I am using a library (ShareDB) for operational transformation, and the server and client side use a websocket-json-stream to communicate. However this ShareDB is being run on nodejs as a service (I'm using zerorpc to control my node processes), as my main web framework is Tornado (python). I understand from this thread that with a stateful protocol such as TCP, the connections are differentiated by the client port (so only one server port is required). And according to this response regarding how websockets handle multiple incoming requests, there is no difference in the underlying transport channel between tcp and websockets.
So my question is, if I create a websocket from the client to the python server, and then also from the client to my nodejs code (the ShareDB service) how can the server differentiate which socket goes with which? Is it the servers responsibility to only have a single socket 'listening' for a connection a given time (i.e. to first establish communication with the Python server and then to start listening for the second websocket?)
The simplest way to run two server processes on the same physical server box is to have each of them listen on a different port and then the client connects to the appropriate port on that server to indicate which server it is trying to connect to.
If you can only have one incoming port due to your server environment, then you can use something like a proxy. You still have your two servers listening on different ports, but neither one is listening on the port that is open to the outside world. The proxy listens on the one incoming port that is open to the outside world and then based on some characteristics of the incoming connection, the proxy directs that incoming connection to the appropriate server process.
The proxy can be configured to identify which process you are trying to connect to either via the URL or the DNS hostname.