Remove QoS 1 and 2 support as they didn't work. Client persistent sta…

…te is needed. Added session resume functionality.

README.rst

@@ -6,7 +6,8 @@ MQTT Tools
 
 Features:
 
-- ``asyncio`` MQTT 5.0 client.
+- ``asyncio`` MQTT 5.0 client. Only QoS 0 (fire and forget) is
+  supported.
 
 Requires Python 3.7 or later!
 
@@ -60,7 +61,7 @@ benchmark the client and the broker.
 
 .. code-block:: text
 
-   $ mqttools publish --count 100 --qos 1 /test/mqttools/foo
+   $ mqttools publish --count 100 /test/mqttools/foo
    Published 100 message(s) in 0.39 seconds from 10 concurrent task(s).
 
 Monitor
@@ -99,7 +100,7 @@ An example connecting to an MQTT broker, subscribing to the topic
        client = mqttools.Client('broker.hivemq.com', 1883)
 
        await client.start()
-       await client.subscribe('/test/#', 0)
+       await client.subscribe('/test/#')
 
        while True:
            topic, message = await client.messages.get()
@@ -128,7 +129,7 @@ An example connecting to an MQTT broker and publishing the message
        client = mqttools.Client('broker.hivemq.com', 1883)
 
        await client.start()
-       await client.publish('/test/mqttools/foo', b'bar', 0)
+       await client.publish('/test/mqttools/foo', b'bar')
        await client.stop()
 
    asyncio.run(publisher())

examples/incrementer.py

@@ -10,7 +10,7 @@ async def main():
     client = mqttools.Client(HOST, PORT)
     await client.start()
     print(f'Connected to {HOST}:{PORT}.')
-    await client.subscribe('/mqttools/incrementer/value/request', 0)
+    await client.subscribe('/mqttools/incrementer/value/request')
 
     print('Subscribed to topic /mqttools/incrementer/value/request.')
 
@@ -25,9 +25,8 @@ async def main():
         print(f'Request count:  {count}')
         count += 1
         print(f'Response count: {count}')
-        await client.publish('/mqttools/counter-client/value/response',
-                             str(count).encode('ascii'),
-                             0)
+        client.publish('/mqttools/counter-client/value/response',
+                       str(count).encode('ascii'))
 
 
 asyncio.run(main())

examples/publisher.py

@@ -6,7 +6,7 @@ async def publisher():
     client = mqttools.Client('broker.hivemq.com', 1883)
 
     await client.start()
-    await client.publish('/test/mqttools/foo', b'bar', 0)
+    client.publish('/test/mqttools/foo', b'bar')
     await client.stop()
     print("Successfully published b'bar' on /test/mqttools/foo.")
 

examples/resume_session.py

@@ -0,0 +1,40 @@
+import asyncio
+import mqttools
+from uuid import uuid1
+
+
+async def resume_session():
+    client = mqttools.Client('broker.hivemq.com',
+                             1883,
+                             client_id='mqttools-{}'.format(uuid1().node),
+                             session_expiry_interval=15)
+
+    try:
+        await client.start(resume_session=True)
+        print('Session resumed.')
+    except mqttools.SessionResumeError:
+        print('No session to resume. Subscribing to topics.')
+
+        # Subscribe to three topics in parallel.
+        print('Subscribing to topics.')
+        await asyncio.gather(
+            client.subscribe('$SYS/#'),
+            client.subscribe('/test/mqttools/foo')
+        )
+
+    print('Waiting for messages.')
+
+    while True:
+        topic, message = await client.messages.get()
+
+        if topic is None:
+            print('Broker connection lost!')
+            break
+
+        print(f'Topic:   {topic}')
+        print(f'Message: {message}')
+
+import logging
+logging.basicConfig(level=logging.DEBUG)
+
+asyncio.run(resume_session())

examples/subscriber.py

@@ -9,11 +9,12 @@ async def subscriber():
 
     # Subscribe to three topics in parallel.
     await asyncio.gather(
-        client.subscribe('$SYS/broker/uptime', 0),
-        client.subscribe('$SYS/broker/bytes/sent', 0),
-        client.subscribe('/test/mqttools/foo', 0)
+        client.subscribe('$SYS/#'),
+        client.subscribe('/test/mqttools/foo')
     )
 
+    print('Waiting for messages.')
+
     while True:
         topic, message = await client.messages.get()
 

examples/topic_alias.py

@@ -10,10 +10,10 @@ async def publisher():
                              ])
 
     await client.start()
-    await client.publish('/test/mqttools/foo', b'sets-alias-in-broker', 0)
-    await client.publish('/test/mqttools/foo', b'published-with-alias', 0)
-    await client.publish('/test/mqttools/fie', b'not-using-alias', 0)
-    await client.publish('/test/mqttools/fie', b'not-using-alias', 0)
+    client.publish('/test/mqttools/foo', b'sets-alias-in-broker')
+    client.publish('/test/mqttools/foo', b'published-with-alias')
+    client.publish('/test/mqttools/fie', b'not-using-alias')
+    client.publish('/test/mqttools/fie', b'not-using-alias')
     await client.stop()
     print("Successfully published b'bar' on /test/mqttools/foo.")
 

examples/unsubscriber.py

@@ -10,7 +10,7 @@ async def unsubscriber():
     await client.start()
 
     print('Subscribing to /test/mqttools/foo.')
-    await client.subscribe('/test/mqttools/foo', 0)
+    await client.subscribe('/test/mqttools/foo')
     topic, message = await client.messages.get()
 
     print(f'Topic:   {topic}')

examples/will.py

@@ -7,7 +7,7 @@ async def will():
                              1883,
                              will_topic='/my/will/topic',
                              will_message=b'my-will-message',
-                             will_qos=0)
+                             will_qos=mqttools.QoS.AT_MOST_ONCE)
 
     await client.start()
     await client.stop()

mqttools/__init__.py

@@ -6,6 +6,7 @@
 from .client import Client
 from .client import MalformedPacketError
 from .client import ConnectError
+from .client import SessionResumeError
 from .client import PublishError
 from .client import QoS