Network.GRPC.Client

A module adding support for gRPC over HTTP2.

Building blocks.

data RPC s (m :: Symbol)

A proxy type for giving static information about RPCs.

Constructors

RPC

type Authority = ByteString

The HTTP2-Authority portion of an URL (e.g., "dicioccio.fr:7777").

newtype Timeout

Timeout in seconds.

Constructors

Timeout Int

open

Arguments

:: (Service s, HasMethod s m)

=> RPC s m

A token carrying information specifying the RPC to call.

-> Http2Client

A connected HTTP2 client.

-> Authority

The HTTP2-Authority portion of the URL (e.g., "dicioccio.fr:7777").

-> HeaderList

A set of HTTP2 headers (e.g., for adding authentication headers).

-> Timeout

Timeout in seconds.

-> Compression

An indication of the compression that you will be using and accepting. Compression should be per message, however a bug in gRPC-Go (to be confirmed) seems to turn message compression mandatory if advertised in the HTTP2 headers, even though the specification states that compression per message is optional irrespectively of headers.

-> RPCCall a

The actual RPC handler.

-> IO (Either TooMuchConcurrency a)

Main handler to perform gRPC calls to a service.

type RawReply a = Either ErrorCode (HeaderList, Maybe HeaderList, Either String a)

A reply.

This reply object contains a lot of information because a single gRPC call returns a lot of data. A future version of the library will have a proper data structure with properly named-fields on the reply object.

For now, remember: - 1st item: initial HTTP2 response - 2nd item: second (trailers) HTTP2 response - 3rd item: proper gRPC answer

Helpers

singleRequest :: (Service s, HasMethod s m) => RPC s m -> Compression -> MethodInput s m -> RPCCall (RawReply (MethodOutput s m))

gRPC call for an unary request.

streamReply :: (Service s, HasMethod s m, MethodStreamingType s m ~ ServerStreaming) => RPC s m -> Compression -> MethodInput s m -> (HeaderList -> Either String (MethodOutput s m) -> IO ()) -> RPCCall (HeaderList, HeaderList)

gRPC call for Server Streaming.

streamRequest :: (Service s, HasMethod s m, MethodStreamingType s m ~ ClientStreaming) => RPC s m -> IO (Compression, Either StreamDone (MethodInput s m)) -> RPCCall (RawReply (MethodOutput s m))

gRPC call for Client Streaming.

data StreamDone

Constructors

StreamDone

Errors.

data InvalidState

Exception raised when a ServerStreaming RPC results in an invalid state machine.

Constructors

InvalidState String

Instances

Show InvalidState

Defined in Network.GRPC.Client

Methods

showsPrec :: Int -> InvalidState -> ShowS

show :: InvalidState -> String

showList :: [InvalidState] -> ShowS

Exception InvalidState

Defined in Network.GRPC.Client

Methods

toException :: InvalidState -> SomeException

fromException :: SomeException -> Maybe InvalidState

displayException :: InvalidState -> String

data StreamReplyDecodingError

Exception raised when a ServerStreaming RPC results in a decoding error.

Constructors

StreamReplyDecodingError String

Instances

Show StreamReplyDecodingError

Defined in Network.GRPC.Client

Methods

showsPrec :: Int -> StreamReplyDecodingError -> ShowS

show :: StreamReplyDecodingError -> String

showList :: [StreamReplyDecodingError] -> ShowS

Exception StreamReplyDecodingError

Defined in Network.GRPC.Client

Methods

toException :: StreamReplyDecodingError -> SomeException

fromException :: SomeException -> Maybe StreamReplyDecodingError

displayException :: StreamReplyDecodingError -> String

data UnallowedPushPromiseReceived

gRPC disables HTTP2 push-promises.

If a server attempts to send push-promises, this exception will be raised.

Constructors

UnallowedPushPromiseReceived

Instances

Show UnallowedPushPromiseReceived

Defined in Network.GRPC.Client

Methods

showsPrec :: Int -> UnallowedPushPromiseReceived -> ShowS

show :: UnallowedPushPromiseReceived -> String

showList :: [UnallowedPushPromiseReceived] -> ShowS

Exception UnallowedPushPromiseReceived

Defined in Network.GRPC.Client

Methods

toException :: UnallowedPushPromiseReceived -> SomeException

fromException :: SomeException -> Maybe UnallowedPushPromiseReceived

displayException :: UnallowedPushPromiseReceived -> String

Compression of individual messages.

data Compression

Opaque type for handling compression.

So far, only "pure" compression algorithms are supported. TODO: suport IO-based compression implementations once we move from Builder.

gzip :: Compression

Use gzip as compression.

uncompressed :: Compression

Do not compress.