Add an MQTT bridged to WAMP example

This shows the basics of using the MQTT adapter
functionality with Crossbar and WAMP

examples/router/.crossbar/config-no-tls.json

@@ -51,6 +51,17 @@
                 }
             ],
             "transports": [
+                {
+                    "type": "mqtt",
+                    "endpoint": {
+                        "type": "tcp",
+                        "port": 1883
+                    },
+                    "options": {
+                        "realm": "crossbardemo",
+                        "role": "anonymous"
+                    }
+                },
                 {
                     "type": "web",
                     "endpoint": {

examples/router/.crossbar/config-with-tls.json

@@ -31,6 +31,17 @@
                 }
             ],
             "transports": [
+                {
+                    "type": "mqtt",
+                    "endpoint": {
+                        "type": "tcp",
+                        "port": 1883
+                    },
+                    "options": {
+                        "realm": "crossbardemo",
+                        "role": "anonymous"
+                    }
+                },
                 {
                     "type": "web",
                     "endpoint": {

examples/twisted/wamp/mqtt/README

@@ -0,0 +1,17 @@
+This demonstrates the use of the MQTT bridge now included in
+Crossbar.io
+
+You need to install "paho-mqtt" to run the MQTT client which you can
+do via pip:
+
+   pip install paho-mqtt
+
+Then, with the crossbar router running from "examples/router" dir you
+can start up either the WAMP or MQTT client first (ideally in
+different shells):
+
+   python wamp-client.py
+   python mqtt-client.py
+
+They both subscribe to "mqtt.test_topic" and then publish some data to
+that same topic (so try starting them in different orders etc).

examples/twisted/wamp/mqtt/mqtt-client.py

@@ -0,0 +1,26 @@
+import paho.mqtt.client as paho
+
+# note that unlike Autobahn and Crossbar, this MQTT client is threaded
+# / synchronous
+
+client = paho.Client()
+client.connect('localhost', port=1883)
+
+
+def on_connect(client, userdata, flags, rc):
+    print("on_connect({}, {}, {}, {})".format(client, userdata, flags, rc))
+    client.subscribe("mqtt.test_topic", qos=0)
+    client.publish(
+        "mqtt.test_topic",
+        "some data via MQTT",
+    )
+
+
+def on_message(client, userdata, msg):
+    print("{}: {}".format(msg.topic, msg.payload))
+
+
+client.on_connect = on_connect
+client.on_message = on_message
+
+client.loop_forever()

examples/twisted/wamp/mqtt/wamp-client.py

@@ -0,0 +1,45 @@
+from os import environ
+
+from autobahn.twisted.wamp import ApplicationSession
+from autobahn.twisted.wamp import ApplicationRunner
+from autobahn.wamp.types import PublishOptions
+
+from twisted.internet.defer import inlineCallbacks
+
+
+class Component(ApplicationSession):
+    topic = u'mqtt.test_topic'
+
+    @inlineCallbacks
+    def onJoin(self, details):
+        print("session attached {}".format(details))
+
+        yield self.subscribe(self.on_event, self.topic)
+        print("Subscribed to '{}'".format(self.topic))
+
+        # if you send args, then all args (and kwargs) in the publish
+        # are encoded into a JSON body as "the" MQTT message. Here we
+        # also ask WAMP to send our message back to us.
+        yield self.publish(
+            u"mqtt.test_topic", "some data via WAMP",
+            options=PublishOptions(exclude_me=False),
+        )
+
+        # if you send *just* mqtt_qos and mqtt_message kwargs, and no
+        # args then it will take mqtt_message as "the" payload
+        yield self.publish(
+            u"mqtt.test_topic",
+            mqtt_qos=0,
+            mqtt_message="hello from WAMP",
+        )
+
+    def on_event(self, *args, **kw):
+        print("'{}' event: args={}, kwargs={}".format(self.topic, args, kw))
+
+
+if __name__ == '__main__':
+    runner = ApplicationRunner(
+        environ.get("AUTOBAHN_DEMO_ROUTER", u"ws://127.0.0.1:8080/ws"),
+        u"crossbardemo",
+    )
+    runner.run(Component)