Real Time Realities!!! This document discusses adding real-time support to web applications. It outlines 4 steps: [1] Prepare the code for real-time using websockets; [2] Support older browsers using comet techniques; [3] Implement pub-sub systems to handle multiple tasks and authentication; [4] Consider deployment, scalability, and high availability to support many connections and crashes. The goal is to provide a full real-time experience across all browsers in a performant and reliable manner.

1. Real Time Realities!!!
Adding Real Time support to Your web app
Kausikram Krishnasayee
Silver Stripe Software

2. The History

3. The Steps
● Step 0 – get your code ready for real-time.
● Step 1 – lets start with some Websockets.
● Step 2 – lets show the same love to some old
browsers.
● Step 3 – Real-time strategies, to make life easy.
● Step 4 – Deployment, Scalability and Hair loss.

4. Code Is a Mess.

5. Truck factor is 1.

6. Business Logic, Data and Rendering
are all tied up.

7. Testing is hard. Feature Addition is Harder...

8. There ARE going to be bugs....

9. Step 0
De Couple Logic, Data and Rendering
(MVC)

10. Step 0
Lets look at the code again ...

11. Step 0
● Code is much more cleaner
● Code is easily testable
● Change in logic, data schema and rendering
is easy.
● Adding new functionality is easy.

12. Step 1: websockets

13. Step 1
Bring in Real Time Support for browsers which
support the awesome HTML5 websocket spec.
Write a fail safe for Browsers written for our
forefathers.

14. Step 1
Note about Technologies used
● Tornado running on a different port which
basically echos back data to all concurrent
connections
● Using the native websocket JS api to make
connections and update changes when there is
a model change taking place.
● Do nothing when on IE, if possible intimidate
the user.

15. How to intimidate users nicely

16. Step 1
Lets look at the code again ...

17. Step 1
● Real-time backend server running on a different
port
● Full real-time support for new browsers
● No real-time support for old browsers

18. Step 1
If you hate IE users you can stop
here....

19. Step 2 : Full Real-time support
Use a combination of comet, Web sockets, flash,
and any other possible technology that is possible
to create a cross browser, almost similar
functioning realtime system.

20. Step 2
Note on technology
● Comet: doing non HTTP things through HTTP
ways...
● Socket.io or js.io or something similar in the
front end.
● Socket.io / servers implementing connection
negotiation mechanisms in the backend.

21. Step 2
● Support for real Real-time even on IE 6.
● Abstracted out API to perform real-time actions.
● Peace of mind.

22. Step 3: pub sub systems
● What if there are more than one task list?
● How about activities performed through the
API?
● How about having a need to authenticate ?

23. Step 3
Note on technology
● Hookbox, Juggernaut or any other channel
based pub-sub system
● I wrote one myself :D

24. Step 3
Note on technology (Cont'd)
Backend to Live Server Connection.
Server Server
LS LS

25. Step 4: Deploy, Scale and much
more

26. Step 4
● Running the LS on a different port is not a great
idea.
● How about handling a few hundred connections
at the same time? What if you get Tech
Crunched ?
● What is the fall back option if LS crashes.

27. Thank You !!