How to design a multi-user ajax web application to be concurrently safe

Question

I have a web page that shows a large amount of data from the server. The communication is done via ajax.

Every time the user interacts and changes this data (Say user A

Answer 1

I know this is an old question, but I thought I'd just chime in.

OT (operational transforms) seem like a good fit for your requirement for concurrent and consistent multi-user editing. It's a technique used in Google Docs (and was also used in Google Wave):

There's a JS-based library for using Operational Transforms - ShareJS (http://sharejs.org/), written by a member from the Google Wave team.

And if you want, there's a full MVC web-framework - DerbyJS (http://derbyjs.com/) built on ShareJS that does it all for you.

It uses BrowserChannel for communication between the server and clients (and I believe WebSockets support should be in the works - it was in there previously via Socket.IO, but was taken out due to the developer's issues with Socket.io) Beginner docs are a bit sparse at the moment, however.