Network.MQTT.Internal

MQTT Internals.

Use with care and expected changes.

User interaction

data Config

The various options when establishing a connection. See below for available accessors.

Constructors

Config

Fields

• cHost :: HostName

  Hostname of the broker.

• cPort :: PortNumber

  Port of the broker.

• cClean :: Bool

  Should the server forget subscriptions and other state on disconnects?

• cWill :: Maybe Will

  Optional Will message.

• cUsername :: Maybe Text

  Optional username used for authentication.

• cPassword :: Maybe Text

  Optional password used for authentication.

• cKeepAlive :: Maybe Word16

  Time (in seconds) after which a PingReq is sent to the broker if no regular message was sent. Nothing means no limit.

• cClientID :: Text

  Client ID used by the server to identify clients.

• cLogDebug :: String -> IO ()

  Function for debug-level logging.

• cResendTimeout :: Int

  Time in seconds after which messages that have not been but should be acknowledged are retransmitted.

• cPublished :: TChan (Message PUBLISH)

  The channel received Publish messages are written to.

• cCommands :: Commands

  The channel used by publish, subscribe, etc.

• cInputBufferSize :: Int

  Maximum number of bytes read from the network at once.

data Terminated

Reasons for why the connection was terminated.

Constructors

ParseFailed [String] String

at the context in [String] with the given message.

ConnectFailed ConnectError

UserRequested

disconnect was called

Instances

Show Terminated

Methods

showsPrec :: Int -> Terminated -> ShowS

show :: Terminated -> String

showList :: [Terminated] -> ShowS

data Command

Commands from the user for the mainLoop.

Constructors

CmdDisconnect

CmdSend SomeMessage

CmdAwait AwaitMessage

CmdStopWaiting AwaitMessage

newtype Commands

The communication channel used by publish, subscribe, etc.

Constructors

Cmds

Fields

• getCmds :: TChan Command

mkCommands :: IO Commands

Create a new Commands channel.

There should be one channel per MQTT connection. It might be reused by subsequent connections, but never by multiple connections concurrently.

send :: SingI t => Config -> Message t -> IO ()

Tell the mainLoop to send the given Message.

await :: SingI t => Config -> MVar (Message t) -> Maybe MsgID -> IO AwaitMessage

Tell the MQTT instance to place the next Message of correct MsgType and MsgID (if present) into the MVar.

data AwaitMessage where

Constructors

AwaitMessage :: SingI t => MVar (Message t) -> Maybe MsgID -> AwaitMessage

Instances

Eq AwaitMessage

Methods

(==) :: AwaitMessage -> AwaitMessage -> Bool

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

stopWaiting :: Config -> AwaitMessage -> IO ()

Stop waiting for the described Message.

sendAwait :: (SingI t, SingI r) => Config -> Message t -> SMsgType r -> IO (Message r)

Execute the common pattern of sending a message and awaiting a response in a safe, non-racy way. The message message is retransmitted if no response has been received after cResendTimeout seconds, with exponential backoff for further retransmissions

An incoming message is considered a response if it is of the requested type and the MsgIDs match (if present).

writeCmd :: Config -> Command -> IO ()

Main loop

mainLoop :: Config -> Handle -> WaitTerminate -> SendSignal -> IO Terminated

type WaitTerminate = STM ()

type SendSignal = MVar ()

data MqttState

Internal state for the main loop

Constructors

MqttState

Fields

• msParseCC :: ParseCC

  Current parser continuation

• msUnconsumed :: ByteString

  Not yet parsed input

• msWaiting :: [AwaitMessage]

  Messages we're waiting for

type ParseCC = ByteString -> IResult ByteString SomeMessage

data Input

Input for the main loop

Constructors

InMsg SomeMessage

InErr Terminated

InCmd Command

waitForInput :: Config -> Handle -> StateT MqttState IO Input

parseBytes :: Monad m => ByteString -> StateT MqttState m (Maybe Input)

Parse the given ByteString and update the current MqttState.

Returns Nothing if more input is needed.

handleMessage :: Config -> WaitTerminate -> SomeMessage -> StateT MqttState IO ()

publishHandler :: Config -> Message PUBLISH -> IO ()

Misc

secToMicro :: Int -> Int