CODEWITHSUNDEEP
pythonautobahncrossbar
Jean-Robert
Jean-Robert

Reputation: 840

Single AppSession can't subscribe to and publish on the same topic

Based on the simple Hello World example, I replace the oncounter topic with the onhello one when publishing. That would mean the AppSession is subscribing to a topic it is itself publishing. I'd guess it should be able to receive its own messages but it looks like it doesn't. Is there a way to do this?

For a reproducible example: 


from twisted.internet.defer import inlineCallbacks



from autobahn.twisted.util import sleep
from autobahn.twisted.wamp import ApplicationSession



class AppSession(ApplicationSession):



@inlineCallbacks
def onJoin(self, details):

    def onhello(msg):
        print("event for 'onhello' received: {}".format(msg))
    sub = yield self.subscribe(onhello, 'com.example.onhello')

    counter = 0
    while True:

        yield self.publish('com.example.onhello', counter)
        print("published to 'onhello' with counter {}".format(counter))
        counter += 1

        yield sleep(1)

After running crossbar start, I see the onhello topic being published, but it is not received.

Upvotes: 3

Views: 339

Answers (1)

oberstet
oberstet

Reputation: 22051

The reason is, that - by default - a publisher does not get an event published even if the publisher is itself subscribed to the topic published to.

You can alter that behavior by provided an options argument to publish():

yield self.publish('com.example.onhello', counter,
   options = autobahn.wamp.types.PublishOptions(excludeMe = False))

Upvotes: 3

Related Questions