Since | Origin / Contributor | Maintainer | Source |
---|---|---|---|
2015-01-23 | Stephen Robinson, Tuan PM | Vowstar | mqtt.c |
The client adheres to version 3.1.1 of the MQTT protocol. Make sure that your broker supports and is correctly configured for version 3.1.1. The client is backwards incompatible with brokers running MQTT 3.1.
Creates a MQTT client.
mqtt.Client(clientid, keepalive[, username, password, cleansession])
clientid
client IDkeepalive
keepalive secondsusername
user namepassword
user passwordcleansession
0/1 for false
/true
MQTT client
-- init mqtt client without logins, keepalive timer 120s
m = mqtt.Client("clientid", 120)
-- init mqtt client with logins, keepalive timer 120sec
m = mqtt.Client("clientid", 120, "user", "password")
-- setup Last Will and Testament (optional)
-- Broker will publish a message with qos = 0, retain = 0, data = "offline"
-- to topic "/lwt" if client don't send keepalive packet
m:lwt("/lwt", "offline", 0, 0)
m:on("connect", function(client) print ("connected") end)
m:on("offline", function(client) print ("offline") end)
-- on publish message receive event
m:on("message", function(client, topic, data)
print(topic .. ":" )
if data ~= nil then
print(data)
end
end)
-- for TLS: m:connect("192.168.11.118", secure-port, 1)
m:connect("192.168.11.118", 1883, 0, function(client)
print("connected")
-- Calling subscribe/publish only makes sense once the connection
-- was successfully established. You can do that either here in the
-- 'connect' callback or you need to otherwise make sure the
-- connection was established (e.g. tracking connection status or in
-- m:on("connect", function)).
-- subscribe topic with qos = 0
client:subscribe("/topic", 0, function(client) print("subscribe success") end)
-- publish a message with data = hello, QoS = 0, retain = 0
client:publish("/topic", "hello", 0, 0, function(client) print("sent") end)
end,
function(client, reason)
print("failed reason: " .. reason)
end)
m:close();
-- you can call m:connect again
Closes connection to the broker.
mqtt:close()
none
true
on success, false
otherwise
Connects to the broker specified by the given host, port, and secure options.
mqtt:connect(host[, port[, secure[, autoreconnect]]][, function(client)[, function(client, reason)]])
host
host, domain or IP (string)port
broker port (number), default 1883secure
0/1 for false
/true
, default 0. Take note of constraints documented in the net module.autoreconnect
0/1 for false
/true
, default 0function(client)
callback function for when the connection was establishedfunction(client, reason)
callback function for when the connection could not be establishedtrue
on success, false
otherwise
Constant | Value | Description |
---|---|---|
mqtt.CONN_FAIL_SERVER_NOT_FOUND |
-5 | There is no broker listening at the specified IP Address and Port |
mqtt.CONN_FAIL_NOT_A_CONNACK_MSG |
-4 | The response from the broker was not a CONNACK as required by the protocol |
mqtt.CONN_FAIL_DNS |
-3 | DNS Lookup failed |
mqtt.CONN_FAIL_TIMEOUT_RECEIVING |
-2 | Timeout waiting for a CONNACK from the broker |
mqtt.CONN_FAIL_TIMEOUT_SENDING |
-1 | Timeout trying to send the Connect message |
mqtt.CONNACK_ACCEPTED |
0 | No errors. Note: This will not trigger a failure callback. |
mqtt.CONNACK_REFUSED_PROTOCOL_VER |
1 | The broker is not a 3.1.1 MQTT broker. |
mqtt.CONNACK_REFUSED_ID_REJECTED |
2 | The specified ClientID was rejected by the broker. (See mqtt.Client() ) |
mqtt.CONNACK_REFUSED_SERVER_UNAVAILABLE |
3 | The server is unavailable. |
mqtt.CONNACK_REFUSED_BAD_USER_OR_PASS |
4 | The broker refused the specified username or password. |
mqtt.CONNACK_REFUSED_NOT_AUTHORIZED |
5 | The username is not authorized. |
Setup Last Will and Testament (optional). A broker will publish a message with qos = 0, retain = 0, data = «offline» to topic «/lwt» if client does not send keepalive packet.
mqtt:lwt(topic, message[, qos[, retain]])
topic
the topic to publish to (string)message
the message to publish, (buffer or string)qos
QoS level, default 0retain
retain flag, default 0nil
Registers a callback function for an event.
mqtt:on(event, function(client[, topic[, message]]))
event
can be «connect», «message» or «offline»function(client[, topic[, message]])
callback function. The first parameter is the client. If event is «message», the 2nd and 3rd param are received topic and message (strings).nil
Publishes a message.
mqtt:publish(topic, payload, qos, retain[, function(client)])
topic
the topic to publish to (topic string)message
the message to publish, (buffer or string)qos
QoS levelretain
retain flagfunction(client)
optional callback fired when PUBACK received. NOTE: When calling publish() more than once, the last callback function defined will be called for ALL publish commands.
true
on success, false
otherwise
Subscribes to one or several topics.
mqtt:subscribe(topic, qos[, function(client)])
mqtt:subscribe(table[, function(client)])
topic
a topic stringqos
QoS subscription level, default 0table
array of ‘topic, qos’ pairs to subscribe tofunction(client)
optional callback fired when subscription(s) succeeded. NOTE: When calling subscribe() more than once, the last callback function defined will be called for ALL subscribe commands.true
on success, false
otherwise
-- subscribe topic with qos = 0
m:subscribe("/topic",0, function(conn) print("subscribe success") end)
-- or subscribe multiple topic (topic/0, qos = 0; topic/1, qos = 1; topic2 , qos = 2)
m:subscribe({["topic/0"]=0,["topic/1"]=1,topic2=2}, function(conn) print("subscribe success") end)
Unsubscribes from one or several topics.
mqtt:unsubscribe(topic[, function(client)])
mqtt:unsubscribe(table[, function(client)])
topic
a topic stringtable
array of ‘topic, anything’ pairs to unsubscribe fromfunction(client)
optional callback fired when unsubscription(s) succeeded. NOTE: When calling unsubscribe() more than once, the last callback function defined will be called for ALL unsubscribe commands.true
on success, false
otherwise
-- unsubscribe topic
m:unsubscribe("/topic", function(conn) print("unsubscribe success") end)
-- or unsubscribe multiple topic (topic/0; topic/1; topic2)
m:unsubscribe({["topic/0"]=0,["topic/1"]=0,topic2="anything"}, function(conn) print("unsubscribe success") end)