WAMP websocket server connection error on Python with Autobahn

Question

I'm trying to connect to a WAMP websocket server using Python and subscribe to receive messages, but I'm not able to achieve it. I have managed to connect using Autobahn on JS with this code:

< script src = "autobahn.js" > < /script> <script >
  var conn = new ab.Session('ws://examplehost.com:8443/ws',
    function() {
      conn.subscribe('channel', function(topic, data) {
        console.log(data);
        alert('New data arrived: "' + topic + '" : ' + data.title);});},
    function() {
      console.warn('WebSocket connection closed');
    }, {'skipSubprotocolCheck': true}); 
  </script>

But using the same library on Python with below code results on 404 error:

from autobahn.asyncio.wamp import ApplicationSession, ApplicationRunner

class Component(ApplicationSession):
    async def onJoin(self, details):
        def on_event(i):
            print("New data arrived: {}".format(i))

        await self.subscribe(on_event, 'channel')

if __name__ == '__main__':
    url = "ws://examplehost.com:8443/ws"
    runner = ApplicationRunner(url)
    runner.run(Component)

And this is the error I get:

failing WebSocket opening handshake ('WebSocket connection upgrade failed (404 - NotFound)')
dropping connection to peer tcp4:123.123.123.123:8443 with abort=True: WebSocket connection upgrade failed (404 - NotFound)

Any idea on how to solve this? After searching a lot maybe using the path /ws on the server is causing some issues, but I'm not sure. I have also tried with many other Python modules, but not luck.

score 0 · Answer 1 · answered Dec 02 '21 at 00:44

This looks like a webserver issue. My understanding is websockets are created by upgrading reglar HTTP connections.

You need to configure the web server, and any proxy in the middle, to upgrade the configuration.

I've mostly encountered this with nginx. This looks like a good example.

WAMP websocket server connection error on Python with Autobahn

1 Answers1