mqttpublish

Publish a message on a topic.

Attention: Available only with Twin Activate commercial edition.

Syntax

[mid,status,messageinfo] = mqttpublish(clientid, topic, Payload, qos, retain)

Inputs

clientid
client id, an output of mqttclient.
Type: string
topic
topic to which message to be published.
Type: string
payload
Message to publish.
Type: string
qos
Quality of service, valid options are 0,1,2.
Type: scalar
qos = 0:
This level guarantees a best-effort delivery. There is no guarantee of delivery. The recipient does not acknowledge receipt of the message and the message is not stored and re-transmitted by the sender.
qos = 1:
This level guarantees that a message is delivered at least one time to the receiver. The sender stores the message until it gets a PUBACK packet from the receiver that acknowledges receipt of the message. It is possible for a message to be sent or delivered multiple times.
qos = 2:
This level guarantees that each message is received only once by the intended recipients. It is the safest and slowest quality of service level.
retain
to specify whether to retain the the message.Valid values are falseand true.
Type: Boolean

Outputs

mid
message id of publish command.
Type: scalar
status
status return codes.
Type: scalar
messageinfo
description of publish status flag.
Type: string
status = 0:
on success.
status = 1:
out of memory condition occurred.
status = 2:
protocol error communicating with the broker.
status = 3:
input parameters were invalid.
status = 4:
client isn’t connected to a broker.
status = 9:
payloadlen is too large.
status = 18:
topic is not valid UTF-8
status = 24:
QoS is greater than that supported by the broker.

Examples

publish to a topic with 
cld = mqttclient('test.mosquitto.org','port',1883);
[mid, rc, Mqttmessageinfo] = mqttpublish(cld, 'topic100','hello - test mqtt broker',2,true);
mid = 1
rc = 0
Mqttmessageinfo = on success.
publish to a topic with on_publish callback 
function test_publishcallback(clientid, mid)
		printf('publish callback is triggered successfully\n');
		printf('message id: %s\n', num2str(mid));
		%printf('return message: %s\n', Mqttmessageinfo);

end
cld = mqttclient('test.mosquitto.org','port',1883,'on_publish','test_publishcallback');
[mid, rc, Mqttmessageinfo] = mqttpublish(cld, 'topic100','hello - test mqtt broker',2,true);
publish callback is triggered successfully
message id: 1