{-# LANGUAGE OverloadedStrings, GeneralizedNewtypeDeriving, ScopedTypeVariables, FlexibleInstances, DeriveDataTypeable, UndecidableInstances, BangPatterns, OverlappingInstances, DataKinds, GADTs, KindSignatures #-} -- | Haskell client for Cassandra's CQL protocol -- -- For examples, take a look at the /tests/ directory in the source archive. -- -- Here's the correspondence between CQL and Haskell types: -- -- * ascii - 'ByteString' -- -- * bigint - 'Int64' -- -- * blob - 'Blob' -- -- * boolean - 'Bool' -- -- * counter - 'Counter' -- -- * decimal - 'Decimal' -- -- * double - 'Double' -- -- * float - 'Float' -- -- * int - 'Int' -- -- * text / varchar - 'Text' -- -- * timestamp - 'UTCTime' -- -- * uuid - 'UUID' -- -- * varint - 'Integer' -- -- * timeuuid - 'TimeUUID' -- -- * inet - 'SockAddr' -- -- * list\ - [a] -- -- * map\ - 'Map' a b -- -- * set\ - 'Set' b -- -- ...and you can define your own 'CasType' instances to extend these types, which is -- a very powerful way to write your code. -- -- One way to do things is to specify your queries with a type signature, like this: -- -- > createSongs :: Query Schema () () -- > createSongs = "create table songs (id uuid PRIMARY KEY, title text, artist text, comment text)" -- > -- > insertSong :: Query Write (UUID, Text, Text, Maybe Text) () -- > insertSong = "insert into songs (id, title, artist, comment) values (?, ?, ?)" -- > -- > getOneSong :: Query Rows UUID (Text, Text, Maybe Text) -- > getOneSong = "select title, artist, comment from songs where id=?" -- -- The three type parameters are the query type ('Schema', 'Write' or 'Rows') followed by the -- input and output types, which are given as tuples whose constituent types must match -- the ones in the query CQL. If you do not match them correctly, you'll get a runtime -- error when you execute the query. If you do, then the query becomes completely type -- safe. -- -- Types can be 'Maybe' types, in which case you can read and write a Cassandra \'null\' -- in the table. Cassandra allows any column to be null, but you can lock this out by -- specifying non-Maybe types. -- -- The query types are: -- -- * 'Schema' for modifications to the schema. The output tuple type must be (). -- -- * 'Write' for row inserts and updates, and such. The output tuple type must be (). -- -- * 'Rows' for selects that give a list of rows in response. -- -- The functions to use for these query types are 'executeSchema', 'executeWrite' and -- 'executeRows' or 'executeRow' respectively. -- -- The following pattern seems to work very well, especially along with your own 'CasType' -- instances, because it gives you a place to neatly add marshalling details that keeps -- away from the body of your code. -- -- > insertSong :: UUID -> Text -> Text -> Maybe Text -> Cas () -- > insertSong id title artist comment = executeWrite QUORUM q (id, title, artist, comment) -- > where q = "insert into songs (id, title, artist, comment) values (?, ?, ?, ?)" -- -- Incidentally, here's Haskell's little-known multi-line string syntax. -- You escape it using \\ and then another \\ where the string starts again. -- -- > str = "multi\ -- > \line" -- -- (gives \"multiline\") -- -- /To do/ -- -- * Add credentials. -- -- * Improve connection pooling. -- -- * Add the ability to easily run queries in parallel. module Database.Cassandra.CQL ( -- * Initialization Server, Keyspace(..), Pool, newPool, -- * Cassandra monad MonadCassandra(..), Cas, runCas, CassandraException(..), CassandraCommsError(..), TransportDirection(..), -- * Queries Query, Style(..), query, -- * Executing queries Consistency(..), Change(..), executeSchema, executeWrite, executeRows, executeRow, -- * Value types Blob(..), Counter(..), TimeUUID(..), metadataTypes, CasType(..), CasValues(..), -- * Lower-level interfaces executeRaw, Result(..), TableSpec(..), ColumnSpec(..), Metadata(..), CType(..), Table(..), PreparedQueryID(..) ) where import Control.Applicative import Control.Concurrent import Control.Concurrent.STM import Control.Exception (IOException, SomeException) import Control.Monad.CatchIO import Control.Monad.Reader import Control.Monad.State hiding (get, put) import qualified Control.Monad.State as State import qualified Control.Monad.Reader import qualified Control.Monad.RWS import qualified Control.Monad.State import qualified Control.Monad.State.Strict import qualified Control.Monad.Error import qualified Control.Monad.Writer import Control.Monad.Trans import Crypto.Hash (hash, Digest, SHA1) import Data.Bits import Data.ByteString (ByteString) import qualified Data.ByteString as B import qualified Data.ByteString.Lazy as L import Data.Data import Data.Decimal import Data.Either (lefts) import Data.Int import Data.List import Data.Map (Map) import qualified Data.Map as M import Data.Maybe import Data.Monoid (Monoid) import Data.Sequence (Seq, (|>)) import qualified Data.Sequence as Seq import Data.Serialize hiding (Result) import Data.Set (Set) import qualified Data.Set as S import Foreign.Storable import Data.String import Data.Text (Text) import qualified Data.Text as T import qualified Data.Text.Encoding as T import Data.Time.Calendar import Data.Time.Clock import Data.Typeable import Data.UUID (UUID) import qualified Data.UUID as UUID import Data.Word import Network.Socket (Socket, HostName, ServiceName, getAddrInfo, socket, AddrInfo(..), connect, sClose, SockAddr(..), SocketType(..), defaultHints) import Network.Socket.ByteString (send, sendAll, recv) import Numeric import Unsafe.Coerce --import qualified Data.ByteString.Char8 as C --import Text.Hexdump type Server = (HostName, ServiceName) data ActiveSession = ActiveSession { actSocket :: Socket, actQueryCache :: Map QueryID PreparedQuery } data Session = Session { sesServer :: Server, sesActive :: Maybe ActiveSession } -- | A handle for the state of the connection pool. data Pool = Pool { piKeyspace :: Keyspace, piSessions :: TVar (Seq Session) } class MonadCatchIO m => MonadCassandra m where getCassandraPool :: m Pool instance MonadCassandra m => MonadCassandra (Control.Monad.Reader.ReaderT a m) where getCassandraPool = lift getCassandraPool instance MonadCassandra m => MonadCassandra (Control.Monad.State.StateT a m) where getCassandraPool = lift getCassandraPool instance (MonadCassandra m, Control.Monad.Error.Error e) => MonadCassandra (Control.Monad.Error.ErrorT e m) where getCassandraPool = lift getCassandraPool instance (MonadCassandra m, Monoid a) => MonadCassandra (Control.Monad.Writer.WriterT a m) where getCassandraPool = lift getCassandraPool instance (MonadCassandra m, Monoid w) => MonadCassandra (Control.Monad.RWS.RWST r w s m) where getCassandraPool = lift getCassandraPool -- | Construct a pool of Cassandra connections. newPool :: [Server] -> Keyspace -> IO Pool newPool svrs ks = do let sessions = map (\svr -> Session svr Nothing) svrs sess <- atomically $ newTVar (Seq.fromList sessions) return $ Pool { piKeyspace = ks, piSessions = sess } takeSession :: Pool -> IO Session takeSession pool = atomically $ do sess <- readTVar (piSessions pool) if Seq.null sess then retry else do let ses = sess `Seq.index` 0 writeTVar (piSessions pool) (Seq.drop 1 sess) return ses putSession :: Pool -> Session -> IO () putSession pool ses = atomically $ modifyTVar (piSessions pool) (|> ses) connectIfNeeded :: Pool -> Session -> IO Session connectIfNeeded pool session = if isJust (sesActive session) then return session else do let hints = defaultHints { addrSocketType = Stream } let (host, service) = sesServer session ais <- getAddrInfo (Just hints) (Just host) (Just service) mSocket <- foldM (\mSocket ai -> do case mSocket of Nothing -> do s <- socket (addrFamily ai) (addrSocketType ai) (addrProtocol ai) do connect s (addrAddress ai) return (Just s) `catch` \(exc :: IOException) -> do sClose s return Nothing Just _ -> return mSocket ) Nothing ais case mSocket of Just socket -> do let active = ActiveSession { actSocket = socket, actQueryCache = M.empty } active' <- execStateT (introduce pool) active return $ session { sesActive = Just active' } Nothing -> return session data Flag = Compression | Tracing deriving Show putFlags :: [Flag] -> Put putFlags flags = putWord8 $ foldl' (+) 0 $ map toWord8 flags where toWord8 Compression = 0x01 toWord8 Tracing = 0x02 getFlags :: Get [Flag] getFlags = do flagsB <- getWord8 return $ case flagsB .&. 3 of 0 -> [] 1 -> [Compression] 2 -> [Tracing] 3 -> [Compression, Tracing] _ -> error "recvFrame impossible" data Opcode = ERROR | STARTUP | READY | AUTHENTICATE | CREDENTIALS | OPTIONS | SUPPORTED | QUERY | RESULT | PREPARE | EXECUTE | REGISTER | EVENT deriving (Eq, Show) instance Serialize Opcode where put op = putWord8 $ case op of ERROR -> 0x00 STARTUP -> 0x01 READY -> 0x02 AUTHENTICATE -> 0x03 CREDENTIALS -> 0x04 OPTIONS -> 0x05 SUPPORTED -> 0x06 QUERY -> 0x07 RESULT -> 0x08 PREPARE -> 0x09 EXECUTE -> 0x0a REGISTER -> 0x0b EVENT -> 0x0c get = do w <- getWord8 case w of 0x00 -> return $ ERROR 0x01 -> return $ STARTUP 0x02 -> return $ READY 0x03 -> return $ AUTHENTICATE 0x04 -> return $ CREDENTIALS 0x05 -> return $ OPTIONS 0x06 -> return $ SUPPORTED 0x07 -> return $ QUERY 0x08 -> return $ RESULT 0x09 -> return $ PREPARE 0x0a -> return $ EXECUTE 0x0b -> return $ REGISTER 0x0c -> return $ EVENT _ -> fail $ "unknown opcode 0x"++showHex w "" data Frame a = Frame { frFlags :: [Flag], frStream :: Int8, frOpcode :: Opcode, frBody :: a } deriving Show recvAll :: Socket -> Int -> IO ByteString recvAll s n = do bs <- recv s n when (B.null bs) $ throw ShortRead let left = n - B.length bs if left == 0 then return bs else do bs' <- recvAll s left return (bs `B.append` bs') protocolVersion :: Word8 protocolVersion = 1 recvFrame :: Text -> StateT ActiveSession IO (Frame ByteString) recvFrame qt = do s <- gets actSocket hdrBs <- liftIO $ recvAll s 8 case runGet parseHeader hdrBs of Left err -> throw $ LocalProtocolError ("recvFrame: " `T.append` T.pack err) qt Right (ver0, flags, stream, opcode, length) -> do let ver = ver0 .&. 0x7f when (ver /= protocolVersion) $ throw $ LocalProtocolError ("unexpected version " `T.append` T.pack (show ver)) qt body <- if length == 0 then pure B.empty else liftIO $ recvAll s (fromIntegral length) --liftIO $ putStrLn $ hexdump 0 (C.unpack $ hdrBs `B.append` body) return $ Frame flags stream opcode body `catch` \exc -> throw $ CassandraIOException exc where parseHeader = do ver <- getWord8 flags <- getFlags stream <- fromIntegral <$> getWord8 opcode <- get length <- getWord32be return (ver, flags, stream, opcode, length) sendFrame :: Frame ByteString -> StateT ActiveSession IO () sendFrame fr@(Frame flags stream opcode body) = do let bs = runPut $ do putWord8 protocolVersion putFlags flags putWord8 (fromIntegral stream) put opcode putWord32be $ fromIntegral $ B.length body putByteString body --liftIO $ putStrLn $ hexdump 0 (C.unpack bs) s <- gets actSocket liftIO $ sendAll s bs `catch` \exc -> throw $ CassandraIOException exc class ProtoElt a where getElt :: Get a putElt :: a -> Put encodeElt :: ProtoElt a => a -> ByteString encodeElt = runPut . putElt encodeCas :: CasType a => a -> ByteString encodeCas = runPut . putCas decodeElt :: ProtoElt a => ByteString -> Either String a decodeElt bs = runGet getElt bs decodeCas :: CasType a => ByteString -> Either String a decodeCas bs = runGet getCas bs decodeEltM :: (ProtoElt a, MonadIO m) => Text -> ByteString -> Text -> m a decodeEltM what bs qt = case decodeElt bs of Left err -> throw $ LocalProtocolError ("can't parse" `T.append` what `T.append` ": " `T.append` T.pack err) qt Right res -> return res newtype Long a = Long { unLong :: a } deriving (Eq, Ord, Show, Read) instance Functor Long where f `fmap` Long a = Long (f a) newtype Short a = Short { unShort :: a } deriving (Eq, Ord, Show, Read) instance Functor Short where f `fmap` Short a = Short (f a) instance ProtoElt (Map Text Text) where putElt = putElt . M.assocs getElt = M.fromList <$> getElt instance ProtoElt [(Text, Text)] where putElt pairs = do putWord16be (fromIntegral $ length pairs) forM_ pairs $ \(key, value) -> do putElt key putElt value getElt = do n <- getWord16be replicateM (fromIntegral n) $ do key <- getElt value <- getElt return (key, value) instance ProtoElt Text where putElt = putElt . T.encodeUtf8 getElt = T.decodeUtf8 <$> getElt instance ProtoElt (Long Text) where putElt = putElt . fmap T.encodeUtf8 getElt = fmap T.decodeUtf8 <$> getElt instance ProtoElt ByteString where putElt bs = do putWord16be (fromIntegral $ B.length bs) putByteString bs getElt = do len <- getWord16be getByteString (fromIntegral len) instance ProtoElt (Long ByteString) where putElt (Long bs) = do putWord32be (fromIntegral $ B.length bs) putByteString bs getElt = do len <- getWord32be Long <$> getByteString (fromIntegral len) data TransportDirection = TransportSending | TransportReceiving deriving (Eq, Show) -- | An exception that indicates an error originating in the Cassandra server. data CassandraException = ServerError Text Text | ProtocolError Text Text | BadCredentials Text Text | UnavailableException Text Consistency Int Int Text | Overloaded Text Text | IsBootstrapping Text Text | TruncateError Text Text | WriteTimeout Text Consistency Int Int Text Text | ReadTimeout Text Consistency Int Int Bool Text | SyntaxError Text Text | Unauthorized Text Text | Invalid Text Text | ConfigError Text Text | AlreadyExists Text Keyspace Table Text | Unprepared Text PreparedQueryID Text deriving (Show, Typeable) instance Exception CassandraException where -- | All errors at the communications level are reported with this exception -- ('IOException's from socket I/O are always wrapped), and this exception -- typically would mean that a retry is warranted. -- -- Note that this exception isn't guaranteed to be a transient one, so a limit -- on the number of retries is likely to be a good idea. -- 'LocalProtocolError' probably indicates a corrupted database or driver -- bug. data CassandraCommsError = AuthenticationException Text | LocalProtocolError Text Text | ValueMarshallingException TransportDirection Text Text | CassandraIOException IOException | ShortRead deriving (Show, Typeable) instance Exception CassandraCommsError throwError :: MonadCatchIO m => Text -> ByteString -> m a throwError qt bs = do case runGet parseError bs of Left err -> throw $ LocalProtocolError ("failed to parse error: " `T.append` T.pack err) qt Right exc -> throw exc where parseError :: Get CassandraException parseError = do code <- getWord32be case code of 0x0000 -> ServerError <$> getElt <*> pure qt 0x000A -> ProtocolError <$> getElt <*> pure qt 0x0100 -> BadCredentials <$> getElt <*> pure qt 0x1000 -> UnavailableException <$> getElt <*> getElt <*> (fromIntegral <$> getWord32be) <*> (fromIntegral <$> getWord32be) <*> pure qt 0x1001 -> Overloaded <$> getElt <*> pure qt 0x1002 -> IsBootstrapping <$> getElt <*> pure qt 0x1003 -> TruncateError <$> getElt <*> pure qt 0x1100 -> WriteTimeout <$> getElt <*> getElt <*> (fromIntegral <$> getWord32be) <*> (fromIntegral <$> getWord32be) <*> getElt <*> pure qt 0x1200 -> ReadTimeout <$> getElt <*> getElt <*> (fromIntegral <$> getWord32be) <*> (fromIntegral <$> getWord32be) <*> ((/=0) <$> getWord8) <*> pure qt 0x2000 -> SyntaxError <$> getElt <*> pure qt 0x2100 -> Unauthorized <$> getElt <*> pure qt 0x2200 -> Invalid <$> getElt <*> pure qt 0x2300 -> ConfigError <$> getElt <*> pure qt 0x2400 -> AlreadyExists <$> getElt <*> getElt <*> getElt <*> pure qt 0x2500 -> Unprepared <$> getElt <*> getElt <*> pure qt _ -> fail $ "unknown error code 0x"++showHex code "" introduce :: Pool -> StateT ActiveSession IO () introduce pool = do let qt = "" sendFrame $ Frame [] 0 STARTUP $ encodeElt $ ([("CQL_VERSION", "3.0.0")] :: [(Text, Text)]) fr <- recvFrame qt case frOpcode fr of AUTHENTICATE -> throw $ AuthenticationException "authentication not implemented yet" READY -> return () ERROR -> throwError qt (frBody fr) op -> throw $ LocalProtocolError ("introduce: unexpected opcode " `T.append` T.pack (show op)) qt let Keyspace ksName = piKeyspace pool let q = query $ "USE " `T.append` ksName :: Query Rows () () res <- executeInternal q () ONE case res of SetKeyspace ks -> return () _ -> throw $ LocalProtocolError ("expected SetKeyspace, but got " `T.append` T.pack (show res)) (queryText q) withSession :: MonadCassandra m => (Pool -> StateT ActiveSession IO a) -> m a withSession code = do pool <- getCassandraPool mA <- liftIO $ do session <- connectIfNeeded pool =<< takeSession pool case sesActive session of Just active -> do (a, active') <- runStateT (code pool) active putSession pool $ session { sesActive = Just active' } return (Just a) `catches` [ -- Close the session if we get any IOException Handler $ \(exc :: IOException) -> do sClose (actSocket active) putSession pool $ session { sesActive = Nothing } throw exc, Handler $ \(exc :: SomeException) -> do putSession pool session throw exc ] Nothing -> do putSession pool session return Nothing case mA of Just a -> return a Nothing -> withSession code -- Try again until we succeed -- | The name of a Cassandra keyspace. See the Cassandra documentation for more -- information. newtype Keyspace = Keyspace Text deriving (Eq, Ord, Show, IsString, ProtoElt) -- | The name of a Cassandra table (a.k.a. column family). newtype Table = Table Text deriving (Eq, Ord, Show, IsString, ProtoElt) -- | A fully qualified identification of a table that includes the 'Keyspace'. data TableSpec = TableSpec Keyspace Table deriving (Eq, Ord, Show) instance ProtoElt TableSpec where putElt _ = error "formatting TableSpec is not implemented" getElt = TableSpec <$> getElt <*> getElt -- | Information about a table column. data ColumnSpec = ColumnSpec TableSpec Text CType deriving Show -- | The specification of a list of result set columns. data Metadata = Metadata [ColumnSpec] deriving Show -- | Cassandra data types as used in metadata. data CType = CCustom Text | CAscii | CBigint | CBlob | CBoolean | CCounter | CDecimal | CDouble | CFloat | CInt | CText | CTimestamp | CUuid | CVarint | CTimeuuid | CInet | CList CType | CMap CType CType | CSet CType | CMaybe CType deriving (Eq) instance Show CType where show ct = case ct of CCustom name -> T.unpack name CAscii -> "ascii" CBigint -> "bigint" CBlob -> "blob" CBoolean -> "boolean" CCounter -> "counter" CDecimal -> "decimal" CDouble -> "double" CFloat -> "float" CInt -> "int" CText -> "text" CTimestamp -> "timestamp" CUuid -> "uuid" CVarint -> "varint" CTimeuuid -> "timeuuid" CInet -> "inet" CList t -> "list<"++show t++">" CMap t1 t2 -> "map<"++show t1++","++show t2++">" CSet t -> "set<"++show t++">" CMaybe t -> "nullable "++show t equivalent :: CType -> CType -> Bool equivalent (CMaybe a) (CMaybe b) = a == b equivalent (CMaybe a) b = a == b equivalent a (CMaybe b) = a == b equivalent a b = a == b -- | A type class for types that can be used in query arguments or column values in -- returned results. -- -- To define your own newtypes for Cassandra data, you only need to define 'getCas', -- 'putCas' and 'casType', like this: -- -- > newtype UserId = UserId UUID deriving (Eq, Show) -- > -- > instance CasType UserId where -- > getCas = UserId <$> getCas -- > putCas (UserId i) = putCas i -- > casType (UserId i) = casType i -- -- The same can be done more simply using the /GeneralizedNewtypeDeriving/ language -- extension, e.g. -- -- > {-# LANGUAGE GeneralizedNewtypeDeriving #-} -- > -- > ... -- > newtype UserId = UserId UUID deriving (Eq, Show, CasType) -- -- If you have a more complex type you want to store as a Cassandra blob, you could -- write an instance like this (assuming it's an instance of the /cereal/ package's -- 'Serialize' class): -- -- > instance CasType User where -- > getCas = decode . unBlob <$> getCas -- > putCas = putCas . Blob . encode -- > casType _ = CBlob class CasType a where getCas :: Get a putCas :: a -> Put -- | For a given Haskell type given as ('undefined' :: a), tell the caller how Cassandra -- represents it. casType :: a -> CType casNothing :: a casNothing = error "casNothing impossible" casObliterate :: a -> ByteString -> Maybe ByteString casObliterate _ bs = Just bs instance CasType a => CasType (Maybe a) where getCas = Just <$> getCas putCas Nothing = return () putCas (Just a) = putCas a casType _ = CMaybe (casType (undefined :: a)) casNothing = Nothing casObliterate (Just a) bs = Just bs casObliterate Nothing _ = Nothing instance CasType ByteString where getCas = getByteString =<< remaining putCas = putByteString casType _ = CAscii instance CasType Int64 where getCas = fromIntegral <$> getWord64be putCas = putWord64be . fromIntegral casType _ = CBigint -- | If you wrap this round a 'ByteString', it will be treated as a /blob/ type -- instead of /ascii/ (if it was a plain 'ByteString' type). newtype Blob = Blob { unBlob :: ByteString } deriving (Eq, Ord, Show) instance CasType Blob where getCas = Blob <$> (getByteString =<< remaining) putCas (Blob bs) = putByteString bs casType _ = CBlob instance CasType Bool where getCas = (/= 0) <$> getWord8 putCas True = putWord8 1 putCas False = putWord8 0 casType _ = CBoolean -- | A Cassandra distributed counter value. newtype Counter = Counter { unCounter :: Int64 } deriving (Eq, Ord, Show, Read) instance CasType Counter where getCas = Counter . fromIntegral <$> getWord64be putCas (Counter c) = putWord64be (fromIntegral c) casType _ = CCounter instance CasType Integer where getCas = do ws <- B.unpack <$> (getByteString =<< remaining) return $ if null ws then 0 else let i = foldl' (\i w -> i `shiftL` 8 + fromIntegral w) 0 ws in if head ws >= 0x80 then i - 1 `shiftL` (length ws * 8) else i putCas i = putByteString . B.pack $ if i < 0 then encodeNeg $ positivize 0x80 i else encodePos i where encodePos :: Integer -> [Word8] encodePos i = reverse $ enc i where enc i | i == 0 = [0] enc i | i < 0x80 = [fromIntegral i] enc i = fromIntegral i : enc (i `shiftR` 8) encodeNeg :: Integer -> [Word8] encodeNeg i = reverse $ enc i where enc i | i == 0 = [] enc i | i < 0x100 = [fromIntegral i] enc i = fromIntegral i : enc (i `shiftR` 8) positivize :: Integer -> Integer -> Integer positivize bits i = case bits + i of i' | i' >= 0 -> i' + bits _ -> positivize (bits `shiftL` 8) i casType _ = CVarint instance CasType Decimal where getCas = Decimal <$> (fromIntegral . min 0xff <$> getWord32be) <*> getCas putCas (Decimal places mantissa) = do putWord32be (fromIntegral places) putCas mantissa casType _ = CDecimal instance CasType Double where getCas = unsafeCoerce <$> getWord64be putCas dbl = putWord64be (unsafeCoerce dbl) casType _ = CDouble instance CasType Float where getCas = unsafeCoerce <$> getWord32be putCas dbl = putWord32be (unsafeCoerce dbl) casType _ = CFloat epoch :: UTCTime epoch = UTCTime (fromGregorian 1970 1 1) 0 instance CasType UTCTime where getCas = do ms <- getWord64be let difft = realToFrac $ (fromIntegral ms :: Double) / 1000 return $ addUTCTime difft epoch putCas utc = do let seconds = realToFrac $ diffUTCTime utc epoch :: Double ms = round (seconds * 1000) :: Word64 putWord64be ms casType _ = CTimestamp instance CasType Int where getCas = fromIntegral <$> getWord32be putCas = putWord32be . fromIntegral casType _ = CInt instance CasType Text where getCas = T.decodeUtf8 <$> (getByteString =<< remaining) putCas = putByteString . T.encodeUtf8 casType _ = CText instance CasType UUID where getCas = do mUUID <- UUID.fromByteString . L.fromStrict <$> (getByteString =<< remaining) case mUUID of Just uuid -> return uuid Nothing -> fail "malformed UUID" putCas = putByteString . L.toStrict . UUID.toByteString casType _ = CUuid -- | If you wrap this round a 'UUID' then it is treated as a /timeuuid/ type instead of -- /uuid/ (if it was a plain 'UUID' type). newtype TimeUUID = TimeUUID { unTimeUUID :: UUID } deriving (Eq, Data, Ord, Read, Show, Typeable) instance CasType TimeUUID where getCas = TimeUUID <$> getCas putCas (TimeUUID uuid) = putCas uuid casType _ = CTimeuuid instance CasType SockAddr where getCas = do len <- remaining case len of 4 -> SockAddrInet 0 <$> getWord32le 16 -> do a <- getWord32be b <- getWord32be c <- getWord32be d <- getWord32be return $ SockAddrInet6 0 0 (a,b,c,d) 0 _ -> fail "malformed Inet" putCas sa = do case sa of SockAddrInet _ w -> putWord32le w SockAddrInet6 _ _ (a,b,c,d) _ -> putWord32be a >> putWord32be b >> putWord32be c >> putWord32be d _ -> fail $ "address type not supported in formatting Inet: " ++ show sa casType _ = CInet instance CasType a => CasType [a] where getCas = do n <- getWord16be replicateM (fromIntegral n) $ do len <- getWord16be bs <- getByteString (fromIntegral len) case decodeCas bs of Left err -> fail err Right x -> return x putCas xs = do putWord16be (fromIntegral $ length xs) forM_ xs $ \x -> do let bs = encodeCas x putWord16be (fromIntegral $ B.length bs) putByteString bs casType _ = CList (casType (undefined :: a)) instance (CasType a, Ord a) => CasType (Set a) where getCas = S.fromList <$> getCas putCas = putCas . S.toList casType _ = CSet (casType (undefined :: a)) instance (CasType a, Ord a, CasType b) => CasType (Map a b) where getCas = do n <- getWord16be items <- replicateM (fromIntegral n) $ do len_a <- getWord16be bs_a <- getByteString (fromIntegral len_a) a <- case decodeCas bs_a of Left err -> fail err Right x -> return x len_b <- getWord16be bs_b <- getByteString (fromIntegral len_b) b <- case decodeCas bs_b of Left err -> fail err Right x -> return x return (a,b) return $ M.fromList items putCas m = do let items = M.toList m putWord16be (fromIntegral $ length items) forM_ items $ \(a,b) -> do let bs_a = encodeCas a putWord16be (fromIntegral $ B.length bs_a) putByteString bs_a let bs_b = encodeCas b putWord16be (fromIntegral $ B.length bs_b) putByteString bs_b casType _ = CMap (casType (undefined :: a)) (casType (undefined :: b)) instance ProtoElt CType where putElt _ = error "formatting CType is not implemented" getElt = do op <- getWord16be case op of 0x0000 -> CCustom <$> getElt 0x0001 -> pure CAscii 0x0002 -> pure CBigint 0x0003 -> pure CBlob 0x0004 -> pure CBoolean 0x0005 -> pure CCounter 0x0006 -> pure CDecimal 0x0007 -> pure CDouble 0x0008 -> pure CFloat 0x0009 -> pure CInt --0x000a -> pure CVarchar -- Server seems to use CText even when 'varchar' is specified -- i.e. they're interchangeable in the CQL and always -- 'text' in the protocol. 0x000b -> pure CTimestamp 0x000c -> pure CUuid 0x000d -> pure CText 0x000e -> pure CVarint 0x000f -> pure CTimeuuid 0x0010 -> pure CInet 0x0020 -> CList <$> getElt 0x0021 -> CMap <$> getElt <*> getElt 0x0022 -> CSet <$> getElt _ -> fail $ "unknown data type code 0x"++showHex op "" instance ProtoElt Metadata where putElt _ = error "formatting Metadata is not implemented" getElt = do flags <- getWord32be colCount <- fromIntegral <$> getWord32be gtSpec <- if (flags .&. 1) /= 0 then Just <$> getElt else pure Nothing cols <- replicateM colCount $ do tSpec <- case gtSpec of Just spec -> pure spec Nothing -> getElt ColumnSpec tSpec <$> getElt <*> getElt return $ Metadata cols newtype PreparedQueryID = PreparedQueryID ByteString deriving (Eq, Ord, Show, ProtoElt) newtype QueryID = QueryID (Digest SHA1) deriving (Eq, Ord, Show) -- | The first type argument for Query. Tells us what kind of query it is. data Style = Schema -- ^ A query that modifies the schema, such as DROP TABLE or CREATE TABLE | Write -- ^ A query that writes data, such as an INSERT or UPDATE | Rows -- ^ A query that returns a list of rows, such as SELECT -- | The text of a CQL query, along with type parameters to make the query type safe. -- The type arguments are 'Style', followed by input and output column types for the -- query each represented as a tuple. -- -- The /DataKinds/ language extension is required for 'Style'. data Query :: Style -> * -> * -> * where Query :: QueryID -> Text -> Query style i o deriving Show queryText :: Query s i o -> Text queryText (Query _ txt) = txt instance IsString (Query style i o) where fromString = query . T.pack -- | Construct a query. Another way to construct one is as an overloaded string through -- the 'IsString' instance if you turn on the /OverloadedStrings/ language extension, e.g. -- -- > {-# LANGUAGE OverloadedStrings #-} -- > ... -- > -- > getOneSong :: Query Rows UUID (Text, Text, Maybe Text) -- > getOneSong = "select title, artist, comment from songs where id=?" query :: Text -> Query style i o query cql = Query (QueryID . hash . T.encodeUtf8 $ cql) cql data PreparedQuery = PreparedQuery PreparedQueryID Metadata deriving Show data Change = CREATED | UPDATED | DROPPED deriving (Eq, Ord, Show) instance ProtoElt Change where putElt _ = error $ "formatting Change is not implemented" getElt = do str <- getElt :: Get Text case str of "CREATED" -> pure CREATED "UPDATED" -> pure UPDATED "DROPPED" -> pure DROPPED _ -> fail $ "unexpected change string: "++show str -- | A low-level query result used with 'executeRaw'. data Result vs = Void | RowsResult Metadata [vs] | SetKeyspace Text | Prepared PreparedQueryID Metadata | SchemaChange Change Keyspace Table deriving Show instance Functor Result where f `fmap` Void = Void f `fmap` RowsResult meta rows = RowsResult meta (f `fmap` rows) f `fmap` SetKeyspace ks = SetKeyspace ks f `fmap` Prepared pqid meta = Prepared pqid meta f `fmap` SchemaChange ch ks t = SchemaChange ch ks t instance ProtoElt (Result [Maybe ByteString]) where putElt _ = error "formatting RESULT is not implemented" getElt = do kind <- getWord32be case kind of 0x0001 -> pure Void 0x0002 -> do meta@(Metadata colSpecs) <- getElt let colCount = length colSpecs rowCount <- fromIntegral <$> getWord32be rows <- replicateM rowCount $ replicateM colCount $ do len <- getWord32be if len == 0xffffffff then return Nothing else Just <$> getByteString (fromIntegral len) return $ RowsResult meta rows 0x0003 -> SetKeyspace <$> getElt 0x0004 -> Prepared <$> getElt <*> getElt 0x0005 -> SchemaChange <$> getElt <*> getElt <*> getElt _ -> fail $ "bad result kind: 0x"++showHex kind "" prepare :: Query style i o -> StateT ActiveSession IO PreparedQuery prepare (Query qid cql) = do cache <- gets actQueryCache case qid `M.lookup` cache of Just pq -> return pq Nothing -> do sendFrame $ Frame [] 0 PREPARE $ encodeElt (Long cql) fr <- recvFrame cql case frOpcode fr of RESULT -> do res <- decodeEltM "RESULT" (frBody fr) cql case (res :: Result [Maybe ByteString]) of Prepared pqid meta -> do let pq = PreparedQuery pqid meta modify $ \act -> act { actQueryCache = M.insert qid pq (actQueryCache act) } return pq _ -> throw $ LocalProtocolError ("prepare: unexpected result " `T.append` T.pack (show res)) cql ERROR -> throwError cql (frBody fr) _ -> throw $ LocalProtocolError ("prepare: unexpected opcode " `T.append` T.pack (show (frOpcode fr))) cql data CodingFailure = Mismatch Int CType CType | WrongNumber Int Int | DecodeFailure Int String | NullValue Int CType instance Show CodingFailure where show (Mismatch i t1 t2) = "at value index "++show (i+1)++", Haskell type specifies "++show t1++", but database metadata says "++show t2 show (WrongNumber i1 i2) = "wrong number of values: Haskell type specifies "++show i1++" but database metadata says "++show i2 show (DecodeFailure i why) = "failed to decode value index "++show (i+1)++": "++why show (NullValue i t) = "at value index "++show (i+1)++" received a null "++show t++" value but Haskell type is not a Maybe" class CasNested v where encodeNested :: Int -> v -> [CType] -> Either CodingFailure [Maybe ByteString] decodeNested :: Int -> [(CType, Maybe ByteString)] -> Either CodingFailure v countNested :: v -> Int instance CasNested () where encodeNested !i () [] = Right [] encodeNested !i () ts = Left $ WrongNumber i (i + length ts) decodeNested !i [] = Right () decodeNested !i vs = Left $ WrongNumber i (i + length vs) countNested _ = 0 instance (CasType a, CasNested rem) => CasNested (a, rem) where encodeNested !i (a, rem) (ta:trem) | ta `equivalent` casType a = case encodeNested (i+1) rem trem of Left err -> Left err Right brem -> Right $ ba : brem where ba = casObliterate a . encodeCas $ a encodeNested !i (a, _) (ta:_) = Left $ Mismatch i (casType a) ta encodeNested !i vs [] = Left $ WrongNumber (i + countNested vs) i decodeNested !i ((ta, mba):rem) | ta `equivalent` casType (undefined :: a) = case (decodeCas <$> mba, casType (undefined :: a), decodeNested (i+1) rem) of (Nothing, CMaybe _, Right arem) -> Right (casNothing, arem) (Nothing, _, _) -> Left $ NullValue i ta (Just (Left err), _, _) -> Left $ DecodeFailure i err (_, _, Left err) -> Left err (Just (Right a), _, Right arem) -> Right (a, arem) decodeNested !i ((ta, _):rem) = Left $ Mismatch i (casType (undefined :: a)) ta decodeNested !i [] = Left $ WrongNumber (i + 1 + countNested (undefined :: rem)) i countNested _ = let n = 1 + countNested (undefined :: rem) in seq n n -- | A type class for a tuple of 'CasType' instances, representing either a list of -- arguments for a query, or the values in a row of returned query results. class CasValues v where encodeValues :: v -> [CType] -> Either CodingFailure [Maybe ByteString] decodeValues :: [(CType, Maybe ByteString)] -> Either CodingFailure v instance CasValues () where encodeValues () types = encodeNested 0 () types decodeValues vs = decodeNested 0 vs instance CasType a => CasValues a where encodeValues a = encodeNested 0 (a, ()) decodeValues vs = (\(a, ()) -> a) <$> decodeNested 0 vs instance (CasType a, CasType b) => CasValues (a, b) where encodeValues (a, b) = encodeNested 0 (a, (b, ())) decodeValues vs = (\(a, (b, ())) -> (a, b)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c) => CasValues (a, b, c) where encodeValues (a, b, c) = encodeNested 0 (a, (b, (c, ()))) decodeValues vs = (\(a, (b, (c, ()))) -> (a, b, c)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d) => CasValues (a, b, c, d) where encodeValues (a, b, c, d) = encodeNested 0 (a, (b, (c, (d, ())))) decodeValues vs = (\(a, (b, (c, (d, ())))) -> (a, b, c, d)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e) => CasValues (a, b, c, d, e) where encodeValues (a, b, c, d, e) = encodeNested 0 (a, (b, (c, (d, (e, ()))))) decodeValues vs = (\(a, (b, (c, (d, (e, ()))))) -> (a, b, c, d, e)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f) => CasValues (a, b, c, d, e, f) where encodeValues (a, b, c, d, e, f) = encodeNested 0 (a, (b, (c, (d, (e, (f, ())))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, ())))))) -> (a, b, c, d, e, f)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g) => CasValues (a, b, c, d, e, f, g) where encodeValues (a, b, c, d, e, f, g) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, ()))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, ()))))))) -> (a, b, c, d, e, f, g)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g, CasType h) => CasValues (a, b, c, d, e, f, g, h) where encodeValues (a, b, c, d, e, f, g, h) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, (h, ())))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, (h, ())))))))) -> (a, b, c, d, e, f, g, h)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g, CasType h, CasType i) => CasValues (a, b, c, d, e, f, g, h, i) where encodeValues (a, b, c, d, e, f, g, h, i) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, (h, (i, ()))))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, (h, (i, ()))))))))) -> (a, b, c, d, e, f, g, h, i)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g, CasType h, CasType i, CasType j) => CasValues (a, b, c, d, e, f, g, h, i, j) where encodeValues (a, b, c, d, e, f, g, h, i, j) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, (h, (i, (j, ())))))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, (h, (i, (j, ())))))))))) -> (a, b, c, d, e, f, g, h, i, j)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g, CasType h, CasType i, CasType j, CasType k) => CasValues (a, b, c, d, e, f, g, h, i, j, k) where encodeValues (a, b, c, d, e, f, g, h, i, j, k) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, ()))))))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, ()))))))))))) -> (a, b, c, d, e, f, g, h, i, j, k)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g, CasType h, CasType i, CasType j, CasType k, CasType l) => CasValues (a, b, c, d, e, f, g, h, i, j, k, l) where encodeValues (a, b, c, d, e, f, g, h, i, j, k, l) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, ())))))))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, ())))))))))))) -> (a, b, c, d, e, f, g, h, i, j, k, l)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g, CasType h, CasType i, CasType j, CasType k, CasType l, CasType m) => CasValues (a, b, c, d, e, f, g, h, i, j, k, l, m) where encodeValues (a, b, c, d, e, f, g, h, i, j, k, l, m) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, ()))))))))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, ()))))))))))))) -> (a, b, c, d, e, f, g, h, i, j, k, l, m)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g, CasType h, CasType i, CasType j, CasType k, CasType l, CasType m, CasType n) => CasValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n) where encodeValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, ())))))))))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, ())))))))))))))) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g, CasType h, CasType i, CasType j, CasType k, CasType l, CasType m, CasType n, CasType o) => CasValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) where encodeValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, (o, ()))))))))))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, (o, ()))))))))))))))) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g, CasType h, CasType i, CasType j, CasType k, CasType l, CasType m, CasType n, CasType o, CasType p) => CasValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p) where encodeValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, (o, (p, ())))))))))))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, (o, (p, ())))))))))))))))) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g, CasType h, CasType i, CasType j, CasType k, CasType l, CasType m, CasType n, CasType o, CasType p, CasType q) => CasValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q) where encodeValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, (o, (p, (q, ()))))))))))))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, (o, (p, (q, ()))))))))))))))))) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g, CasType h, CasType i, CasType j, CasType k, CasType l, CasType m, CasType n, CasType o, CasType p, CasType q, CasType r) => CasValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r) where encodeValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, (o, (p, (q, (r, ())))))))))))))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, (o, (p, (q, (r, ())))))))))))))))))) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g, CasType h, CasType i, CasType j, CasType k, CasType l, CasType m, CasType n, CasType o, CasType p, CasType q, CasType r, CasType s) => CasValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s) where encodeValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, (o, (p, (q, (r, (s, ()))))))))))))))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, (o, (p, (q, (r, (s, ()))))))))))))))))))) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s)) <$> decodeNested 0 vs instance (CasType a, CasType b, CasType c, CasType d, CasType e, CasType f, CasType g, CasType h, CasType i, CasType j, CasType k, CasType l, CasType m, CasType n, CasType o, CasType p, CasType q, CasType r, CasType s, CasType t) => CasValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t) where encodeValues (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t) = encodeNested 0 (a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, (o, (p, (q, (r, (s, (t, ())))))))))))))))))))) decodeValues vs = (\(a, (b, (c, (d, (e, (f, (g, (h, (i, (j, (k, (l, (m, (n, (o, (p, (q, (r, (s, (t, ())))))))))))))))))))) -> (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t)) <$> decodeNested 0 vs -- | Cassandra consistency level. See the Cassandra documentation for an explanation. data Consistency = ANY | ONE | TWO | THREE | QUORUM | ALL | LOCAL_QUORUM | EACH_QUORUM deriving (Eq, Ord, Show, Bounded, Enum) instance ProtoElt Consistency where putElt c = putWord16be $ case c of ANY -> 0x0000 ONE -> 0x0001 TWO -> 0x0002 THREE -> 0x0003 QUORUM -> 0x0004 ALL -> 0x0005 LOCAL_QUORUM -> 0x0006 EACH_QUORUM -> 0x0007 getElt = do w <- getWord16be case w of 0x0000 -> pure ANY 0x0001 -> pure ONE 0x0002 -> pure TWO 0x0003 -> pure THREE 0x0004 -> pure QUORUM 0x0005 -> pure ALL 0x0006 -> pure LOCAL_QUORUM 0x0007 -> pure EACH_QUORUM _ -> fail $ "unknown consistency value 0x"++showHex w "" -- | A low-level function in case you need some rarely-used capabilities. executeRaw :: (MonadCassandra m, CasValues i) => Query style any_i any_o -> i -> Consistency -> m (Result [Maybe ByteString]) executeRaw query i cons = withSession $ \_ -> executeInternal query i cons executeInternal :: CasValues values => Query style any_i any_o -> values -> Consistency -> StateT ActiveSession IO (Result [Maybe ByteString]) executeInternal query i cons = do pq@(PreparedQuery pqid queryMeta) <- prepare query values <- case encodeValues i (metadataTypes queryMeta) of Left err -> throw $ ValueMarshallingException TransportSending (T.pack $ show err) (queryText query) Right values -> return values sendFrame $ Frame [] 0 EXECUTE $ runPut $ do putElt pqid putWord16be (fromIntegral $ length values) forM_ values $ \mValue -> case mValue of Nothing -> putWord32be 0xffffffff Just value -> do let enc = encodeCas value putWord32be (fromIntegral $ B.length enc) putByteString enc putElt cons fr <- recvFrame (queryText query) case frOpcode fr of RESULT -> decodeEltM "RESULT" (frBody fr) (queryText query) ERROR -> throwError (queryText query) (frBody fr) _ -> throw $ LocalProtocolError ("execute: unexpected opcode " `T.append` T.pack (show (frOpcode fr))) (queryText query) -- | Execute a query that returns rows. executeRows :: (MonadCassandra m, CasValues i, CasValues o) => Consistency -> Query Rows i o -- ^ CQL query to execute -> i -- ^ Input values substituted in the query -> m [o] executeRows cons q i = do res <- executeRaw q i cons case res of RowsResult meta rows -> decodeRows q meta rows _ -> throw $ LocalProtocolError ("expected Rows, but got " `T.append` T.pack (show res)) (queryText q) -- | Helper for 'executeRows' useful in situations where you are only expecting one row -- to be returned. executeRow :: (MonadCassandra m, CasValues i, CasValues o) => Consistency -> Query Rows i o -- ^ CQL query to execute -> i -- ^ Input values substituted in the query -> m (Maybe o) executeRow cons q i = do rows <- executeRows cons q i return $ listToMaybe rows decodeRows :: (MonadCatchIO m, CasValues values) => Query Rows any_i values -> Metadata -> [[Maybe ByteString]] -> m [values] decodeRows query meta rows0 = do let rows1 = flip map rows0 $ \cols -> decodeValues (zip (metadataTypes meta) cols) case lefts rows1 of (err:_) -> throw $ ValueMarshallingException TransportReceiving (T.pack $ show err) (queryText query) [] -> return () let rows2 = flip map rows1 $ \(Right v) -> v return $ rows2 -- | Execute a write operation that returns void. executeWrite :: (MonadCassandra m, CasValues i) => Consistency -> Query Write i () -- ^ CQL query to execute -> i -- ^ Input values substituted in the query -> m () executeWrite cons q i = do res <- executeRaw q i cons case res of Void -> return () _ -> throw $ LocalProtocolError ("expected Void, but got " `T.append` T.pack (show res)) (queryText q) -- | Execute a schema change, such as creating or dropping a table. executeSchema :: (MonadCassandra m, CasValues i) => Consistency -> Query Schema i () -- ^ CQL query to execute -> i -- ^ Input values substituted in the query -> m (Change, Keyspace, Table) executeSchema cons q i = do res <- executeRaw q i cons case res of SchemaChange ch ks ta -> return (ch, ks, ta) _ -> throw $ LocalProtocolError ("expected SchemaChange, but got " `T.append` T.pack (show res)) (queryText q) -- | A helper for extracting the types from a metadata definition. metadataTypes :: Metadata -> [CType] metadataTypes (Metadata colspecs) = map (\(ColumnSpec _ _ typ) -> typ) colspecs -- | The monad used to run Cassandra queries in. newtype Cas a = Cas (ReaderT Pool IO a) deriving (Functor, Applicative, Monad, MonadIO, MonadCatchIO) instance MonadCassandra Cas where getCassandraPool = Cas ask -- | Execute Cassandra queries. runCas :: Pool -> Cas a -> IO a runCas pool (Cas code) = runReaderT code pool