Difference between revisions of "MQTTCLIENT"
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− | <topicName> field is case insensitive and will be reported in lower case, furthermore the MQTT broker will replace every whitespace present in the topic name with '_'. E.g. if a client publish a message on topic "Topic Test", the MQTT broker will convert this value in "topic_test" | + | <topicName> field is case insensitive and will be reported in lower case, furthermore the MQTT broker will replace every whitespace present in the topic name with '_'. E.g. if a client publish a message on topic "Topic Test", the MQTT broker will convert this value in "topic_test" and this change will be reflected in <topicName> field present in datapoints |
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Revision as of 14:32, 8 May 2020
This driver acts as an MQTT client (publisher/subscriber) for Hsyco, it fully supports MQTT version 3.1.1. This driver uses Java methods from the library Eclipse Paho, version 1.2.2.
Contents
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
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 | ||
cleansession | false | true | cleans eventually existing previous session held by the MQTT broker. This will remove any previous subscription and unacknowledged messages |
false | restores eventually existing previous session held by the MQTT broker. This will restore all existing subscriptions and resend any unacknowledged message | ||
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. |
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 there could be a file named "mqttsubscriptions-<IOServerId>.ini" (e.g "mqttsubscriptions-myclientid.ini") which can contain a series of line, each line represents a topic to subscribe and the topic's quality-of-service (qos). On each line topic and relative qos are separated by a white space:
E.g.
/mqtt/test 2 home/bathroom 1 /outdoor 0
Datapoints
ID | Value | R/W | Description |
---|---|---|---|
connection | online | R | the client is connected to the MQTT broker |
offline | R | initialization of the driver failed or loop cycle failed | |
received.<topicName> | <message> | R | the client received a message on topicName |
publish.<topicName> | <message> | R/W | the client published a message on topicName |
subscribe.<topicName> | 0 | R/W | the client subscribes to topicName with qos=0 |
1 | R/W | the client subscribes to topicName with qos=1 | |
2 | R/W | the client subscribes to topicName with qos=2 | |
unsubscribe | R/W | the client unsubscribes from topicName |
- Attention
<topicName> field is case insensitive and will be reported in lower case, furthermore the MQTT broker will replace every whitespace present in the topic name with '_'. E.g. if a client publish a message on topic "Topic Test", the MQTT broker will convert this value in "topic_test" and this change will be reflected in <topicName> field present in datapoints
- Note
All the subscriptions and unsubscriptions made at run-time are not persistent so they will be lost in case of driver restart.
All publish messages with QoS > 0 are temporarily stored in the directory "qos2store" waiting for the acknowledge by the MQTT broker. Once they are acknowledged they are deleted.