implementing a ios chat (like whatsapp): websocket?

Question

I am trying to implement a chat service in ios. My question is: how services (like whatsApp) work?

I found a tutorial (here) about how use websockets. Is it right direction? In that case the chat only alive when the app is running.

Anyone have experinces on this ?

Answer 1

Tutorial looks really nice, would say good direction. If you want to implement socket in background too you need to look at background modes.

http://www.raywenderlich.com/29948/backgrounding-for-ios

In short if you open socket, you mark it as VOIP one, which will keep it opened even when in background.