Women in Technology

Article:		Building a PHP Front Controller
Subject:		Why use a controller paradigm?
Date:		2004-07-14 00:25:36
From:		gaeldesign
I don't want to sound like I'm criticizing this article, because I'm not. The "front controller" design pattern is well-known in Web app circles. But, from my perspective, I have never understood any reason to use it. No article I've read on the matter, and no PHP app I've inspected, has shown me any good reason for it. I've seen good PHP apps that don't use it (even while being very OO in nature), and my own apps don't use it. Honestly, what's the point? The argument seems to be that you can run the same kind of "set up the app framework" stuff on every page. But, er, that can be done anyway. See here in a fake code example: "page1.php" $myapp = new MyWebApp(); $myapp->setupWhateverYouNeed(); // program logic Page1LogicGoesHere(); // include page template includePage1Template(); // Optional: clean up code $myapp->cleanUp(); "page2.php" $myapp = new MyWebApp(); $myapp->setupWhateverYouNeed(); // program logic Page2LogicGoesHere(); // include page template includePage2Template(); // Optional: clean up code $myapp->cleanUp(); Honestly, there's no reason you'd have to duplicate any code other than a very small handful of lines in each file. The separate objects in their own code files would handle 99% of the work. The benefit of this approach is that you can use real files for real URLs. Using the above example, you get: http://www.mydomain.com/page1.php http://www.mydomain.com/subfolder/page2.php And so on. Real pages! Real files! No fake stuff. I hate fake stuff! So there you go. Maybe there's something I've overlooked, but I can't think of anything. Like I said, no Web app I've come across seems like it HAS to use the front controller paradigm to be easy to design and manage. Regards, Jared

Showing messages 1 through 1 of 1.

• Why use a controller paradigm?
  2004-08-04 14:37:30  thomaskostecki [View]
  
  
  There are a few reasons that I've found that make front controllers better than the way you are doing. I'll give you the first two that popped into my head.
  
  One: You gave this example.
  "page2.php"
  
  $myapp = new MyWebApp();
  $myapp->setupWhateverYouNeed();
  
  // program logic
  Page2LogicGoesHere();
  
  // include page template
  includePage2Template();
  
  // Optional: clean up code
  $myapp->cleanUp();
  ---------------------------------------
  
  What if this structure needed to change for some reason? Lets say you now need to do
  $myapp = new MyWebApp($someParam);
  instead of
  $myapp = new MyWebApp();
  You now need to change this in many places instead of just one!
  
  Two:
  php paths are based on the file in the url. If you use your example of
  http://www.mydomain.com/page1.php
  http://www.mydomain.com/subfolder/page2.php
  then it gets really complicated. The relative paths of all the requires in all the files used in page2.php will need to be different than all the requires for all the files used in page1.php. There are ways around this, but I think it's cleaner to use a controller