Best way to make a webpage live and multiuser

Question

I'm building a web app for 'brainstorming.' Here's how it works: essentially, a user can come onto the app, and submit a challenge, or click on one that's already there, then think up ideas to resolve that challenge and post them up. I hacked together a basic example here on couchdb: http://wamoyo.iriscouch.com/ideageneration/_design/IdeaGeneration/attachments%2findex.html

I'm going to rebuild it from scratch and all, and I'm hitting up against a challenge that's very unfamiliar to me. I'd like for multiple users to be able to generate ideas for the same challenge at the same time. Kinda like the way google docs allows multiple people to edit a shared document. I have some preliminary thoughts on how to go about this, but I thought I'd ask the expert network here.

I'm fairly comfortable with AJAX, is there a pure AJAX way to make it live and multiuser? Would there be an enormous benefit to going with node.js? What might be some other options?

Thanks soo much!

Answer 1

There are several approaches in making such web pages, using plain ajax polling, using long polling and using web sockets.

• Ajax polling - easy to implement, essentially connecting to server recurrently via javascript timer, retrieve data from server and send it back via regular Ajax.

  • Advantages: easy to implement, works everywhere
  • Disadvantages: the updates are not in real-time, the data is exchanged only when the timer ticks.

• Long polling - the idea is that the connection stays open until it times out, then the connection is reestablished. Can be tricky to implement because of different settings for request timeouts for different web servers, routers, etc.

• Web sockets - part of HTML5 umbrella, works only in fairly modern browsers, the protocol changes often which may cause incompatibilities during development and production. Can be used natively with modern browsers and via a Flash plugin with older ones. This technology is most lightweight, because it doesn't incur all the HTTP overhead. Think of it as bi-directional, full-duplex communication channel between a browser and a web server via TCP.

For a detailed discussion, I recommend reading this good post by Scott Hanselman. It tells the story about SignalR, but is applicable to other server-side frameworks.

There is also a podcast by same author, the guest goes fairly deeply into explaining these technologies. Worth listening, IMO.

To answer your question about node.js, please share us your current server technology, so we could get more insight into your stack.