PostgRESTWS.Broadcast

This module provides a type called Multiplexer. The multiplexer contains a map of channels and a producer thread.

This module avoids any database implementation details, it is used by HasqlBroadcast where the database logic is combined.

Documentation

data Multiplexer

data Message

Constructors

Message

Fields

• channel :: ByteString
• payload :: ByteString

Instances

Eq Message

Methods

(==) :: Message -> Message -> Bool

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

Show Message

Methods

showsPrec :: Int -> Message -> ShowS

show :: Message -> String

showList :: [Message] -> ShowS

data SourceCommands

Constructors

Open ByteString

Close ByteString

Instances

Show SourceCommands

Methods

showsPrec :: Int -> SourceCommands -> ShowS

show :: SourceCommands -> String

showList :: [SourceCommands] -> ShowS

newMultiplexer :: (TQueue SourceCommands -> TQueue Message -> IO a) -> (Either SomeException a -> IO ()) -> IO Multiplexer

onMessage :: Multiplexer -> ByteString -> (TChan Message -> IO ()) -> IO ()

Adds a listener to a certain multiplexer's channel. The listener must be a function that takes a 'TChan Message' and perform any IO action. All listeners run in their own thread. The first listener will open the channel, when a listener dies it will check if there acquire any others and close the channel when that's the case.

relayMessages :: Multiplexer -> IO ()

Reads the messages from the producer and relays them to the active listeners in their respective channels.

relayMessagesForever :: Multiplexer -> IO ThreadId

Opens a thread that relays messages from the producer thread to the channels forever

openChannelProducer :: Multiplexer -> ByteString -> STM ()

Open a multiplexer's channel

closeChannelProducer :: Multiplexer -> ByteString -> STM ()

Close a multiplexer's channel

Re-exports

readTQueue :: TQueue a -> STM a

Read the next value from the TQueue.

writeTQueue :: TQueue a -> a -> STM ()

Write a value to a TQueue.

readTChan :: TChan a -> STM a

Read the next value from the TChan.