Channels: Unable to route a consumer through an included path

[MCBama]

I’m attempting to route a channel to a consumer to handle messages from both javascript and model changes via a post_save signal. This works when I includethe routes without a path, but including WITH the path produces an error:

ERROR - worker - Could not find match for message on consumer! Check your routing

The error occurs on socket connection since I’m sending a message on connect from my javascript and also appears when I attempt to save my model.

It appears that something within the includefunctionality is preventing Channelrouting if a path is provided. Either that or the documentation failed to mention how to properly set up channels to handle paths within the routes.

// javascript call

socket = new WebSocket("ws://" + window.location.host + "/mission");
socket.onmessage = function(e) {
    alert(e.data);
}
socket.onopen = function() {
    socket.send("hello world");
}
// Call onopen directly if socket is already open
if (socket.readyState == WebSocket.OPEN) socket.onopen();

# routing.py 

from channels.routing import route, include
from vits.consumers import ws_connect, ws_message, ws_disconnect, msg_consumer

mission_routing = [
    route("websocket.connect", ws_connect),
    route("websocket.receive", ws_message),
    route("websocket.disconnect", ws_disconnect),
    route("consumer", msg_consumer),
]

routing = [
  include(mission_routing, path=r"^/mission") # note: this is where the path is declared. Without path declaration routing works as expected, with path error from above is produced
]

# In consumers.py
from channels import Channel
from channels.sessions import channel_session
from channels import Group


# Connected to chat-messages
def msg_consumer(message):
  print("Message Consumed")
  Group("mission_listeners").send({
    "text": message.content['message']
  })

# Connected to websocket.connect
@channel_session
def ws_connect(message):
    print("ws_connect")
    # Work out room name from path (ignore slashes)
    room = message.content['path'].strip("/")
    # Save room in session and add us to the group
    message.channel_session['room'] = room
    Group("mission_listeners").add(message.reply_channel)
    # Accept the connection request
    message.reply_channel.send({"accept": True})

# Connected to websocket.receive
@channel_session
def ws_message(message):
    # Stick the message onto the processing queue
    print(message['text'])
    Channel("consumer").send({
        "message": message['text'],
    })

# Connected to websocket.disconnect
@channel_session
def ws_disconnect(message):
    Group("mission_listeners").discard(message.reply_channel)

[andrewgodwin]

Does it work if you add the path individually to the routes rather than on the include?

[MCBama]

It does not actually. So the error isn't limited to the include functionality as I originally surmised. Or I'm still doing something wrong :/

mission_routing = [
    route("websocket.connect", ws_connect, path=r"^/mission"),
    route("websocket.receive", ws_message),
    route("websocket.disconnect", ws_disconnect),
    route("consumer", msg_consumer, path=r"^/mission"),
]

[andrewgodwin]

Hm, are you complaining that the consumer channel one isn't working? Where are messages for that coming from?

[MCBama]

From both javascript and model changes via a post_save signal. When I attempt to route any of my messages through the consumer via

Channel("consumer").send({
         "message": message['text'],
     })

I get the error:

ERROR - worker - Could not find match for message on consumer! Check your routing

[andrewgodwin]

Ah, well that's because you don't have a path key in your message - the routing isn't magical, it just goes off of the contents of the message. websocket.connect and websocket.receive messages include a path key so they can be routed, whereas yours just has a message key.

Given you have made a separate channel especially for this, there's no need for the path routing unless you really want to distinguish it, in which case you should ensure a path is added to the message when it's sent onto the channel.

[MCBama]

Ah. That would explain it then. Much obliged.

Is this documented somewhere that I can go and review or would I have needed to dive into the code base itself to figure out that the message required a path key?

[andrewgodwin]

It's somewhat covered here: http://channels.readthedocs.io/en/latest/getting-started.html#routing

I will say we could probably specifically call this out, however. You're not the first person to make this mistake by far.