@@ -1,29 +1,29 @@
1−{-# LANGUAGE AllowAmbiguousTypes #-}
1+{-# LANGUAGE CPP #-}
22{-# LANGUAGE ConstraintKinds #-}
33{-# LANGUAGE DataKinds #-}
44{-# LANGUAGE DeriveDataTypeable #-}
55{-# LANGUAGE FlexibleContexts #-}
66{-# LANGUAGE FlexibleInstances #-}
7−{-# LANGUAGE InstanceSigs #-}
87{-# LANGUAGE MultiParamTypeClasses #-}
98{-# LANGUAGE OverloadedStrings #-}
109{-# LANGUAGE PolyKinds #-}
11−{-# LANGUAGE QuantifiedConstraints #-}
1210{-# LANGUAGE RankNTypes #-}
1311{-# LANGUAGE ScopedTypeVariables #-}
1412{-# LANGUAGE TupleSections #-}
15−{-# LANGUAGE TypeApplications #-}
1613{-# LANGUAGE TypeFamilies #-}
1714{-# LANGUAGE TypeOperators #-}
1815{-# LANGUAGE UndecidableInstances #-}
1916
17+#if MIN_VERSION_base(4,9,0) && __GLASGOW_HASKELL__ >= 802
18+#define HAS_TYPE_ERROR
19+#endif
20+
2021module Servant.Server.Internal
2122 ( module Servant.Server.Internal
2223 , module Servant.Server.Internal.BasicAuth
2324 , module Servant.Server.Internal.Context
2425 , module Servant.Server.Internal.Delayed
2526 , 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
@@ -41,11 +41,12 @@ 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(..))
4544import Data.Either
4645 (partitionEithers)
4746import Data.Maybe
4847 (fromMaybe, isNothing, mapMaybe, maybeToList)
48+import Data.Semigroup
49+ ((<>))
4950import Data.String
5051 (IsString (..))
5152import Data.String.Conversions
@@ -54,9 +55,8 @@ import Data.Tagged
5455 (Tagged (..), retag, untag)
5556import qualified Data.Text as T
5657import Data.Typeable
57−import GHC.Generics
5858import GHC.TypeLits
59− (KnownNat, KnownSymbol, TypeError, symbolVal)
59+ (KnownNat, KnownSymbol, natVal, symbolVal)
6060import qualified Network.HTTP.Media as NHM
6161import Network.HTTP.Types hiding
6262 (Header, ResponseHeaders)
@@ -64,52 +64,47 @@ import Network.Socket
6464 (SockAddr)
6565import Network.Wai
6666 (Application, Request, httpVersion, isSecure, lazyRequestBody,
67− queryString, remoteHost, getRequestBodyChunk, requestHeaders,
67+ rawQueryString, remoteHost, requestBody, requestHeaders,
6868 requestMethod, responseLBS, responseStream, vault)
6969import Prelude ()
7070import Prelude.Compat
7171import Servant.API
7272 ((:<|>) (..), (:>), Accept (..), BasicAuth, Capture',
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)
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, NoContentVerb,
79+ WithNamedContext)
8180import Servant.API.ContentTypes
8281 (AcceptHeader (..), AllCTRender (..), AllCTUnrender (..),
83− AllMime, MimeRender (..), MimeUnrender (..), NoContent,
84− canHandleAcceptH)
82+ AllMime, MimeRender (..), MimeUnrender (..), canHandleAcceptH,
83+ NoContent (NoContent))
8584import Servant.API.Modifiers
8685 (FoldLenient, FoldRequired, RequestArgument,
8786 unfoldRequestArgument)
8887import Servant.API.ResponseHeaders
8988 (GetHeaders, Headers, getHeaders, getResponse)
90−import Servant.API.Status
91− (statusFromNat)
9289import qualified Servant.Types.SourceT as S
93−import Servant.API.TypeErrors
9490import Web.HttpApiData
95− (FromHttpApiData, parseHeader, parseQueryParam, parseUrlPiece,
96− parseUrlPieces)
91+ (FromHttpApiData, parseHeader, parseQueryParam,
92+ parseUrlPieceMaybe, parseUrlPieces, parseUrlPiece)
9793
9894import Servant.Server.Internal.BasicAuth
9995import Servant.Server.Internal.Context
10096import Servant.Server.Internal.Delayed
10197import Servant.Server.Internal.DelayedIO
102−import Servant.Server.Internal.ErrorFormatter
10398import Servant.Server.Internal.Handler
10499import Servant.Server.Internal.Router
105100import Servant.Server.Internal.RouteResult
106101import Servant.Server.Internal.RoutingApplication
107102import Servant.Server.Internal.ServerError
108103
104+#ifdef HAS_TYPE_ERROR
109105import GHC.TypeLits
110106 (ErrorMessage (..), TypeError)
111−import Servant.API.TypeLevel
112− (AtLeastOneFragment, FragmentUnique)
107+#endif
113108
114109class HasServer api context where
115110 type ServerT api (m :: * -> *) :: *
@@ -173,10 +168,7 @@ instance (HasServer a context, HasServer b context) => HasServer (a :<|> b) cont
173168-- > server = getBook
174169-- > where getBook :: Text -> Handler Book
175170-- > getBook isbn = ...
176−instance (KnownSymbol capture, FromHttpApiData a, Typeable a
177− , HasServer api context, SBoolI (FoldLenient mods)
178− , HasContextEntry (MkContextWithErrorFormatter context) ErrorFormatters
179− )
171+instance (KnownSymbol capture, FromHttpApiData a, HasServer api context, SBoolI (FoldLenient mods))
180172 => HasServer (Capture' mods capture a :> api) context where
181173
182174 type ServerT (Capture' mods capture a :> api) m =
@@ -185,19 +177,15 @@ instance (KnownSymbol capture, FromHttpApiData a, Typeable a
185177 hoistServerWithContext _ pc nt s = hoistServerWithContext (Proxy :: Proxy api) pc nt . s
186178
187179 route Proxy context d =
188− CaptureRouter [hint] $
180+ CaptureRouter $
189181 route (Proxy :: Proxy api)
190182 context
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))
183+ (addCapture d $ \ txt -> case ( sbool :: SBool (FoldLenient mods)
184+ , parseUrlPiece txt :: Either T.Text a) of
185+ (SFalse, Left e) -> delayedFail err400 { errBody = cs e }
186+ (SFalse, Right v) -> return v
187+ (STrue, piece) -> return $ (either (Left . cs) Right) piece
188+ )
201189
202190-- | If you use 'CaptureAll' in one of the endpoints for your API,
203191-- this automatically requires your server-side handler to be a
@@ -216,10 +204,7 @@ instance (KnownSymbol capture, FromHttpApiData a, Typeable a
216204-- > server = getSourceFile
217205-- > where getSourceFile :: [Text] -> Handler Book
218206-- > getSourceFile pathSegments = ...
219−instance (KnownSymbol capture, FromHttpApiData a, Typeable a
220− , HasServer api context
221− , HasContextEntry (MkContextWithErrorFormatter context) ErrorFormatters
222− )
207+instance (KnownSymbol capture, FromHttpApiData a, HasServer api context)
223208 => HasServer (CaptureAll capture a :> api) context where
224209
225210 type ServerT (CaptureAll capture a :> api) m =
@@ -228,18 +213,14 @@ instance (KnownSymbol capture, FromHttpApiData a, Typeable a
228213 hoistServerWithContext _ pc nt s = hoistServerWithContext (Proxy :: Proxy api) pc nt . s
229214
230215 route Proxy context d =
231− CaptureAllRouter [hint] $
216+ CaptureAllRouter $
232217 route (Proxy :: Proxy api)
233218 context
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
219+ (addCapture d $ \ txts -> case parseUrlPieces txts of
220+ Left _ -> delayedFail err400
221+ Right v -> return v
238222 )
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]))
223+
243224
244225allowedMethodHead :: Method -> Request -> Bool
245226allowedMethodHead method request = method == methodGet && requestMethod request == methodHead
@@ -259,10 +240,10 @@ methodCheck method request
259240-- body check is no longer an option. However, we now run the accept
260241-- check before the body check and can therefore afford to make it
261242-- recoverable.
262−acceptCheck :: (AllMime list) => Proxy list -> AcceptHeader -> DelayedIO ()
243+acceptCheck :: (AllMime list) => Proxy list -> B.ByteString -> DelayedIO ()
263244acceptCheck proxy accH
264− | canHandleAcceptH proxy accH = return ()
265− | otherwise = delayedFail err406
245+ | canHandleAcceptH proxy (AcceptHeader accH) = return ()
246+ | otherwise = delayedFail err406
266247
267248methodRouter :: (AllCTRender ctypes a)
268249 => (b -> ([(HeaderName, B.ByteString)], a))
@@ -272,12 +253,12 @@ methodRouter :: (AllCTRender ctypes a)
272253methodRouter splitHeaders method proxy status action = leafRouter route'
273254 where
274255 route' env request respond =
275− let accH = getAcceptHeader request
256+ let accH = fromMaybe ct_wildcard $ lookup hAccept $ requestHeaders request
276257 in runAction (action `addMethodCheck` methodCheck method request
277258 `addAcceptCheck` acceptCheck proxy accH
278259 ) env request respond $ \ output -> do
279260 let (headers, b) = splitHeaders output
280− case handleAcceptH proxy accH b of
261+ case handleAcceptH proxy (AcceptHeader accH) b of
281262 Nothing -> FailFatal err406 -- this should not happen (checked before), so we make it fatal if it does
282263 Just (contentT, body) ->
283264 let bdy = if allowedMethodHead method request then "" else body
@@ -291,7 +272,7 @@ noContentRouter method status action = leafRouter route'
291272 where
292273 route' env request respond =
293274 runAction (action `addMethodCheck` methodCheck method request)
294− env request respond $ \ _output ->
275+ env request respond $ \ output ->
295276 Route $ responseLBS status [] ""
296277
297278instance {-# OVERLAPPABLE #-}
@@ -303,7 +284,7 @@ instance {-# OVERLAPPABLE #-}
303284
304285 route Proxy _ = methodRouter ([],) method (Proxy :: Proxy ctypes) status
305286 where method = reflectMethod (Proxy :: Proxy method)
306− status = statusFromNat (Proxy :: Proxy status)
287+ status = toEnum . fromInteger $ natVal (Proxy :: Proxy status)
307288
308289instance {-# OVERLAPPING #-}
309290 ( AllCTRender ctypes a, ReflectMethod method, KnownNat status
@@ -315,7 +296,7 @@ instance {-# OVERLAPPING #-}
315296
316297 route Proxy _ = methodRouter (\x -> (getHeaders x, getResponse x)) method (Proxy :: Proxy ctypes) status
317298 where method = reflectMethod (Proxy :: Proxy method)
318− status = statusFromNat (Proxy :: Proxy status)
299+ status = toEnum . fromInteger $ natVal (Proxy :: Proxy status)
319300
320301instance (ReflectMethod method) =>
321302 HasServer (NoContentVerb method) context where
@@ -336,7 +317,7 @@ instance {-# OVERLAPPABLE #-}
336317
337318 route Proxy _ = streamRouter ([],) method status (Proxy :: Proxy framing) (Proxy :: Proxy ctype)
338319 where method = reflectMethod (Proxy :: Proxy method)
339− status = statusFromNat (Proxy :: Proxy status)
320+ status = toEnum . fromInteger $ natVal (Proxy :: Proxy status)
340321
341322
342323instance {-# OVERLAPPING #-}
@@ -350,7 +331,7 @@ instance {-# OVERLAPPING #-}
350331
351332 route Proxy _ = streamRouter (\x -> (getHeaders x, getResponse x)) method status (Proxy :: Proxy framing) (Proxy :: Proxy ctype)
352333 where method = reflectMethod (Proxy :: Proxy method)
353− status = statusFromNat (Proxy :: Proxy status)
334+ status = toEnum . fromInteger $ natVal (Proxy :: Proxy status)
354335
355336
356337streamRouter :: forall ctype a c chunk env framing. (MimeRender ctype chunk, FramingRender framing, ToSourceIO chunk a) =>
@@ -362,7 +343,7 @@ streamRouter :: forall ctype a c chunk env framing. (MimeRender ctype chunk, Fra
362343 -> Delayed env (Handler c)
363344 -> Router env
364345streamRouter splitHeaders method status framingproxy ctypeproxy action = leafRouter $ \env request respond ->
365− let AcceptHeader accH = getAcceptHeader request
346+ let accH = fromMaybe ct_wildcard $ lookup hAccept $ requestHeaders request
366347 cmediatype = NHM.matchAccept [contentType ctypeproxy] accH
367348 accCheck = when (isNothing cmediatype) $ delayedFail err406
368349 contentHeader = (hContentType, NHM.renderHeader . maybeToList $ cmediatype)
@@ -407,7 +388,6 @@ streamRouter splitHeaders method status framingproxy ctypeproxy action = leafRou
407388instance
408389 (KnownSymbol sym, FromHttpApiData a, HasServer api context
409390 , SBoolI (FoldRequired mods), SBoolI (FoldLenient mods)
410− , HasContextEntry (MkContextWithErrorFormatter context) ErrorFormatters
411391 )
412392 => HasServer (Header' mods sym a :> api) context where
413393------
@@ -419,9 +399,6 @@ instance
419399 route Proxy context subserver = route (Proxy :: Proxy api) context $
420400 subserver `addHeaderCheck` withRequest headerCheck
421401 where
422− rep = typeRep (Proxy :: Proxy Header')
423− formatError = headerParseErrorFormatter $ getContextEntry (mkContextWithErrorFormatter context)
424−
425402 headerName :: IsString n => n
426403 headerName = fromString $ symbolVal (Proxy :: Proxy sym)
427404
@@ -432,13 +409,15 @@ instance
432409 mev :: Maybe (Either T.Text a)
433410 mev = fmap parseHeader $ lookup headerName (requestHeaders req)
434411
435− errReq = delayedFailFatal $ formatError rep req
436− $ "Header " <> headerName <> " is required"
412+ errReq = delayedFailFatal err400
413+ { errBody = "Header " <> headerName <> " is required"
414+ }
437415
438− errSt e = delayedFailFatal $ formatError rep req
439− $ cs $ "Error parsing header "
440− <> headerName
441− <> " failed: " <> e
416+ errSt e = delayedFailFatal err400
417+ { errBody = cs $ "Error parsing header "
418+ <> headerName
419+ <> " failed: " <> e
420+ }
442421
443422-- | If you use @'QueryParam' "author" Text@ in one of the endpoints for your API,
444423-- this automatically requires your server-side handler to be a function
@@ -464,7 +443,6 @@ instance
464443instance
465444 ( KnownSymbol sym, FromHttpApiData a, HasServer api context
466445 , SBoolI (FoldRequired mods), SBoolI (FoldLenient mods)
467− , HasContextEntry (MkContextWithErrorFormatter context) ErrorFormatters
468446 )
469447 => HasServer (QueryParam' mods sym a :> api) context where
470448------
@@ -474,12 +452,9 @@ instance
474452 hoistServerWithContext _ pc nt s = hoistServerWithContext (Proxy :: Proxy api) pc nt . s
475453
476454 route Proxy context subserver =
477− let querytext = queryToQueryText . queryString
455+ let querytext req = parseQueryText $ rawQueryString req
478456 paramname = cs $ symbolVal (Proxy :: Proxy sym)
479457
480− rep = typeRep (Proxy :: Proxy QueryParam')
481− formatError = urlParseErrorFormatter $ getContextEntry (mkContextWithErrorFormatter context)
482−
483458 parseParam :: Request -> DelayedIO (RequestArgument mods a)
484459 parseParam req =
485460 unfoldRequestArgument (Proxy :: Proxy mods) errReq errSt mev
@@ -487,12 +462,14 @@ instance
487462 mev :: Maybe (Either T.Text a)
488463 mev = fmap parseQueryParam $ join $ lookup paramname $ querytext req
489464
490− errReq = delayedFailFatal $ formatError rep req
491− $ cs $ "Query parameter " <> paramname <> " is required"
465+ errReq = delayedFailFatal err400
466+ { errBody = cs $ "Query parameter " <> paramname <> " is required"
467+ }
492468
493− errSt e = delayedFailFatal $ formatError rep req
494− $ cs $ "Error parsing query parameter "
495− <> paramname <> " failed: " <> e
469+ errSt e = delayedFailFatal err400
470+ { errBody = cs $ "Error parsing query parameter "
471+ <> paramname <> " failed: " <> e
472+ }
496473
497474 delayed = addParameterCheck subserver . withRequest $ \req ->
498475 parseParam req
@@ -518,8 +495,7 @@ instance
518495-- > server = getBooksBy
519496-- > where getBooksBy :: [Text] -> Handler [Book]
520497-- > getBooksBy authors = ...return all books by these authors...
521−instance (KnownSymbol sym, FromHttpApiData a, HasServer api context
522− , HasContextEntry (MkContextWithErrorFormatter context) ErrorFormatters)
498+instance (KnownSymbol sym, FromHttpApiData a, HasServer api context)
523499 => HasServer (QueryParams sym a :> api) context where
524500
525501 type ServerT (QueryParams sym a :> api) m =
@@ -530,23 +506,21 @@ instance (KnownSymbol sym, FromHttpApiData a, HasServer api context
530506 route Proxy context subserver = route (Proxy :: Proxy api) context $
531507 subserver `addParameterCheck` withRequest paramsCheck
532508 where
533− rep = typeRep (Proxy :: Proxy QueryParams)
534− formatError = urlParseErrorFormatter $ getContextEntry (mkContextWithErrorFormatter context)
535−
536509 paramname = cs $ symbolVal (Proxy :: Proxy sym)
537510 paramsCheck req =
538511 case partitionEithers $ fmap parseQueryParam params of
539512 ([], parsed) -> return parsed
540− (errs, _) -> delayedFailFatal $ formatError rep req
541− $ cs $ "Error parsing query parameter(s) "
542− <> paramname <> " failed: "
543− <> T.intercalate ", " errs
513+ (errs, _) -> delayedFailFatal err400
514+ { errBody = cs $ "Error parsing query parameter(s) "
515+ <> paramname <> " failed: "
516+ <> T.intercalate ", " errs
517+ }
544518 where
545519 params :: [T.Text]
546520 params = mapMaybe snd
547521 . filter (looksLikeParam . fst)
548− . queryToQueryText
549− . queryString
522+ . parseQueryText
523+ . rawQueryString
550524 $ req
551525
552526 looksLikeParam name = name == paramname || name == (paramname <> "[]")
@@ -572,7 +546,7 @@ instance (KnownSymbol sym, HasServer api context)
572546 hoistServerWithContext _ pc nt s = hoistServerWithContext (Proxy :: Proxy api) pc nt . s
573547
574548 route Proxy context subserver =
575− let querytext = queryToQueryText . queryString
549+ let querytext r = parseQueryText $ rawQueryString r
576550 param r = case lookup paramname (querytext r) of
577551 Just Nothing -> True -- param is there, with no value
578552 Just (Just v) -> examine v -- param with a value
@@ -614,7 +588,7 @@ instance HasServer Raw context where
614588-- The @Content-Type@ header is inspected, and the list provided is used to
615589-- attempt deserialization. If the request does not have a @Content-Type@
616590-- header, it is treated as @application/octet-stream@ (as specified in
617−-- [RFC 7231 section 3.1.1.5](http://tools.ietf.org/html/rfc7231#section-3.1.1.5)).
591+-- <http://tools.ietf.org/html/rfc7231#section-3.1.1.5 RFC7231>.
618592-- This lets servant worry about extracting it from the request and turning
619593-- it into a value of the type you specify.
620594--
@@ -630,7 +604,6 @@ instance HasServer Raw context where
630604-- > where postBook :: Book -> Handler Book
631605-- > postBook book = ...insert into your db...
632606instance ( AllCTUnrender list a, HasServer api context, SBoolI (FoldLenient mods)
633− , HasContextEntry (MkContextWithErrorFormatter context) ErrorFormatters
634607 ) => HasServer (ReqBody' mods list a :> api) context where
635608
636609 type ServerT (ReqBody' mods list a :> api) m =
@@ -642,9 +615,6 @@ instance ( AllCTUnrender list a, HasServer api context, SBoolI (FoldLenient mods
642615 = route (Proxy :: Proxy api) context $
643616 addBodyCheck subserver ctCheck bodyCheck
644617 where
645− rep = typeRep (Proxy :: Proxy ReqBody')
646− formatError = bodyParserErrorFormatter $ getContextEntry (mkContextWithErrorFormatter context)
647−
648618 -- Content-Type check, we only lookup we can try to parse the request body
649619 ctCheck = withRequest $ \ request -> do
650620 -- See HTTP RFC 2616, section 7.2.1
@@ -663,7 +633,7 @@ instance ( AllCTUnrender list a, HasServer api context, SBoolI (FoldLenient mods
663633 case sbool :: SBool (FoldLenient mods) of
664634 STrue -> return mrqbody
665635 SFalse -> case mrqbody of
666− Left e -> delayedFailFatal $ formatError rep request e
636+ Left e -> delayedFailFatal err400 { errBody = cs e }
667637 Right v -> return v
668638
669639instance
@@ -686,7 +656,7 @@ instance
686656 bodyCheck fromRS = withRequest $ \req -> do
687657 let mimeUnrender' = mimeUnrender (Proxy :: Proxy ctype) :: BL.ByteString -> Either String chunk
688658 let framingUnrender' = framingUnrender (Proxy :: Proxy framing) mimeUnrender' :: SourceIO B.ByteString -> SourceIO chunk
689− let body = getRequestBodyChunk req
659+ let body = requestBody req
690660 let rs = S.fromAction B.null body
691661 let rs' = fromRS $ framingUnrender' rs
692662 return rs'
@@ -755,12 +725,12 @@ data EmptyServer = EmptyServer deriving (Typeable, Eq, Show, Bounded, Enum)
755725emptyServer :: ServerT EmptyAPI m
756726emptyServer = Tagged EmptyServer
757727
758−-- | The server for an `EmptyAPI` is `emptyServer`.
728+-- | The server for an `EmptyAPI` is `emptyAPIServer`.
759729--
760730-- > type MyApi = "nothing" :> EmptyApi
761731-- >
762732-- > server :: Server MyApi
763−-- > server = emptyServer
733+-- > server = emptyAPIServer
764734instance HasServer EmptyAPI context where
765735 type ServerT EmptyAPI m = Tagged m EmptyServer
766736
@@ -789,10 +759,7 @@ instance ( KnownSymbol realm
789759-- * helpers
790760
791761ct_wildcard :: B.ByteString
792−ct_wildcard = "*" <> "/" <> "*"
793−
794−getAcceptHeader :: Request -> AcceptHeader
795−getAcceptHeader = AcceptHeader . fromMaybe ct_wildcard . lookup hAccept . requestHeaders
762+ct_wildcard = "*" <> "/" <> "*" -- Because CPP
796763
797764-- * General Authentication
798765
@@ -817,15 +784,39 @@ instance (HasContextEntry context (NamedContext name subContext), HasServer subA
817784 hoistServerWithContext _ _ nt s = hoistServerWithContext (Proxy :: Proxy subApi) (Proxy :: Proxy subContext) nt s
818785
819786-------------------------------------------------------------------------------
820−-- Custom type errors
787+-- TypeError helpers
821788-------------------------------------------------------------------------------
822789
823−-- Erroring instance for 'HasServer' when a combinator is not fully applied
824−instance TypeError (PartialApplication HasServer arr) => HasServer ((arr :: a -> b) :> sub) context
790+#ifdef HAS_TYPE_ERROR
791+-- | This instance catches mistakes when there are non-saturated
792+-- type applications on LHS of ':>'.
793+--
794+-- >>> serve (Proxy :: Proxy (Capture "foo" :> Get '[JSON] Int)) (error "...")
795+-- ...
796+-- ...Expected something of kind Symbol or *, got: k -> l on the LHS of ':>'.
797+-- ...Maybe you haven't applied enough arguments to
798+-- ...Capture' '[] "foo"
799+-- ...
800+--
801+-- >>> undefined :: Server (Capture "foo" :> Get '[JSON] Int)
802+-- ...
803+-- ...Expected something of kind Symbol or *, got: k -> l on the LHS of ':>'.
804+-- ...Maybe you haven't applied enough arguments to
805+-- ...Capture' '[] "foo"
806+-- ...
807+--
808+instance TypeError (HasServerArrowKindError arr) => HasServer ((arr :: k -> l) :> api) context
825809 where
826− type ServerT (arr :> sub) _ = TypeError (PartialApplication (HasServer :: * -> [*] -> Constraint) arr)
827− route = error "unreachable"
828− hoistServerWithContext _ _ _ _ = error "unreachable"
810+ type ServerT (arr :> api) m = TypeError (HasServerArrowKindError arr)
811+ -- it doens't really matter what sub route we peak
812+ route _ _ _ = error "servant-server panic: impossible happened in HasServer (arr :> api)"
813+ hoistServerWithContext _ _ _ = id
814+
815+-- Cannot have TypeError here, otherwise use of this symbol will error :)
816+type HasServerArrowKindError arr =
817+ 'Text "Expected something of kind Symbol or *, got: k -> l on the LHS of ':>'."
818+ ':$$: 'Text "Maybe you haven't applied enough arguments to"
819+ ':$$: 'ShowType arr
829820
830821-- | This instance prevents from accidentally using '->' instead of ':>'
831822--
@@ -859,103 +850,7 @@ type HasServerArrowTypeError a b =
859850 ':$$: 'ShowType a
860851 ':$$: 'Text "and"
861852 ':$$: 'ShowType b
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)
853+#endif
890854
891855-- $setup
892856-- >>> 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