Network.MQTT.Client

An MQTT protocol client, based on the 3.1.1 specification: http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html

Configuring the client.

data MQTTConfig

Configuration for setting up an MQTT client.

Constructors

MQTTConfig

Fields

• _hostname :: String

  Host to connect to.

• _port :: Int

  Port number.

• _connID :: String

  Unique connection ID (required).

• _username :: Maybe String

  Optional username.

• _password :: Maybe String

  Optional password.

• _cleanSession :: Bool

  False if a session should be reused.

• _lwt :: Maybe LastWill

  LastWill message to be sent on client disconnect.

• _msgCB :: Maybe (MQTTClient -> Topic -> ByteString -> IO ())

  Callback for incoming messages.

data MQTTClient

The MQTT client. A client may be built using either runClient or runClientTLS. For example:

  mc <- runClient mqttConfig{}
  publish mc "some/topic" "some message" False

data QoS

QoS values for publishing and subscribing.

Constructors

QoS0

QoS1

QoS2

Instances

Bounded QoS

Defined in Network.MQTT.Types

Methods

minBound :: QoS

maxBound :: QoS

Enum QoS

Defined in Network.MQTT.Types

Methods

succ :: QoS -> QoS

pred :: QoS -> QoS

toEnum :: Int -> QoS

fromEnum :: QoS -> Int

enumFrom :: QoS -> [QoS]

enumFromThen :: QoS -> QoS -> [QoS]

enumFromTo :: QoS -> QoS -> [QoS]

enumFromThenTo :: QoS -> QoS -> QoS -> [QoS]

Eq QoS

Defined in Network.MQTT.Types

Methods

(==) :: QoS -> QoS -> Bool

(/=) :: QoS -> QoS -> Bool

Show QoS

Defined in Network.MQTT.Types

Methods

showsPrec :: Int -> QoS -> ShowS

show :: QoS -> String

showList :: [QoS] -> ShowS

type Topic = Text

An MQTT topic.

mqttConfig :: MQTTConfig

A default MQTTConfig. A _connID should be provided by the client in the returned config, but the defaults should work for testing.

mkLWT :: Topic -> ByteString -> Bool -> LastWill

A convenience method for creating a LastWill.

data LastWill

An MQTT Will message.

Constructors

LastWill

Fields

• _willRetain :: Bool
• _willQoS :: QoS
• _willTopic :: ByteString
• _willMsg :: ByteString

Instances

Eq LastWill

Defined in Network.MQTT.Types

Methods

(==) :: LastWill -> LastWill -> Bool

(/=) :: LastWill -> LastWill -> Bool

Show LastWill

Defined in Network.MQTT.Types

Methods

showsPrec :: Int -> LastWill -> ShowS

show :: LastWill -> String

showList :: [LastWill] -> ShowS

Running and waiting for the client.

runClient :: MQTTConfig -> IO MQTTClient

Set up and run a client from the given config.

runClientTLS :: MQTTConfig -> IO MQTTClient

Set up and run a client connected via TLS.

waitForClient :: MQTTClient -> IO (Either SomeException ())

Wait for a client to terminate its connection.

connectURI :: MQTTConfig -> URI -> IO MQTTClient

Connect to an MQTT server by URI. Currently only mqtt and mqtts URLs are supported. The host, port, username, and password will be derived from the URI and the values supplied in the config will be ignored.

disconnect :: MQTTClient -> IO ()

Disconnect from the MQTT server.

General client interactions.

subscribe :: MQTTClient -> [(Filter, QoS)] -> IO [Maybe QoS]

Subscribe to a list of topic filters with their respective QoSes. The accepted QoSes are returned in the same order as requested.

unsubscribe :: MQTTClient -> [Filter] -> IO ()

Unsubscribe from a list of topic filters.

publish

Arguments

:: MQTTClient

-> Topic

Topic

-> ByteString

Message body

-> Bool

Retain flag

-> IO ()

Publish a message (QoS 0).

publishq

Arguments

:: MQTTClient

-> Topic

Topic

-> ByteString

Message body

-> Bool

Retain flag

-> QoS

QoS

-> IO ()

Publish a message with the specified QoS.