MQTTCLIENT

This driver acts as an MQTT client (publisher/subscriber) for Hsyco, it fully supports MQTT version 3.1.1.

HSYCO Configuration

Add the MQTTCLIENT I/O Server in the I/O Servers section of the Settings and set its parameters:

Communication

• IP Address: host name or IP address of the MQTT broker
• IP Port: TCP/IP port of the MQTT broker

Authentication

• User: username for authentication with MQTT broker
• Password: password for authentication with MQTT broker

If presents, these two fields must be both not empty

Options

ID	Default	Values	Description
startupevents	false	true	generate IO events also during the driver’s start-up phase
		false	start generating events only after HSYCO is aligned with the current status of the system
autoreconnect	false	true	reconnects automatically to the MQTT broker when connection is lost
		false	doesn't reconnect to the MQTT broker when connection is lost
cleansession	false	true	cleans eventually existing previous session held by the MQTT broker
		false	restores eventually existing previous session held by the MQTT broker
messageretain	false	true	with this option true the MQTT broker will save publish messages for future subscribers
		false	with this option false the MQTT broker will not save publish messages for future subscribers
keepalive	60	n >= 0	this value, measured in seconds, defines the maximum time interval between messages sent or received. It enables this driver to detect if the MQTT broker is no longer available. In the absence of a data-related message during this time period, the client sends a very small "ping" message, which the server will acknowledge. A value of 0 disables keepalive processing in the client.
connecttimeout	30	n >= 0	this value, measured in seconds, defines the maximum time interval this driver will wait for the network connection to the MQTT broker to be established. A value of 0 disables timeout processing meaning the driver will wait until the network connection is made successfully or fails.
id		<text>	id of this MQTT client in UTF-8 format. This field is compulsory to establish connection with the MQTT broker
messageqos	0	0	every publish message is sent at most one time, so it doesn't receive acknowledge message from the MQTT broker
		1	every publish message is sent at least one time, so it waits acknowledge message from the MQTT broker
		2	every publish message is sent exactly one time, so there will be a series of acknowledge messages between the MQTT client and broker

Subscriptions file

Under the hsyco root directory you could have a file named "mqttsubscriptions-.ini" which can contain a series of line, each line represents a topic to subscribe and the topic's quality-of-service (Qos):

<clientid>:username=<username>,password=<password>

E.g.

client123:username=homesensor,password=abc123

Clientid must be present in each line while username and password are optional; if username and password are not present there will be two cases:

• if default username and password are specified in "hsyco.ini" they will be used by the authentication mechanism
• if default username and password are not specified in "hsyco.ini" the authentication mechanism is disabled