Lithium apps that go beyond CRUD

Question

This is more or less a framework-centric version of a past Stack Overflow question, which is about how most introductory material on MVC applications tends to present a tight coupling between models, views, and controllers. For example, you'll have a User table that is modified by a User controller which in turn pushes filtered data to a User view. It's my impression that a lot of MVC frameworks tend to reflect this pattern as well. This is all fine and well for what it is, but it never really leads me to anything beyond building and displaying monotonous lists of things with an HTML form.

The MVC framework that looking at right now is Lithium, which seems quite interesting as a case study of clever PHP5.3 coding techniques. On one end, Lithium has a Model class that offers wrapper objects around a individual tables, and abstracts away some simple queries. On the other end, it's got a nifty convention of routing URLs to method calls on controller objects, which then render to display templates.

But in the midst of this, I find myself at a loss as to where to place all of the interesting logic that relates data in table A to data in tables B through Z. Or at least, I'm not sure where to place such logic in a manner that's consistent with the design of the framework. To my understanding, Lithium's Model abstraction doesn't do much more than eliminate some row-level insert/update/delete boilerplate, and the controller/view architecture seems mostly about user interface. I wouldn't want to put a lot of business logic in the same Controller class that is receiving routed function calls from URL requests.

My instinct would be to fill the gap with a bunch of my own code that exists more or less entirely outside of the framework. I'm not sure if I ought to expect more than that, but given how rigidly structured everything else is in Lithium, it feels somehow unsatisfying, like I could have just rolled my own boilerplate-reduction code without the overhead of grokking the source of a big framework.

What am I missing here? Is there a recommended architecture or philosophy to using this type of framework?

Answer 1

One thing you have to remember with Lithium is that theres no production ready release yet (although some sites are using it in production). The main missing feature right now is model relations. With relations in place i assume your question would be partially answered as that is an important brick in the big picture of creating more complex applications. You could check out the x-data branch where the work on relations should be ongoing.

For the second part of writing domain logic the simple answer is "in the model". See this (rather useless) example of extending model functionality for example. Another example to look at is the open source mini application Analogue that is one of the few working open examples of Lithium in use. The Analogue model class shows a slightly more meaty model.

And finally its a matter of connecting the dots between M, V and C. A Lithium controller should mainly delegate jobs over to models, and perhaps restructure the input data if needed. The simple examples of having a Post model, PostsController and views/posts/add,index,etc doesn't mean that you have to merely have Post::all() in there. PostsController::view need to load a set of Comment models probably.

So you will toss a lot of your own code in there, of course! Else it would not be much of an application. But keep the domain logic tied to the model where it is natural.

• Need to verify that blog post has a unique title? Write a validator.
• Need to ensure the user has write access to the post? Override the save method and verify it, or filter it.

But I think we need to wait for relations to land and a 1.0 release before we can fully judge how structuring applications in Lithium can be solved best.