WebSocket channels

The server is written for Python3 using AIOHTTP. As pub/sub mechanism is used MongoDB with a capped collection and a tailable cursor.

It's like a chat where rooms are called 'channels'.

For example your web-page listens for messages for the loggged in user on channel /users/{user_id} You subscribe to (listen on) a channel and receive messages when someone posts messages to it. For example the server has some notifications or updates to data. You can send messages to subchannels. For example posting a message to channel /users/ will send the messages to clients listening on channel /users as well to clients listing on any subchannel /users/**/*.

The client can also send messages to server and the message will be sent to all clients listening on the same channel (including himself).

Start the server under Gunicorn to have more workers:

gunicorn wschannels:app --bind=localhost:5000 --worker-class=aiohttp.worker.GunicornWebWorker --workers=2

You can publish a message to a channel(s) using HTTP API:

curl http://127.0.0.1:5000/publish --data '[{"channel": "test", "message": "111"}, {"channel": "test2", "message": "222"}]'

Or you can post the message directly into the MongoDB:

# ensure that _id is generated on the server
database.eval('db.messages.insert({})'.format(json.dumps(
    {'data': message, 'channel': channel}, ensure_ascii=False)))

There is simple demo web-interface to send-receive messages on a channel: http://127.0.0.1:5000

Sample Nginx config:

upstream wschannels {
    server 127.0.0.1:5000;
}

server {
    ...

    location ~ /ws/(?<channel>.+) {
        proxy_pass http://wschannels/$channel;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "Upgrade";
    }
}