MQTT Client Service¶

Summary¶

This service allows solution to act as a MQTT client, so that you can communicate with a 3^rd-party MQTT broker, eg: AWS IoT.

Operations

Name	Tag	Summary
mqtt.publish()		Publish messages to MQTT topics

Events

Name	Summary
message	Message received from MQTT broker

Configuration parameters¶

Name	Type	Description
host	string	Host address of MQTT broker
port	integer	Port of MQTT broker (Note: only support SSL) Default: 8883
security	object, null	MQTT broker security settings
security.password	string(password)	Password used to login to MQTT broker
security.username	string	Username used to login to MQTT broker
security.sslOptions	object	SSL options
security.sslOptions.key	string	Private key pem
security.sslOptions.cert	string	Certificate pem
security.sslOptions.cacerts	string	Root CA Certificate
topics	[ string ]	Default topics to subscribe
advanced	object, null	Advanced settings
advanced.clientid	string	The clientid used when connecting to MQTT broker. By default, it is solution_id.

Operations¶

publish¶

Description

Publish message to MQTT topic, need to specify topic and message

Arguments

Name	Type	Description
messages	[ object ]	Topics and messages to be published
messages[].topic	string	A topic
messages[].message	string	A message to send to the topic

Responses

Returns nil for Published

Example

local res = Mqtt.publish({messages={ {topic="topic1", message="hello"} } })
return res

Events¶

message¶

Description

After subscribe to a topic, the message from that topic will be received here.

Arguments

Name	Type	Description
topic	string	Topic of this message
payload	string	Message content in json string
timestamp	integer	Timestamp in milliseconds

Example

-- Use `event` to get the payload
local len = table.getn(batch.messages)
print("Received " .. len .. " messages")
for i=1,len do
  print("Message #" .. i .. ": topic is " .. batch.messages[i].topic)
  -- print("Message #" .. i .. ": payload is " .. batch.messages[i].payload)
  -- print("Message #" .. i .. ": timestamp is " .. batch.messages[i].timestamp)
end