CODEWITHSUNDEEP
mqtt
HW Siew
HW Siew

Reputation: 1003

How to handle duplicated messages in MQTT with qos 1

I am using MQTT with qos 1 which means messages may be sent to client more than once? How can i prevent client from handle same messages twice?

Upvotes: 1

Views: 3479

Answers (1)

hardillb
hardillb

Reputation: 59866

The only way to know for sure if you have received the message twice is to include an ID in the message payload and maintain a list of processed messages in the client.

The PAHO API includes a isDuplicate() (Javascript version) method on received messages, but this is only an indication that the message may be a duplicate, because the original message may never have arrived.

Upvotes: 4

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