Capnp.Rpc.Server

Documentation

type CallHandler = Map Word64 (Vector UntypedMethodHandler)

A handler for arbitrary RPC calls. Maps (interfaceId, methodId) pairs to UntypedMethodHandlers.

type MethodHandler p r = Raw p 'Const -> Fulfiller (Raw r 'Const) -> IO ()

Type alias for a handler for a particular rpc method.

type UntypedMethodHandler = MethodHandler (Maybe AnyPointer) (Maybe AnyPointer)

Type alias for a handler for an untyped RPC method.

data CallInfo

A CallInfo contains information about a method call.

Constructors

CallInfo

Fields

• interfaceId :: !Word64

  The id of the interface whose method is being called.

• methodId :: !Word16

  The method id of the method being called.

• arguments :: Maybe (Ptr 'Const)

  The arguments to the method call.

• response :: Fulfiller (Maybe (Ptr 'Const))

  A Fulfiller which accepts the method's return value.

data ServerOps

The operations necessary to receive and handle method calls, i.e. to implement an object.

Constructors

ServerOps

Fields

• handleCall :: Word64 -> Word16 -> UntypedMethodHandler

  Handle a method call; takes the interface and method id and returns a handler for the specific method.

• handleStop :: IO ()

  Handle shutting-down the receiver; this is called when the last reference to the capability is dropped.

• handleCast :: forall a. Typeable a => Maybe a

  used to unwrap the server when reflecting on a local client.

class (IsCap i, HasTypeId i) => Export i where

Generated interface types have instances of Export, which allows a server for that interface to be exported as a Client.

Associated Types

type Server i :: Type -> Constraint

The constraint needed for a server to implement an interface; if Server i s is satisfied, s is a server for interface i. The code generator generates a type class for each interface, and this will aways be an alias for that type class.

Methods

methodHandlerTree :: Server i s => Proxy i -> s -> MethodHandlerTree

Convert the server to a MethodHandlerTree populated with appropriate MethodHandlers for the interface. This is really only exported for use by generated code; users of the library will generally prefer to use export.

Instances

(TypeParam sturdyRef, TypeParam owner) => Export (Persistent sturdyRef owner)

Defined in Capnp.Gen.Capnp.Persistent

Associated Types

type Server (Persistent sturdyRef owner) :: Type -> Constraint

Methods

methodHandlerTree :: Server (Persistent sturdyRef owner) s => Proxy (Persistent sturdyRef owner) -> s -> MethodHandlerTree

(TypeParam internalRef, TypeParam externalRef, TypeParam internalOwner, TypeParam externalOwner) => Export (RealmGateway internalRef externalRef internalOwner externalOwner)

Defined in Capnp.Gen.Capnp.Persistent

Associated Types

type Server (RealmGateway internalRef externalRef internalOwner externalOwner) :: Type -> Constraint

Methods

methodHandlerTree :: Server (RealmGateway internalRef externalRef internalOwner externalOwner) s => Proxy (RealmGateway internalRef externalRef internalOwner externalOwner) -> s -> MethodHandlerTree

exportToServerOps :: forall i s. (Export i, Server i s, SomeServer s) => Proxy i -> s -> ServerOps

findMethod :: Word64 -> Word16 -> CallHandler -> Maybe UntypedMethodHandler

Look up a particlar MethodHandler in the CallHandler.

class SomeServer a where

Base class for things that can act as capnproto servers.

Minimal complete definition

Nothing

Methods

shutdown :: a -> IO ()

Called when the last live reference to a server is dropped.

unwrap :: Typeable b => a -> Maybe b

Try to extract a value of a given type. The default implementation always fails (returns Nothing). If an instance chooses to implement this, it will be possible to use "reflection" on clients that point at local servers to dynamically unwrap the server value. A typical implementation will just call Typeable's cast method, but this needn't be the case -- a server may wish to allow local peers to unwrap some value that is not exactly the data the server has access to.

runServer :: Q CallInfo -> ServerOps -> IO ()

Handle incoming messages for a given object.

Accepts a queue of messages to handle, and ServerOps used to handle them. returns when it receives a Stop message.

castHandler :: forall p q r s. (ReprFor p ~ ReprFor q, ReprFor r ~ ReprFor s) => MethodHandler p r -> MethodHandler q s

Helpers for writing method handlers

handleParsed :: (Parse p pp, IsStruct p, Parse r pr, IsStruct r) => (pp -> IO pr) -> MethodHandler p r

Handle a method, working with the parsed form of parameters and results.

handleRaw :: (IsStruct p, IsStruct r) => (Raw p 'Const -> IO (Raw r 'Const)) -> MethodHandler p r

Handle a method, working with the raw (unparsed) form of parameters and results.

methodUnimplemented :: MethodHandler p r

MethodHandler that always throws unimplemented.

toUntypedMethodHandler :: forall p r. (IsStruct p, IsStruct r) => MethodHandler p r -> UntypedMethodHandler

Convert a typed method handler to an untyped one. Mostly intended for use by generated code.

Internals; exposed only for use by generated code.

data MethodHandlerTree

Lazily computed tree of the method handlers exposed by an interface. Only of interest to generated code.

Constructors

MethodHandlerTree

Fields

• mhtId :: Word64

  type id for the primary interface

• mhtHandlers :: [UntypedMethodHandler]

  method handlers for methods of the primary interface.

• mhtParents :: [MethodHandlerTree]

  Trees for parent interfaces. In the case of diamond dependencies, there may be duplicates, which are eliminated by mhtToCallHandler.