Safe Haskell	None
Language	Haskell2010

Network.AMQP.Worker.Message

Synopsis

data Message a = Message {
- body :: ByteString
- value :: a
}
publish :: (RequireRoute a, ToJSON msg, MonadIO m) => Connection -> Key a msg -> msg -> m ()
publishToExchange :: (RequireRoute a, ToJSON msg, MonadIO m) => Connection -> Key a msg -> msg -> m ()
takeMessage :: (MonadIO m, FromJSON a) => Connection -> Queue a -> m (Message a)
worker :: (FromJSON a, MonadIO m) => Connection -> Queue a -> (Message a -> m ()) -> m ()
consumeNext :: (FromJSON msg, MonadIO m) => Microseconds -> Connection -> Queue msg -> m (ConsumeResult msg)
consume :: (FromJSON msg, MonadIO m) => Connection -> Queue msg -> m (Maybe (ConsumeResult msg))
data ConsumeResult a
- = Parsed (Message a)
- | Error ParseError
data ParseError = ParseError String ByteString
type Microseconds = Int

Documentation

data Message a Source #

a parsed message from the queue

Constructors

Message
Fields body :: ByteString value :: a

Instances

Instances details

Show a => Show (Message a) Source #
Instance details Defined in Network.AMQP.Worker.Message Methods showsPrec :: Int -> Message a -> ShowS # show :: Message a -> String # showList :: [Message a] -> ShowS #
Eq a => Eq (Message a) Source #
Instance details Defined in Network.AMQP.Worker.Message Methods (==) :: Message a -> Message a -> Bool # (/=) :: Message a -> Message a -> Bool #

publish :: (RequireRoute a, ToJSON msg, MonadIO m) => Connection -> Key a msg -> msg -> m () Source #

send a message to a queue. Enforces that the message type and queue name are correct at the type level

let newUsers = key "users" & word "new":: Key Route User
publish conn newUsers (User "username")

Publishing to a Binding Key results in an error

-- Compiler error! This doesn't make sense
let users = key "users" & many :: Key Binding User
publish conn users (User "username")

publishToExchange :: (RequireRoute a, ToJSON msg, MonadIO m) => Connection -> Key a msg -> msg -> m () Source #

publish a message to a routing key, without making sure a queue exists to handle it

publishToExchange conn key (User "username")

takeMessage :: (MonadIO m, FromJSON a) => Connection -> Queue a -> m (Message a) Source #

worker :: (FromJSON a, MonadIO m) => Connection -> Queue a -> (Message a -> m ()) -> m () Source #

Create a worker which loops and handles messages

Worker.worker conn queue $ \m -> do
  print (value m)

consumeNext :: (FromJSON msg, MonadIO m) => Microseconds -> Connection -> Queue msg -> m (ConsumeResult msg) Source #

Block while checking for messages every N microseconds. Return once you find one.

res <- consumeNext conn queue
case res of
  (Parsed m) -> print m
  (Error e) -> putStrLn "could not parse message"

consume :: (FromJSON msg, MonadIO m) => Connection -> Queue msg -> m (Maybe (ConsumeResult msg)) Source #

Check for a message once and attempt to parse it

res <- consume conn queue
case res of
  Just (Parsed m) -> print m
  Just (Error e) -> putStrLn "could not parse message"
  Nothing -> putStrLn "No messages on the queue"

data ConsumeResult a Source #

Constructors

Parsed (Message a)
Error ParseError

data ParseError Source #

Constructors

ParseError String ByteString

Instances

Instances details

Exception ParseError Source #
Instance details Defined in Network.AMQP.Worker.Message Methods toException :: ParseError -> SomeException # fromException :: SomeException -> Maybe ParseError # displayException :: ParseError -> String # backtraceDesired :: ParseError -> Bool #
Show ParseError Source #
Instance details Defined in Network.AMQP.Worker.Message Methods showsPrec :: Int -> ParseError -> ShowS # show :: ParseError -> String # showList :: [ParseError] -> ShowS #

type Microseconds = Int Source #