MQTT Client DAT
The MQTT Client DAT receives and sends data from/to MQTT devices via MQTT servers (broker). TouchDesigner can act as a client and another computer needs to act as a MQTT Server. Once a client establishes a connection with a server, it can do two things:
- Send a message to the server to express interest in any data that has a specific "topic" string. This is called "subscribing". Then the MQTT Client DAT will receive all messages that the server gets with that topic.
- Inform the server that it will send messages to the server with a certain topic string, and then send messages with that topic. The messages then get forward to any client that has expressed interest in that topic.
Parameters - Connect Page
active - Enable the connection.
netaddress - The IP address to connect to.
specifyid - Allows naming the client with parameter
User Client ID, otherwise automatically and uniquely generated for each connection.
User Client ID
usercid - Client name when
Specify ID enabled.
Keep Alive Interval
keepalive - Specifies in seconds, the maximum time to expect without communication. If no data is sent during this time, a lightweight ping message is sent to the server instead. Can be set to 0 to avoid pings.
Max In Flight
maxinflight - Controls how many messages can be in-flight simultaneously
cleansession - If
Specify ID is selected, the server will preserve any state information associated with the connection of that ID, such as subscriptions, delivery attempts, etc.
reconnect - Will attempt to reconnect to the MQTT broker.
Parameters - Received Data Page
callbacks - The Callbacks DAT contains functions that are called when connections are made, lost or published data arrives. See mqttclientDAT_Class for usage.
executeloc - Determines the location the script is run from.
- Current Node
current- The script is executed from the current node location (for example, where 'cc' points to).
- Callbacks DAT
script- The script is executed from the location of the DAT specified in the Callbacks DAT parameter.
- Specified Operator
op- The script is executed from the operator specified in the From Operator parameter below.
fromop - The operator whose state change will trigger the DAT to execute its script when Execute From is set to Specified Operator. This operator is also the path that the script will be executed from if the Execute From parameter is set to Specified Operator.
clamp - The DAT is limited to 100 messages by default but with Clamp Output, this can be set to anything including unlimited.
maxlines - Limits the number of messages, older messages are removed from the list first.
clear - Deletes all lines except the heading. To clear with a python script
bytes - Outputs the raw bytes of the message in a separate column.
A publicly available MQTT test server/broker is accessible at
http://test.mosquitto.org/. It provides a topic under "
temp/random" resembling a temperature gauge which you can subscribe but also publish to.
Create a MQTT Client DAT and specify as Network Address
test.mosquitto.org:1883 which is the unencrypted MQTT port.
Open up the Textport or use a separate Text DAT and reference the MQTT Client DAT in a variable. After you can use the mqttclientDAT_Class Methods for subscribing and publishing to the gauge. When publishing to it you can see it change in real-time under
# reference the MQTT Client DAT a = op('/project1/mqttclient1') # subscribe to the temp/random topic a.subscribe('temp/random') # send a single byte, value 23 to the gauge and watch it change on http://test.mosquitto.org/gauge/ a.publish('temp/random',b'23')
Subscribing to a topic that doesn't exist is the same as creating the topic. This makes it very easy to start publishing data on any MQTT Broker.
Another public MQTT Broker can be found at HiveMQ. You can publish and subscribe to topics under
There is a rich amount of resources available on the Internet, a good general introduction in 12 parts can for example be found at HiveMQ