触发ASP.NET网站服务器端推送的方法有哪些

Question

We are implementing Signalr to provide real time updates to browser clients. But we are curretnly stuck as we need to make http server itself (IIS+ASP) detect the changes from database and external services or from any other source without polling? I believe this should be a common problem with all real time websites (irrespective of what technology is used for server side push SignalR, Comet or WebSync). Please provide what are general approaches used in such situations?

Answer 1

If you can, raise an event in whatever code is updating your database. Use that event to trigger the message publication.

Ready to update database -> Update database
                         -> Publish to WebSync

If you can't control the code updating your database, use the SqlDependency class. It lets you define a SELECT statement and then notifies you whenever the results of that query change. Use the notification event to trigger the message publication.

Update database -> SqlDependency -> Publish to WebSync