Swift MQTT libmosquitto cleanSession set to false yet unable to set up a persistent subscription

Question

client = MosquittoClient(clientId: "client1")
client?.delegate = self
client?.port = 1883
client?.host = "someIPAddress"
client!.cleanSession = false
client?.connect()

libmosquitto is a objective c library that is bridged over into a swift project. So after setting the cleanSession to false, i am still unable to set up a persistent subscription or receive message when offline.

There is no error. However, when i push a message to the client when it is offline, it is expected for the client to get the message once it is reconnected. But that is not the case. @pableiros — Wei Meng C., Aug 19 '16 at 03:01

rohan dhama · Accepted Answer · 2016-08-20T01:41:19.440

0

Setting a cleanSession = false will not do your job.. If you want to receive a message after reconnection it will require QOS..

By default qos of message and subscribe is 0 which will not guarantee that message will be delivered to the offline clients..

You need to do 2 things:
1. When you subscribe for a topic subscribe it with QOS 1 or 2.
2. When you publish a message that you want to be delivered to offline clients send with qos 1 or 2.

Nd also use same client IDs for connecting.. If you want that the messages also be received by new clients that use retain=true while publishing message

edited Aug 20 '16 at 01:41

answered Aug 20 '16 at 01:33

rohan dhama

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I am already subscribed to a topic with QOS 1 and also published message to offline clients with QOS 1 as well. However, the client are still unable to receive any message when offline. – Wei Meng C. Aug 22 '16 at 04:10
Using same client id while connecting to broker? – rohan dhama Aug 23 '16 at 01:40
Yeah. Definitely the same – Wei Meng C. Aug 23 '16 at 02:30

Swift MQTT libmosquitto cleanSession set to false yet unable to set up a persistent subscription

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