Just wanted clarification about the API differences between Websockets, WAMP over Websockets, and WAMP Sessions

[rlott]

Hi, there.

I'm in the process of updating a very old piece of software that uses autobahn 0.5.1 and Twisted. This software is essentially acting as a Broker between our web interface and some backend JSON-RPC services. In the old server, we used these calls:

from autobahn.wamp import exportRpc
from autobahn.wamp import WampServerFactory
from autobahn.wamp import WampCraServerProtocol
from autobahn.websocket import listenWS
[...]
class WampJsonServerProtocol(WampCraServerProtocol):
[...]
    @exportRpc
    def rpc(self, service, method, params=None):
[...]
    @exportRpc
    def ping(self):
        return 'pong'


class WampJsonServerFactory(WampServerFactory):
    # Base URI for all pub/sub topics.
    TOPIC_BASE_URI = 'http://evertz.com/wamp-topic/'
    protocol = WampJsonServerProtocol

    def __init__(self, wamp, port, debugWamp=False):
        self.wamp = wamp
        self.url = 'ws://0.0.0.0:%d' % port
        WampServerFactory.__init__(self, self.url, debugWamp=debugWamp)

    def serve(self):
        log.info('Starting WAMP Server. URL [%s]', self.url)
        listenWS(self)

    def notify_connection_made(self, name):
        self.dispatch(self.TOPIC_BASE_URI + name,
            {'method': 'connection_made'})

    def notify_connection_lost(self, name):
        self.dispatch(self.TOPIC_BASE_URI + name,
            {'method': 'connection_lost'})

    def notify(self, service, method, params=None):
        self.dispatch(self.TOPIC_BASE_URI + service,
            {'method': method, 'params': params})

Based on what I have read in the documentation, I believe the following is true about these 3 categories of the API:

1. The WAMP Sessions are the highest level API calls and are generally used for situations where you are connecting to a broker application like crossbar.io (i.e. using Component, ApplicationSession and ApplicationRunner).
2. The WAMP over Websockets is used for scenarios where you want to use WAMP over Websockets but are not using a dedicated software like crossbar.io.
3. The Websockets API are just plain client and server APIs using just Websockets.

So, in my case, I think what is a replacement for the old stuff I'm using is the autobahn.twisted.websocket.WampWebSocketServerFactory, but it doesn't look like this class and its associated protocol has the authentication functionality that the older WampCraServerProtocol and WampServerFactory possessed. So, I don't know if I should be using a Component class or the ApplicationSession class.

What would be suitable replacements for WampCraServerProtocol and WampServerFactory in this context?

Thanks for any insight and help.

Best regards,

Rodney Lott

[meejah]

There is no WAMP without a router.

Yes Autobahn can be used as just a WebSockets library (no WAMP no router).

Component is a high level WAMP API so probably a good choice to replace older stuff?

[rlott]

There is no WAMP without a router.

Thanks for the clarification. I looked at the WAMP standard and b/c this service is acting as a Broker that means it is fulfilling the role as a Router.

So, then, it looks like Component could then be the basis for a Router, if I'm understanding you correctly. Okay, I'll give that a try. Thanks, @meejah !