Web framework API

I'm not a Web Developer, and I don't know a lot about the web application frameworks out there.

Recently, however, I got into Wt. It's a web framework written in C++ (that's why I got into it), but what impressed me the most is the idea it's based on.

Its API is different from any web framework I ever heard of (CppCMS, Yii, Django, Pylons, Zope, Drupals, Java Servlets, Struts ...): a new Application object gets created for any user sessio开发者_StackOverflow社区n, and it stays alive until the session expires (only at this point the Application object gets destroied). This Application object works like a desktop window: you put Widgets in it (widgets like forms, links, labels ...); when the user clicks on a link (when the HTTP server receives a new GET/POST request) a function gets called on the object tight to the user session (in a nice Signal/Slot way), which can remove/add/change the widgets, thus changing the page the user will see.

As I said, I'm not very skilled with web frameworks, I develop almost only desktop applications; maybe for this reason I think this paradigm behind Wt is great.

I'd like to know what are the pros and cons of this framework API in respect to the other ones, and if there are other frameworks (also in other languages) based on the same concepts.

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Wt is a great framework for its intended range of applications.

Wt is great for :

• web apps tightly coupled to a session, i.e.
  • made to be accessed only by users that are logged in (except the landing page)
  • display a lot of user-dependent content (so not for a wiki)
  • relying heavily on state
• web apps that need to have a lot of controls/buttons and user input.

For exemple, I plan to write a browser MMORPG. Pages will all be having a state tied to a user, and there will be a lot of buttons. Wt is perfect for that. I used to be a Ruby on Rails developper, and switching to Wt for this kind of app was a great moment. It's increadibly cumbersome to design forms with traditional frameworks that try to enforce pure REST.

Wt would also be perfect for a control interface on some process. For example, an interface allowing your customers to configure their adword campain, etc.

Of course, using Wt is not perfect regarding control and separation, but it allows extremely fast development when you need only the "classic" features (buttons, editors, etc.)

So as a rule of thumb, if you are trying to put a desktop application on the web (which is a great idea, removing the need to deploy and update on your customers' machines), Wt is a good candidate.

Also, if you are interfacing with an existing C++ codebase, Wt has an advantage.

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I think this is generally bad idea.

Web application is very different from GUI one and there are many reasons:

99% of the web is about the content rather then about iteration.

You go to web to get or share content rather then to do some real time interaction like drawing a picture, working with spreadsheet or anything else. Web is content driven rather then "event driven" interactive application.

This has strong impact on how do you create most of web - you bring information to user rather then interact with him.

The server and client programming is very different

There are some web GUI applications like e-Mail, Chats clients but to perform well they require very good separation between the client side written in high quality Java Script and the high quality server side backend that is used over AJAX for content retrieval.

Hiding this separation like Wt does or (other known frameworks) lead to crappy software and generally brings more problems then solutions in long run.

Because it should be very clear separation between server side and client side jobs as some require real time response and some don't.

When you try to solve all this in one wait for problems. Note, there are client-server solutions for GUI (see X-Server as example) but unlike web they designed for this and rather work more like IPC rather then client-server solitions.

The web is stateless most of the time.

Or to be more correct the state usually keeps quite small amount of data.

Creation of instant session object is nice idea until you need to... Scale up save state in long terms then this model becomes not so good, of course this not "forced" model by Wt but it is general concept that fits certain concept and some does not.

Bottom Line

If you want to design good GUI like web application. Start learning JavaScript and use good GUI JavaScript frameworks that fit well to GUI even driven design. Then combine them with some server side API using some interaction RPC model like Json-RPC, XML-RPC and other AJAX tools.

This is the way to do things right for highly interactive applications.

If your application is more content oriented then most of server side web frameworks do great job - concentrate on server side with its great tools suitable for the job.

All in one solution? It just does not work...

Disclosure: I'm developer of CppCMS and I think Wt just goes in wrong way.

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ASP.NET is similar; it has the same goal to make web development look like desktop application development.