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MQTTSubscribe

Updated

Description

This Action must be performed immediately after successfully connecting to the MQTT server, for each topic to which we want to subscribe. If a packet has been published by the server for this topic, we will receive information about it via the Message event using the MQTTEvent Action.

Properties

Specific

Connection

EXPRESSION (object:MQTTConnection)

The name of the connection to the MQTT server.

Topic

EXPRESSION (string)

The name of the topic to which we want to subscribe. A subscription may be to an explicit topic, in which case only messages to that topic will be received, or it may include wildcards. Two wildcards are available, + or #. + can be used as a wildcard for a single level of hierarchy. It could be used with the topic above to get information on all computers and hard drives as follows:

sensors/+/temperature/+

As another example, for a topic of a/b/c/d, the following example subscriptions will match:

a/b/c/d
+/b/c/d
a/+/c/d
a/+/+/d
+/+/+/+

The following subscriptions will not match:

a/b/c
b/+/c/d
+/+/+

# can be used as a wildcard for all remaining levels of hierarchy. This means that it must be the final character in a subscription. With a topic of a/b/c/d, the following example subscriptions will match:

a/b/c/d
#
a/#
a/b/#
a/b/c/#
+/b/c/#

Inputs

seqin

SEQ | OPTIONAL

A standard sequence input.

Outputs

seqout

SEQ | OPTIONAL

A standard sequence output.

Examples

  • MQTT
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