Network.GRPC.Server.Handlers

Documentation

type UnaryHandler i o = Request -> i -> IO o

Handy type to refer to Handler for unary RPCs handler.

type ServerStreamHandler i o a = Request -> i -> IO (a, ServerStream o a)

Handy type for 'server-streaming' RPCs.

We expect an implementation to: - read the input request - return an initial state and an state-passing action that the server code will call to fetch the output to send to the client (or close an a Nothing) See ServerStream for the type which embodies these requirements.

newtype ServerStream o a

Constructors

ServerStream

Fields

• serverStreamNext :: a -> IO (Maybe (a, o))

type ClientStreamHandler i o a = Request -> IO (a, ClientStream i o a)

Handy type for 'client-streaming' RPCs.

We expect an implementation to: - acknowledge a the new client stream by returning an initial state and two functions: - a state-passing handler for new client message - a state-aware handler for answering the client when it is ending its stream See ClientStream for the type which embodies these requirements.

data ClientStream i o a

Constructors

ClientStream

Fields

• clientStreamHandler :: a -> i -> IO a
• clientStreamFinalizer :: a -> IO o

type BiDiStreamHandler i o a = Request -> IO (a, BiDiStream i o a)

Handy type for 'bidirectional-streaming' RPCs.

We expect an implementation to: - acknowlege a new bidirection stream by returning an initial state and one functions: - a state-passing function that returns a single action step The action may be to - stop immediately - wait and handle some input with a callback and a finalizer (if the client closes the stream on its side) that may change the state - return a value and a new state

There is no way to stop locally (that would mean sending HTTP2 trailers) and keep receiving messages from the client.

data BiDiStep i o a

Constructors

Abort

WaitInput !(a -> i -> IO a) !(a -> IO a)

WriteOutput !a o

newtype BiDiStream i o a

Constructors

BiDiStream

Fields

• bidirNextStep :: a -> IO (BiDiStep i o a)

unary :: (GRPCInput r i, GRPCOutput r o) => r -> UnaryHandler i o -> ServiceHandler

Construct a handler for handling a unary RPC.

serverStream :: (GRPCInput r i, GRPCOutput r o) => r -> ServerStreamHandler i o a -> ServiceHandler

Construct a handler for handling a server-streaming RPC.

clientStream :: (GRPCInput r i, GRPCOutput r o) => r -> ClientStreamHandler i o a -> ServiceHandler

Construct a handler for handling a client-streaming RPC.

bidiStream :: (GRPCInput r i, GRPCOutput r o) => r -> BiDiStreamHandler i o a -> ServiceHandler

Construct a handler for handling a bidirectional-streaming RPC.

generalStream :: (GRPCInput r i, GRPCOutput r o) => r -> GeneralStreamHandler i o a b -> ServiceHandler

Construct a handler for handling a bidirectional-streaming RPC.

handleUnary :: (GRPCInput r i, GRPCOutput r o) => r -> UnaryHandler i o -> WaiHandler

Handle unary RPCs.

handleServerStream :: (GRPCInput r i, GRPCOutput r o) => r -> ServerStreamHandler i o a -> WaiHandler

Handle Server-Streaming RPCs.

handleClientStream :: (GRPCInput r i, GRPCOutput r o) => r -> ClientStreamHandler i o a -> WaiHandler

Handle Client-Streaming RPCs.

handleBiDiStream :: (GRPCInput r i, GRPCOutput r o) => r -> BiDiStreamHandler i o a -> WaiHandler

Handle Bidirectional-Streaming RPCs.

type GeneralStreamHandler i o a b = Request -> IO (a, IncomingStream i a, b, OutgoingStream o b)

A GeneralStreamHandler combining server and client asynchronous streams.

data IncomingStream i a

Pair of handlers for reacting to incoming messages.

Constructors

IncomingStream

Fields

• incomingStreamHandler :: a -> i -> IO a
• incomingStreamFinalizer :: a -> IO ()

newtype OutgoingStream o a

Handler to decide on the next message (if any) to return.

Constructors

OutgoingStream

Fields

• outgoingStreamNext :: a -> IO (Maybe (a, o))

handleGeneralStream :: (GRPCInput r i, GRPCOutput r o) => r -> GeneralStreamHandler i o a b -> WaiHandler

Handler for the somewhat general case where two threads behave concurrently: - one reads messages from the client - one returns messages to the client

handleRequestChunksLoop

Arguments

:: Decoder (Either String a)

Message decoder.

-> (ByteString -> a -> IO b)

Handler for a single message. The ByteString corresponds to leftover data.

-> IO b

Handler for handling end-of-streams.

-> IO ByteString

Action to retrieve the next chunk.

-> IO b

Helpers to consume input in chunks.

errorOnLeftOver :: (a -> IO b) -> ByteString -> a -> IO b

Combinator around message handler to error on left overs.

This combinator ensures that, unless for client stream, an unparsed piece of data with a correctly-read message is treated as an error.