overlapping_topics

Andy Piper edited this page Dec 2, 2013 · 1 revision
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Overlapping Topics

Scenario 1

(all commands are sent by the same client):

  1. Subscribe to A/#
  2. Subscribe to A/B
  3. Publish message M to topic A/B

The client will receive the message once.

Scenario 2

(all commands are sent by the same client):

  1. Publish message M1 to topic A/B with retain
  2. Publish message M2 to topic A/C with retain
  3. Publish message M3 to topic A/D with retain
  4. Subscribe to A/#

The client will receive all three of the retained messages.

Scenario 3

Given the topic tree: test test/one test/two/two

  • Subscribe to test/#
  • Unsubscribe from test/one
  • Unsubscribe from test/two

The client will still receive messages sent to test/one and test/two. You can only unsubscribe from a topic you have explicitly subscribed to; you cannot punch holes in previous subscription.