@@ -1,29 +1,29 @@
1−{-# LANGUAGE CPP #-}
1+{-# LANGUAGE AllowAmbiguousTypes #-}
22{-# LANGUAGE ConstraintKinds #-}
33{-# LANGUAGE DataKinds #-}
44{-# LANGUAGE DeriveDataTypeable #-}
55{-# LANGUAGE FlexibleContexts #-}
66{-# LANGUAGE FlexibleInstances #-}
7+{-# LANGUAGE InstanceSigs #-}
78{-# LANGUAGE MultiParamTypeClasses #-}
89{-# LANGUAGE OverloadedStrings #-}
910{-# LANGUAGE PolyKinds #-}
11+{-# LANGUAGE QuantifiedConstraints #-}
1012{-# LANGUAGE RankNTypes #-}
1113{-# LANGUAGE ScopedTypeVariables #-}
1214{-# LANGUAGE TupleSections #-}
15+{-# LANGUAGE TypeApplications #-}
1316{-# LANGUAGE TypeFamilies #-}
1417{-# LANGUAGE TypeOperators #-}
1518{-# LANGUAGE UndecidableInstances #-}
1619
17−#if MIN_VERSION_base(4,9,0) && __GLASGOW_HASKELL__ >= 802
18−#define HAS_TYPE_ERROR
19−#endif
20−
2120module Servant.Server.Internal
2221 ( module Servant.Server.Internal
2322 , module Servant.Server.Internal.BasicAuth
2423 , module Servant.Server.Internal.Context
2524 , module Servant.Server.Internal.Delayed
2625 , module Servant.Server.Internal.DelayedIO
26+ , module Servant.Server.Internal.ErrorFormatter
2727 , module Servant.Server.Internal.Handler
2828 , module Servant.Server.Internal.Router
2929 , module Servant.Server.Internal.RouteResult
@@ -41,12 +41,11 @@ import qualified Data.ByteString as B
4141import qualified Data.ByteString.Builder as BB
4242import qualified Data.ByteString.Char8 as BC8
4343import qualified Data.ByteString.Lazy as BL
44+import Data.Constraint (Constraint, Dict(..))
4445import Data.Either
4546 (partitionEithers)
4647import Data.Maybe
4748 (fromMaybe, isNothing, mapMaybe, maybeToList)
48−import Data.Semigroup
49− ((<>))
5049import Data.String
5150 (IsString (..))
5251import Data.String.Conversions
@@ -55,8 +54,9 @@ import Data.Tagged
5554 (Tagged (..), retag, untag)
5655import qualified Data.Text as T
5756import Data.Typeable
57+import GHC.Generics
5858import GHC.TypeLits
59− (KnownNat, KnownSymbol, natVal, symbolVal)
59+ (KnownNat, KnownSymbol, TypeError, symbolVal)
6060import qualified Network.HTTP.Media as NHM
6161import Network.HTTP.Types hiding
6262 (Header, ResponseHeaders)
@@ -64,45 +64,52 @@ import Network.Socket
6464 (SockAddr)
6565import Network.Wai
6666 (Application, Request, httpVersion, isSecure, lazyRequestBody,
67− rawQueryString, remoteHost, requestBody, requestHeaders,
67+ queryString, remoteHost, getRequestBodyChunk, requestHeaders,
6868 requestMethod, responseLBS, responseStream, vault)
6969import Prelude ()
7070import Prelude.Compat
7171import Servant.API
7272 ((:<|>) (..), (:>), Accept (..), BasicAuth, Capture',
73− CaptureAll, Description, EmptyAPI, FramingRender (..),
74− FramingUnrender (..), FromSourceIO (..), Header', If,
75− IsSecure (..), QueryFlag, QueryParam', QueryParams, Raw,
76− ReflectMethod (reflectMethod), RemoteHost, ReqBody',
77− SBool (..), SBoolI (..), SourceIO, Stream, StreamBody',
78− Summary, ToSourceIO (..), Vault, Verb, WithNamedContext)
73+ CaptureAll, Description, EmptyAPI, Fragment,
74+ FramingRender (..), FramingUnrender (..), FromSourceIO (..),
75+ Header', If, IsSecure (..), NoContentVerb, QueryFlag,
76+ QueryParam', QueryParams, Raw, ReflectMethod (reflectMethod),
77+ RemoteHost, ReqBody', SBool (..), SBoolI (..), SourceIO,
78+ Stream, StreamBody', Summary, ToSourceIO (..), Vault, Verb,
79+ WithNamedContext, NamedRoutes)
80+import Servant.API.Generic (GenericMode(..), ToServant, ToServantApi, GServantProduct, toServant, fromServant)
7981import Servant.API.ContentTypes
8082 (AcceptHeader (..), AllCTRender (..), AllCTUnrender (..),
81− AllMime, MimeRender (..), MimeUnrender (..), canHandleAcceptH)
83+ AllMime, MimeRender (..), MimeUnrender (..), NoContent,
84+ canHandleAcceptH)
8285import Servant.API.Modifiers
8386 (FoldLenient, FoldRequired, RequestArgument,
8487 unfoldRequestArgument)
8588import Servant.API.ResponseHeaders
8689 (GetHeaders, Headers, getHeaders, getResponse)
90+import Servant.API.Status
91+ (statusFromNat)
8792import qualified Servant.Types.SourceT as S
93+import Servant.API.TypeErrors
8894import Web.HttpApiData
89− (FromHttpApiData, parseHeader, parseQueryParam,
90− parseUrlPieceMaybe, parseUrlPieces)
95+ (FromHttpApiData, parseHeader, parseQueryParam, parseUrlPiece,
96+ parseUrlPieces)
9197
9298import Servant.Server.Internal.BasicAuth
9399import Servant.Server.Internal.Context
94100import Servant.Server.Internal.Delayed
95101import Servant.Server.Internal.DelayedIO
102+import Servant.Server.Internal.ErrorFormatter
96103import Servant.Server.Internal.Handler
97104import Servant.Server.Internal.Router
98105import Servant.Server.Internal.RouteResult
99106import Servant.Server.Internal.RoutingApplication
100107import Servant.Server.Internal.ServerError
101108
102−#ifdef HAS_TYPE_ERROR
103109import GHC.TypeLits
104110 (ErrorMessage (..), TypeError)
105−#endif
111+import Servant.API.TypeLevel
112+ (AtLeastOneFragment, FragmentUnique)
106113
107114class HasServer api context where
108115 type ServerT api (m :: * -> *) :: *
@@ -166,22 +173,31 @@ instance (HasServer a context, HasServer b context) => HasServer (a :<|> b) cont
166173-- > server = getBook
167174-- > where getBook :: Text -> Handler Book
168175-- > getBook isbn = ...
169−instance (KnownSymbol capture, FromHttpApiData a, HasServer api context)
176+instance (KnownSymbol capture, FromHttpApiData a, Typeable a
177+ , HasServer api context, SBoolI (FoldLenient mods)
178+ , HasContextEntry (MkContextWithErrorFormatter context) ErrorFormatters
179+ )
170180 => HasServer (Capture' mods capture a :> api) context where
171181
172182 type ServerT (Capture' mods capture a :> api) m =
173− a -> ServerT api m
183+ If (FoldLenient mods) (Either String a) a -> ServerT api m
174184
175185 hoistServerWithContext _ pc nt s = hoistServerWithContext (Proxy :: Proxy api) pc nt . s
176186
177187 route Proxy context d =
178− CaptureRouter $
188+ CaptureRouter [hint] $
179189 route (Proxy :: Proxy api)
180190 context
181− (addCapture d $ \ txt -> case parseUrlPieceMaybe txt of
182− Nothing -> delayedFail err400
183− Just v -> return v
184− )
191+ (addCapture d $ \ txt -> withRequest $ \ request ->
192+ case ( sbool :: SBool (FoldLenient mods)
193+ , parseUrlPiece txt :: Either T.Text a) of
194+ (SFalse, Left e) -> delayedFail $ formatError rep request $ cs e
195+ (SFalse, Right v) -> return v
196+ (STrue, piece) -> return $ (either (Left . cs) Right) piece)
197+ where
198+ rep = typeRep (Proxy :: Proxy Capture')
199+ formatError = urlParseErrorFormatter $ getContextEntry (mkContextWithErrorFormatter context)
200+ hint = CaptureHint (T.pack $ symbolVal $ Proxy @capture) (typeRep (Proxy :: Proxy a))
185201
186202-- | If you use 'CaptureAll' in one of the endpoints for your API,
187203-- this automatically requires your server-side handler to be a
@@ -200,7 +216,10 @@ instance (KnownSymbol capture, FromHttpApiData a, HasServer api context)
200216-- > server = getSourceFile
201217-- > where getSourceFile :: [Text] -> Handler Book
202218-- > getSourceFile pathSegments = ...
203−instance (KnownSymbol capture, FromHttpApiData a, HasServer api context)
219+instance (KnownSymbol capture, FromHttpApiData a, Typeable a
220+ , HasServer api context
221+ , HasContextEntry (MkContextWithErrorFormatter context) ErrorFormatters
222+ )
204223 => HasServer (CaptureAll capture a :> api) context where
205224
206225 type ServerT (CaptureAll capture a :> api) m =
@@ -209,14 +228,18 @@ instance (KnownSymbol capture, FromHttpApiData a, HasServer api context)
209228 hoistServerWithContext _ pc nt s = hoistServerWithContext (Proxy :: Proxy api) pc nt . s
210229
211230 route Proxy context d =
212− CaptureAllRouter $
231+ CaptureAllRouter [hint] $
213232 route (Proxy :: Proxy api)
214233 context
215− (addCapture d $ \ txts -> case parseUrlPieces txts of
216− Left _ -> delayedFail err400
217− Right v -> return v
234+ (addCapture d $ \ txts -> withRequest $ \ request ->
235+ case parseUrlPieces txts of
236+ Left e -> delayedFail $ formatError rep request $ cs e
237+ Right v -> return v
218238 )
219−
239+ where
240+ rep = typeRep (Proxy :: Proxy CaptureAll)
241+ formatError = urlParseErrorFormatter $ getContextEntry (mkContextWithErrorFormatter context)
242+ hint = CaptureHint (T.pack $ symbolVal $ Proxy @capture) (typeRep (Proxy :: Proxy [a]))
220243
221244allowedMethodHead :: Method -> Request -> Bool
222245allowedMethodHead method request = method == methodGet && requestMethod request == methodHead
@@ -236,10 +259,10 @@ methodCheck method request
236259-- body check is no longer an option. However, we now run the accept
237260-- check before the body check and can therefore afford to make it
238261-- recoverable.
239−acceptCheck :: (AllMime list) => Proxy list -> B.ByteString -> DelayedIO ()
262+acceptCheck :: (AllMime list) => Proxy list -> AcceptHeader -> DelayedIO ()
240263acceptCheck proxy accH
241− | canHandleAcceptH proxy (AcceptHeader accH) = return ()
242− | otherwise = delayedFail err406
264+ | canHandleAcceptH proxy accH = return ()
265+ | otherwise = delayedFail err406
243266
244267methodRouter :: (AllCTRender ctypes a)
245268 => (b -> ([(HeaderName, B.ByteString)], a))
@@ -249,17 +272,28 @@ methodRouter :: (AllCTRender ctypes a)
249272methodRouter splitHeaders method proxy status action = leafRouter route'
250273 where
251274 route' env request respond =
252− let accH = fromMaybe ct_wildcard $ lookup hAccept $ requestHeaders request
275+ let accH = getAcceptHeader request
253276 in runAction (action `addMethodCheck` methodCheck method request
254277 `addAcceptCheck` acceptCheck proxy accH
255278 ) env request respond $ \ output -> do
256279 let (headers, b) = splitHeaders output
257− case handleAcceptH proxy (AcceptHeader accH) b of
280+ case handleAcceptH proxy accH b of
258281 Nothing -> FailFatal err406 -- this should not happen (checked before), so we make it fatal if it does
259282 Just (contentT, body) ->
260283 let bdy = if allowedMethodHead method request then "" else body
261284 in Route $ responseLBS status ((hContentType, cs contentT) : headers) bdy
262285
286+noContentRouter :: Method
287+ -> Status
288+ -> Delayed env (Handler b)
289+ -> Router env
290+noContentRouter method status action = leafRouter route'
291+ where
292+ route' env request respond =
293+ runAction (action `addMethodCheck` methodCheck method request)
294+ env request respond $ \ _output ->
295+ Route $ responseLBS status [] ""
296+
263297instance {-# OVERLAPPABLE #-}
264298 ( AllCTRender ctypes a, ReflectMethod method, KnownNat status
265299 ) => HasServer (Verb method status ctypes a) context where
@@ -269,7 +303,7 @@ instance {-# OVERLAPPABLE #-}
269303
270304 route Proxy _ = methodRouter ([],) method (Proxy :: Proxy ctypes) status
271305 where method = reflectMethod (Proxy :: Proxy method)
272− status = toEnum . fromInteger $ natVal (Proxy :: Proxy status)
306+ status = statusFromNat (Proxy :: Proxy status)
273307
274308instance {-# OVERLAPPING #-}
275309 ( AllCTRender ctypes a, ReflectMethod method, KnownNat status
@@ -281,8 +315,16 @@ instance {-# OVERLAPPING #-}
281315
282316 route Proxy _ = methodRouter (\x -> (getHeaders x, getResponse x)) method (Proxy :: Proxy ctypes) status
283317 where method = reflectMethod (Proxy :: Proxy method)
284− status = toEnum . fromInteger $ natVal (Proxy :: Proxy status)
318+ status = statusFromNat (Proxy :: Proxy status)
319+
320+instance (ReflectMethod method) =>
321+ HasServer (NoContentVerb method) context where
285322
323+ type ServerT (NoContentVerb method) m = m NoContent
324+ hoistServerWithContext _ _ nt s = nt s
325+
326+ route Proxy _ = noContentRouter method status204
327+ where method = reflectMethod (Proxy :: Proxy method)
286328
287329instance {-# OVERLAPPABLE #-}
288330 ( MimeRender ctype chunk, ReflectMethod method, KnownNat status,
@@ -294,7 +336,7 @@ instance {-# OVERLAPPABLE #-}
294336
295337 route Proxy _ = streamRouter ([],) method status (Proxy :: Proxy framing) (Proxy :: Proxy ctype)
296338 where method = reflectMethod (Proxy :: Proxy method)
297− status = toEnum . fromInteger $ natVal (Proxy :: Proxy status)
339+ status = statusFromNat (Proxy :: Proxy status)
298340
299341
300342instance {-# OVERLAPPING #-}
@@ -308,7 +350,7 @@ instance {-# OVERLAPPING #-}
308350
309351 route Proxy _ = streamRouter (\x -> (getHeaders x, getResponse x)) method status (Proxy :: Proxy framing) (Proxy :: Proxy ctype)
310352 where method = reflectMethod (Proxy :: Proxy method)
311− status = toEnum . fromInteger $ natVal (Proxy :: Proxy status)
353+ status = statusFromNat (Proxy :: Proxy status)
312354
313355
314356streamRouter :: forall ctype a c chunk env framing. (MimeRender ctype chunk, FramingRender framing, ToSourceIO chunk a) =>
@@ -320,7 +362,7 @@ streamRouter :: forall ctype a c chunk env framing. (MimeRender ctype chunk, Fra
320362 -> Delayed env (Handler c)
321363 -> Router env
322364streamRouter splitHeaders method status framingproxy ctypeproxy action = leafRouter $ \env request respond ->
323− let accH = fromMaybe ct_wildcard $ lookup hAccept $ requestHeaders request
365+ let AcceptHeader accH = getAcceptHeader request
324366 cmediatype = NHM.matchAccept [contentType ctypeproxy] accH
325367 accCheck = when (isNothing cmediatype) $ delayedFail err406
326368 contentHeader = (hContentType, NHM.renderHeader . maybeToList $ cmediatype)
@@ -365,6 +407,7 @@ streamRouter splitHeaders method status framingproxy ctypeproxy action = leafRou
365407instance
366408 (KnownSymbol sym, FromHttpApiData a, HasServer api context
367409 , SBoolI (FoldRequired mods), SBoolI (FoldLenient mods)
410+ , HasContextEntry (MkContextWithErrorFormatter context) ErrorFormatters
368411 )
369412 => HasServer (Header' mods sym a :> api) context where
370413------
@@ -376,6 +419,9 @@ instance
376419 route Proxy context subserver = route (Proxy :: Proxy api) context $
377420 subserver `addHeaderCheck` withRequest headerCheck
378421 where
422+ rep = typeRep (Proxy :: Proxy Header')
423+ formatError = headerParseErrorFormatter $ getContextEntry (mkContextWithErrorFormatter context)
424+
379425 headerName :: IsString n => n
380426 headerName = fromString $ symbolVal (Proxy :: Proxy sym)
381427
@@ -386,15 +432,13 @@ instance
386432 mev :: Maybe (Either T.Text a)
387433 mev = fmap parseHeader $ lookup headerName (requestHeaders req)
388434
389− errReq = delayedFailFatal err400
390− { errBody = "Header " <> headerName <> " is required"
391− }
435+ errReq = delayedFailFatal $ formatError rep req
436+ $ "Header " <> headerName <> " is required"
392437
393− errSt e = delayedFailFatal err400
394− { errBody = cs $ "Error parsing header "
395− <> headerName
396− <> " failed: " <> e
397− }
438+ errSt e = delayedFailFatal $ formatError rep req
439+ $ cs $ "Error parsing header "
440+ <> headerName
441+ <> " failed: " <> e
398442
399443-- | If you use @'QueryParam' "author" Text@ in one of the endpoints for your API,
400444-- this automatically requires your server-side handler to be a function
@@ -420,6 +464,7 @@ instance
420464instance
421465 ( KnownSymbol sym, FromHttpApiData a, HasServer api context
422466 , SBoolI (FoldRequired mods), SBoolI (FoldLenient mods)
467+ , HasContextEntry (MkContextWithErrorFormatter context) ErrorFormatters
423468 )
424469 => HasServer (QueryParam' mods sym a :> api) context where
425470------
@@ -429,9 +474,12 @@ instance
429474 hoistServerWithContext _ pc nt s = hoistServerWithContext (Proxy :: Proxy api) pc nt . s
430475
431476 route Proxy context subserver =
432− let querytext req = parseQueryText $ rawQueryString req
477+ let querytext = queryToQueryText . queryString
433478 paramname = cs $ symbolVal (Proxy :: Proxy sym)
434479
480+ rep = typeRep (Proxy :: Proxy QueryParam')
481+ formatError = urlParseErrorFormatter $ getContextEntry (mkContextWithErrorFormatter context)
482+
435483 parseParam :: Request -> DelayedIO (RequestArgument mods a)
436484 parseParam req =
437485 unfoldRequestArgument (Proxy :: Proxy mods) errReq errSt mev
@@ -439,14 +487,12 @@ instance
439487 mev :: Maybe (Either T.Text a)
440488 mev = fmap parseQueryParam $ join $ lookup paramname $ querytext req
441489
442− errReq = delayedFailFatal err400
443− { errBody = cs $ "Query parameter " <> paramname <> " is required"
444− }
490+ errReq = delayedFailFatal $ formatError rep req
491+ $ cs $ "Query parameter " <> paramname <> " is required"
445492
446− errSt e = delayedFailFatal err400
447− { errBody = cs $ "Error parsing query parameter "
448− <> paramname <> " failed: " <> e
449− }
493+ errSt e = delayedFailFatal $ formatError rep req
494+ $ cs $ "Error parsing query parameter "
495+ <> paramname <> " failed: " <> e
450496
451497 delayed = addParameterCheck subserver . withRequest $ \req ->
452498 parseParam req
@@ -472,7 +518,8 @@ instance
472518-- > server = getBooksBy
473519-- > where getBooksBy :: [Text] -> Handler [Book]
474520-- > getBooksBy authors = ...return all books by these authors...
475−instance (KnownSymbol sym, FromHttpApiData a, HasServer api context)
521+instance (KnownSymbol sym, FromHttpApiData a, HasServer api context
522+ , HasContextEntry (MkContextWithErrorFormatter context) ErrorFormatters)
476523 => HasServer (QueryParams sym a :> api) context where
477524
478525 type ServerT (QueryParams sym a :> api) m =
@@ -483,21 +530,23 @@ instance (KnownSymbol sym, FromHttpApiData a, HasServer api context)
483530 route Proxy context subserver = route (Proxy :: Proxy api) context $
484531 subserver `addParameterCheck` withRequest paramsCheck
485532 where
533+ rep = typeRep (Proxy :: Proxy QueryParams)
534+ formatError = urlParseErrorFormatter $ getContextEntry (mkContextWithErrorFormatter context)
535+
486536 paramname = cs $ symbolVal (Proxy :: Proxy sym)
487537 paramsCheck req =
488538 case partitionEithers $ fmap parseQueryParam params of
489539 ([], parsed) -> return parsed
490− (errs, _) -> delayedFailFatal err400
491− { errBody = cs $ "Error parsing query parameter(s) "
492− <> paramname <> " failed: "
493− <> T.intercalate ", " errs
494− }
540+ (errs, _) -> delayedFailFatal $ formatError rep req
541+ $ cs $ "Error parsing query parameter(s) "
542+ <> paramname <> " failed: "
543+ <> T.intercalate ", " errs
495544 where
496545 params :: [T.Text]
497546 params = mapMaybe snd
498547 . filter (looksLikeParam . fst)
499− . parseQueryText
500− . rawQueryString
548+ . queryToQueryText
549+ . queryString
501550 $ req
502551
503552 looksLikeParam name = name == paramname || name == (paramname <> "[]")
@@ -523,7 +572,7 @@ instance (KnownSymbol sym, HasServer api context)
523572 hoistServerWithContext _ pc nt s = hoistServerWithContext (Proxy :: Proxy api) pc nt . s
524573
525574 route Proxy context subserver =
526− let querytext r = parseQueryText $ rawQueryString r
575+ let querytext = queryToQueryText . queryString
527576 param r = case lookup paramname (querytext r) of
528577 Just Nothing -> True -- param is there, with no value
529578 Just (Just v) -> examine v -- param with a value
@@ -565,7 +614,7 @@ instance HasServer Raw context where
565614-- The @Content-Type@ header is inspected, and the list provided is used to
566615-- attempt deserialization. If the request does not have a @Content-Type@
567616-- header, it is treated as @application/octet-stream@ (as specified in
568−-- <http://tools.ietf.org/html/rfc7231#section-3.1.1.5 RFC7231>.
617+-- [RFC 7231 section 3.1.1.5](http://tools.ietf.org/html/rfc7231#section-3.1.1.5)).
569618-- This lets servant worry about extracting it from the request and turning
570619-- it into a value of the type you specify.
571620--
@@ -581,6 +630,7 @@ instance HasServer Raw context where
581630-- > where postBook :: Book -> Handler Book
582631-- > postBook book = ...insert into your db...
583632instance ( AllCTUnrender list a, HasServer api context, SBoolI (FoldLenient mods)
633+ , HasContextEntry (MkContextWithErrorFormatter context) ErrorFormatters
584634 ) => HasServer (ReqBody' mods list a :> api) context where
585635
586636 type ServerT (ReqBody' mods list a :> api) m =
@@ -592,6 +642,9 @@ instance ( AllCTUnrender list a, HasServer api context, SBoolI (FoldLenient mods
592642 = route (Proxy :: Proxy api) context $
593643 addBodyCheck subserver ctCheck bodyCheck
594644 where
645+ rep = typeRep (Proxy :: Proxy ReqBody')
646+ formatError = bodyParserErrorFormatter $ getContextEntry (mkContextWithErrorFormatter context)
647+
595648 -- Content-Type check, we only lookup we can try to parse the request body
596649 ctCheck = withRequest $ \ request -> do
597650 -- See HTTP RFC 2616, section 7.2.1
@@ -610,7 +663,7 @@ instance ( AllCTUnrender list a, HasServer api context, SBoolI (FoldLenient mods
610663 case sbool :: SBool (FoldLenient mods) of
611664 STrue -> return mrqbody
612665 SFalse -> case mrqbody of
613− Left e -> delayedFailFatal err400 { errBody = cs e }
666+ Left e -> delayedFailFatal $ formatError rep request e
614667 Right v -> return v
615668
616669instance
@@ -633,7 +686,7 @@ instance
633686 bodyCheck fromRS = withRequest $ \req -> do
634687 let mimeUnrender' = mimeUnrender (Proxy :: Proxy ctype) :: BL.ByteString -> Either String chunk
635688 let framingUnrender' = framingUnrender (Proxy :: Proxy framing) mimeUnrender' :: SourceIO B.ByteString -> SourceIO chunk
636− let body = requestBody req
689+ let body = getRequestBodyChunk req
637690 let rs = S.fromAction B.null body
638691 let rs' = fromRS $ framingUnrender' rs
639692 return rs'
@@ -702,12 +755,12 @@ data EmptyServer = EmptyServer deriving (Typeable, Eq, Show, Bounded, Enum)
702755emptyServer :: ServerT EmptyAPI m
703756emptyServer = Tagged EmptyServer
704757
705−-- | The server for an `EmptyAPI` is `emptyAPIServer`.
758+-- | The server for an `EmptyAPI` is `emptyServer`.
706759--
707760-- > type MyApi = "nothing" :> EmptyApi
708761-- >
709762-- > server :: Server MyApi
710−-- > server = emptyAPIServer
763+-- > server = emptyServer
711764instance HasServer EmptyAPI context where
712765 type ServerT EmptyAPI m = Tagged m EmptyServer
713766
@@ -736,7 +789,10 @@ instance ( KnownSymbol realm
736789-- * helpers
737790
738791ct_wildcard :: B.ByteString
739−ct_wildcard = "*" <> "/" <> "*" -- Because CPP
792+ct_wildcard = "*" <> "/" <> "*"
793+
794+getAcceptHeader :: Request -> AcceptHeader
795+getAcceptHeader = AcceptHeader . fromMaybe ct_wildcard . lookup hAccept . requestHeaders
740796
741797-- * General Authentication
742798
@@ -761,39 +817,15 @@ instance (HasContextEntry context (NamedContext name subContext), HasServer subA
761817 hoistServerWithContext _ _ nt s = hoistServerWithContext (Proxy :: Proxy subApi) (Proxy :: Proxy subContext) nt s
762818
763819-------------------------------------------------------------------------------
764−-- TypeError helpers
820+-- Custom type errors
765821-------------------------------------------------------------------------------
766822
767−#ifdef HAS_TYPE_ERROR
768−-- | This instance catches mistakes when there are non-saturated
769−-- type applications on LHS of ':>'.
770−--
771−-- >>> serve (Proxy :: Proxy (Capture "foo" :> Get '[JSON] Int)) (error "...")
772−-- ...
773−-- ...Expected something of kind Symbol or *, got: k -> l on the LHS of ':>'.
774−-- ...Maybe you haven't applied enough arguments to
775−-- ...Capture' '[] "foo"
776−-- ...
777−--
778−-- >>> undefined :: Server (Capture "foo" :> Get '[JSON] Int)
779−-- ...
780−-- ...Expected something of kind Symbol or *, got: k -> l on the LHS of ':>'.
781−-- ...Maybe you haven't applied enough arguments to
782−-- ...Capture' '[] "foo"
783−-- ...
784−--
785−instance TypeError (HasServerArrowKindError arr) => HasServer ((arr :: k -> l) :> api) context
823+-- Erroring instance for 'HasServer' when a combinator is not fully applied
824+instance TypeError (PartialApplication HasServer arr) => HasServer ((arr :: a -> b) :> sub) context
786825 where
787− type ServerT (arr :> api) m = TypeError (HasServerArrowKindError arr)
788− -- it doens't really matter what sub route we peak
789− route _ _ _ = error "servant-server panic: impossible happened in HasServer (arr :> api)"
790− hoistServerWithContext _ _ _ = id
791−
792−-- Cannot have TypeError here, otherwise use of this symbol will error :)
793−type HasServerArrowKindError arr =
794− 'Text "Expected something of kind Symbol or *, got: k -> l on the LHS of ':>'."
795− ':$$: 'Text "Maybe you haven't applied enough arguments to"
796− ':$$: 'ShowType arr
826+ type ServerT (arr :> sub) _ = TypeError (PartialApplication (HasServer :: * -> [*] -> Constraint) arr)
827+ route = error "unreachable"
828+ hoistServerWithContext _ _ _ _ = error "unreachable"
797829
798830-- | This instance prevents from accidentally using '->' instead of ':>'
799831--
@@ -827,7 +859,103 @@ type HasServerArrowTypeError a b =
827859 ':$$: 'ShowType a
828860 ':$$: 'Text "and"
829861 ':$$: 'ShowType b
830−#endif
862+
863+-- Erroring instances for 'HasServer' for unknown API combinators
864+
865+-- XXX: This omits the @context@ parameter, e.g.:
866+--
867+-- "There is no instance for HasServer (Bool :> …)". Do we care ?
868+instance {-# OVERLAPPABLE #-} TypeError (NoInstanceForSub HasServer ty) => HasServer (ty :> sub) context
869+
870+instance {-# OVERLAPPABLE #-} TypeError (NoInstanceFor (HasServer api context)) => HasServer api context
871+
872+-- | Ignore @'Fragment'@ in server handlers.
873+-- See <https://ietf.org/rfc/rfc2616.html#section-15.1.3> for more details.
874+--
875+-- Example:
876+--
877+-- > type MyApi = "books" :> Fragment Text :> Get '[JSON] [Book]
878+-- >
879+-- > server :: Server MyApi
880+-- > server = getBooks
881+-- > where getBooks :: Handler [Book]
882+-- > getBooks = ...return all books...
883+instance (AtLeastOneFragment api, FragmentUnique (Fragment a1 :> api), HasServer api context)
884+ => HasServer (Fragment a1 :> api) context where
885+ type ServerT (Fragment a1 :> api) m = ServerT api m
886+
887+ route _ = route (Proxy :: Proxy api)
888+
889+ hoistServerWithContext _ = hoistServerWithContext (Proxy :: Proxy api)
831890
832891-- $setup
833892-- >>> import Servant
893+
894+-- | A type that specifies that an API record contains a server implementation.
895+data AsServerT (m :: * -> *)
896+instance GenericMode (AsServerT m) where
897+ type AsServerT m :- api = ServerT api m
898+
899+type AsServer = AsServerT Handler
900+
901+
902+-- | Set of constraints required to convert to / from vanilla server types.
903+type GServerConstraints api m =
904+ ( ToServant api (AsServerT m) ~ ServerT (ToServantApi api) m
905+ , GServantProduct (Rep (api (AsServerT m)))
906+ )
907+
908+-- | This class is a necessary evil: in the implementation of 'HasServer' for
909+-- @'NamedRoutes' api@, we essentially need the quantified constraint @forall
910+-- m. 'GServerConstraints' m@ to hold.
911+--
912+-- We cannot require do that directly as the definition of 'GServerConstraints'
913+-- contains type family applications ('Rep' and 'ServerT'). The trick is to hide
914+-- those type family applications behind a typeclass providing evidence for
915+-- @'GServerConstraints' api m@ in the form of a dictionary, and require that
916+-- @forall m. 'GServer' api m@ instead.
917+--
918+-- Users shouldn't have to worry about this class, as the only possible instance
919+-- is provided in this module for all record APIs.
920+
921+class GServer (api :: * -> *) (m :: * -> *) where
922+ gServerProof :: Dict (GServerConstraints api m)
923+
924+instance
925+ ( ToServant api (AsServerT m) ~ ServerT (ToServantApi api) m
926+ , GServantProduct (Rep (api (AsServerT m)))
927+ ) => GServer api m where
928+ gServerProof = Dict
929+
930+instance
931+ ( HasServer (ToServantApi api) context
932+ , forall m. Generic (api (AsServerT m))
933+ , forall m. GServer api m
934+ ) => HasServer (NamedRoutes api) context where
935+
936+ type ServerT (NamedRoutes api) m = api (AsServerT m)
937+
938+ route
939+ :: Proxy (NamedRoutes api)
940+ -> Context context
941+ -> Delayed env (api (AsServerT Handler))
942+ -> Router env
943+ route _ ctx delayed =
944+ case gServerProof @api @Handler of
945+ Dict -> route (Proxy @(ToServantApi api)) ctx (toServant <$> delayed)
946+
947+ hoistServerWithContext
948+ :: forall m n. Proxy (NamedRoutes api)
949+ -> Proxy context
950+ -> (forall x. m x -> n x)
951+ -> api (AsServerT m)
952+ -> api (AsServerT n)
953+ hoistServerWithContext _ pctx nat server =
954+ case (gServerProof @api @m, gServerProof @api @n) of
955+ (Dict, Dict) ->
956+ fromServant servantSrvN
957+ where
958+ servantSrvM :: ServerT (ToServantApi api) m =
959+ toServant server
960+ servantSrvN :: ServerT (ToServantApi api) n =
961+ hoistServerWithContext (Proxy @(ToServantApi api)) pctx nat servantSrvM