How to integrate SockJS with another web framework

Question

As an alternative to Socket.io, there is SockJS (https://github.com/sockjs/sockjs-client), which seems to be better maintained and more stable than Socket.io.

This question is about the conceptual understanding the architecture of using SockJS with a web framework, say, for building a chat application

My current understanding is that you need the SockJS-client and a SocketJS server (in my case, I intend to use SockJS-Tornado (https://github.com/MrJoes/sockjs-tornado)) to be able to make websockets-style communication.

But how does SockJS (SockJS-client + SockJS-Tornado) tie together with a web framework that does the rest of the work (e.g. serving the page, writing/reading to/from db, etc). For instance, how would SockJS-Tornado component communicates with the web server of the framework? In particular, any direction of doing this with web2py (a python web framework) is highly appreciated.

Answer 1

You're right, for SockJS you need a sockjs-capable server and a in-browser javascript client library.

There are generally two integration patterns, let's say you want to use sockjs-tornado:

1. You may have all your site served from Tornado. With that, hook sockjs-tornado to some path, for example 'http://mysite.com/sockjs'. In this scenario both your website and sockjs will be served from mysite.com domain.
2. You may keep your site in whatever language/framework it's written and add sockjs-serveras another compontent, under a different domain, like. 'http://sockjs.mysite.com/sockjs'.

Additionally, you may use any variation of this - for example: have two servers internally but expose them as one domain by using a smart loadblancer (like haproxy).

Answer 2

If you're using web2py as a framework you could look a comet_messaging.py in gluon/contrib. It provides a function (comet_send) for getting messages from web2py app out to your websocket clients. It is based on tornado (w/o SockJS support) but the DistributeHandler can subclass a SockJS connection to provide fallback transport support. In this approach your clients send messages via typical GET or POST HTTP requests which are handled by web2py controllers (or other framework) and receive messages from the web2py controllers calling comet_messaging.comet_send() which sends a post request to the tornado instance which then blasts it out to its list of listeners.

The modified lines in comet_messaging look like (Notice open becomes on_open):

class DistributeHandler(sockjs.tornado.SockJSConnection):
    def on_open(self, r):
    group,token,name = [None, None, None]
    self.group = group or 'default'
    self.token = token or 'none'
    self.name = name or 'anonymous'   

and

urls=[
    (r'/', PostHandler),
    (r'/token', TokenHandler),
    (r'/realtime', DistributeHandler)]

Notice I had to remove the regex group in the DistributeHandler URLSpec because sockJS-tornado was choking on it. Still trying to figure out how get parameters from the path to the on_open handler.

Answer 3

This provides a full answer on how to integrate SockJS into Django: https://stackoverflow.com/a/10950702/675065

Basically you need:

• Tornado + SockJS-Tornado
• Redis + Brukva

I use this configuration in my own project and it works pretty well.

Or: You try the autobahn way: http://autobahn.ws/ (i didn't try it out yet)