Request and Response decorators

It may be useful to extend the Request and Response objects in your application, if you for example would like them to carry a bit more information about the current request.

For instance, you may want to add an isLoggedIn method to the Request object.

Simply extending Request and Response may pose some problems:

1. You may want to extend the objects with new behaviors differently, in different subsystems of your application,
2. The Sapi::getRequest factory always returns an instance of Request so you would have to override the factory method as well,
3. By controlling the instantiation and depend on specific Request and Response instances in your library or application, you make it harder to work with other applications which also use sabre/http.

In short: it would be bad design. Instead, it's recommended to use the decorator pattern to add new behavior where you need it. sabre/http provides helper classes to quickly do this.

Example:

use Sabre\HTTP;

class MyRequest extends HTTP\RequestDecorator {

    function isLoggedIn() {

        return true;

    }

}

Our application assumes that the true Request object was instantiated somewhere else, by some other subsystem. This could simply be a call like $request = Sapi::getRequest() at the top of your application, but could also be somewhere in a unit test.

All we know in the current subsystem is that we received a $request and that it implements Sabre\HTTP\RequestInterface. To decorate this object, all we need to do is:

$request = new MyRequest($request);

And that's it, we now have an isLoggedIn method, without having to mess with the core instances.