Overview
Attributes common to all MQTT data point are:
- Name: the name of the point for use as an identifier in lists of points.
- Data type: the data type of the point. See below for details.
- Topic filter: addressing subscribers to receive messages from the broker
- Client ID: unique identifier of a given client, there cannot be two clients with the same id. This value is automatically generated.
Topic filter
About:
You can define a topic matching filter, thanks to which we will associate a message with a topic,
which in turn will allow sending a message to the subscribers of a given topic.
Basic example:
/clientId/rooms/living/temperature/
- + (plus) Single level wildcard: /a/+/b then: /a/c/b ok, /a/c/d/b no ok, /a/b/ no ok
- # (hash) Multi level wildcard: /a/b/# then: /a/b/c ok, /a/b/c/d ok, /c no ok, /a/c/d no ok.
You can only use one such character in an expression, and you can only use it at the end of an expression.
- $ (dollar) you cannot publish to topics that start with $, they are readable.
Filter points containing wildcards cannot publish values(no settable), they can only read.