Question

I’ve searched around but there doesn’t seem to be a clear consensus on which one is better. Currently, all the HTML forms on the site point to a single PHP file. Each form has a hidden input specifying the action (e.g. ‘user-login’, ‘user-logout’), and the PHP file calls methods from that.

So my question is: Should I point each form back to itself, related forms to a single file or all forms to a single file? And in terms of MVC, should processing take place in the controller or form?

Answer 1

Should I point each form back to itself, related forms to a single file or all forms to a single file?

You should point everything to index.php, which then delegates other components (controllers in MVC terms) to take care of the processing. The controller will then decide which view it wants to render. index.php would be in this case something we call the front controller. (note: below I am recommending ZF1 as a learning platform. ZF1 has a “front controller” class. Some people may argue that THAT one is the front controller and index.php is what they call the entry script. In my opinion, that is only the second “front” controller. Nevertheless, both opinions are controversed, so make your own opinion).

And in terms of MVC, should processing take place in the controller or form?

In terms of OOP first and foremost: the object is the only one who knows how to validate its own data (the principle of self-containment), so the form should validate itself. If it’s about a model, the model should be called by either the controller, or the form – it’s a matter of taste. No matter which way, the same principle applies: you feed the Model with data and call its validation method.

As you may have noticed, the Form class is a Model.

Don’t let yourself fooled by the hype called MVC. Respect the OOP principles above all.

Regarding MVC: the MVC pattern says: the controller only coordonates the other components, for instance it takes the input, creates a Form instance, and calls the Form’s validation method.

I advise you to use a framework to better see how all these pieces work together. The best would be zend framework 1, which has little to do with real life requirements, BUT which is a masterpiece in terms of patterns and practices.

Maybe ZF2 will change that mistake with the extra front controller.

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Looking at the other answers, I feel the need to clarify some terminology used in my answer:

• Model is a model. There’s plenty of documentation about MVC
• Form is a subclass of Model. It takes care of the validation. It may also have a method Form::__toString() which renders the HTML form in the view (the V in MVC)
• view is the html file, and it’s rendered under the supervision of the controller (C in MVC)

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To recap, the overall execution flow would look like this:

1. <form action ...
2. entry script (a front controller)
3. router (it decides which Controller to forward the request to)
4. the Controller coordinates all the actions, calling the Model::validate() of one or many models (including Form, which is also a Model)
5. in the end, the Controller choses to render() a view (a html file), which could contain a call to Form::__toString(), in which case the Form is a hybrid of Model and “renderer”.
6. Fun
7. Profit

That’s it, basically. Different frameworks have different data/execution flow. ZF1’s looks like this for instance: http://www.slideshare.net/polleywong/zend-framework-dispatch-workflow