper. The Server Url view helper allows developers to quickly access the current URL and URI. Other information can be accessed by passing the variables from your controller to your view. While technically you can still access the front controller, it goes against the entire design of Zend Framework to do so.

Controllers have direct access to the request object. This is because every standard controller in Zend extends the Zend Controller Action. This class file contains methods to access the HTTP request through several different methods. One is able to get the scheme, the domain, path to the current script, and parameters with ease. The parameters method is specifically useful, as it returns parameters as an array.

When working in library files you do not have direct access to the Zend Controller Action class. Thus, you can't get direct access to the HTTP request object. Instead you can create an instance of the front controller and access the information just like you would in the controller as previously discussed. This is one of the few times you can access information in this style: singleton patterns are used few and far between.

To make things easier in getting a base URL, you may use a base URL helper. This allows you to quickly access a set base URL in any part of the application. You set this helper in the bootstrap and in your application configuration file. The base URL helper takes more time in setting up, but it's a joy to have when working in the view to quickly piece together URL information.

Final Thoughts

Built on PHP, it's natural that Zend Framework offers everything that PHP does in regards to getting URI information. The only difference is that Zend Framework makes it easier to access these objects and also does so in a consistent manner. Just remember to use the proper methods of accessing the information so you don't violate the Zend Framework rule set.




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