The document discusses different techniques for real-time communication between a client and server, including short polling, long polling, and websockets. It explains that websockets allow for full-duplex communication and are more efficient than polling techniques. The document then outlines how to use websockets with the Play! framework, including creating enumerators and iteratees on the server and connecting via websockets on the client. It provides a link to a Play! chat application sample that demonstrates using websockets.

1. Knoldus Software LLP
Using WebSockets In Play!
Neelkanth Sachdeva
Software Consultant
neelkanthsachdeva.wordpress.com

2. Agenda
Short Polling
Long Polling
WebSockets
Websockets with Play !
The Play Chat Application Using Wesockets

3. Short Polling
Drawbacks :
Resource Intensive
Slow Even Very Slow
One Request / One Response

4. Long Polling
Drawbacks :
- Half Duplax
- Again one request / one response

5. Whats our probelm
Lots of incoming messages

6. Websockets

7. WebSocket Features & Limitations
Features :
Full duplax communication
Real time messages
Efficient & Fast
Drawbacks :
Available with newer browsers

8. Using Websockets with Play !
Producer
Consumer

9. Using Websockets with Play !
Producer
Enumerator
Consumer
Iteratee

10. Iteratees
The Consumer
Consumes chunks from Producer

11. Enumerator
The Producer
- Produces typed chunks
- Only produces if consumer is there.

12. At Server :
Creating a websocket connection needs a
Producer (Enumerator) & a Consumer
(Iteratee)

13. At Client :
Creating a socket connection.
var socket = new WebSocket(“ws://localhost:9000”)
The Events
- onmessage
- onopen
- onclose

14. Understand it through play sample chat
application available here :
https://github.com/playframework/playframework/tree/master/samples/scala/websocket-chat

15. Cheers !