Technique behing creating a google wave like asynchronous web app

Question

I want to try creating a canvas were multiple users can type and edit for brainstorming etc. I am thinking of php as backend. What are the technique used for it? For example, lets say its pure text. How do we update the text like in the google wave(b4) and in google doc?

Is it just using websocket(or js pooling) and updating the text file? or are there any better logical way to solve this issue?

Answer 1

Well, its not as easy as it is said in Brad's answer but he is partially right. You will definitely need WebSockets today to make it happen. But logically, it is not that simple to create a collaborative environment. There are issues like broadcasting changes of every user to every other user viewing the same document. Then you will have to make sure that every user gets to see exactly the same thing no matter who changes what and when. This gets difficult when multiple users are working on the same document collaboratively. There can be conflicts while merging changes of one another.

As far as PHP is concerned, language is not really a problem. Its how you handle the above stated problem.

Google released its research and engineering details on Google Wave (I guess after abandoning the project). This link might be some help to you: http://www.waveprotocol.org/whitepapers/

Answer 2

Websockets are the way to go for this. However, they are difficult to implement in PHP, and not supported by many browsers as of yet. You can do long-polling of AJAX requests pretty easily with PHP, but it can be quite a waste of resources.

This might not be what you are looking for, but I'd suggest changing your server-side technology. You can use Node.js with Socket.IO to easily use Websockets (or seemlessly emulate them for browsers that don't support them). This will provide the fastest method for pushing data to your users.