Ahem. So anybody that’s known me for a while has likely heard me say something similar to what is quoted in Cal’s article about OSCON. I should clarify because I hear jokes about "Tell us what you really think".
Choosing a framework to implement your web app is a trade off like any other design decision. Let’s focus in on specifics and talk about what the trade off is that you make when you choose a framework. Specifically, I’m talking about MVC frameworks in PHP.
- Frameworks provide a common method of code organization, so developers can both a) get up to speed fast, and b) don’t have to think hard about how to architect an app. They are effectively a standard for application architecture. This is particularly useful when working with large dev teams or junior devs.
- Frameworks encourage the separation of the presentation layer from the business logic, avoiding a frequent PHP worst practice where stuff is all mixed in together.
- A framework can encourage secure coding through the use of dispatch architectures.
- In general, frameworks avoid spaghetti coding.
- MVC is a design pattern. As frequently mentioned by the good ol’ Gang of Four, every implementation of a design pattern is different, depending on the specific viewpoint of the implementor, and the specific application we are trying to produce. This causes two problems. One is that the implementor’s viewpoint is not necessarily the same as mine. The second is that trying to shoehorn every app into the MVC structure isn’t always appropriate.
- Most MVC frameworks have an intentionally flat design - models, views, controllers - and when codebases grow, you need to modularize for maintainability. There are different ways to do this, but many frameworks don’t lend themselves well to this.
- In the world of PHP, as with Perl, there is More Than One Way To Do It. Specifically with frameworks, I believe Luke has been known to say there are 2.3 frameworks per PHP developer. They are like content management systems or blogging systems. We’ve all done it, sad to say. The downside of this is that you lose a lot of the programmer speedup if programmers have to learn a new framework on every project.
- Bloat is a problem in a lot of frameworks. That’s what "makes the magic happen", but typically using a framework means lots of files getting opened (required/included) behind the scenes. This slows down your app. See for example Paul M. Jones’ (updated) benchmarks. (That, by the way, is an excellent, excellent article that displays a good methodology for researching design decisions.) I’ll also refer here to what I sometimes jokingly call Thomson’s first rule of software design: First, do the simplest thing that could possibly work.
- It’s virtually impossible to retrofit an MVC framework on to existing code. A lot of us spend most of our careers dealing with existing applications.
Let’s be clear here: I am not recommending people write spaghetti code, or that they embed HTML willy- nilly in their PHP. My recommendation in making any kind of architectural decision is to know what tradeoffs you are making and make an educated decision. It’s important to remember that you can follow some of the basic rules of MVC and get a good number of the benefits without the bloat. It’s equally important to remember that there is more than one way to architect a web app.
I’ll try and blog in future about a couple of other related topics: MVC in Rails compared to MVC frameworks in PHP, and templating systems. (Unlike frameworks, all templating systems really do suck )