diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,675 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. By contrast, +the GNU General Public License is intended to guarantee your freedom to +share and change all versions of a program--to make sure it remains free +software for all its users. We, the Free Software Foundation, use the +GNU General Public License for most of our software; it applies also to +any other work released this way by its authors. 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If not, see . + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + Copyright (C) + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. + diff --git a/Network/MQTT.hs b/Network/MQTT.hs new file mode 100644 --- /dev/null +++ b/Network/MQTT.hs @@ -0,0 +1,534 @@ +{-# Language OverloadedStrings, + DataKinds, + ScopedTypeVariables, + GADTs, + DeriveDataTypeable #-} +{-| +Module: MQTT +Copyright: Lukas Braun 2014 +License: GPL-3 +Maintainer: koomi+mqtt@hackerspace-bamberg.de + +A MQTT client library. + +A simple example, assuming a broker is running on localhost +(needs -XOverloadedStrings): + +>>> import Network.MQTT +>>> import Network.MQTT.Logger +>>> Just mqtt <- connect defaultConfig { cLogger = warnings stdLogger } +>>> let f t payload = putStrLn $ "A message was published to " ++ show t ++ ": " ++ show payload +>>> subscribe mqtt NoConfirm "#" f +NoConfirm +>>> publish mqtt Handshake False "some random/topic" "Some content!" +A message was published to "some random/topic": "Some content!" +-} +module Network.MQTT + ( -- * Creating connections + connect + , MQTT + , disconnect + , reconnect + , onReconnect + , resubscribe + -- * Connection settings + , MQTTConfig + , defaultConfig + -- ** Field accessors + , cHost + , cPort + , cClean + , cWill + , cUsername + , cPassword + , cKeepAlive + , cClientID + , cConnectTimeout + , cReconnPeriod + , cLogger + -- * Subscribing and publishing + , subscribe + , unsubscribe + , publish + -- * Sending and receiving 'Message's + , send + , addHandler + , removeHandler + , awaitMsg + , awaitMsg' + -- * Reexports + , module Network.MQTT.Types + ) where + +import Control.Applicative (pure, (<$>), (<*>), (<$)) +import Control.Concurrent +import Control.Exception hiding (handle) +import Control.Monad hiding (sequence_) +import Data.Attoparsec.ByteString (parseOnly) +import Data.Bits ((.&.)) +import Data.ByteString (hGet, ByteString) +import qualified Data.ByteString as BS +import Data.Foldable (for_, sequence_, traverse_) +import Data.Maybe (isJust, fromJust) +import Data.Singletons (withSomeSing, SingI(..)) +import Data.Singletons.Decide +import Data.Text (Text) +import Data.Traversable (for) +import Data.Typeable (Typeable) +import Data.Unique +import Data.Word +import Network +import Prelude hiding (sequence_) +import System.IO (Handle, hClose, hIsEOF, hSetBinaryMode) +import System.Timeout (timeout) + +import Network.MQTT.Types +import Network.MQTT.Parser (mqttBody, mqttHeader) +import Network.MQTT.Encoding +import qualified Network.MQTT.Logger as L + +----------------------------------------- +-- Interface +----------------------------------------- + +-- | Abstract type representing a connection to a broker. +data MQTT + = MQTT + { config :: MQTTConfig + , handle :: MVar Handle + , handlers :: MVar [MessageHandler] + , topicHandlers :: MVar [TopicHandler] + , recvThread :: MVar ThreadId + , reconnectHandler :: MVar (IO ()) + , keepAliveThread :: MVar ThreadId + , sendSem :: Maybe QSem + } + +data TopicHandler + = TopicHandler + { thTopic :: Topic + , thQoS :: QoS + , thHandler :: Topic -> ByteString -> IO () + } + +data MessageHandler where + MessageHandler :: SingI t + => Unique + -> (Message t -> IO ()) + -> MessageHandler + +-- | The various options when establishing a connection. +data MQTTConfig + = MQTTConfig + { 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 Int + -- ^ Maximum interval (in seconds) in which a message must be sent. + -- 0 means no limit. + , cClientID :: Text + -- ^ Client ID used by the server to identify clients. + , cConnectTimeout :: Maybe Int + -- ^ Time in seconds after which waiting for a CONNACK is aborted. + -- 'Nothing' means no timeout. + , cReconnPeriod :: Maybe Int + -- ^ Time in seconds to wait between reconnect attempts. + -- 'Nothing' means no reconnects are attempted. + , cLogger :: L.Logger + -- ^ Functions for logging, see 'Network.MQTT.Logger.Logger'. + } + +-- | Defaults for 'MQTTConfig', connects to a server running on +-- localhost. +defaultConfig :: MQTTConfig +defaultConfig = MQTTConfig + { cHost = "localhost" + , cPort = 1883 + , cClean = True + , cWill = Nothing + , cUsername = Nothing + , cPassword = Nothing + , cKeepAlive = Nothing + , cClientID = "mqtt-haskell" + , cConnectTimeout = Nothing + , cReconnPeriod = Nothing + , cLogger = L.stdLogger + } + + +-- | Establish a connection. This might fail with an 'IOException' or +-- return 'Nothing' if the server did not accept the connection. +connect :: MQTTConfig -> IO (Maybe MQTT) +connect conf = do + h <- connectTo (cHost conf) (PortNumber $ cPort conf) + hSetBinaryMode h True + mqtt <- MQTT conf + <$> newMVar h + <*> newMVar [] + <*> newMVar [] + <*> newEmptyMVar + <*> newEmptyMVar + <*> newEmptyMVar + <*> for (cKeepAlive conf) (const (newQSem 0)) + mCode <- handshake mqtt + if mCode == Just 0 + then Just mqtt <$ do forkIO (recvLoop mqtt) >>= putMVar (recvThread mqtt) + forkIO (keepAliveLoop mqtt) >>= + putMVar (keepAliveThread mqtt) + addHandler mqtt (publishHandler mqtt) + else Nothing <$ hClose h + +-- | Send a 'Message' to the server. +send :: MQTT -> Message t -> IO () +send mqtt msg = do + logInfo mqtt $ "Sending " ++ show (toMsgType msg) + h <- readMVar (handle mqtt) + writeTo h msg + for_ (sendSem mqtt) signalQSem + +handshake :: MQTT -> IO (Maybe Word8) +handshake mqtt = do + let timeout' = maybe (fmap Just) (timeout . (* 1000000)) + (cConnectTimeout (config mqtt)) + sendConnect mqtt + msg <- timeout' (getMessage mqtt) `catch` \e -> + Nothing <$ logError mqtt (show (e :: MQTTException) ++ + " while waiting for CONNACK") + return $ case msg of + Just (SomeMessage (Message _ (MConnAck (ConnAck code)))) -> Just code + _ -> Nothing + +sendConnect :: MQTT -> IO () +sendConnect mqtt = send mqtt connect + where + conf = config mqtt + connect = Message + (Header False NoConfirm False) + (MConnect $ Connect + (cClean conf) + (cWill conf) + (MqttText $ cClientID conf) + (MqttText <$> cUsername conf) + (MqttText <$> cPassword conf) + (maybe 0 fromIntegral $ cKeepAlive conf)) + +-- | Block until a 'Message' of the given type, optionally with the given +-- 'MsgID', arrives. +-- +-- Note this expects a singleton to guarantee the returned 'Message' is of +-- the 'MsgType' that is being waited for. Singleton constructors are the +-- 'MsgType' constructors prefixed with a capital @S@, e.g. 'SPUBLISH'. +awaitMsg :: SingI t => MQTT -> SMsgType t -> Maybe MsgID -> IO (Message t) +awaitMsg mqtt _ mMsgID = do + var <- newEmptyMVar + handlerID <- addHandler mqtt (putMVar var) + let wait = do + msg <- readMVar var + if isJust mMsgID + then if mMsgID == getMsgID (body msg) + then removeHandler mqtt handlerID >> return msg + else wait + else removeHandler mqtt handlerID >> return msg + wait + +-- | A version of 'awaitMsg' that infers the type of the 'Message' that +-- is expected. +awaitMsg' :: SingI t => MQTT -> Maybe MsgID -> IO (Message t) +awaitMsg' mqtt mMsgID = awaitMsg mqtt sing mMsgID + +-- | Register a callback that gets invoked whenever a 'Message' of the +-- expected 'MsgType' is received. Returns the ID of the handler which can be +-- passed to 'removeHandler'. +addHandler :: SingI t => MQTT -> (Message t -> IO ()) -> IO Unique +addHandler mqtt handler = do + mhID <- newUnique + modifyMVar_ (handlers mqtt) $ \hs -> + return $ MessageHandler mhID handler : hs + return mhID + +-- | Remove the handler with the given ID. +removeHandler :: MQTT -> Unique -> IO () +removeHandler mqtt mhID = modifyMVar_ (handlers mqtt) $ \hs -> + return $ filter (\(MessageHandler mhID' _) -> mhID' /= mhID) hs + +-- | Subscribe to a 'Topic' with the given 'QoS' and invoke the callback +-- whenever something is published to the 'Topic'. Returns the 'QoS' that +-- was granted by the broker (lower or equal to the one requested). +-- +-- The 'Topic' may contain +-- . +-- The 'Topic' passed to the callback is the fully expanded version where +-- the message was actually published. +subscribe :: MQTT -> QoS -> Topic -> (Topic -> ByteString -> IO ()) + -> IO QoS +subscribe mqtt qos topic handler = do + qosGranted <- sendSubscribe mqtt qos topic + modifyMVar_ (topicHandlers mqtt) $ \hs -> + return $ TopicHandler topic qosGranted handler : hs + return qosGranted + +sendSubscribe :: MQTT -> QoS -> Topic -> IO QoS +sendSubscribe mqtt qos topic = do + msgID <- fromIntegral . hashUnique <$> newUnique + send mqtt $ Message + (Header False Confirm False) + (MSubscribe $ Subscribe + msgID + [(topic, qos)]) + msg <- awaitMsg mqtt SSUBACK (Just msgID) + case msg of + (Message _ (MSubAck (SubAck _ [qosGranted]))) -> return qosGranted + _ -> fail $ "Received invalid message as response to subscribe: " + ++ show (toMsgType msg) + +-- | Unsubscribe from the given 'Topic' and remove any handlers. +unsubscribe :: MQTT -> Topic -> IO () +unsubscribe mqtt topic = do + modifyMVar_ (topicHandlers mqtt) $ return . filter ((== topic) . thTopic) + msgID <- fromIntegral . hashUnique <$> newUnique + send mqtt $ Message + (Header False Confirm False) + (MUnsubscribe $ Unsubscribe msgID [topic]) + void $ awaitMsg mqtt SUNSUBACK (Just msgID) + +-- | Publish a message to the given 'Topic' at the requested 'QoS' level. +-- The payload can be any sequence of bytes, including none at all. The 'Bool' +-- parameter decides if the server should retain the message for future +-- subscribers to the topic. +-- +-- The 'Topic' must not contain +-- . +publish :: MQTT -> QoS -> Bool -> Topic -> ByteString -> IO () +publish mqtt qos retain topic body = do + msgID <- if qos > NoConfirm + then Just . fromIntegral . hashUnique <$> newUnique + else return Nothing + send mqtt $ Message + (Header False qos retain) + (MPublish $ Publish topic msgID body) + case qos of + NoConfirm -> return () + Confirm -> void $ awaitMsg mqtt SPUBACK msgID + Handshake -> do + void $ awaitMsg mqtt SPUBREC msgID + send mqtt $ Message + (Header False Confirm False) + (MPubRel $ SimpleMsg (fromJust msgID)) + void $ awaitMsg mqtt SPUBCOMP msgID + +-- | Close the connection to the server. +disconnect :: MQTT -> IO () +disconnect mqtt = do + h <- takeMVar $ handle mqtt + writeTo h $ + Message + (Header False NoConfirm False) + MDisconnect + readMVar (recvThread mqtt) >>= killThread + readMVar (keepAliveThread mqtt) >>= killThread + hClose h + +-- | Try creating a new connection with the same config (retrying after the +-- specified amount of seconds has passed) and invoke the callback that is +-- set with 'onReconnect' once a new connection has been established. +-- +-- Does not terminate the old connection. +reconnect :: MQTT -> Int -> IO () +reconnect mqtt period = do + -- Other threads can't write while the MVar is empty + _ <- takeMVar (handle mqtt) + logInfo mqtt "Reconnecting..." + -- Temporarily create a new MVar for the handshake so other threads + -- don't write before the connection is fully established + handleVar <- newEmptyMVar + go (mqtt { handle = handleVar }) + readMVar handleVar >>= putMVar (handle mqtt) + -- forkIO so recvLoop isn't blocked + tryReadMVar (reconnectHandler mqtt) >>= traverse_ (void . forkIO) + logInfo mqtt "Reconnect successfull" + where + -- try reconnecting until it works + go mqtt' = do + let conf = config mqtt + connectTo (cHost conf) (PortNumber $ cPort conf) + >>= putMVar (handle mqtt') + mCode <- handshake mqtt' + unless (mCode == Just 0) $ do + void $ takeMVar (handle mqtt') + threadDelay (period * 10^6) + go mqtt' + `catch` + \e -> do + logWarning mqtt $ "reconnect: " ++ show (e :: IOException) + threadDelay (period * 10^6) + go mqtt' + +-- | Register a callback that will be invoked when a reconnect has +-- happened. +onReconnect :: MQTT -> IO () -> IO () +onReconnect mqtt io = do + let mvar = reconnectHandler mqtt + empty <- isEmptyMVar mvar + unless empty (void $ takeMVar mvar) + putMVar mvar io + +-- | Resubscribe to all topics. Returns the new list of granted 'QoS'. +resubscribe :: MQTT -> IO [QoS] +resubscribe mqtt = do + ths <- readMVar (topicHandlers mqtt) + mapM (\th -> sendSubscribe mqtt (thQoS th) (thTopic th)) ths + +maybeReconnect :: MQTT -> IO () +maybeReconnect mqtt = do + catch + (readMVar (handle mqtt) >>= hClose) + (const (pure ()) :: IOException -> IO ()) + for_ (cReconnPeriod $ config mqtt) $ reconnect mqtt + + +----------------------------------------- +-- Logger utility functions +----------------------------------------- + +logInfo :: MQTT -> String -> IO () +logInfo mqtt = L.logInfo (cLogger (config mqtt)) + +logWarning :: MQTT -> String -> IO () +logWarning mqtt = L.logWarning (cLogger (config mqtt)) + +logError :: MQTT -> String -> IO () +logError mqtt = L.logError (cLogger (config mqtt)) + + +----------------------------------------- +-- Internal +----------------------------------------- + +recvLoop :: MQTT -> IO () +recvLoop mqtt = forever $ do + h <- readMVar (handle mqtt) + eof <- hIsEOF h + if eof + then do + logError mqtt "EOF in recvLoop" + maybeReconnect mqtt + else getMessage mqtt >>= dispatchMessage mqtt + `catches` + [ Handler $ \e -> do + logError mqtt $ "recvLoop: Caught " ++ show (e :: IOException) + maybeReconnect mqtt + , Handler $ \e -> + logWarning mqtt $ "recvLoop: Caught " ++ show (e :: MQTTException) + ] + +dispatchMessage :: MQTT -> SomeMessage -> IO () +dispatchMessage mqtt (SomeMessage (msg :: Message t)) = + readMVar (handlers mqtt) >>= mapM_ applyMsg + where + typeSing :: SMsgType t + typeSing = toSMsgType msg + + applyMsg :: MessageHandler -> IO () + applyMsg (MessageHandler _ (handler :: Message t' -> IO ())) = + case typeSing %~ (sing :: SMsgType t') of + Proved Refl -> void $ forkIO $ handler msg + Disproved _ -> return () + +-- | Block on a semaphore that is signaled by 'send'. If a timeout occurs +-- while waiting, send a 'PINGREQ' to the server and wait for PINGRESP. +-- Ignores errors that occur while writing to the handle, reconnects are +-- initiated by 'recvLoop'. +-- +-- Returns immediately if no Keep Alive is specified. +keepAliveLoop :: MQTT -> IO () +keepAliveLoop mqtt = + sequence_ (loop <$> cKeepAlive (config mqtt) <*> sendSem mqtt) + where + loop period sem = forever $ do + rslt <- timeout (period * 1000000) $ waitQSem sem + case rslt of + Nothing -> (do send mqtt $ Message + (Header False NoConfirm False) + MPingReq + void $ awaitMsg mqtt SPINGRESP Nothing) + `catch` + (\e -> logError mqtt $ "keepAliveLoop: " ++ show (e :: IOException)) + Just _ -> return () + +publishHandler :: MQTT -> Message PUBLISH -> IO () +publishHandler mqtt (Message header (MPublish body)) = do + case (qos header, pubMsgID body) of + (Confirm, Just msgid) -> + send mqtt $ Message + (Header False NoConfirm False) + (MPubAck $ SimpleMsg msgid) + (Handshake, Just msgid) -> do + send mqtt $ Message + (Header False NoConfirm False) + (MPubRec $ SimpleMsg msgid) + void $ awaitMsg mqtt SPUBREL (Just msgid) + send mqtt $ Message + (Header False NoConfirm False) + (MPubComp $ SimpleMsg msgid) + _ -> return () + callbacks <- filter (matches (topic body) . thTopic) + <$> readMVar (topicHandlers mqtt) + for_ callbacks $ \th -> thHandler th (topic body) (payload body) + +getMessage :: MQTT -> IO SomeMessage +getMessage mqtt = do + h <- readMVar (handle mqtt) + headerByte <- hGet' h 1 + remaining <- getRemaining h 0 + rest <- hGet' h remaining + let parseRslt = do + (mType, header) <- parseOnly mqttHeader headerByte + withSomeSing mType $ \sMsgType -> + parseOnly + (SomeMessage . Message header + <$> mqttBody header sMsgType (fromIntegral remaining)) + rest + case parseRslt of + Left err -> logError mqtt ("Error while parsing: " ++ err) >> + throw (ParseError err) + Right msg -> msg <$ + logInfo mqtt ("Received " ++ show (toMsgType' msg)) + +getRemaining :: Handle -> Int -> IO Int +getRemaining h n = go n 1 + where + go acc fac = do + b <- getByte h + let acc' = acc + (b .&. 127) * fac + if b .&. 128 == 0 + then return acc' + else go acc' (fac * 128) + +getByte :: Handle -> IO Int +getByte h = fromIntegral . BS.head <$> hGet' h 1 + +hGet' :: Handle -> Int -> IO BS.ByteString +hGet' h n = do + bs <- hGet h n + if BS.length bs < n + then throw EOF + else return bs + +-- | Exceptions that may arise while parsing messages. A user should +-- never see one of these. +data MQTTException + = EOF + | ParseError String + deriving (Show, Typeable) + +instance Exception MQTTException where diff --git a/Network/MQTT/Encoding.hs b/Network/MQTT/Encoding.hs new file mode 100644 --- /dev/null +++ b/Network/MQTT/Encoding.hs @@ -0,0 +1,190 @@ +{-# Language OverloadedStrings, RecordWildCards, GADTs #-} +{-| +Module: MQTT.Encoding +Copyright: Lukas Braun 2014 +License: GPL-3 +Maintainer: koomi+mqtt@hackerspace-bamberg.de + +Binary encoding for MQTT messages. +-} + +module Network.MQTT.Encoding where + +import Data.Bits (Bits(..)) +import qualified Data.ByteString as BS +import qualified Data.ByteString.Lazy as BSL +import Data.ByteString.Builder +import Data.Foldable (foldMap) +import Data.Int (Int64) +import Data.Maybe (isJust) +import Data.Monoid ((<>), mconcat, mempty) +import Data.Word (Word8) +import Data.Text.Encoding (encodeUtf8) +import System.IO (Handle) + +import Network.MQTT.Types + +-- | Directly write a 'Message' to the buffer of a 'Handle'. +writeTo :: Handle -> Message t -> IO () +writeTo h msg = hPutBuilder h (putMessage msg) + +-- | Generate a 'Builder' for any 'Message'. +putMessage :: Message t -> Builder +putMessage Message{..} = mconcat + [ putMqttHeader header (msgType body) + , encodeRemaining remaining + , lazyByteString bodyBS + ] + where + -- the header contains the length of the remaining message, so we have + -- to build the body to determine the length in bytes + bodyBS = toLazyByteString (putBody body) + remaining = BSL.length bodyBS + + +--------------------------------- +-- * Fixed Header +--------------------------------- + +-- | Build a 'MqttHeader' for the given message type. +putMqttHeader :: MqttHeader -> Word8 -> Builder +putMqttHeader (Header dup qos retain) msgType = + word8 $ shiftL msgType 4 .|. + shiftL (toBit dup) 3 .|. + shiftL (fromQoS qos) 1 .|. + toBit retain + +-- | Encode the remaining length field. +encodeRemaining :: Int64 -> Builder +encodeRemaining n = + let (n', digit) = n `quotRem` 128 + digit' = fromIntegral digit + in if n' > 0 + -- set top bit to indicate more digits are following + then word8 (digit' .|. 0x80) <> encodeRemaining n' + else word8 digit' + + +--------------------------------- +-- * Body +--------------------------------- + +-- | Build the 'MessageBody' for any message type. +putBody :: MessageBody t -> Builder +putBody (MConnect connect) = putConnect connect +putBody (MConnAck connAck) = putConnAck connAck +putBody (MPublish publish) = putPublish publish +putBody (MPubAck simpleMsg) = putSimple simpleMsg +putBody (MPubRec simpleMsg) = putSimple simpleMsg +putBody (MPubRel simpleMsg) = putSimple simpleMsg +putBody (MPubComp simpleMsg) = putSimple simpleMsg +putBody (MSubscribe subscribe) = putSubscribe subscribe +putBody (MSubAck subAck) = putSubAck subAck +putBody (MUnsubscribe unsubscribe) = putUnsubscribe unsubscribe +putBody (MUnsubAck simpleMsg) = putSimple simpleMsg +putBody MPingReq = mempty +putBody MPingResp = mempty +putBody MDisconnect = mempty + + +putConnect :: Connect -> Builder +putConnect Connect{..} = mconcat + [ putMqttText "MQIsdp" -- protocol + , word8 3 -- version + , word8 flags + , word16BE keepAlive + , putMqttText clientID + , maybe mempty putTopic (fmap wTopic will) + , maybePut (fmap wMsg will) + , maybePut username + , maybePut password + ] + where + maybePut = maybe mempty putMqttText + flags = shiftL (toBit (isJust username)) 7 .|. + shiftL (toBit (isJust password)) 6 .|. + shiftL (maybe 0 (toBit . wRetain) will) 5 .|. + shiftL (maybe 0 (fromQoS . wQoS) will) 3 .|. + shiftL (toBit (isJust will)) 2 .|. + shiftL (toBit cleanSession) 1 + + +putConnAck :: ConnAck -> Builder +putConnAck = word8 . returnCode + + +putPublish :: Publish -> Builder +putPublish Publish{..} = mconcat + [ putTopic topic + , maybe mempty putMsgID pubMsgID + , byteString payload + ] + + +putSubscribe :: Subscribe -> Builder +putSubscribe Subscribe{..} = mconcat + [ putMsgID subscribeMsgID + , foldMap (\(txt, qos) -> putTopic txt <> word8 (fromQoS qos)) subTopics + ] + + +putSubAck :: SubAck -> Builder +putSubAck SubAck{..} = mconcat + [ putMsgID subAckMsgID + , foldMap (word8 . fromQoS) granted + ] + +putUnsubscribe :: Unsubscribe -> Builder +putUnsubscribe Unsubscribe{..} = mconcat + [ putMsgID unsubMsgID + , foldMap putTopic unsubTopics + ] + +putSimple :: SimpleMsg -> Builder +putSimple = putMsgID . msgID + + +--------------------------------- +-- * Utility functions +--------------------------------- + +-- | Build a 'MsgID'. +putMsgID :: MsgID -> Builder +putMsgID = word16BE + +-- | Build a length-prefixed 'MqttText'. +putMqttText :: MqttText -> Builder +putMqttText (MqttText text) = let utf = encodeUtf8 text in + word16BE (fromIntegral (BS.length utf)) <> byteString utf + +-- | Build a 'Topic'. +putTopic :: Topic -> Builder +putTopic = putMqttText . fromTopic + +-- | Encode a 'QoS'. +fromQoS :: (Num a) => QoS -> a +fromQoS NoConfirm = 0 +fromQoS Confirm = 1 +fromQoS Handshake = 2 + +-- | Convert a 'Bool' to 0 or 1. +toBit :: (Num a) => Bool -> a +toBit False = 0 +toBit True = 1 + +-- | Encode the type of a 'MessageBody'. +msgType :: (Num a) => MessageBody t -> a +msgType (MConnect _) = 1 +msgType (MConnAck _) = 2 +msgType (MPublish _) = 3 +msgType (MPubAck _) = 4 +msgType (MPubRec _) = 5 +msgType (MPubRel _) = 6 +msgType (MPubComp _) = 7 +msgType (MSubscribe _) = 8 +msgType (MSubAck _) = 9 +msgType (MUnsubscribe _) = 10 +msgType (MUnsubAck _) = 11 +msgType MPingReq = 12 +msgType MPingResp = 13 +msgType MDisconnect = 14 diff --git a/Network/MQTT/Logger.hs b/Network/MQTT/Logger.hs new file mode 100644 --- /dev/null +++ b/Network/MQTT/Logger.hs @@ -0,0 +1,39 @@ +{-| +Module: MQTT.Logger +Copyright: Lukas Braun 2014 +License: GPL-3 +Maintainer: koomi+mqtt@hackerspace-bamberg.de + +A simple logger abstraction. +-} +module Network.MQTT.Logger where + +import System.IO + +-- | Absract logger with three levels of importance. +data Logger + = Logger + { logInfo :: String -> IO () + , logWarning :: String -> IO () + , logError :: String -> IO () + } + +-- | 'logInfo' prints to stdout, 'logWarning' and 'logError' to stderr +-- (with [Warning]/[Error] prefix) +stdLogger :: Logger +stdLogger = Logger + putStrLn + (\msg -> hPutStrLn stderr $ "[Warning] " ++ msg) + (\msg -> hPutStrLn stderr $ "[Error] " ++ msg) + +-- | Log only warnings and errors, ignoring anything passed to 'logInfo'. +warnings :: Logger -> Logger +warnings l = l { logInfo = ignore } + +-- | Like 'warnings', but logs only errors. +errors :: Logger -> Logger +errors l = l { logInfo = ignore, logWarning = ignore } + +-- | Ignore the message. +ignore :: String -> IO () +ignore _ = return () diff --git a/Network/MQTT/Parser.hs b/Network/MQTT/Parser.hs new file mode 100644 --- /dev/null +++ b/Network/MQTT/Parser.hs @@ -0,0 +1,242 @@ +{-# Language OverloadedStrings, GADTs #-} +{-| +Module: MQTT.Parsers +Copyright: Lukas Braun 2014 +License: GPL-3 +Maintainer: koomi+mqtt@hackerspace-bamberg.de + +Parsers for MQTT messages. +-} +module Network.MQTT.Parser where + +import Control.Monad +import Control.Monad.Loops +import Control.Monad.State.Strict +import Control.Applicative +import Data.Attoparsec.ByteString +import Data.Bits +import qualified Data.ByteString as BS +import Data.Singletons (withSomeSing) +import Data.Text.Encoding (decodeUtf8') +import Data.Word +import Prelude hiding (takeWhile, take) + +import Network.MQTT.Types hiding (body) + +-- | Type of a parser that also keeps track of the remaining length. +type MessageParser a = StateT Word32 Parser a + +-- | Parse any MQTT message. +message :: Parser SomeMessage +message = do + (msgType, header) <- mqttHeader + remaining <- parseRemaining + withSomeSing msgType $ \sMsgType -> + SomeMessage . Message header <$> mqttBody header sMsgType remaining + + +--------------------------------- +-- * Fixed Header +--------------------------------- + +-- | Parser for the fixed header part of a MQTT message. +mqttHeader :: Parser (MsgType, MqttHeader) +mqttHeader = do + byte1 <- anyWord8 + qos <- toQoS $ 3 .&. shiftR byte1 1 + let retain = testBit byte1 0 + dup = testBit byte1 3 + msgType = shiftR byte1 4 + msgType' <- case msgType of + 1 -> return CONNECT + 2 -> return CONNACK + 3 -> return PUBLISH + 4 -> return PUBACK + 5 -> return PUBREC + 6 -> return PUBREL + 7 -> return PUBCOMP + 8 -> return SUBSCRIBE + 9 -> return SUBACK + 10 -> return UNSUBSCRIBE + 11 -> return UNSUBACK + 12 -> return PINGREQ + 13 -> return PINGRESP + 14 -> return DISCONNECT + x -> fail $ "Invalid message type: " ++ show x + return (msgType', Header dup qos retain) + +-- | Parse the 'remaining length' field that indicates how long the rest of +-- the message is. +parseRemaining :: Parser Word32 +parseRemaining = do + bytes <- takeWhile (> 0x7f) -- bytes with first bit set + when (BS.length bytes > 3) $ + fail "'Remaining length' field must not be longer than 4 bytes" + stopByte <- anyWord8 + return $ snd $ BS.foldr' f (128, fromIntegral stopByte) bytes + where + f byte (factor, acc) = + (factor*128, acc + factor * fromIntegral (0x7f .&. byte)) + + +--------------------------------- +-- * Message Body +--------------------------------- + +-- | «@mqttBody header msgtype remaining@» parses a 'Message' of type +-- @msgtype@ that is @remaining@ bytes long. +mqttBody :: MqttHeader -> SMsgType t -> Word32 -> Parser (MessageBody t) +mqttBody header msgType remaining = + let parser = + case msgType of + SCONNECT -> MConnect <$> connect + SCONNACK -> MConnAck <$> connAck + SPUBLISH -> MPublish <$> publish header + SPUBACK -> MPubAck <$> simpleMsg + SPUBREC -> MPubRec <$> simpleMsg + SPUBREL -> MPubRel <$> simpleMsg + SPUBCOMP -> MPubComp <$> simpleMsg + SSUBSCRIBE -> MSubscribe <$> subscribe + SSUBACK -> MSubAck <$> subAck + SUNSUBSCRIBE -> MUnsubscribe <$> unsubscribe + SUNSUBACK -> MUnsubAck <$> simpleMsg + SPINGREQ -> pure MPingReq + SPINGRESP -> pure MPingResp + SDISCONNECT -> pure MDisconnect + in evalStateT parser remaining + +connect :: MessageParser Connect +connect = do + protocol + version + + flags <- anyWord8' + let clean = testBit flags 1 + willFlag = testBit flags 2 + usernameFlag = testBit flags 7 + passwordFlag = testBit flags 6 + + keepAlive <- anyWord16BE + + clientID <- getClientID + + mWill <- parseIf willFlag $ + Will (testBit flags 5) + <$> toQoS (3 .&. shiftR flags 3) + <*> fmap toTopic mqttText + <*> mqttText + + username <- parseIf usernameFlag mqttText + + password <- parseIf passwordFlag mqttText + + return $ Connect clean mWill clientID username password keepAlive + where + protocol = do + prot <- mqttText + when (prot /= "MQIsdp") $ + fail $ "Invalid protocol: " ++ show prot + + version = do + version <- anyWord8' + when (version /= 3) $ + fail $ "Invalid version: " ++ show version + + getClientID = do + before <- get + clientID <- mqttText + after <- get + let len = before - after - 2 -- 2 for length prefix + when (len > 23) $ + fail $ "Client ID must not be longer than 23 chars: " + ++ show (text clientID) ++ " (" ++ show len ++ ")" + return clientID + + parseIf :: Applicative f => Bool -> f a -> f (Maybe a) + parseIf flag parser = if flag then Just <$> parser else pure Nothing + + +connAck :: MessageParser ConnAck +connAck = ConnAck <$> anyWord8' + +publish :: MqttHeader -> MessageParser Publish +publish header = Publish + <$> getTopic + <*> (if qos header > NoConfirm + then Just <$> parseMsgID + else return Nothing) + <*> (get >>= take') + +subscribe :: MessageParser Subscribe +subscribe = Subscribe + <$> parseMsgID + <*> whileM ((0 <) <$> get) + ((,) <$> getTopic <*> (anyWord8' >>= toQoS)) + +subAck :: MessageParser SubAck +subAck = SubAck + <$> parseMsgID + <*> whileM ((0 <) <$> get) (anyWord8' >>= toQoS) + +unsubscribe :: MessageParser Unsubscribe +unsubscribe = Unsubscribe + <$> parseMsgID + <*> whileM ((0 <) <$> get) getTopic + +simpleMsg :: MessageParser SimpleMsg +simpleMsg = SimpleMsg <$> parseMsgID + + +--------------------------------- +-- * Utility functions +--------------------------------- + +-- | Parse a topic name. +getTopic :: MessageParser Topic +getTopic = toTopic <$> mqttText + +-- | Parse a length-prefixed UTF-8 string. +mqttText :: MessageParser MqttText +mqttText = do + n <- anyWord16BE + rslt <- decodeUtf8' <$> take' n + case rslt of + Left err -> fail $ "Invalid UTF-8: " ++ show err + Right txt -> return $ MqttText txt + +-- | Synonym for 'anyWord16BE'. +parseMsgID :: MessageParser Word16 +parseMsgID = anyWord16BE + +-- | Parse a big-endian 16bit integer. +anyWord16BE :: (Num a, Bits a) => MessageParser a +anyWord16BE = do + msb <- anyWord8' + lsb <- anyWord8' + return $ shiftL (fromIntegral msb) 8 .|. fromIntegral lsb + +-- | A lifted version of attoparsec's 'anyWord8' that also subtracts 1 from +-- the remaining length. +anyWord8' :: MessageParser Word8 +anyWord8' = parseLength 1 >> lift anyWord8 + +-- | A lifted version of attoparsec's 'take' that also subtracts the +-- length. +take' :: Word32 -> MessageParser BS.ByteString +take' n = parseLength n >> lift (take (fromIntegral n)) + +-- | Subtract 'n' from the remaining length or 'fail' if there is not +-- enough input left. +parseLength :: Word32 -> MessageParser () +parseLength n = do + rem <- get + if rem < n + then fail "Reached remaining = 0 before end of message." + else put $ rem - n + +-- | Convert a number to a 'QoS'. 'fail' if the number can't be converted. +toQoS :: (Num a, Eq a, Show a, Monad m) => a -> m QoS +toQoS 0 = return NoConfirm +toQoS 1 = return Confirm +toQoS 2 = return Handshake +toQoS x = fail $ "Invalid QoS value: " ++ show x diff --git a/Network/MQTT/Types.hs b/Network/MQTT/Types.hs new file mode 100644 --- /dev/null +++ b/Network/MQTT/Types.hs @@ -0,0 +1,322 @@ +{-# Language GeneralizedNewtypeDeriving, + PatternSynonyms, + OverloadedStrings, + DataKinds, + KindSignatures, + GADTs, + TypeFamilies, + ScopedTypeVariables, + TemplateHaskell + #-} +{-| +Module: MQTT.Types +Copyright: Lukas Braun 2014 +License: GPL-3 +Maintainer: koomi+mqtt@hackerspace-bamberg.de + +Types representing MQTT messages. +-} +module Network.MQTT.Types + ( -- * Messages + Message(..) + , SomeMessage(..) + , MqttHeader(..) + -- * Message bodies + , MessageBody(..) + , Connect(..) + , ConnAck(..) + , Publish(..) + , Subscribe(..) + , SubAck(..) + , Unsubscribe(..) + , SimpleMsg(..) + -- * Miscellaneous + , Will(..) + , QoS(..) + , MsgID + , getMsgID + , Topic + , fromTopic + , toTopic + , matches + , MqttText(..) + -- * Message types + , MsgType(..) + , toMsgType + , toMsgType' + -- ** Singletons + -- | Singletons are used to build a bridge between the type and value level. + -- See the @singletons@ package for more information. + -- + -- You do not have to use or understand these in order to use this + -- library, they are mostly used internally to get better guarantees + -- about the flow of 'Message's. + , toSMsgType + , SMsgType + , Sing( SCONNECT + , SCONNACK + , SPUBLISH + , SPUBACK + , SPUBREC + , SPUBREL + , SPUBCOMP + , SSUBSCRIBE + , SSUBACK + , SUNSUBSCRIBE + , SUNSUBACK + , SPINGREQ + , SPINGRESP + , SDISCONNECT) + ) where + +import Data.ByteString (ByteString) +import Data.Singletons.TH +import Data.String (IsString(..)) +import Data.Text (Text) +import qualified Data.Text as T +import Data.Word + +-- | A MQTT message, indexed by the type of the message ('MsgType'). +data Message (t :: MsgType) + = Message + { header :: MqttHeader + , body :: MessageBody t + } + +-- | Any message, hiding the index. +data SomeMessage where + SomeMessage :: Message t -> SomeMessage + +-- | Fixed header required in every message. +data MqttHeader + = Header + { -- msgType :: MsgType -- ^ Type of the message + dup :: Bool -- ^ Has this message been sent before? + , qos :: QoS -- ^ Quality of Service-level + , retain :: Bool -- ^ Should the broker retain the message for + -- future subscribers? + } + deriving (Eq, Ord, Show) + +-- | The body of a MQTT message, indexed by the type of the message ('MsgType'). +data MessageBody (t :: MsgType) where + MConnect :: Connect -> MessageBody CONNECT + MConnAck :: ConnAck -> MessageBody CONNACK + MPublish :: Publish -> MessageBody PUBLISH + MPubAck :: SimpleMsg -> MessageBody PUBACK + MPubRec :: SimpleMsg -> MessageBody PUBREC + MPubRel :: SimpleMsg -> MessageBody PUBREL + MPubComp :: SimpleMsg -> MessageBody PUBCOMP + MSubscribe :: Subscribe -> MessageBody SUBSCRIBE + MSubAck :: SubAck -> MessageBody SUBACK + MUnsubscribe :: Unsubscribe -> MessageBody UNSUBSCRIBE + MUnsubAck :: SimpleMsg -> MessageBody UNSUBACK + MPingReq :: MessageBody PINGREQ + MPingResp :: MessageBody PINGRESP + MDisconnect :: MessageBody DISCONNECT + +-- | The fields of a CONNECT message. +data Connect + = Connect + { cleanSession :: Bool + -- ^ Should the server forget subscriptions and other state on + -- disconnects? + , will :: Maybe Will + -- ^ Optional 'Will' message. + , clientID :: MqttText + -- ^ Client ID used by the server to identify clients. + , username :: Maybe MqttText + -- ^ Optional username used for authentication. + , password :: Maybe MqttText + -- ^ Optional password used for authentication. + , keepAlive :: Word16 + -- ^ Maximum interval (in seconds) in which a message must be sent. + -- 0 means no limit. + } deriving (Show, Eq) + +-- | The response to a CONNECT. Anything other than 0 means the broker +-- refused the connection +-- (). +newtype ConnAck = ConnAck { returnCode :: Word8 } + deriving (Show, Eq) + +-- | The fields of a PUBLISH message. +data Publish + = Publish + { topic :: Topic + -- ^ The 'Topic' to which the message should be published. + , pubMsgID :: Maybe MsgID + -- ^ 'MsgID' of the message if 'QoS' > 'NoConfirm'. + , payload :: ByteString + -- ^ The content that will be published. + } deriving (Show, Eq) + +-- | The fields of a SUBSCRIBE message. +data Subscribe + = Subscribe + { subscribeMsgID :: MsgID + , subTopics :: [(Topic, QoS)] + -- ^ The 'Topic's and corresponding requested 'QoS'. + } deriving (Show, Eq) + +-- | The fields of a SUBACK message. +data SubAck + = SubAck + { subAckMsgID :: MsgID + , granted :: [QoS] + -- ^ The 'QoS' granted for each 'Topic' in the order they were sent + -- in the SUBSCRIBE. + } deriving (Show, Eq) + +-- | The fields of a UNSUBSCRIBE message. +data Unsubscribe + = Unsubscribe + { unsubMsgID :: MsgID + , unsubTopics :: [Topic] + -- ^ The 'Topic's from which the client should be unsubscribed. + } deriving (Show, Eq) + +-- | Any message body that consists only of a 'MsgID'. +newtype SimpleMsg = SimpleMsg { msgID :: MsgID } + deriving (Show, Eq) + +-- | The different levels of QoS +data QoS + = NoConfirm -- ^ Fire and forget + | Confirm -- ^ Acknowledged delivery (repeat until ack) + | Handshake -- ^ Assured delivery (four-step handshake) + deriving (Eq, Ord, Enum, Show) + +-- | A Will message is published by the broker if a client disconnects +-- without sending a DISCONNECT. +data Will + = Will + { wRetain :: Bool + , wQoS :: QoS + , wTopic :: Topic + , wMsg :: MqttText + } + deriving (Eq, Show) + +-- | MQTT uses length-prefixed UTF-8 as text encoding. +newtype MqttText = MqttText { text :: Text } + deriving (Eq, Show, IsString) + +-- | A topic is a "hierarchical name space that defines a taxonomy of +-- information sources for which subscribers can register an interest." +-- +-- See +-- +-- for more information on topics. +data Topic = Topic { levels :: [Text], orig :: Text } +-- levels and orig should always refer to the same topic, this way no text +-- has to be copied when converting from/to text + +type MsgID = Word16 + +-- | Get the message ID of any message, if it exists. +getMsgID :: MessageBody t -> Maybe MsgID +getMsgID (MConnect _) = Nothing +getMsgID (MConnAck _) = Nothing +getMsgID (MPublish pub) = pubMsgID pub +getMsgID (MPubAck simple) = Just (msgID simple) +getMsgID (MPubRec simple) = Just (msgID simple) +getMsgID (MPubRel simple) = Just (msgID simple) +getMsgID (MPubComp simple) = Just (msgID simple) +getMsgID (MSubscribe sub) = Just (subscribeMsgID sub) +getMsgID (MSubAck subA) = Just (subAckMsgID subA) +getMsgID (MUnsubscribe unsub) = Just (unsubMsgID unsub) +getMsgID (MUnsubAck simple) = Just (msgID simple) +getMsgID MPingReq = Nothing +getMsgID MPingResp = Nothing +getMsgID MDisconnect = Nothing + +instance Show Topic where + show (Topic _ t) = show t + +instance Eq Topic where + Topic _ t1 == Topic _ t2 = t1 == t2 + +-- | Check if one of the 'Topic's matches the other. +matches :: Topic -> Topic -> Bool +matches (Topic t1 _) (Topic t2 _) = go t1 t2 + where + go [] [] = True + go [] (l:_) = l == "#" + go (l:_) [] = l == "#" + go (l1:ls1) (l2:ls2) = l1 == "#" || l2 == "#" + || ((l1 == "+" || l2 == "+" || l1 == l2) + && go ls1 ls2) + +toTopic :: MqttText -> Topic +toTopic (MqttText txt) = Topic (T.split (== '/') txt) txt + +fromTopic :: Topic -> MqttText +fromTopic = MqttText . orig + +instance IsString Topic where + fromString str = let txt = T.pack str in + Topic (T.split (== '/') txt) txt + +-- | The various types of messages. +data MsgType + = CONNECT + | CONNACK + | PUBLISH + | PUBACK + | PUBREC + | PUBREL + | PUBCOMP + | SUBSCRIBE + | SUBACK + | UNSUBSCRIBE + | UNSUBACK + | PINGREQ + | PINGRESP + | DISCONNECT + deriving (Eq, Enum, Ord, Show) + +genSingletons [''MsgType] +singDecideInstance ''MsgType + +-- | Determine the 'MsgType' of a 'Message'. +toMsgType :: Message t -> MsgType +toMsgType msg = + case body msg of + MConnect _ -> CONNECT + MConnAck _ -> CONNACK + MPublish _ -> PUBLISH + MPubAck _ -> PUBACK + MPubRec _ -> PUBREC + MPubRel _ -> PUBREL + MPubComp _ -> PUBCOMP + MSubscribe _ -> SUBSCRIBE + MSubAck _ -> SUBACK + MUnsubscribe _ -> UNSUBSCRIBE + MUnsubAck _ -> UNSUBACK + MPingReq -> PINGREQ + MPingResp -> PINGRESP + MDisconnect -> DISCONNECT + +-- | Determine the 'MsgType' of a 'SomeMessage'. +toMsgType' :: SomeMessage -> MsgType +toMsgType' (SomeMessage msg) = toMsgType msg + +-- | Determine the singleton 'SMsgType' of a 'Message'. +toSMsgType :: Message t -> SMsgType t +toSMsgType msg = + case body msg of + MConnect _ -> SCONNECT + MConnAck _ -> SCONNACK + MPublish _ -> SPUBLISH + MPubAck _ -> SPUBACK + MPubRec _ -> SPUBREC + MPubRel _ -> SPUBREL + MPubComp _ -> SPUBCOMP + MSubscribe _ -> SSUBSCRIBE + MSubAck _ -> SSUBACK + MUnsubscribe _ -> SUNSUBSCRIBE + MUnsubAck _ -> SUNSUBACK + MPingReq -> SPINGREQ + MPingResp -> SPINGRESP + MDisconnect -> SDISCONNECT diff --git a/README.md b/README.md new file mode 100644 --- /dev/null +++ b/README.md @@ -0,0 +1,17 @@ +mqtt-hs +======= + +A Haskell MQTT client library. + +A simple example, assuming a broker is running on localhost (needs -XOverloadedStrings): + +```haskell +import Network.MQTT +import Network.MQTT.Logger +Just mqtt <- connect defaultConfig { cLogger = warnings stdLogger } +let f t payload = putStrLn $ "A message was published to " ++ show t ++ ": " ++ show payload +subscribe mqtt NoConfirm "#" f +publish mqtt Handshake False "some random/topic" "Some content!" +``` + +See the haddock for more documentation. diff --git a/Setup.hs b/Setup.hs new file mode 100644 --- /dev/null +++ b/Setup.hs @@ -0,0 +1,2 @@ +import Distribution.Simple +main = defaultMain diff --git a/mqtt-hs.cabal b/mqtt-hs.cabal new file mode 100644 --- /dev/null +++ b/mqtt-hs.cabal @@ -0,0 +1,40 @@ +-- Initial mqtt-hs.cabal generated by cabal init. For further +-- documentation, see http://haskell.org/cabal/users-guide/ + +name: mqtt-hs +version: 0.2.0 +synopsis: A MQTT client library. +homepage: github.com/k00mi/mqtt-hs +license: GPL-3 +license-file: LICENSE +author: Lukas Braun +maintainer: Lukas Braun +copyright: (c) 2014 Lukas Braun +category: Network +build-type: Simple +extra-source-files: README.md +cabal-version: >=1.10 +stability: experimental +description: + A library to communicate with MQTT brokers. + + See the @Network.MQTT@ module for documentation and a small example. + + +library + exposed-modules: Network.MQTT, Network.MQTT.Parser, Network.MQTT.Encoding, + Network.MQTT.Types, Network.MQTT.Logger + build-depends: base >=4.7 && <4.8, + mtl >=1.1 && <2.3, + attoparsec >=0.10 && <0.13, + bytestring >=0.10.2 && <0.11, + text >=0.11.0.6 && <1.2, + network >=2.0 && <2.7, + singletons >=0.9 && < 1.1, + monad-loops >=0.3 && <0.5 + default-language: Haskell2010 + + +source-repository head + type: git + location: git://github.com/k00mi/mqtt-hs.git