====== Page Controller ======

A Page Controller is one object or file declaration designed to handle the request for one logical web page or action.

With a simple mapping between a page request (URL) and files, this is the default pattern for scripting solutions (PHP, ASP, JSP).  A single file handles the request for a specific page.  This simple mechanism mirrors how static web pages are handled.

Scripting solutions provide a poor separation between the view and the controller when implementing a [[Model View Controller]] architecture.  This can make testing and reuse difficult.  Also See [[Template View]] for separating the View from other application logic.

The primary responsibility of the page controller as part of [[Model View Controller]] is to process input and coordinate the model and the view.  The page controller extracts information from the web server request and invoke an action on the model or calls a view based on that information.  Page controller is distinguished from a [[Front Controller]] in that the page controller operates on only a single logical page, where a [[Front Controller]] performs this functions for a set of logical pages.

Page Controllers are useful on web sites with static navigation structures.

===== Base Controller =====

When multiple page controllers share duplicate logic, a common practice is to move that logic to a base page controller which each page controller can inherit from.  This is one way of implementing [[centralized request logic]].

ASP.NET provides a special mechanism for implementing base controllers in scripts, called [[dotNet:Code Behind]].

When the base controller class begins to have special case logic in it for types of requests, it might be a good idea to consider a [[Front Controller]] instead.

===== Additional Information =====

  * [[http://msdn.microsoft.com/library/en-us/dnpatterns/html/DesPageController.asp|Microsoft Patterns: Page Controller]]
  * [[http://www.martinfowler.com/eaaCatalog/pageController.html|Martin Fowler: Page Controller]]