page-controller

Page Controller

An object that handles a request for a specific page or action on a Web site.

• Overview
• How It Works
• When to Use It

Overview

Page Controller has one input controller for logical page of a web site. That controller may be the page itself, as it often is in server page environments, or it may be a separate object that corresponds to that page.

How It Works

• There are three basic responsibilities for a Page Controller:

  • Decode the URL and extract any form data to figure out all the data for the action.

  • Create and invoke any model object to process the data. All relevant data from the HTML request should be passed to the model.

  • Determine which view should display the result page and forward the model information to it.

• Have one module on the web server act as the controller for each page on the web site. More strictly, the controllers tie in to each action, which may be clicking a link or a button.

• It can be structured either as a script or as a server page.

  • Using a server page usually combines the Page Controller and a Template View in the same file.
  • Using a script can involve the server page calling a helper object to handle all the logic, or make a script the handler and controller, so that the web server passes control to the script and it finally forwards to an appropriate view.
  • You can have some URLs handled by server pages and some by scripts. Any URLs that have little or no controller logic are best handled with a server page, since that provides a simple mechanism.

When to Use It

The main decision is whether to use Page Controller or Front Controller. It's not uncommon to have a site where some requests are dealt with one and some with the other.

• Page Controller is the most familiar to work with and leads to a natural structuring mechanism where particular actions are handled by particular server pages or script classes. Your trade-off is thus the greater complexity of Front Controller against its various advantages, most of which make a difference in web sites that have more navigational complexity.

• Page Controller works particularly well in a site where most of the controller logic is pretty simple.