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Merge pull request #457 from kosmikus/fix-router-sharing

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Fix router sharing
This commit is contained in:
Andres Löh 2016-04-12 10:04:05 +02:00
commit 15143cc900
10 changed files with 292 additions and 269 deletions
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9
servant-server/CHANGELOG.md
View file

@ -1,10 +1,11 @@
0.7
---
* The `Router` type has been changed. There are now more situations where
servers will make use of static lookups to efficiently route the request
to the correct endpoint. Functions `layout` and `layoutWithContext` have
been added to visualize the router layout for debugging purposes. Test
* The `Router` type has been changed. Static router tables should now
be properly shared between requests, drastically increasing the
number of situations where servers will be able to route requests
efficiently. Functions `layout` and `layoutWithContext` have been
added to visualize the router layout for debugging purposes. Test
cases for expected router layouts have been added.
* Export `throwError` from module `Servant`
* Add `Handler` type synonym

22
servant-server/src/Servant/Server.hs
View file

@ -132,21 +132,13 @@ serve p = serveWithContext p EmptyContext
serveWithContext :: (HasServer layout context)
=> Proxy layout -> Context context -> Server layout -> Application
serveWithContext p context server = toApplication (runRouter (route p context d))
where
d = Delayed r r r r (\ _ _ _ -> Route server)
r = return (Route ())
serveWithContext p context server =
toApplication (runRouter (route p context (emptyDelayed (Route server))))
-- | The function 'layout' produces a textual description of the internal
-- router layout for debugging purposes. Note that the router layout is
-- determined just by the API, not by the handlers.
--
-- This function makes certain assumptions about the well-behavedness of
-- the 'HasServer' instances of the combinators which should be ok for the
-- core servant constructions, but might not be satisfied for some other
-- combinators provided elsewhere. It is possible that the function may
-- crash for these.
--
-- Example:
--
-- For the following API
@ -168,7 +160,7 @@ serveWithContext p context server = toApplication (runRouter (route p context d)
-- > │ └─ e/
-- > │ └─•
-- > ├─ b/
-- > │ └─ <dyn>/
-- > │ └─ <capture>/
-- > │ ├─•
-- > │ ┆
-- > │ └─•
@ -185,7 +177,7 @@ serveWithContext p context server = toApplication (runRouter (route p context d)
--
-- [@─•@] Leaves reflect endpoints.
--
-- [@\<dyn\>/@] This is a delayed capture of a path component.
-- [@\<capture\>/@] This is a delayed capture of a path component.
--
-- [@\<raw\>@] This is a part of the API we do not know anything about.
--
@ -200,10 +192,8 @@ layout p = layoutWithContext p EmptyContext
-- | Variant of 'layout' that takes an additional 'Context'.
layoutWithContext :: (HasServer layout context)
=> Proxy layout -> Context context -> Text
layoutWithContext p context = routerLayout (route p context d)
where
d = Delayed r r r r (\ _ _ _ -> FailFatal err501)
r = return (Route ())
layoutWithContext p context =
routerLayout (route p context (emptyDelayed (FailFatal err501)))
-- Documentation

18
servant-server/src/Servant/Server/Experimental/Auth.hs
View file

@ -12,6 +12,7 @@
module Servant.Server.Experimental.Auth where
import Control.Monad.Trans (liftIO)
import Control.Monad.Trans.Except (runExceptT)
import Data.Proxy (Proxy (Proxy))
import Data.Typeable (Typeable)
@ -24,10 +25,11 @@ import Servant.Server.Internal (HasContextEntry,
HasServer, ServerT,
getContextEntry,
route)
import Servant.Server.Internal.Router (Router' (WithRequest))
import Servant.Server.Internal.RoutingApplication (RouteResult (FailFatal, Route),
addAuthCheck)
import Servant.Server.Internal.ServantErr (ServantErr, Handler)
import Servant.Server.Internal.RoutingApplication (addAuthCheck,
delayedFailFatal,
DelayedIO,
withRequest)
import Servant.Server.Internal.ServantErr (Handler)
-- * General Auth
@ -57,8 +59,10 @@ instance ( HasServer api context
type ServerT (AuthProtect tag :> api) m =
AuthServerData (AuthProtect tag) -> ServerT api m
route Proxy context subserver = WithRequest $ \ request ->
route (Proxy :: Proxy api) context (subserver `addAuthCheck` authCheck request)
route Proxy context subserver =
route (Proxy :: Proxy api) context (subserver `addAuthCheck` withRequest authCheck)
where
authHandler :: Request -> Handler (AuthServerData (AuthProtect tag))
authHandler = unAuthHandler (getContextEntry context)
authCheck = fmap (either FailFatal Route) . runExceptT . authHandler
authCheck :: Request -> DelayedIO (AuthServerData (AuthProtect tag))
authCheck = (>>= either delayedFailFatal return) . liftIO . runExceptT . authHandler

109
servant-server/src/Servant/Server/Internal.hs
View file

@ -22,6 +22,7 @@ module Servant.Server.Internal
, module Servant.Server.Internal.ServantErr
) where
import Control.Monad.Trans (liftIO)
import qualified Data.ByteString as B
import qualified Data.ByteString.Char8 as BC8
import qualified Data.ByteString.Lazy as BL
@ -70,7 +71,11 @@ import Servant.Server.Internal.ServantErr
class HasServer layout context where
type ServerT layout (m :: * -> *) :: *
route :: Proxy layout -> Context context -> Delayed (Server layout) -> Router
route ::
Proxy layout
-> Context context
-> Delayed env (Server layout)
-> Router env
type Server layout = ServerT layout Handler
@ -120,12 +125,12 @@ instance (KnownSymbol capture, FromHttpApiData a, HasServer sublayout context)
a -> ServerT sublayout m
route Proxy context d =
DynamicRouter $ \ first ->
CaptureRouter $
route (Proxy :: Proxy sublayout)
context
(addCapture d $ case parseUrlPieceMaybe first :: Maybe a of
Nothing -> return $ Fail err400
Just v -> return $ Route v
(addCapture d $ \ txt -> case parseUrlPieceMaybe txt :: Maybe a of
Nothing -> delayedFail err400
Just v -> return v
)
allowedMethodHead :: Method -> Request -> Bool
@ -144,41 +149,41 @@ processMethodRouter handleA status method headers request = case handleA of
bdy = if allowedMethodHead method request then "" else body
hdrs = (hContentType, cs contentT) : (fromMaybe [] headers)
methodCheck :: Method -> Request -> IO (RouteResult ())
methodCheck :: Method -> Request -> DelayedIO ()
methodCheck method request
| allowedMethod method request = return $ Route ()
| otherwise = return $ Fail err405
| allowedMethod method request = return ()
| otherwise = delayedFail err405
acceptCheck :: (AllMime list) => Proxy list -> B.ByteString -> IO (RouteResult ())
acceptCheck :: (AllMime list) => Proxy list -> B.ByteString -> DelayedIO ()
acceptCheck proxy accH
| canHandleAcceptH proxy (AcceptHeader accH) = return $ Route ()
| otherwise = return $ FailFatal err406
| canHandleAcceptH proxy (AcceptHeader accH) = return ()
| otherwise = delayedFailFatal err406
methodRouter :: (AllCTRender ctypes a)
=> Method -> Proxy ctypes -> Status
-> Delayed (Handler a)
-> Router
-> Delayed env (Handler a)
-> Router env
methodRouter method proxy status action = leafRouter route'
where
route' request respond =
route' env request respond =
let accH = fromMaybe ct_wildcard $ lookup hAccept $ requestHeaders request
in runAction (action `addMethodCheck` methodCheck method request
`addAcceptCheck` acceptCheck proxy accH
) respond $ \ output -> do
) env request respond $ \ output -> do
let handleA = handleAcceptH proxy (AcceptHeader accH) output
processMethodRouter handleA status method Nothing request
methodRouterHeaders :: (GetHeaders (Headers h v), AllCTRender ctypes v)
=> Method -> Proxy ctypes -> Status
-> Delayed (Handler (Headers h v))
-> Router
-> Delayed env (Handler (Headers h v))
-> Router env
methodRouterHeaders method proxy status action = leafRouter route'
where
route' request respond =
route' env request respond =
let accH = fromMaybe ct_wildcard $ lookup hAccept $ requestHeaders request
in runAction (action `addMethodCheck` methodCheck method request
`addAcceptCheck` acceptCheck proxy accH
) respond $ \ output -> do
) env request respond $ \ output -> do
let headers = getHeaders output
handleA = handleAcceptH proxy (AcceptHeader accH) (getResponse output)
processMethodRouter handleA status method (Just headers) request
@ -230,8 +235,8 @@ instance (KnownSymbol sym, FromHttpApiData a, HasServer sublayout context)
type ServerT (Header sym a :> sublayout) m =
Maybe a -> ServerT sublayout m
route Proxy context subserver = WithRequest $ \ request ->
let mheader = parseHeaderMaybe =<< lookup str (requestHeaders request)
route Proxy context subserver =
let mheader req = parseHeaderMaybe =<< lookup str (requestHeaders req)
in route (Proxy :: Proxy sublayout) context (passToServer subserver mheader)
where str = fromString $ symbolVal (Proxy :: Proxy sym)
@ -262,10 +267,10 @@ instance (KnownSymbol sym, FromHttpApiData a, HasServer sublayout context)
type ServerT (QueryParam sym a :> sublayout) m =
Maybe a -> ServerT sublayout m
route Proxy context subserver = WithRequest $ \ request ->
let querytext = parseQueryText $ rawQueryString request
param =
case lookup paramname querytext of
route Proxy context subserver =
let querytext r = parseQueryText $ rawQueryString r
param r =
case lookup paramname (querytext r) of
Nothing -> Nothing -- param absent from the query string
Just Nothing -> Nothing -- param present with no value -> Nothing
Just (Just v) -> parseQueryParamMaybe v -- if present, we try to convert to
@ -298,13 +303,13 @@ instance (KnownSymbol sym, FromHttpApiData a, HasServer sublayout context)
type ServerT (QueryParams sym a :> sublayout) m =
[a] -> ServerT sublayout m
route Proxy context subserver = WithRequest $ \ request ->
let querytext = parseQueryText $ rawQueryString request
route Proxy context subserver =
let querytext r = parseQueryText $ rawQueryString r
-- if sym is "foo", we look for query string parameters
-- named "foo" or "foo[]" and call parseQueryParam on the
-- corresponding values
parameters = filter looksLikeParam querytext
values = mapMaybe (convert . snd) parameters
parameters r = filter looksLikeParam (querytext r)
values r = mapMaybe (convert . snd) (parameters r)
in route (Proxy :: Proxy sublayout) context (passToServer subserver values)
where paramname = cs $ symbolVal (Proxy :: Proxy sym)
looksLikeParam (name, _) = name == paramname || name == (paramname <> "[]")
@ -329,9 +334,9 @@ instance (KnownSymbol sym, HasServer sublayout context)
type ServerT (QueryFlag sym :> sublayout) m =
Bool -> ServerT sublayout m
route Proxy context subserver = WithRequest $ \ request ->
let querytext = parseQueryText $ rawQueryString request
param = case lookup paramname querytext of
route Proxy context subserver =
let querytext r = parseQueryText $ rawQueryString r
param r = case lookup paramname (querytext r) of
Just Nothing -> True -- param is there, with no value
Just (Just v) -> examine v -- param with a value
Nothing -> False -- param not in the query string
@ -352,8 +357,8 @@ instance HasServer Raw context where
type ServerT Raw m = Application
route Proxy _ rawApplication = RawRouter $ \ request respond -> do
r <- runDelayed rawApplication
route Proxy _ rawApplication = RawRouter $ \ env request respond -> do
r <- runDelayed rawApplication env request
case r of
Route app -> app request (respond . Route)
Fail a -> respond $ Fail a
@ -386,10 +391,10 @@ instance ( AllCTUnrender list a, HasServer sublayout context
type ServerT (ReqBody list a :> sublayout) m =
a -> ServerT sublayout m
route Proxy context subserver = WithRequest $ \ request ->
route (Proxy :: Proxy sublayout) context (addBodyCheck subserver (bodyCheck request))
route Proxy context subserver =
route (Proxy :: Proxy sublayout) context (addBodyCheck subserver bodyCheck)
where
bodyCheck request = do
bodyCheck = withRequest $ \ request -> do
-- See HTTP RFC 2616, section 7.2.1
-- http://www.w3.org/Protocols/rfc2616/rfc2616-sec7.html#sec7.2.1
-- See also "W3C Internet Media Type registration, consistency of use"
@ -397,11 +402,11 @@ instance ( AllCTUnrender list a, HasServer sublayout context
let contentTypeH = fromMaybe "application/octet-stream"
$ lookup hContentType $ requestHeaders request
mrqbody <- handleCTypeH (Proxy :: Proxy list) (cs contentTypeH)
<$> lazyRequestBody request
<$> liftIO (lazyRequestBody request)
case mrqbody of
Nothing -> return $ FailFatal err415
Just (Left e) -> return $ FailFatal err400 { errBody = cs e }
Just (Right v) -> return $ Route v
Nothing -> delayedFailFatal err415
Just (Left e) -> delayedFailFatal err400 { errBody = cs e }
Just (Right v) -> return v
-- | Make sure the incoming request starts with @"/path"@, strip it and
-- pass the rest of the request path to @sublayout@.
@ -418,28 +423,28 @@ instance (KnownSymbol path, HasServer sublayout context) => HasServer (path :> s
instance HasServer api context => HasServer (RemoteHost :> api) context where
type ServerT (RemoteHost :> api) m = SockAddr -> ServerT api m
route Proxy context subserver = WithRequest $ \req ->
route (Proxy :: Proxy api) context (passToServer subserver $ remoteHost req)
route Proxy context subserver =
route (Proxy :: Proxy api) context (passToServer subserver remoteHost)
instance HasServer api context => HasServer (IsSecure :> api) context where
type ServerT (IsSecure :> api) m = IsSecure -> ServerT api m
route Proxy context subserver = WithRequest $ \req ->
route (Proxy :: Proxy api) context (passToServer subserver $ secure req)
route Proxy context subserver =
route (Proxy :: Proxy api) context (passToServer subserver secure)
where secure req = if isSecure req then Secure else NotSecure
instance HasServer api context => HasServer (Vault :> api) context where
type ServerT (Vault :> api) m = Vault -> ServerT api m
route Proxy context subserver = WithRequest $ \req ->
route (Proxy :: Proxy api) context (passToServer subserver $ vault req)
route Proxy context subserver =
route (Proxy :: Proxy api) context (passToServer subserver vault)
instance HasServer api context => HasServer (HttpVersion :> api) context where
type ServerT (HttpVersion :> api) m = HttpVersion -> ServerT api m
route Proxy context subserver = WithRequest $ \req ->
route (Proxy :: Proxy api) context (passToServer subserver $ httpVersion req)
route Proxy context subserver =
route (Proxy :: Proxy api) context (passToServer subserver httpVersion)
-- | Basic Authentication
instance ( KnownSymbol realm
@ -450,12 +455,12 @@ instance ( KnownSymbol realm
type ServerT (BasicAuth realm usr :> api) m = usr -> ServerT api m
route Proxy context subserver = WithRequest $ \ request ->
route (Proxy :: Proxy api) context (subserver `addAuthCheck` authCheck request)
route Proxy context subserver =
route (Proxy :: Proxy api) context (subserver `addAuthCheck` authCheck)
where
realm = BC8.pack $ symbolVal (Proxy :: Proxy realm)
basicAuthContext = getContextEntry context
authCheck req = runBasicAuth req realm basicAuthContext
authCheck = withRequest $ \ req -> runBasicAuth req realm basicAuthContext
-- * helpers

11
servant-server/src/Servant/Server/Internal/BasicAuth.hs
View file

@ -6,6 +6,7 @@
module Servant.Server.Internal.BasicAuth where
import Control.Monad (guard)
import Control.Monad.Trans (liftIO)
import qualified Data.ByteString as BS
import Data.ByteString.Base64 (decodeLenient)
import Data.Monoid ((<>))
@ -57,13 +58,13 @@ decodeBAHdr req = do
-- | Run and check basic authentication, returning the appropriate http error per
-- the spec.
runBasicAuth :: Request -> BS.ByteString -> BasicAuthCheck usr -> IO (RouteResult usr)
runBasicAuth :: Request -> BS.ByteString -> BasicAuthCheck usr -> DelayedIO usr
runBasicAuth req realm (BasicAuthCheck ba) =
case decodeBAHdr req of
Nothing -> plzAuthenticate
Just e -> ba e >>= \res -> case res of
Just e -> liftIO (ba e) >>= \res -> case res of
BadPassword -> plzAuthenticate
NoSuchUser -> plzAuthenticate
Unauthorized -> return $ FailFatal err403
Authorized usr -> return $ Route usr
where plzAuthenticate = return $ FailFatal err401 { errHeaders = [mkBAChallengerHdr realm] }
Unauthorized -> delayedFailFatal err403
Authorized usr -> return usr
where plzAuthenticate = delayedFailFatal err401 { errHeaders = [mkBAChallengerHdr realm] }

125
servant-server/src/Servant/Server/Internal/Router.hs
View file

@ -1,5 +1,7 @@
{-# LANGUAGE DeriveFunctor #-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE OverloadedStrings #-}
module Servant.Server.Internal.Router where
@ -8,36 +10,41 @@ import qualified Data.Map as M
import Data.Monoid
import Data.Text (Text)
import qualified Data.Text as T
import Network.Wai (Request, Response, pathInfo)
import Network.Wai (Response, pathInfo)
import Servant.Server.Internal.RoutingApplication
import Servant.Server.Internal.ServantErr
type Router = Router' RoutingApplication
type Router env = Router' env RoutingApplication
-- | Internal representation of a router.
data Router' a =
WithRequest (Request -> Router' a)
-- ^ current request is passed to the router
| StaticRouter (Map Text (Router' a)) [a]
--
-- The first argument describes an environment type that is
-- expected as extra input by the routers at the leaves. The
-- environment is filled while running the router, with path
-- components that can be used to process captures.
--
data Router' env a =
StaticRouter (Map Text (Router' env a)) [env -> a]
-- ^ the map contains routers for subpaths (first path component used
-- for lookup and removed afterwards), the list contains handlers
-- for the empty path, to be tried in order
| DynamicRouter (Text -> Router' a)
-- ^ first path component passed to the function and removed afterwards
| RawRouter a
| CaptureRouter (Router' (Text, env) a)
-- ^ first path component is passed to the child router in its
-- environment and removed afterwards
| RawRouter (env -> a)
-- ^ to be used for routes we do not know anything about
| Choice (Router' a) (Router' a)
| Choice (Router' env a) (Router' env a)
-- ^ left-biased choice between two routers
deriving Functor
-- | Smart constructor for a single static path component.
pathRouter :: Text -> Router' a -> Router' a
pathRouter :: Text -> Router' env a -> Router' env a
pathRouter t r = StaticRouter (M.singleton t r) []
-- | Smart constructor for a leaf, i.e., a router that expects
-- the empty path.
--
leafRouter :: a -> Router' a
leafRouter :: (env -> a) -> Router' env a
leafRouter l = StaticRouter M.empty [l]
-- | Smart constructor for the choice between routers.
@ -46,40 +53,27 @@ leafRouter l = StaticRouter M.empty [l]
-- * Two static routers can be joined by joining their maps
-- and concatenating their leaf-lists.
-- * Two dynamic routers can be joined by joining their codomains.
-- * Two 'WithRequest' routers can be joined by passing them
-- the same request and joining their codomains.
-- * A 'WithRequest' router can be joined with anything else by
-- passing the same request to both but ignoring it in the
-- component that does not need it.
-- * Choice nodes can be reordered.
--
choice :: Router -> Router -> Router
choice :: Router' env a -> Router' env a -> Router' env a
choice (StaticRouter table1 ls1) (StaticRouter table2 ls2) =
StaticRouter (M.unionWith choice table1 table2) (ls1 ++ ls2)
choice (DynamicRouter fun1) (DynamicRouter fun2) =
DynamicRouter (\ first -> choice (fun1 first) (fun2 first))
choice (WithRequest router1) (WithRequest router2) =
WithRequest (\ request -> choice (router1 request) (router2 request))
choice (WithRequest router1) router2 =
WithRequest (\ request -> choice (router1 request) router2)
choice router1 (WithRequest router2) =
WithRequest (\ request -> choice router1 (router2 request))
choice (CaptureRouter router1) (CaptureRouter router2) =
CaptureRouter (choice router1 router2)
choice router1 (Choice router2 router3) = Choice (choice router1 router2) router3
choice router1 router2 = Choice router1 router2
-- | Datatype used for representing and debugging the
-- structure of a router. Abstracts from the functions
-- being used in the actual router and the handlers at
-- the leaves.
-- structure of a router. Abstracts from the handlers
-- at the leaves.
--
-- Two 'Router's can be structurally compared by computing
-- their 'RouterStructure' using 'routerStructure' and
-- then testing for equality, see 'sameStructure'.
--
data RouterStructure =
WithRequestStructure RouterStructure
| StaticRouterStructure (Map Text RouterStructure) Int
| DynamicRouterStructure RouterStructure
StaticRouterStructure (Map Text RouterStructure) Int
| CaptureRouterStructure RouterStructure
| RawRouterStructure
| ChoiceStructure RouterStructure RouterStructure
deriving (Eq, Show)
@ -87,18 +81,15 @@ data RouterStructure =
-- | Compute the structure of a router.
--
-- Assumes that the request or text being passed
-- in 'WithRequest' or 'DynamicRouter' does not
-- in 'WithRequest' or 'CaptureRouter' does not
-- affect the structure of the underlying tree.
--
routerStructure :: Router' a -> RouterStructure
routerStructure (WithRequest f) =
WithRequestStructure $
routerStructure (f (error "routerStructure: dummy request"))
routerStructure :: Router' env a -> RouterStructure
routerStructure (StaticRouter m ls) =
StaticRouterStructure (fmap routerStructure m) (length ls)
routerStructure (DynamicRouter f) =
DynamicRouterStructure $
routerStructure (f (error "routerStructure: dummy text"))
routerStructure (CaptureRouter router) =
CaptureRouterStructure $
routerStructure router
routerStructure (RawRouter _) =
RawRouterStructure
routerStructure (Choice r1 r2) =
@ -108,21 +99,20 @@ routerStructure (Choice r1 r2) =
-- | Compare the structure of two routers.
--
sameStructure :: Router' a -> Router' b -> Bool
sameStructure :: Router' env a -> Router' env b -> Bool
sameStructure r1 r2 =
routerStructure r1 == routerStructure r2
-- | Provide a textual representation of the
-- structure of a router.
--
routerLayout :: Router' a -> Text
routerLayout :: Router' env a -> Text
routerLayout router =
T.unlines (["/"] ++ mkRouterLayout False (routerStructure router))
where
mkRouterLayout :: Bool -> RouterStructure -> [Text]
mkRouterLayout c (WithRequestStructure r) = mkRouterLayout c r
mkRouterLayout c (StaticRouterStructure m n) = mkSubTrees c (M.toList m) n
mkRouterLayout c (DynamicRouterStructure r) = mkSubTree c "<dyn>" (mkRouterLayout False r)
mkRouterLayout c (CaptureRouterStructure r) = mkSubTree c "<capture>" (mkRouterLayout False r)
mkRouterLayout c RawRouterStructure =
if c then ["├─ <raw>"] else ["└─ <raw>"]
mkRouterLayout c (ChoiceStructure r1 r2) =
@ -146,45 +136,52 @@ routerLayout router =
mkSubTree False path children = ("└─ " <> path <> "/") : map (" " <>) children
-- | Apply a transformation to the response of a `Router`.
tweakResponse :: (RouteResult Response -> RouteResult Response) -> Router -> Router
tweakResponse :: (RouteResult Response -> RouteResult Response) -> Router env -> Router env
tweakResponse f = fmap (\a -> \req cont -> a req (cont . f))
-- | Interpret a router as an application.
runRouter :: Router -> RoutingApplication
runRouter (WithRequest router) request respond =
runRouter (router request) request respond
runRouter (StaticRouter table ls) request respond =
runRouter :: Router () -> RoutingApplication
runRouter r = runRouterEnv r ()
runRouterEnv :: Router env -> env -> RoutingApplication
runRouterEnv router env request respond =
case router of
StaticRouter table ls ->
case pathInfo request of
[] -> runChoice ls request respond
[] -> runChoice ls env request respond
-- This case is to handle trailing slashes.
[""] -> runChoice ls request respond
first : rest | Just router <- M.lookup first table
[""] -> runChoice ls env request respond
first : rest | Just router' <- M.lookup first table
-> let request' = request { pathInfo = rest }
in runRouter router request' respond
in runRouterEnv router' env request' respond
_ -> respond $ Fail err404
runRouter (DynamicRouter fun) request respond =
CaptureRouter router' ->
case pathInfo request of
[] -> respond $ Fail err404
-- This case is to handle trailing slashes.
[""] -> respond $ Fail err404
first : rest
-> let request' = request { pathInfo = rest }
in runRouter (fun first) request' respond
runRouter (RawRouter app) request respond = app request respond
runRouter (Choice r1 r2) request respond =
runChoice [runRouter r1, runRouter r2] request respond
in runRouterEnv router' (first, env) request' respond
RawRouter app ->
app env request respond
Choice r1 r2 ->
runChoice [runRouterEnv r1, runRouterEnv r2] env request respond
-- | Try a list of routing applications in order.
-- We stop as soon as one fails fatally or succeeds.
-- If all fail normally, we pick the "best" error.
--
runChoice :: [RoutingApplication] -> RoutingApplication
runChoice [] _request respond = respond (Fail err404)
runChoice [r] request respond = r request respond
runChoice (r : rs) request respond =
r request $ \ response1 ->
runChoice :: [env -> RoutingApplication] -> env -> RoutingApplication
runChoice ls =
case ls of
[] -> \ _ _ respond -> respond (Fail err404)
[r] -> r
(r : rs) ->
\ env request respond ->
r env request $ \ response1 ->
case response1 of
Fail _ -> runChoice rs request $ \ response2 ->
Fail _ -> runChoice rs env request $ \ response2 ->
respond $ highestPri response1 response2
_ -> respond response1
where

210
servant-server/src/Servant/Server/Internal/RoutingApplication.hs
View file

@ -8,7 +8,10 @@
{-# LANGUAGE StandaloneDeriving #-}
module Servant.Server.Internal.RoutingApplication where
import Control.Monad (ap, liftM)
import Control.Monad.Trans (MonadIO(..))
import Control.Monad.Trans.Except (runExceptT)
import Data.Text (Text)
import Network.Wai (Application, Request,
Response, ResponseReceived)
import Prelude ()
@ -95,69 +98,108 @@ toApplication ra request respond = ra request routingRespond
-- The accept header check can be performed as the final
-- computation in this block. It can cause a 406.
--
data Delayed c where
Delayed :: { capturesD :: IO (RouteResult captures)
, methodD :: IO (RouteResult ())
, authD :: IO (RouteResult auth)
, bodyD :: IO (RouteResult body)
, serverD :: (captures -> auth -> body -> RouteResult c)
} -> Delayed c
data Delayed env c where
Delayed :: { capturesD :: env -> DelayedIO captures
, methodD :: DelayedIO ()
, authD :: DelayedIO auth
, bodyD :: DelayedIO body
, serverD :: captures -> auth -> body -> Request -> RouteResult c
} -> Delayed env c
instance Functor Delayed where
fmap f Delayed{..}
= Delayed { capturesD = capturesD
, methodD = methodD
, authD = authD
, bodyD = bodyD
, serverD = (fmap.fmap.fmap.fmap) f serverD
instance Functor (Delayed env) where
fmap f Delayed{..} =
Delayed
{ serverD = \ c a b req -> f <$> serverD c a b req
, ..
} -- Note [Existential Record Update]
-- | Computations used in a 'Delayed' can depend on the
-- incoming 'Request', may perform 'IO, and result in a
-- 'RouteResult, meaning they can either suceed, fail
-- (with the possibility to recover), or fail fatally.
--
newtype DelayedIO a = DelayedIO { runDelayedIO :: Request -> IO (RouteResult a) }
instance Functor DelayedIO where
fmap = liftM
instance Applicative DelayedIO where
pure = return
(<*>) = ap
instance Monad DelayedIO where
return x = DelayedIO (const $ return (Route x))
DelayedIO m >>= f =
DelayedIO $ \ req -> do
r <- m req
case r of
Fail e -> return $ Fail e
FailFatal e -> return $ FailFatal e
Route a -> runDelayedIO (f a) req
instance MonadIO DelayedIO where
liftIO m = DelayedIO (const $ Route <$> m)
-- | A 'Delayed' without any stored checks.
emptyDelayed :: RouteResult a -> Delayed env a
emptyDelayed result =
Delayed (const r) r r r (\ _ _ _ _ -> result)
where
r = return ()
-- | Fail with the option to recover.
delayedFail :: ServantErr -> DelayedIO a
delayedFail err = DelayedIO (const $ return $ Fail err)
-- | Fail fatally, i.e., without any option to recover.
delayedFailFatal :: ServantErr -> DelayedIO a
delayedFailFatal err = DelayedIO (const $ return $ FailFatal err)
-- | Gain access to the incoming request.
withRequest :: (Request -> DelayedIO a) -> DelayedIO a
withRequest f = DelayedIO (\ req -> runDelayedIO (f req) req)
-- | Add a capture to the end of the capture block.
addCapture :: Delayed (a -> b)
-> IO (RouteResult a)
-> Delayed b
addCapture Delayed{..} new
= Delayed { capturesD = combineRouteResults (,) capturesD new
, methodD = methodD
, authD = authD
, bodyD = bodyD
, serverD = \ (x, v) y z -> ($ v) <$> serverD x y z
addCapture :: Delayed env (a -> b)
-> (Text -> DelayedIO a)
-> Delayed (Text, env) b
addCapture Delayed{..} new =
Delayed
{ capturesD = \ (txt, env) -> (,) <$> capturesD env <*> new txt
, serverD = \ (x, v) a b req -> ($ v) <$> serverD x a b req
, ..
} -- Note [Existential Record Update]
-- | Add a method check to the end of the method block.
addMethodCheck :: Delayed a
-> IO (RouteResult ())
-> Delayed a
addMethodCheck Delayed{..} new
= Delayed { capturesD = capturesD
, methodD = combineRouteResults const methodD new
, authD = authD
, bodyD = bodyD
, serverD = serverD
addMethodCheck :: Delayed env a
-> DelayedIO ()
-> Delayed env a
addMethodCheck Delayed{..} new =
Delayed
{ methodD = methodD <* new
, ..
} -- Note [Existential Record Update]
-- | Add an auth check to the end of the auth block.
addAuthCheck :: Delayed (a -> b)
-> IO (RouteResult a)
-> Delayed b
addAuthCheck Delayed{..} new
= Delayed { capturesD = capturesD
, methodD = methodD
, authD = combineRouteResults (,) authD new
, bodyD = bodyD
, serverD = \ x (y, v) z -> ($ v) <$> serverD x y z
addAuthCheck :: Delayed env (a -> b)
-> DelayedIO a
-> Delayed env b
addAuthCheck Delayed{..} new =
Delayed
{ authD = (,) <$> authD <*> new
, serverD = \ c (y, v) b req -> ($ v) <$> serverD c y b req
, ..
} -- Note [Existential Record Update]
-- | Add a body check to the end of the body block.
addBodyCheck :: Delayed (a -> b)
-> IO (RouteResult a)
-> Delayed b
addBodyCheck Delayed{..} new
= Delayed { capturesD = capturesD
, methodD = methodD
, authD = authD
, bodyD = combineRouteResults (,) bodyD new
, serverD = \ x y (z, v) -> ($ v) <$> serverD x y z
addBodyCheck :: Delayed env (a -> b)
-> DelayedIO a
-> Delayed env b
addBodyCheck Delayed{..} new =
Delayed
{ bodyD = (,) <$> bodyD <*> new
, serverD = \ c a (z, v) req -> ($ v) <$> serverD c a z req
, ..
} -- Note [Existential Record Update]
@ -165,43 +207,24 @@ addBodyCheck Delayed{..} new
-- The accept header check should occur after the body check,
-- but this will be the case, because the accept header check
-- is only scheduled by the method combinators.
addAcceptCheck :: Delayed a
-> IO (RouteResult ())
-> Delayed a
addAcceptCheck Delayed{..} new
= Delayed { capturesD = capturesD
, methodD = methodD
, authD = authD
, bodyD = combineRouteResults const bodyD new
, serverD = serverD
addAcceptCheck :: Delayed env a
-> DelayedIO ()
-> Delayed env a
addAcceptCheck Delayed{..} new =
Delayed
{ bodyD = bodyD <* new
, ..
} -- Note [Existential Record Update]
-- | Many combinators extract information that is passed to
-- the handler without the possibility of failure. In such a
-- case, 'passToServer' can be used.
passToServer :: Delayed (a -> b) -> a -> Delayed b
passToServer d x = ($ x) <$> d
-- | The combination 'IO . RouteResult' is a monad, but we
-- don't explicitly wrap it in a newtype in order to make it
-- an instance. This is the '>>=' of that monad.
--
-- We stop on the first error.
bindRouteResults :: IO (RouteResult a) -> (a -> IO (RouteResult b)) -> IO (RouteResult b)
bindRouteResults m f = do
r <- m
case r of
Fail e -> return $ Fail e
FailFatal e -> return $ FailFatal e
Route a -> f a
-- | Common special case of 'bindRouteResults', corresponding
-- to 'liftM2'.
combineRouteResults :: (a -> b -> c) -> IO (RouteResult a) -> IO (RouteResult b) -> IO (RouteResult c)
combineRouteResults f m1 m2 =
m1 `bindRouteResults` \ a ->
m2 `bindRouteResults` \ b ->
return (Route (f a b))
passToServer :: Delayed env (a -> b) -> (Request -> a) -> Delayed env b
passToServer Delayed{..} x =
Delayed
{ serverD = \ c a b req -> ($ x req) <$> serverD c a b req
, ..
} -- Note [Existential Record Update]
-- | Run a delayed server. Performs all scheduled operations
-- in order, and passes the results from the capture and body
@ -209,24 +232,29 @@ combineRouteResults f m1 m2 =
--
-- This should only be called once per request; otherwise the guarantees about
-- effect and HTTP error ordering break down.
runDelayed :: Delayed a
runDelayed :: Delayed env a
-> env
-> Request
-> IO (RouteResult a)
runDelayed Delayed{..} =
capturesD `bindRouteResults` \ c ->
methodD `bindRouteResults` \ _ ->
authD `bindRouteResults` \ a ->
bodyD `bindRouteResults` \ b ->
return (serverD c a b)
runDelayed Delayed{..} env = runDelayedIO $ do
c <- capturesD env
methodD
a <- authD
b <- bodyD
DelayedIO (\ req -> return $ serverD c a b req)
-- | Runs a delayed server and the resulting action.
-- Takes a continuation that lets us send a response.
-- Also takes a continuation for how to turn the
-- result of the delayed server into a response.
runAction :: Delayed (Handler a)
runAction :: Delayed env (Handler a)
-> env
-> Request
-> (RouteResult Response -> IO r)
-> (a -> RouteResult Response)
-> IO r
runAction action respond k = runDelayed action >>= go >>= respond
runAction action env req respond k =
runDelayed action env req >>= go >>= respond
where
go (Fail e) = return $ Fail e
go (FailFatal e) = return $ FailFatal e

12
servant-server/test/Servant/Server/RouterSpec.hs
View file

@ -25,9 +25,9 @@ routerSpec = do
let app' :: Application
app' = toApplication $ runRouter router'
router', router :: Router
router', router :: Router ()
router' = tweakResponse (fmap twk) router
router = leafRouter $ \_ cont -> cont (Route $ responseBuilder (Status 201 "") [] "")
router = leafRouter $ \_ _ cont -> cont (Route $ responseBuilder (Status 201 "") [] "")
twk :: Response -> Response
twk (ResponseBuilder (Status i s) hs b) = ResponseBuilder (Status (i + 1) s) hs b
@ -69,11 +69,9 @@ shouldHaveSameStructureAs p1 p2 =
unless (sameStructure (makeTrivialRouter p1) (makeTrivialRouter p2)) $
expectationFailure ("expected:\n" ++ unpack (layout p2) ++ "\nbut got:\n" ++ unpack (layout p1))
makeTrivialRouter :: (HasServer layout '[]) => Proxy layout -> Router
makeTrivialRouter p = route p EmptyContext d
where
d = Delayed r r r r (\ _ _ _ -> FailFatal err501)
r = return (Route ())
makeTrivialRouter :: (HasServer layout '[]) => Proxy layout -> Router ()
makeTrivialRouter p =
route p EmptyContext (emptyDelayed (FailFatal err501))
type End = Get '[JSON] ()

3
servant-server/test/Servant/Server/UsingContextSpec/TestCombinators.hs
View file

@ -20,7 +20,6 @@ module Servant.Server.UsingContextSpec.TestCombinators where
import GHC.TypeLits
import Servant
import Servant.Server.Internal.RoutingApplication
data ExtractFromContext
@ -31,7 +30,7 @@ instance (HasContextEntry context String, HasServer subApi context) =>
String -> ServerT subApi m
route Proxy context delayed =
route subProxy context (fmap (inject context) delayed :: Delayed (Server subApi))
route subProxy context (fmap (inject context) delayed)
where
subProxy :: Proxy subApi
subProxy = Proxy

2
servant-server/test/Servant/ServerSpec.hs
View file

@ -48,7 +48,7 @@ import Servant.API ((:<|>) (..), (:>), AuthProtect,
Raw, RemoteHost, ReqBody,
StdMethod (..), Verb, addHeader)
import Servant.API.Internal.Test.ComprehensiveAPI
import Servant.Server (ServantErr (..), Server, Handler, err401, err403,
import Servant.Server (Server, Handler, err401, err403,
err404, serve, serveWithContext,
Context((:.), EmptyContext))
import Test.Hspec (Spec, context, describe, it,