Feed Reader updates (Eg Google Reader or Bloglines)

What is the method through which online feed 开发者_如何转开发reader sites like google reader updates its feed is it cron or something else.

Sorry if question is too basic i am still a novice in programming.

cron or something else

That's actually right to the point. The basic idea is that you need to run non-user-triggered scheduled work in the application to update the feeds, and how this is done depends very much on the server environment and the web framework. In a LAMP application it might be cron, in ASP.NET it might be a Windows Service or a Scheduled Task. Some web frameworks, like Ruby on Rails, have specialized modules for this.

Your only real obstacle will be finding a way to run code that is not the result of a user requesting a resource from your server.