diff --git a/CHANGELOG.md b/CHANGELOG.md new file mode 100644 --- /dev/null +++ b/CHANGELOG.md @@ -0,0 +1,5 @@ +# Revision history for mu-haskell + +## 0.1.0.0 -- YYYY-mm-dd + +* First version. Released on an unsuspecting world. diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,202 @@ + + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. Definitions. + + "License" shall mean the terms and conditions for use, reproduction, + and distribution as defined by Sections 1 through 9 of this document. + + "Licensor" shall mean the copyright owner or entity authorized by + the copyright owner that is granting the License. + + "Legal Entity" shall mean the union of the acting entity and all + other entities that control, are controlled by, or are under common + control with that entity. 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We also recommend that a + file or class name and description of purpose be included on the + same "printed page" as the copyright notice for easier + identification within third-party archives. + + Copyright © 2019-2020 47 Degrees. + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. diff --git a/Setup.hs b/Setup.hs new file mode 100644 --- /dev/null +++ b/Setup.hs @@ -0,0 +1,2 @@ +import Distribution.Simple +main = defaultMain diff --git a/exe/ExampleServer.hs b/exe/ExampleServer.hs new file mode 100644 --- /dev/null +++ b/exe/ExampleServer.hs @@ -0,0 +1,46 @@ +{-# language DataKinds #-} +{-# language OverloadedStrings #-} +{-# language PartialTypeSignatures #-} +{-# language TypeApplications #-} +{-# language TypeFamilies #-} + +module Main where + +import qualified Data.Text.IO as Text +import Mu.Rpc.Annotations +import Mu.Rpc.Examples +import Mu.Schema.Annotations +import Mu.Servant.Server +import Mu.Server +import Network.Wai.Handler.Warp +import Servant + +main :: IO () +main = do + putStrLn "running quickstart application" + Text.putStrLn $ layout quickstartAPI + run 8081 (serve quickstartAPI servantServer) + +servantServer :: _ +servantServer = servantServerHandlers toHandler quickstartServer + +quickstartAPI :: Proxy _ +quickstartAPI = packageAPI (quickstartServer @ServerErrorIO) + +type instance + AnnotatedPackage ServantRoute QuickStartService = + '[ 'AnnService "Greeter" ('ServantTopLevelRoute '["greet"]), + 'AnnMethod "Greeter" "SayHello" + ('ServantRoute '["say", "hello"] 'POST 200), + 'AnnMethod "Greeter" "SayHi" + ('ServantRoute '["say", "hi"] 'POST 200), + 'AnnMethod "Greeter" "SayManyHellos" + ('ServantRoute '["say", "many", "hellos"] 'POST 200) + ] + +type instance + AnnotatedSchema ServantContentTypes QuickstartSchema = + '[ 'AnnType "HelloRequest" DefaultServantContentTypes, + 'AnnType "HelloResponse" DefaultServantContentTypes, + 'AnnType "HiRequest" DefaultServantContentTypes + ] diff --git a/mu-servant-server.cabal b/mu-servant-server.cabal new file mode 100644 --- /dev/null +++ b/mu-servant-server.cabal @@ -0,0 +1,61 @@ +name: mu-servant-server +version: 0.4.0.0 +synopsis: Servant servers for Mu definitions +description: + With @mu-servant-server@ you can easily build Servant servers for mu-haskell! + +license: Apache-2.0 +license-file: LICENSE +author: Andre Marianiello +maintainer: alejandro.serrano@47deg.com +copyright: Copyright © 2019-2020 +cabal-version: >=1.10 +category: Network +build-type: Simple +extra-source-files: CHANGELOG.md +homepage: https://higherkindness.io/mu-haskell/ +bug-reports: https://github.com/higherkindness/mu-haskell/issues + +source-repository head + type: git + location: https://github.com/higherkindness/mu-haskell + +library + exposed-modules: Mu.Servant.Server + build-depends: + aeson >=1.4 && <2 + , async >=2.2 && < 3 + , base >=4.12 && <5 + , conduit >=1.3.2 && <2 + , generic-aeson >=0.2 && <0.3 + , ghc-prim >=0.5 && <0.7 + , mtl >=2.2 && <3 + , mu-rpc ==0.4.* + , mu-schema ==0.3.* + , servant >=0.16 && <0.19 + , servant-server >=0.16 && <0.19 + , servant-swagger >=1.1.7 && <2 + , stm >=2.5 && <3 + , swagger2 >=2.5 && <3 + , utf8-string >=1 && <2 + + hs-source-dirs: src + default-language: Haskell2010 + ghc-options: -Wall -fprint-potential-instances + +executable servant-example-server + main-is: ExampleServer.hs + build-depends: + aeson >=1.4 && <2 + , base >=4.12 && <5 + , conduit >=1.3.2 && <2 + , mu-rpc ==0.4.* + , mu-schema ==0.3.* + , mu-servant-server + , servant-server >=0.16 && <0.19 + , text >=1.2 && <2 + , warp >=3.3 && <4 + + hs-source-dirs: exe + default-language: Haskell2010 + ghc-options: -Wall -fprint-explicit-kinds -fprint-explicit-foralls diff --git a/src/Mu/Servant/Server.hs b/src/Mu/Servant/Server.hs new file mode 100644 --- /dev/null +++ b/src/Mu/Servant/Server.hs @@ -0,0 +1,509 @@ +{-# language ConstraintKinds #-} +{-# language DataKinds #-} +{-# language DeriveGeneric #-} +{-# language FlexibleContexts #-} +{-# language FlexibleInstances #-} +{-# language GADTs #-} +{-# language MultiParamTypeClasses #-} +{-# language PolyKinds #-} +{-# language RankNTypes #-} +{-# language ScopedTypeVariables #-} +{-# language TypeApplications #-} +{-# language TypeFamilies #-} +{-# language TypeOperators #-} +{-# language UndecidableInstances #-} + +{-| +Description : Execute a Mu 'Server' using Servant + +This module allows you to serve a Mu 'Server' +as an OpenAPI / Swagger / REST end-point. +In particular, it translates to the kind of +type-level APIs used by Servant. +-} +module Mu.Servant.Server ( + -- * Convert Mu to Servant + servantServerHandlers, + servantServerHandlersExtra, + toHandler, + packageAPI, + swagger, + -- * Required annotations + ServantRoute(..), + DefaultServantContentTypes, + ServantContentTypes(..), + ServantStreamContentType(..), + -- Reexports + StdMethod(..), + module Servant.API +) where + +import Conduit +import Control.Concurrent +import Control.Concurrent.Async +import Control.Monad.Except +import Data.Aeson +import qualified Data.ByteString.Lazy.UTF8 as LB8 +import Data.Conduit.Internal (ConduitT (..), Pipe (..)) +import Data.Kind +import Data.Swagger (Swagger, ToSchema (..)) +import Generics.Generic.Aeson +import GHC.Generics +import GHC.TypeLits +import GHC.Types (Any) +import Mu.Rpc +import Mu.Rpc.Annotations +import Mu.Schema +import Mu.Schema.Annotations +import Mu.Server +import Servant +import Servant.API +import Servant.Swagger +import Servant.Types.SourceT + +-- | Reinterprets a Mu server action as a Servant handler. +toHandler :: ServerErrorIO a -> Handler a +toHandler = Handler . withExceptT convertServerError + +-- | Translates a Mu `Mu.Server.ServerError` into a Servant `Servant.ServerError`. +convertServerError :: Mu.Server.ServerError -> Servant.ServerError +convertServerError (Mu.Server.ServerError code msg) = case code of + Unknown -> err502 {errBody = LB8.fromString msg} + Unavailable -> err503 {errBody = LB8.fromString msg} + Unimplemented -> err501 {errBody = LB8.fromString msg} + Unauthenticated -> err401 {errBody = LB8.fromString msg} + Internal -> err500 {errBody = LB8.fromString msg} + Invalid -> err400 {errBody = LB8.fromString msg} + NotFound -> err404 {errBody = LB8.fromString msg} + +-- | Converts a Mu server into Servant server +-- by running all Mu handler actions in the `Handler` type. +-- This version assumes /no/ additional routes +-- in the Servant server when compared to Mu's. +servantServerHandlers :: + forall pname m chn ss handlers. + ( ServantServiceHandlers + ('Package pname ss) + m + chn + ss + handlers + , ExtraFor ('Package pname ss) ~ EmptyAPI + ) + => (forall a. m a -> Handler a) -- ^ how to turn the inner Mu monad into 'Handler', use 'toHandler' (or a composition with it) in most cases + -> Mu.Server.ServerT chn () ('Package pname ss) m handlers -- ^ server to be converted + -> Servant.Server (PackageAPI ('Package pname ss) handlers) +servantServerHandlers f (Services svcs) = + emptyServer :<|> servantServiceHandlers f (Proxy @('Package pname ss)) svcs + +-- | Converts a Mu server into Servant server +-- by running all Mu handler actions in the `Handler` type. +-- This version should be used when additional +-- routes have been added in the Servant version. +servantServerHandlersExtra :: + forall pname m chn ss handlers. + ( ServantServiceHandlers + ('Package pname ss) + m + chn + ss + handlers + ) + => (forall a. m a -> Handler a) -- ^ how to turn the inner Mu monad into 'Handler', use 'toHandler' (or a composition with it) in most cases + -> Server (ExtraFor ('Package pname ss)) -- ^ additional handler for the extra route + -> Mu.Server.ServerT chn () ('Package pname ss) m handlers -- ^ server to be converted + -> Servant.Server (PackageAPI ('Package pname ss) handlers) +servantServerHandlersExtra f extra (Services svcs) = + extra :<|> servantServiceHandlers f (Proxy @('Package pname ss)) svcs + +-- | Converts the information from a Mu server +-- into a 'Swagger' document. +swagger :: forall pname ss handlers chn m. + HasSwagger (ServicesAPI ('Package pname ss) ss handlers) + => Mu.Server.ServerT chn () ('Package pname ss) m handlers + -> Swagger +swagger _ = toSwagger (Proxy @(ServicesAPI ('Package pname ss) ss handlers)) + +-- | Obtains a Servant API 'Proxy' value for use +-- with functions like 'serve' and 'layout'. +packageAPI :: Mu.Server.ServerT chn t pkg s handlers -> Proxy (PackageAPI pkg handlers) +packageAPI _ = Proxy + +type family PackageAPI (pkg :: Package snm mnm anm (TypeRef snm)) handlers where + PackageAPI ('Package pnm ss) handlers = PackageAPI' (ExtraFor ('Package pnm ss)) ('Package pnm ss) handlers + +type family PackageAPI' (extra :: Type) (pkg :: Package snm mnm anm (TypeRef snm)) handlers where + PackageAPI' extra ('Package pnm ss) handlers = extra :<|> ServicesAPI ('Package pnm ss) ss handlers + +class + ServantServiceHandlers + (pkg :: Package snm mnm anm (TypeRef snm)) + (m :: Type -> Type) + (chn :: ServiceChain snm) + (ss :: [Service snm mnm anm (TypeRef snm)]) + (hss :: [[Type]]) where + type ServicesAPI pkg ss hss + + servantServiceHandlers :: + (forall a. m a -> Handler a) -> + Proxy pkg -> + ServicesT chn info ss m hss -> + Servant.Server (ServicesAPI pkg ss hss) + +instance ServantServiceHandlers pkg m chn '[] '[] where + type ServicesAPI pkg '[] '[] = EmptyAPI + servantServiceHandlers _ _ S0 = emptyServer + +instance + ( ServantMethodHandlers + pkg + sname + m + chn + (MappingRight chn sname) + methods + hs, + ServantServiceHandlers pkg m chn rest hss + ) => + ServantServiceHandlers pkg m chn ('Service sname methods ': rest) (hs ': hss) + where + type + ServicesAPI pkg ('Service sname methods ': rest) (hs ': hss) = + MethodsAPI pkg sname methods hs :<|> ServicesAPI pkg rest hss + servantServiceHandlers f pkgP (svr :<&>: rest) = + servantMethodHandlers f pkgP (Proxy @sname) svr + :<|> servantServiceHandlers f pkgP rest + +class + ServantMethodHandlers + (pkg :: Package Symbol Symbol anm (TypeRef Symbol)) + (sname :: Symbol) + (m :: Type -> Type) + (chn :: ServiceChain snm) + (inh :: Type) + (ms :: [Method snm Symbol anm (TypeRef snm)]) + (hs :: [Type]) where + type MethodsAPI pkg sname ms hs + servantMethodHandlers :: + (forall a. m a -> Handler a) -> + Proxy pkg -> + Proxy sname -> + HandlersT chn info inh ms m hs -> + Servant.Server (MethodsAPI pkg sname ms hs) + +instance + ServantMethodHandlers pkg svc m chn inh '[] '[] where + type MethodsAPI _ _ '[] '[] = EmptyAPI + servantMethodHandlers _ _ _ H0 = emptyServer + +instance + ( ServantMethodHandler httpMethod httpStatus m args ret h, + ServantMethodHandlers pkg sname m chn () rest hs, + HttpMethodFor pkg sname mname ~ httpMethod, + HttpStatusFor pkg sname mname ~ httpStatus, + Server (MethodAPI pkg sname ('Method mname args ret) h) ~ Server (HandlerAPI httpMethod httpStatus args ret h) + ) => + ServantMethodHandlers pkg sname m chn () ('Method mname args ret ': rest) (h ': hs) + where + type + MethodsAPI pkg sname ('Method mname args ret ': rest) (h ': hs) = + MethodAPI pkg sname ('Method mname args ret) h + :<|> MethodsAPI pkg sname rest hs + servantMethodHandlers f pkgP snameP (Hmore _ _ h rest) = + servantMethodHandler + f + (Proxy @httpMethod) + (Proxy @httpStatus) + (Proxy @args) + (Proxy @ret) + (h NoRpcInfo ()) + :<|> servantMethodHandlers f pkgP snameP rest + +type family MethodAPI pkg sname method h where + MethodAPI pkg sname ('Method mname args ret) h = + PrefixRoute (RouteFor pkg sname mname) + ( HandlerAPI + (HttpMethodFor pkg sname mname) + (HttpStatusFor pkg sname mname) + args + ret + h + ) + +class + ServantMethodHandler + (httpMethod :: StdMethod) + (httpStatus :: Nat) + (m :: Type -> Type) + (args :: [Argument snm anm (TypeRef snm)]) + (ret :: Return snm (TypeRef snm)) + (h :: Type) where + type + HandlerAPI + httpMethod + httpStatus + args + ret + h + servantMethodHandler :: + (forall a. m a -> Handler a) -> + Proxy httpMethod -> + Proxy httpStatus -> + Proxy args -> + Proxy ret -> + h -> + Servant.Server (HandlerAPI httpMethod httpStatus args ret h) + +instance ServantMethodHandler httpMethod httpStatus m '[] 'RetNothing (m ()) where + type + HandlerAPI httpMethod httpStatus '[] 'RetNothing (m ()) = + -- according to https://github.com/haskell-servant/servant/issues/683 + -- we always need a content type for NoContent + Verb httpMethod httpStatus '[JSON] NoContent + servantMethodHandler f _ _ _ _ = fmap (const NoContent) . f + +instance ServantMethodHandler httpMethod httpStatus m '[] ('RetSingle rref) (m r) where + type + HandlerAPI httpMethod httpStatus '[] ('RetSingle rref) (m r) = + Verb httpMethod httpStatus (UnaryContentTypesFor rref) r + servantMethodHandler f _ _ _ _ = f + +instance + (MonadServer m) => + ServantMethodHandler httpMethod httpStatus m '[] ('RetStream rref) (ConduitT r Void m () -> m ()) + where + type + HandlerAPI httpMethod httpStatus '[] ('RetStream rref) (ConduitT r Void m () -> m ()) = + Stream httpMethod httpStatus (StreamFramingFor rref) (StreamContentTypeFor rref) (SourceIO (StreamResult r)) + servantMethodHandler f _ _ _ _ = liftIO . sinkToSource f + +-- | represents a single element that will be streamed from the server to the client. That element will either be a `Result` containing a return value, or an `Error` indicating that something went wrong. Without this wrapper, server streams that encountered an error after the response headers have been sent would simply terminate without communicating to the client that anything went wrong. +data StreamResult a = Error String | Result a + deriving (Generic, Show) + +instance Data.Swagger.ToSchema a => Data.Swagger.ToSchema (StreamResult a) +instance ToJSON a => ToJSON (StreamResult a) where + toJSON = gtoJson + +-- converts a conduit sink into a Servant SourceIO for interoperating with server streaming handlers +sinkToSource :: + forall r m. + (MonadServer m) => + (forall a. m a -> Handler a) -> + (ConduitT r Void m () -> m ()) -> + IO (SourceIO (StreamResult r)) +sinkToSource f sink = do + var <- newEmptyMVar :: IO (MVar (Maybe r)) + forwarder <- liftIO $ async $ do + e <- runHandler . f . sink $ toMVarConduit var + -- signal that the conduit finished + putMVar var Nothing + pure e + let step :: StepT IO (StreamResult r) + step = Effect $ do + nextOutput <- takeMVar var + case nextOutput of + Just r -> pure $ Yield (Result r) step + Nothing -> do + -- waiting on this thread should get us sync and async exceptions + res <- wait forwarder + case res of + Left err -> do + let streamErr = LB8.toString $ errBody err + pure $ Yield (Mu.Servant.Server.Error streamErr) Stop + Right () -> pure Stop + pure $ fromStepT step + +toMVarConduit :: MonadServer m => MVar (Maybe r) -> ConduitT r Void m () +toMVarConduit var = do + x <- await + case x of + Nothing -> pure () + Just _ -> do + liftIO $ putMVar var x + toMVarConduit var + +instance + (ServantMethodHandler httpMethod httpStatus m rest ret h) => + ServantMethodHandler httpMethod httpStatus m ('ArgSingle anm aref ': rest) ret (t -> h) + where + type + HandlerAPI httpMethod httpStatus ('ArgSingle anm aref ': rest) ret (t -> h) = + ReqBody (UnaryContentTypesFor aref) t :> HandlerAPI httpMethod httpStatus rest ret h + servantMethodHandler f mP sP _ retP h t = + servantMethodHandler f mP sP (Proxy @rest) retP (h t) + +instance + (MonadServer m, ServantMethodHandler httpMethod httpStatus m rest ret h) => + ServantMethodHandler httpMethod httpStatus m ('ArgStream anm aref ': rest) ret (ConduitT () t m () -> h) + where + type + HandlerAPI httpMethod httpStatus ('ArgStream anm aref ': rest) ret (ConduitT () t m () -> h) = + StreamBody (StreamFramingFor aref) (StreamContentTypeFor aref) (SourceIO t) + :> HandlerAPI httpMethod httpStatus rest ret h + servantMethodHandler f mP sP _ retP h = + servantMethodHandler f mP sP (Proxy @rest) retP . h . sourceToSource + +-- converts a Servant SourceIO into a conduit for interoperating with client streaming handlers +sourceToSource :: (MonadServer m) => SourceIO t -> ConduitT () t m () +sourceToSource (SourceT src) = ConduitT (PipeM (liftIO $ src (pure . go)) >>=) + where + go :: (MonadServer m) => StepT IO t -> Pipe i i t u m () + go Stop = Done () + go (Skip s) = go s + go (Yield t s) = HaveOutput (go s) t + go (Effect m) = PipeM (liftIO $ go <$> m) + go (Servant.Types.SourceT.Error msg) = + PipeM (throwError $ Mu.Server.ServerError Invalid ("error reading stream: " ++ msg)) + +-- | ServantRoute represents the URL path components of a route. It is used as an `AnnotatedPackage` domain to override the default path for a `Method`. When used in an `AnnService`, the specified `TopLevelRoute` is used as a prefix for all `Method`s in that `Service`. +-- 1. List of components for the route, +-- 2. HTTP method which must be used, +-- 3. HTTP status code of a successful HTTP response from a specific `Method`. Use 200 for the usual status code. +data ServantRoute + = ServantAdditional Type + | ServantTopLevelRoute [Symbol] + | ServantRoute [Symbol] StdMethod Nat + +type family Assert (err :: Constraint) (break :: k1) (a :: k2) :: k2 where + -- these cases exist to force evaluation of the "break" parameter when it either has kind [RpcAnnotation ...] or [Annotation ...] + Assert _ '[ 'AnnSchema a, 'AnnSchema a ] _ = Any + Assert _ '[ 'AnnPackage a, 'AnnPackage a ] _ = Any + -- this case should be used whenever "break" is not stuck + Assert _ _ a = a + +-- a helper type synonym used to provide better errors when a required AnnotatedPackage instance doesn't exist +type WithAnnotatedPackageInstance domain pkg a = + Assert (NoPackageAnnotations domain pkg) (AnnotatedPackage domain pkg) a + +-- a helper type synonym used to provide better errors when a required AnnotatedSchema instance doesn't exist +type WithAnnotatedSchemaInstance domain sch a = + Assert (NoSchemaAnnotations domain sch) (AnnotatedSchema domain sch) a + + +-- a helper type family for generating custom error messages about missing AnnotatedPackage instances +type family NoPackageAnnotations domain pkg :: Constraint where + NoPackageAnnotations domain ('Package ('Just pname) _) + = TypeError ( + 'Text "Missing required AnnotatedPackage " ':<>: 'ShowType domain ':<>: 'Text " type instance" ':$$: + 'Text "for " ':<>: 'ShowType pname ':<>: 'Text " package" + ) + NoPackageAnnotations domain pkg + = TypeError ( + 'Text "Missing required AnnotatedPackage " ':<>: 'ShowType domain ':<>: 'Text " type instance" ':$$: + 'Text "for unnamed package: " ':$$: 'ShowType pkg + ) + +-- a helper type family for generating custom error messages about missing AnnotatedSchema instances +type family NoSchemaAnnotations domain sch :: Constraint where + NoSchemaAnnotations domain sch + = TypeError ( + 'Text "Missing required AnnotatedSchema " ':<>: 'ShowType domain ':<>: 'Text " type instance" ':$$: + 'Text "for schema:" ':$$: 'ShowType sch + ) + +-- used to construct a route for a specific method m of service s in package pkg from the @AnnotatedPackage ServantRoute pkg@ instance, along with a custom error message +type family RouteFor (pkg :: Package snm mnm anm tyref) (s :: Symbol) (m :: Symbol) :: [Symbol] where + RouteFor pkg s m = + WithAnnotatedPackageInstance ServantRoute pkg ( + Concat + (UnwrapServantRoute (FromMaybe ('ServantRoute '[s] Any Any) (GetServiceAnnotationMay (AnnotatedPackage ServantRoute pkg) s))) + (UnwrapServantRoute (FromMaybe ('ServantRoute '[m] Any Any) (GetMethodAnnotationMay (AnnotatedPackage ServantRoute pkg) s m))) + ) + +type family UnwrapServantRoute s where + UnwrapServantRoute ('ServantTopLevelRoute s) = s + UnwrapServantRoute ('ServantRoute s _ _) = s + +type family ExtraFor (pkg :: Package snm mnm anm tyref) :: Type where + ExtraFor pkg = + WithAnnotatedPackageInstance ServantRoute pkg + (UnwrapServantExtra (FromMaybe ('ServantAdditional EmptyAPI) (GetPackageAnnotationMay (AnnotatedPackage ServantRoute pkg)))) + +type family UnwrapServantExtra s where + UnwrapServantExtra ('ServantAdditional e) = e + +type family FromMaybe (a :: k) (ma :: Maybe k) :: k where + FromMaybe a 'Nothing = a + FromMaybe _ ('Just a) = a + +type family Concat (as :: [k]) (bs :: [k]) :: [k] where + Concat '[] bs = bs + Concat (a ': as) bs = a ': Concat as bs + +type family PrefixRoute (prefix :: [Symbol]) route where + PrefixRoute '[] route = route + PrefixRoute (p ': rest) route = p :> PrefixRoute rest route + +-- | ServantContentTypes represents that acceptable content types that can be used when a message in encoded: +-- 1. in a unary (non-streaming) HTTP request\/response body, +-- 2. encoded in a streaming HTTP request\/response body. +-- It is used as an `AnnotatedSchema` domain. +data ServantContentTypes + = ServantContentTypes + { unary :: [Type] + , stream :: Maybe ServantStreamContentType + } + +type DefaultServantContentTypes + = 'ServantContentTypes '[JSON] ('Just ('ServantStreamContentType NewlineFraming JSON)) + +data ServantStreamContentType + = ServantStreamContentType + { framing :: Type, + streamContentType :: Type + } + +-- extracts a StdMethod from a ServantMethod annotation of a given method, defaulting to POST if such an annotation doesn't exist +type family HttpMethodFor pkg sname mname :: StdMethod where + HttpMethodFor pkg sname mname = + WithAnnotatedPackageInstance ServantRoute pkg ( + UnwrapServantMethod (FromMaybe ('ServantRoute Any 'POST Any) (GetMethodAnnotationMay (AnnotatedPackage ServantRoute pkg) sname mname)) + ) + +type family UnwrapServantMethod m where + UnwrapServantMethod ('ServantRoute _ m _) = m + +-- extracts the HTTP status code from the ServantStatus annotation of a given method, or defaults to 200 if such an annotation doesn't exist +type family HttpStatusFor pkg sname mname :: Nat where + HttpStatusFor pkg sname mname = + WithAnnotatedPackageInstance ServantRoute pkg ( + UnwrapServantStatus (FromMaybe ('ServantRoute Any Any 200) (GetMethodAnnotationMay (AnnotatedPackage ServantRoute pkg) sname mname)) + ) + +type family UnwrapServantStatus s where + UnwrapServantStatus ('ServantRoute _ _ s) = s + +-- extracts a list of content types from a ServantUnaryContentTypes annotation of a given method +type family UnaryContentTypesFor (tyRef :: TypeRef sname) :: [Type] where + UnaryContentTypesFor ('SchemaRef schema typeName) = + WithAnnotatedSchemaInstance ServantContentTypes schema ( + UnwrapServantUnaryContentType (GetTypeAnnotation (AnnotatedSchema ServantContentTypes schema) typeName) + ) + +type family UnwrapServantUnaryContentType (sctype :: ServantContentTypes) :: [Type] where + UnwrapServantUnaryContentType ('ServantContentTypes ctype stype) = ctype + +-- extracts a content type from a ServantStreamContentType annotation of a given method +type family StreamContentTypeFor (tyRef :: TypeRef sname) :: Type where + StreamContentTypeFor ('SchemaRef schema typeName) = + WithAnnotatedSchemaInstance ServantContentTypes schema ( + StreamContentType (GetTypeAnnotation (AnnotatedSchema ServantContentTypes schema) typeName) + ) + +type family StreamContentType (sct :: ServantContentTypes) where + StreamContentType ('ServantContentTypes _ 'Nothing) + = TypeError ('Text "missing stream content type") + StreamContentType ('ServantContentTypes _ ('Just ('ServantStreamContentType _ ctype))) = ctype + +-- extracts a framing from a ServantStreamContentType annotation of a given method +type family StreamFramingFor (tyRef :: TypeRef sname) :: Type where + StreamFramingFor ('SchemaRef schema typeName) = + WithAnnotatedSchemaInstance ServantContentTypes schema ( + StreamFraming (GetTypeAnnotation (AnnotatedSchema ServantContentTypes schema) typeName) + ) + +type family StreamFraming (sct :: ServantContentTypes) where + StreamFraming ('ServantContentTypes _ 'Nothing) + = TypeError ('Text "missing stream content type") + StreamFraming ('ServantContentTypes _ ('Just ('ServantStreamContentType framing _))) = framing