Web Browser Programming Blurring the Lines of MVC

lkcl tips his in-depth article up at Advogato on the difficulties for the MVC programming model that are introduced by Javascript and AJAX, and solutions for them. He writes: "This article outlines how the MVC concept is made incredibly awkward by the gradual but necessary introduction of Javascript and AJAX. A solution is found in the form of Javascript Compiler Technology such as GWT or Pyjamas (PyPy's JS backend or Rb2Js could be used, with some additional work). The article outlines how and why the traditional MVC patterns are fragmented by Javascript and AJAX, advocating that if a site is programmed purely in a high-level language that is then compiled to Javascript for the Web Browser sections, the same high-level source code can be executed either client-side on the browser, or server-side, or even both, depending on the requirements. The implications of this approach are discussed in depth."

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[Alt_Cognito]

The lines between what is an application are blurring. We have disparate data sources which are being combined in ways which the original sources never necessarily intended. The user application may or may not even be one written by the service provider.

The semantic web, despite all the nay saying, is here.

Not even MVC

[GrouchoMarx]

I have long argued that MVC doesn't even make sense on the web to begin with. MVC is a great architectural model for live interactive systems, but a web site or web app is not a live interactive system. It's an asynchronous challenge/response system.

I blame Sun for completely abusing the term in their Java stacks (I think they called it "model 2"?), and Ruby on Rails for popularizing the wrong impression. MVC by definition requires a direct observer connection from View to Model. All web-MVC frameworks I've seen start with the initial statement that the Controller, not the View, is responsible for handling user interaction and communicating with the Model. Sorry, that's not MVC. It's not a bad model for the web, but it's not MVC. If anything it's closer to PAC.

See the link above for a lengthier analysis and links to Wikipedia. :-)

Really, the whole point of design patterns is to have a common vocabulary. How is that useful if you're going to bastardize your terminology due to stubborn ignorance?

Re:Not even MVC

[Shados]

(I think they called it "model 2"?),

Lets make things clear first: MVC model 2 has nothing to do with the original MVC, as you already pointed out. The original MVC isn't used much, not even in live interactive system anymore, so they reused the term, and clearly documented it (it made sense at the time: there is a model, a view and a controller, and its a strict design pattern, and the original MVC is rarely seen outside of legacy system and 4G tools that die faster than they pop up).

Otherwise, you end up with a lot of terms that eventually all mean the same thing but not, and it is even more confusing. The main issue came with people thinking that MVC is ANYTHING with a model, a view, and a controller. That put aside, there's no abuse of language here. There's MVC, and MVC Type 2, and if you're talking about the web, aside in extremely rare scenarios, you're always talking about Type 2, so its redundant.

Still, that doesn't change much... MVC, because of frameworks like Struts and Rails is seen by the unwashed mass of developers as the "end all be all: if its not MVC, its not a well architecture application", totally ignoring all of the alternatives. Now THAT is a problem. MVC Type 2 is only good for a subset (large, but still just a subset) of web apps.