In a modern web application framework, MVC is well defined: requests get routed to a controller, which requests data from the model (which is probably using an ORM) and instantiates a templated view with this data. This view is sent as HTML to the browser which creates a DOM from the HTML, and renders the DOM (with CSS and images) as a web page.
MVC of the future
All the server needs to do is provide JSON responses when the client asks for more data, ideally using simple RESTful resources.
One benefit of the server being a simple JSON store is that it enables us to
easily add redundancy to our apps – if
server1 fails to deliver a response,
fall back to
No more HTML
The DOM is the means by which we display our app to the user. The browser thinks in terms of the DOM. HTML is just a serialisation of the DOM. Modern web app developers shouldn’t be thinking in terms of HTML. HTML is the assembly language of the web, and we should be working at a higher level of abstraction if we want to get stuff done. Most of the time we should be thinking in terms of layouts, widgets and dialogs, like grown-up UI designers.
The problem at the moment is that HTML is being used as a combined data and presentation format, and it should be obvious that this is a Bad ThingTM.
Of course at some point we’ll need to go down to the level of the HTML, and at that point we should be using templates. jQuery.tmpl is one (see my slides and presentation on the subject), but there are many others too. One interesting development (thanks to James Pearce for putting me onto this) is Model-driven Views (MDV).
I’m not suggesting that HTML will go away, or that developers won’t need to learn it – just that most of the time, most developers won’t need to be worrying about it, just like most of the time, most C developers don’t need to worry about assembly code.
Most web-apps are currently halfway there in terms of moving functionality to the client. The problem is that we have ended up in the worst of both worlds as app developers. Our serverside MVC framework provides a nice template-based abstraction over the HTML, which we then break apart on the client. We’re forced to work at too many different levels of abstraction simultaneously, which is never a good thing.
Things were simple when everything happened on the server. Things will be simple again when everything happens on the client. Over time new tools and best practices will emerge to encourage this new way of working. In the meantime, it’s going to take a bit of extra effort, but it’ll be worth it.