Topic Alias incorrect on new connection

[dennynguyen]

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• [ ] Bug exists Release Version 1.2.0 ( Master Branch)
• [ ] Bug exists in MQTTv3 Client on Snapshot Version 1.2.1-SNAPSHOT (Develop Branch)
• [ x ] Bug exists in MQTTv5 Client on Snapshot Version 1.2.1-SNAPSHOT (Develop Branch)

If this is a bug regarding the Android Service, please raise the bug here instead: https://github.com/eclipse/paho.mqtt.android/issues/new

Topic alias still doesn't seem to be working right.

Paho client connects, publishes message to topic Messagesight trace:

2018-04-26T17:15:38.663Z tcpiop.1 mqtt.c:915: MQTT receive 32 PUBLISH connect=15: len=45
00000: 00062f53 4d5f3033 00010323 00015445 58543a20 7075626c 6f6f7020 4d657373  [../SM_03...#..TEXT: publoop Mess]
00032: 61676520 6e756d62 65723a20 31                                            [age number: 1]

Subsequent messages have topic alias

2018-04-26T17:15:38.674Z tcpiop.1 mqtt.c:915: MQTT receive 32 PUBLISH connect=15: len=39
00000: 00000002 03230001 54455854 3a207075 626c6f6f 70204d65 73736167 65206e75  [.....#..TEXT: publoop Message nu]
00032: 6d626572 3a2032                                                          [mber: 2]

We restart the server, which disconnects the clients. When the clients reconnect (new connection), the topic alias is not working correctly

2018-04-26T17:15:59.181Z tcpiop.1 mqtt.c:915: MQTT receive 32 PUBLISH connect=3: len=37
00000: 000002e3 03230001 5075624c 6f6f7032 5075626c 6973684d 65737361 67657332  [.....#..PubLoop2PublishMessages2]
00032: 3a203733 39                                                              [: 739]
2018-04-26T17:15:59.181Z tcpiop.1 mqtt.c:2366: Set error "The topic is not valid: " (276)

[jpwsutton]

Thanks for raising this @dennynguyen, When I fixed the issue with persisting messages with Topic aliases, I forgot to add the same check / strip to the DisconnectedMessageBuffer as well. I've now done this and added tests to validate.

[leetosc]

I'm still getting the same problem after the fix.

More details on the test case:

• Client connects with cleanSession/cleanStart=false, with session expiry set to maximum (no expiry, durable session)
• Client publishes messages to topic, /SM_03 in this case
  • After the first publish, subsequent messages have topic aliased as expected
• Restart the server
• Client has reconnect logic, upon disconnect it sets cleanStart=false (to continue existing session) and tries reconnecting until it is successful
• Upon reconnect, the client publishes more messages to the same topic. All PUBLISH messages are coming in with the topic alias, which leads to the server rejecting them as invalid.

[jpwsutton]

Ok, I've written a new test case to cover this scenario and found the source of this problem, the topic alias queue wasn't being cleared on closure of the TCP connection. The build with this fix is available here: https://repo.eclipse.org/content/repositories/paho-snapshots/org/eclipse/paho/org.eclipse.paho.mqttv5.client/1.2.1-SNAPSHOT/org.eclipse.paho.mqttv5.client-1.2.1-20180502.102547-23.jar

[dennynguyen]

works now