nested-routes-7.1.1: src/Web/Routes/Nested.hs
{-# LANGUAGE
GADTs
, PolyKinds
, TypeFamilies
, BangPatterns
, TypeOperators
, TupleSections
, DoAndIfThenElse
, ConstraintKinds
, FlexibleContexts
, OverloadedStrings
, ScopedTypeVariables
#-}
{- |
Module : Web.Routes.Nested
Copyright : (c) 2015 Athan Clark
License : BSD-style
Maintainer : athan.clark@gmail.com
Stability : experimental
Portability : GHC
This module exports most of what you'll need for sophisticated routing -
all the tools from <https://hackage.haskell.org/package/wai-middleware-verbs wai-middleware-verbs>
(routing for the incoming HTTP method) and
<https://hackage.haskell.org/package/wai-middleware-content-type wai-middleware-content-type>
(routing for the incoming Accept header, and implied file extension),
<https://hackage.haskell.org/package/wai WAI> itself, and
<https://hackage.haskell.org/package/wai-transformers wai-transformers> - some simple
type aliases wrapped around WAI's @Application@ and @Middleware@ types, allowing us
to embed monad transformer stacks for our applications.
To match a route, you have a few options - you can match against a string literal,
a regular expression (via <https://hackage.haskell.org/package/regex-compat regex-compat>),
or an <https://hackage.haskell.org/package/attoparsec attoparsec> parser. This list
will most likely grow in the future, depending on demand.
There is also support for embedding security layers in your routes, in the same
nested manner. By "tagging" a set of routes with an authorization role (with @auth@),
you populate a list of roles breached during any request. The function argument to
'routeAuth' guards a Request to pass or fail at the high level, while 'auth' lets
you create your authorization boundaries on a case-by-case basis. Both allow
you to tap into the monad transformer stack for logging, STM variables, database queries,
etc.
-}
module Web.Routes.Nested
( -- * Combinators
match
, matchHere
, matchAny
, matchGroup
, auth
, -- * Routing
route
, routeAuth
, extractMatch
, extractMatchAny
, extractAuthSym
, extractAuth
, extractNearestVia
, -- * Metadata
SecurityToken (..)
, AuthScope (..)
, -- * Re-Exports
module Web.Routes.Nested.Match
, module Web.Routes.Nested.Types
, module Network.Wai.Middleware.Verbs
, module Network.Wai.Middleware.ContentType
) where
import Web.Routes.Nested.Match
import Web.Routes.Nested.Types
import Network.Wai.Trans
import Network.Wai.Middleware.Verbs
import Network.Wai.Middleware.ContentType hiding (responseStatus, responseHeaders, responseData)
import Data.Foldable (foldlM)
import qualified Data.HashTable.ST.Basic as HT
import Data.PredSet.Mutable as HS
import Data.Trie.Pred.Mutable (HashTableTrie (..), RootedHashTableTrie (..), RawValue (..))
import qualified Data.Trie.Pred.Mutable as MPT
import Data.Trie.Pred.Mutable.Morph (toMutableRooted)
import Data.Trie.Pred.Base (RootedPredTrie (..))
import Data.Trie.Pred.Interface.Types (Singleton (..), Extrude (..), CatMaybes)
import Data.List.NonEmpty (NonEmpty (..))
import qualified Data.Text as T
import Data.Hashable
import Data.Monoid
import Data.Function.Poly
import Data.Typeable
import qualified Control.Monad.State as S
import Control.Monad.Catch
import Control.Monad.Trans
import Control.Monad.ST
-- | Embed a 'Network.Wai.Trans.MiddlewareT' into a set of routes via a matching string. You should
-- expect the match to create /arity/ in your handler - the @childContent@ variable.
-- The arity of @childContent@ may grow or shrink, depending on the heterogeneous
-- list created from the list of parsers, regular expressions, or arbitrary predicates
-- /in the order written/ - so something like:
--
-- > match (p_ "double-parser" double </> o_)
-- > handler
--
-- ...then @handler@ /must/ have arity @Double ->@. If this
-- route was at the top level, then the total arity __must__ be @Double -> MiddlewareT m@.
--
-- Generally, if the routes you are building get grouped
-- by a predicate with 'matchGroup',
-- then we would need another level of arity /before/ the @Double@.
match :: ( Monad m
, Singleton (UrlChunks xs)
childContent
(RootedPredTrie T.Text resultContent)
, cleanxs ~ CatMaybes xs
, ArityTypeListIso childContent cleanxs resultContent
) => UrlChunks xs
-> childContent
-> HandlerT resultContent sec m ()
match !ts !vl =
tell' $ Tries (singleton ts vl)
mempty
mempty
{-# INLINEABLE match #-}
-- | Create a handle for the /current/ route - an alias for @\h -> match o_ h@.
matchHere :: ( Monad m
) => content
-> HandlerT content sec m ()
matchHere = match origin_
{-# INLINEABLE matchHere #-}
-- | Match against any route, as a last resort against all failing matches -
-- use this for a catch-all at some level in their routes, something
-- like a @not-found 404@ page is useful.
matchAny :: ( Monad m
) => content
-> HandlerT content sec m ()
matchAny !vl =
tell' $ Tries mempty
(singleton origin_ vl)
mempty
{-# INLINEABLE matchAny #-}
-- | Prepends a common route to an existing set of routes. You should note that
-- doing this with a parser or regular expression will necessitate the existing
-- arity in the handlers before the progam can compile.
matchGroup :: ( Monad m
, cleanxs ~ CatMaybes xs
, ExtrudeSoundly cleanxs xs childContent resultContent
, ExtrudeSoundly cleanxs xs childSec resultSec
) => UrlChunks xs
-> HandlerT childContent childSec m ()
-> HandlerT resultContent resultSec m ()
matchGroup !ts cs = do
(Tries trieContent' trieNotFound trieSec) <- lift $ execHandlerT cs
tell' $ Tries (extrude ts trieContent')
(extrude ts trieNotFound)
(extrude ts trieSec)
{-# INLINEABLE matchGroup #-}
-- | Use a custom security token type and an 'AuthScope' to define
-- /where/ and /what kind/ of security should take place.
data SecurityToken s = SecurityToken
{ securityToken :: !s
, securityScope :: !AuthScope
} deriving (Show)
-- | Designate the scope of security to the set of routes - either only the adjacent
-- routes, or the adjacent /and/ the parent container node (root node if not
-- declared).
data AuthScope
= ProtectHere
| DontProtectHere
deriving (Show, Eq)
-- | Sets the security role and error handler for a set of routes, optionally
-- including its parent route.
auth :: ( Monad m
) => sec
-> AuthScope
-> HandlerT content (SecurityToken sec) m ()
auth !token !scope =
tell' $ Tries mempty
mempty
(singleton origin_ $ SecurityToken token scope)
{-# INLINEABLE auth #-}
-- * Routing ---------------------------------------
route :: ( Monad m
, MonadIO m
, Typeable m
) => HandlerT (MiddlewareT m) sec m a
-> MiddlewareT m
route hs app req resp = do
let path = pathInfo req
mightMatch <- extractMatch path hs
case mightMatch of
Nothing -> do
mMatch <- extractMatchAny path hs
maybe
(app req resp)
(\mid -> mid app req resp)
mMatch
Just mid -> mid app req resp
routeAuth :: ( Monad m
, MonadIO m
, MonadThrow m
, Typeable sec
, Typeable m
) => (Request -> [sec] -> m ())
-> HandlerT (MiddlewareT m) (SecurityToken sec) m a
-> MiddlewareT m
routeAuth authorize hs app req resp = do
extractAuth authorize req hs
route hs app req resp
-- * Extraction -------------------------------
-- | Extracts only the normal 'match' and 'matchHere'
extractMatch :: ( Monad m
, MonadIO m
, Typeable r
) => [T.Text]
-> HandlerT r sec m a
-> m (Maybe r)
extractMatch path !hs = do
tries <- execHandlerT hs
liftIO $ stToIO $ do
trie <- trieContentMutable tries
mResult <- lookupWithLRPT trimFileExt path trie
case mResult of
Nothing ->
if not (null path)
&& trimFileExt (last path) == "index"
then MPT.lookupR (init path) trie
else pure Nothing
Just r -> return (Just r)
{-# INLINEABLE extractMatch #-}
-- | Extracts only the @notFound@ responses
extractMatchAny :: ( Monad m
, MonadIO m
, Typeable r
) => [T.Text]
-> HandlerT r sec m a
-> m (Maybe r)
extractMatchAny path = extractNearestVia path (\x -> trieCatchAll <$> execHandlerT x)
{-# INLINEABLE extractMatchAny #-}
-- | Find the security tokens / authorization roles affiliated with
-- a request for a set of routes.
extractAuthSym :: ( Monad m
, MonadIO m
, Typeable sec
) => [T.Text]
-> HandlerT x (SecurityToken sec) m a
-> m [sec]
extractAuthSym path hs = do
tries <- execHandlerT hs
liftIO . stToIO $ do
results <- MPT.matchesR path =<< trieSecurityMutable tries
pure $! foldr go [] results
where
go (_,SecurityToken _ DontProtectHere,[]) ys = ys
go (_,SecurityToken x _ ,_ ) ys = x:ys
{-# INLINEABLE extractAuthSym #-}
-- | Extracts only the security handling logic, and turns it into a guard
extractAuth :: ( Monad m
, MonadIO m
, MonadThrow m
, Typeable sec
) => (Request -> [sec] -> m ()) -- authorization method
-> Request
-> HandlerT x (SecurityToken sec) m a
-> m ()
extractAuth authorize req hs = do
ss <- extractAuthSym (pathInfo req) hs
authorize req ss
{-# INLINEABLE extractAuth #-}
-- | Given a way to draw out a special-purpose trie from our route set, route
-- to the responses based on a /furthest-reached/ method.
extractNearestVia :: ( MonadIO m
, Monad m
, Typeable r
) => [T.Text]
-> (HandlerT r sec m a -> m (RootedPredTrie T.Text r))
-> HandlerT r sec m a
-> m (Maybe r)
extractNearestVia path extr hs = do
trie <- extr hs
liftIO . stToIO $ do
mResult <- MPT.matchR path =<< toMutableRooted trie
pure (mid <$> mResult)
where
mid (_,r,_) = r
{-# INLINEABLE extractNearestVia #-}
-- * Pred-Trie related -----------------
-- | Removes @.txt@ from @foo.txt@
trimFileExt :: T.Text -> T.Text
trimFileExt !s = fst $! T.breakOn "." s
{-# INLINEABLE trimFileExt #-}
-- | A quirky function for processing the last element of a lookup path, only
-- on /literal/ matches.
-- lookupWithLPT :: ( Hashable s
-- , Eq s
-- ) => (s -> s) -> NonEmpty s -> PredTrie s a -> Maybe ([s], a)
-- lookupWithLPT f (t:|ts) (PredTrie (HashMapStep ls) (PredSteps ps))
-- | null ts = getFirst $ First ((goLit $! f t) ls) <> foldMap (First . goPred) ps
-- | otherwise = getFirst $ First (goLit t ls) <> foldMap (First . goPred) ps
-- where
-- goLit t' xs = do
-- (HashMapChildren mx mxs) <- HM.lookup t' xs
-- if null ts
-- then ([t],) <$> mx
-- else fmap (\(ts',x) -> (t:ts',x)) $! lookupWithLPT f (NE.fromList ts) =<< mxs
--
-- goPred (PredStep _ predicate mx xs) = do
-- d <- predicate t
-- if null ts
-- then ([t],) <$> (mx <$~> d)
-- else fmap (\(ts',x) -> (t:ts',x d)) $! lookupWithLPT f (NE.fromList ts) xs
lookupWithLPT :: ( Eq k
, Hashable k
, Typeable s
, Typeable k
) => PredSet s k
-> (k -> k)
-> NonEmpty k
-> HashTableTrie s k a
-> ST s (Maybe a)
lookupWithLPT predSet f (k:|ks) (HashTableTrie raw preds) = do
mx <- HT.lookup raw $ if null ks then f k else k
case mx of
Just (RawValue mx' children) ->
case ks of
[] -> pure mx'
(k':ks') -> lookupWithLPT predSet f (k':|ks') children
Nothing ->
let -- go :: Typeable t => Maybe t -> PredStep s k t -> ST s (Maybe t)
go solution@(Just _) _ = pure solution
go Nothing (MPT.PredStep predKey mHandler children) = do
mx' <- HS.lookup predKey k predSet
case mx' of
Nothing -> pure Nothing
Just x ->
case ks of
[] ->
pure $! ($ x) <$> mHandler
(k':ks') -> do
mf <- lookupWithLPT predSet f (k':|ks') children
pure $! ($ x) <$> mf
in foldlM go Nothing preds
-- lookupWithLPT :: ( Eq k
-- , Hashable k
-- , Typeable s
-- , Typeable k
-- ) => PredSet s k
-- -> (k -> k)
-- -> NonEmpty k
-- -> HashTableTrie s k a
-- -> ST s (Maybe (NonEmpty k, a, [k]))
-- lookupWithLPT predSet f (k:|ks) (HashTableTrie raw preds) = do
-- mLit <- goLit raw
-- case mLit of
-- Just _ -> pure mLit
-- Nothing ->
-- let go solution@(Just _) _ = pure solution
-- go Nothing pred = goPred pred
-- in foldlM go Nothing preds
-- where
-- goLit xs = do
-- mx' <- if null ks
-- then HT.lookup raw (f k)
-- else HT.lookup raw k
-- case mx' of
-- Nothing -> pure Nothing
-- Just (RawValue mx children) ->
-- let mFoundHere = (\x -> (k:|[], x, ks)) <$> mx
-- prependAncestry (pre,x,suff) = (k:|NE.toList pre,x,suff)
-- in case ks of
-- [] -> pure mFoundHere
-- (k':ks') -> do
-- mFoundThere <- MPT.match predSet (k':|ks') children
-- pure $! getFirst $
-- First (prependAncestry <$> mFoundThere)
-- <> First mFoundHere
--
-- goPred (MPT.PredStep predKey mx children) = do
-- mr' <- HS.lookup predKey k predSet
-- case mr' of
-- Nothing -> pure Nothing
-- Just r ->
-- let mFoundHere = (\x -> (k:|[], x r, ks)) <$> mx
-- prependAncestryAndApply (pre,f,suff) =
-- (k:|NE.toList pre,f r,suff)
-- in case ks of
-- [] -> pure mFoundHere
-- (k':ks') -> do
-- mFoundThere <- MPT.match predSet (k':|ks') children
-- pure $! getFirst $
-- First (prependAncestryAndApply <$> mFoundThere)
-- <> First mFoundHere
{-# INLINEABLE lookupWithLPT #-}
--lookupWithLRPT :: ( Hashable s
-- , Eq s
-- ) => (s -> s) -> [s] -> RootedPredTrie s a -> Maybe ([s], a)
--lookupWithLRPT _ [] (RootedPredTrie mx _) = ([],) <$> mx
--lookupWithLRPT f ts (RootedPredTrie _ xs) = lookupWithLPT f (NE.fromList ts) xs
-- lookupWithLRPT :: ( Eq k
-- , Hashable k
-- , Typeable s
-- , Typeable k
-- , Typeable a
-- ) => (k -> k)
-- -> [k]
-- -> RootedHashTableTrie s k a
-- -> ST s (Maybe ([k],a,[k]))
-- lookupWithLRPT _ [] (RootedHashTableTrie mx _ _) =
-- pure $! (\x -> ([],x,[])) <$> mx
-- lookupWithLRPT f (k:ks) (RootedHashTableTrie mx xs predSet) = do
-- mFoundThere <- lookupWithLPT predSet f (k:|ks) xs
-- pure $! getFirst $
-- First ((\(pre,x,suff) -> (NE.toList pre,x,suff)) <$> mFoundThere)
-- <> First ((\x -> ([],x,k:ks)) <$> mx)
lookupWithLRPT :: ( Eq k
, Hashable k
, Typeable s
, Typeable k
, Typeable a
) => (k -> k)
-> [k]
-> RootedHashTableTrie s k a
-> ST s (Maybe a)
lookupWithLRPT _ [] (RootedHashTableTrie mx _ _) = pure mx
lookupWithLRPT f (k:ks) (RootedHashTableTrie _ xs predSet) =
lookupWithLPT predSet f (k:|ks) xs
{-# INLINEABLE lookupWithLRPT #-}
tell' :: (Monoid w, S.MonadState w m) => w -> m ()
tell' x = S.modify' (<> x)
{-# INLINEABLE tell' #-}