PHP - MVC - Fetching the view

问题:

Greetings all!

Looking for some help with MVC in a PHP context. Currently I am building a small, lightweight MVC framework to help expedite application development at work. It's a long hard separation eliminating inline code - at least with numerous projects looming overhead and the temptation to utilize it ever-present.

I understand most of the basic requirements of MVC, and I've already begun porting some of my existing classes that are in Singleton pattern over as utilities in my new framework (these are mostly basic 'handlers' to perform site services - a class for file uploads, authorization, wrapped PDO database queries, error printing etc.)

What I can't seem to grasp moving forward after reading much documentation is the best approach to instantiating views. In my old, inefficient design I would switch off a $_GET variable to switch ouput from within the home view. Just going off intuition, this seems like an extremely bad way of getting the job done.

I've looking into CodeIgniter, and it would seem that there are predefined functions for loading views within that framework. What is the best approach to such an application design? Would it be a class based 'link factory' that utilizes the same variables to fetch content, select the proper view file, and place it in the page flow? Also, how could the new view be included between the header and footer includes in the root index without using switches? This is the only thing really confusing me - I really hope I have worded myself clearly enough.

Thanks all as ever!

回答1:

I highly recommend "PHP Objects, Patterns, and Practice" by Matt Zandstra. A good bit of the book deals with creating MVC frameworks and would be very, very helpful to you.

It covers these patterns (which you can also research elsewhere):

• Front Controller
• Application Controller
• Page Controller
• Template View
• View Helper

回答2:

While I'd suggest going with an established, flexible framework (like Zend), to answer your question, here are the steps involved as I see them (understand I stopped trying to write this kind of stuff a while ago, this is based on my understanding of the existing frameworks I've used).

1. Some kind of router parses the request and translates to a controller object with an action (or takes the default) and optional parameters. The router then calls the controller object's function matching the action.
2. The controller object (usually extended from a generic controller object) process the request and determines what data to pass to the view, as well as what view to use. Most frameworks setup a default view based on the action, but ultimately it's up to the controller to decided what view to use.
3. The view takes the data and displays it.

That is my very simplified take on the process.