X-Git-Url: http://git.cielonegro.org/gitweb.cgi?a=blobdiff_plain;f=Network%2FHTTP%2FLucu%2FResource%2FTree.hs;h=8fbe2bf2d6b529aa1b00ad4fc4c6b17b943b64b8;hb=ea2b7838f1b3d9d4923a220a601be2e04cc559d7;hp=062ffdca9217b5dd5462cf238fdb97e033b01ca7;hpb=c6b11025d1f81c668e9995e856b7bb34175230d3;p=Lucu.git

diff --git a/Network/HTTP/Lucu/Resource/Tree.hs b/Network/HTTP/Lucu/Resource/Tree.hs
index 062ffdc..8fbe2bf 100644
--- a/Network/HTTP/Lucu/Resource/Tree.hs
+++ b/Network/HTTP/Lucu/Resource/Tree.hs
@@ -1,188 +1,297 @@
+{-# LANGUAGE
+    DoAndIfThenElse
+  , OverloadedStrings
+  , RecordWildCards
+  , UnicodeSyntax
+  #-}
+
+-- | Repository of the resources in httpd.
 module Network.HTTP.Lucu.Resource.Tree
     ( ResourceDef(..)
-    , Resource
+    , emptyResource
+
     , ResTree
-    , mkResTree    -- [ ([String], ResourceDef) ] -> ResTree
+    , FallbackHandler
+
+    , mkResTree
 
-    , findResource -- ResTree -> URI -> Maybe ResourceDef
-    , runResource  -- ResourceDef -> Interaction -> IO ThreadId
+    , findResource
+    , runResource
     )
     where
-
+import           Control.Arrow
+import Control.Applicative
+import Data.Ascii (Ascii)
+import qualified Data.Ascii as A
 import           Control.Concurrent
 import           Control.Concurrent.STM
 import           Control.Exception
-import           Control.Monad.Reader
-import           Data.Dynamic
+import           Control.Monad
+import Data.Text (Text)
+import qualified Data.Text as T
+import qualified Data.Text.Lazy.Encoding as LT
 import           Data.List
 import qualified Data.Map as M
 import           Data.Map (Map)
 import           Data.Maybe
+import Data.Monoid.Unicode
 import           Network.HTTP.Lucu.Abortion
 import           Network.HTTP.Lucu.Config
+import           Network.HTTP.Lucu.Headers (fromHeaders)
 import           Network.HTTP.Lucu.Request
 import           Network.HTTP.Lucu.Resource
 import           Network.HTTP.Lucu.Response
 import           Network.HTTP.Lucu.Interaction
 import           Network.HTTP.Lucu.Utils
-import           Network.URI
+import           Network.URI hiding (path)
 import           System.IO
-import           System.IO.Error hiding (catch)
 import           Prelude hiding (catch)
+import Prelude.Unicode
+
+
+-- |'FallbackHandler' is an extra resource handler for resources which
+-- can't be statically located anywhere in the resource tree. The Lucu
+-- httpd first searches for a resource in the tree, and then calls
+-- fallback handlers to ask them for a resource. If all of the
+-- handlers returned 'Nothing', the httpd responds with 404 Not Found.
+type FallbackHandler = [Text] → IO (Maybe ResourceDef)
 
 
-{- /aaa/bbb/ccc にアクセスされた時、もし /aaa/bbb に貪欲なリソースがあ
-   れば、假に /aaa/bbb/ccc に何らかのリソースがあったとしても必ず
-   /aaa/bbb が撰ばれる。/aaa/bbb のリソースが貪欲でなければ、それは無視
-   される。 -}
+-- "/aaa/bbb/ccc" にアクセスされた時、もし "/aaa/bbb" に貪欲なリソース
+-- があれば、假に "/aaa/bbb/ccc" に何らかのリソースがあったとしても必ず
+-- "/aaa/bbb" が撰ばれる。"/aaa/bbb" のリソースが貪欲でなければ、それは
+-- 無視される。
+
+-- | 'ResourceDef' is basically a set of 'Resource' monads for each
+-- HTTP methods.
 data ResourceDef = ResourceDef {
-      resUsesNativeThread :: Bool
-    , resIsGreedy         :: Bool
-    , resGet              :: Maybe (Resource ())
-    , resHead             :: Maybe (Resource ())
-    , resPost             :: Maybe (Resource ())
-    , resPut              :: Maybe (Resource ())
-    , resDelete           :: Maybe (Resource ())
+    -- |Whether to run a 'Resource' on a native thread (spawned by
+    -- 'forkOS') or to run it on a user thread (spanwed by
+    -- 'forkIO'). Generally you don't need to set this field to
+    -- 'True'.
+      resUsesNativeThread ∷ !Bool
+    -- | Whether to be greedy or not.
+    -- 
+    -- Say a client is trying to access \/aaa\/bbb\/ccc. If there is a
+    -- greedy resource at \/aaa\/bbb, it is always chosen even if
+    -- there is another resource at \/aaa\/bbb\/ccc. If the resource
+    -- at \/aaa\/bbb is not greedy, it is just ignored. Greedy
+    -- resources are like CGI scripts.
+    , resIsGreedy         ∷ !Bool
+    -- | A 'Resource' to be run when a GET request comes for the
+    -- resource path. If 'resGet' is Nothing, the system responds
+    -- \"405 Method Not Allowed\" for GET requests.
+    -- 
+    -- It also runs for HEAD request if the 'resHead' is Nothing. In
+    -- this case 'output' and such like don't actually write a
+    -- response body.
+    , resGet              ∷ !(Maybe (Resource ()))
+    -- | A 'Resource' to be run when a HEAD request comes for the
+    -- resource path. If 'resHead' is Nothing, the system runs
+    -- 'resGet' instead. If 'resGet' is also Nothing, the system
+    -- responds \"405 Method Not Allowed\" for HEAD requests.
+    , resHead             ∷ !(Maybe (Resource ()))
+    -- | A 'Resource' to be run when a POST request comes for the
+    -- resource path. If 'resPost' is Nothing, the system responds
+    -- \"405 Method Not Allowed\" for POST requests.
+    , resPost             ∷ !(Maybe (Resource ()))
+    -- | A 'Resource' to be run when a PUT request comes for the
+    -- resource path. If 'resPut' is Nothing, the system responds
+    -- \"405 Method Not Allowed\" for PUT requests.
+    , resPut              ∷ !(Maybe (Resource ()))
+    -- | A 'Resource' to be run when a DELETE request comes for the
+    -- resource path. If 'resDelete' is Nothing, the system responds
+    -- \"405 Method Not Allowed\" for DELETE requests.
+    , resDelete           ∷ !(Maybe (Resource ()))
     }
-type ResTree    = ResNode -- root だから Map ではない
-type ResSubtree = Map String ResNode
-data ResNode    = ResNode (Maybe ResourceDef) ResSubtree
 
+-- |'emptyResource' is a resource definition with no actual
+-- handlers. You can construct a 'ResourceDef' by selectively
+-- overriding 'emptyResource'. It is defined as follows:
+--
+-- @
+--   emptyResource = ResourceDef {
+--                     resUsesNativeThread = False
+--                   , resIsGreedy         = False
+--                   , resGet              = Nothing
+--                   , resHead             = Nothing
+--                   , resPost             = Nothing
+--                   , resPut              = Nothing
+--                   , resDelete           = Nothing
+--                   }
+-- @
+emptyResource ∷ ResourceDef
+emptyResource = ResourceDef {
+                  resUsesNativeThread = False
+                , resIsGreedy         = False
+                , resGet              = Nothing
+                , resHead             = Nothing
+                , resPost             = Nothing
+                , resPut              = Nothing
+                , resDelete           = Nothing
+                }
+
+-- |'ResTree' is an opaque structure which is a map from resource path
+-- to 'ResourceDef'.
+newtype ResTree = ResTree ResNode -- root だから Map ではない
+type ResSubtree = Map Text ResNode
+data ResNode    = ResNode (Maybe ResourceDef) ResSubtree
 
-mkResTree :: [ ([String], ResourceDef) ] -> ResTree
-mkResTree list = processRoot list
+-- |'mkResTree' converts a list of @(path, def)@ to a 'ResTree' e.g.
+--
+-- @
+--   mkResTree [ ([]        , 'Network.HTTP.Lucu.StaticFile.staticFile' \"\/usr\/include\/stdio.h\" ) -- \/
+--             , ([\"unistd\"], 'Network.HTTP.Lucu.StaticFile.staticFile' \"\/usr\/include\/unistd.h\") -- \/unistd
+--             ]
+-- @
+mkResTree ∷ [ ([Text], ResourceDef) ] → ResTree
+mkResTree = processRoot ∘ map (first canonicalisePath)
     where
-      processRoot :: [ ([String], ResourceDef) ] -> ResTree
+      canonicalisePath ∷ [Text] → [Text]
+      canonicalisePath = filter (≢ "")
+
+      processRoot ∷ [ ([Text], ResourceDef) ] → ResTree
       processRoot list
-          = let (roots, nonRoots) = partition (\ (path, _) -> path == []) list
+          = let (roots, nonRoots) = partition (\(path, _) → null path) list
                 children = processNonRoot nonRoots
             in
               if null roots then
-                  -- / にリソースが定義されない。/foo とかにはあるかも。
-                  ResNode Nothing children
+                  -- The root has no resources. Maybe there's one at
+                  -- somewhere like "/foo".
+                  ResTree (ResNode Nothing children)
               else
-                  -- / がある。
+                  -- There is a root resource.
                   let (_, def) = last roots
                   in 
-                    ResNode (Just def) children
+                    ResTree (ResNode (Just def) children)
 
-      processNonRoot :: [ ([String], ResourceDef) ] -> ResSubtree
+      processNonRoot ∷ [ ([Text], ResourceDef) ] → ResSubtree
       processNonRoot list
           = let subtree    = M.fromList [(name, node name)
-                                             | name <- childNames]
-                childNames = [name | (name:_, _) <- list]
-                node name  = let defs = [def | (path, def) <- list, path == [name]]
+                                             | name ← childNames]
+                childNames = [name | (name:_, _) ← list]
+                node name  = let defs = [def | (path, def) ← list, path ≡ [name]]
                              in
                                if null defs then
-                                   -- この位置にリソースが定義されない。
-                                   -- もっと下にはあるかも。
+                                   -- No resources are defined
+                                   -- here. Maybe there's one at
+                                   -- somewhere below this node.
                                    ResNode Nothing children
                                else
-                                   -- この位置にリソースがある。
+                                   -- There is a resource here.
                                    ResNode (Just $ last defs) children
                 children   = processNonRoot [(path, def)
-                                                 | (_:path, def) <- list, not (null path)]
+                                                 | (_:path, def) ← list]
             in
               subtree
 
-
-findResource :: ResTree -> URI -> Maybe ResourceDef
-findResource (ResNode rootDefM subtree) uri
-    = let pathStr = uriPath uri
-          path    = [x | x <- splitBy (== '/') pathStr, x /= ""]
-      in
-        if null path then
-            rootDefM
-        else
-            walkTree subtree path
+findResource ∷ ResTree → [FallbackHandler] → URI → IO (Maybe ([Text], ResourceDef))
+findResource (ResTree (ResNode rootDefM subtree)) fbs uri
+    = do let path          = splitPathInfo uri
+             hasGreedyRoot = maybe False resIsGreedy rootDefM
+             foundInTree    = if hasGreedyRoot ∨ null path then
+                                  do def ← rootDefM
+                                     return ([], def)
+                              else
+                                  walkTree subtree path []
+         if isJust foundInTree then
+             return foundInTree
+         else
+             fallback path fbs
     where
-      walkTree :: ResSubtree -> [String] -> Maybe ResourceDef
-
-      walkTree subtree (name:[])
-          = case M.lookup name subtree of
-              Nothing               -> Nothing
-              Just (ResNode defM _) -> defM
-
-      walkTree subtree (x:xs)
-          = case M.lookup x subtree of
-              Nothing                      -> Nothing
-              Just (ResNode defM children) -> case defM of
-                                                Just (ResourceDef { resIsGreedy = True })
-                                                    -> defM
-                                                _   -> walkTree children xs
-
-
-runResource :: ResourceDef -> Interaction -> IO ThreadId
-runResource def itr
-    = fork
-      $ catch ( runReaderT ( do fromMaybe notAllowed rsrc 
-                                driftTo Done
-                           ) itr
-              )
-      $ \ exc -> processException (itrConfig itr) exc
+      walkTree ∷ ResSubtree → [Text] → [Text] → Maybe ([Text], ResourceDef)
+
+      walkTree _ [] _
+          = error "Internal error: should not reach here."
+
+      walkTree tree (name:[]) soFar
+          = do ResNode defM _ ← M.lookup name tree
+               def            ← defM
+               return (soFar ⧺ [name], def)
+
+      walkTree tree (x:xs) soFar
+          = do ResNode defM sub ← M.lookup x tree
+               case defM of
+                 Just (ResourceDef { resIsGreedy = True })
+                     → do def ← defM
+                          return (soFar ⧺ [x], def)
+                 _   → walkTree sub xs (soFar ⧺ [x])
+
+      fallback ∷ [Text] → [FallbackHandler] → IO (Maybe ([Text], ResourceDef))
+      fallback _    []     = return Nothing
+      fallback path (x:xs) = do m ← x path
+                                case m of
+                                  Just def → return $ Just ([], def)
+                                  Nothing  → fallback path xs
+
+
+runResource ∷ ResourceDef → Interaction → IO ThreadId
+runResource (ResourceDef {..}) itr@(Interaction {..})
+    = fork $ run `catch` processException
     where
-      fork :: IO () -> IO ThreadId
-      fork = if (resUsesNativeThread def)
-             then forkOS
-             else forkIO
+      fork ∷ IO () → IO ThreadId
+      fork | resUsesNativeThread = forkOS
+           | otherwise           = forkIO
+
+      run ∷ IO ()
+      run = flip runRes itr $
+            do req ← getRequest
+               fromMaybe notAllowed $ rsrc req
+               driftTo Done
       
-      rsrc :: Maybe (Resource ())
-      rsrc = case reqMethod $ fromJust $ itrRequest itr of
-               GET    -> resGet def
-               HEAD   -> case resHead def of
-                           Just r  -> Just r
-                           Nothing -> resGet def
-               POST   -> resPost def
-               PUT    -> resPut def
-               DELETE -> resDelete def
-
-      notAllowed :: Resource ()
-      notAllowed = do setStatus MethodNotAllowed
-                      setHeader "Allow" $ joinWith ", " allowedMethods
-
-      allowedMethods :: [String]
-      allowedMethods = nub $ foldr (++) [] [ methods resGet    ["GET"]
-                                           , methods resHead   ["GET", "HEAD"]
-                                           , methods resPost   ["POST"]
-                                           , methods resPut    ["PUT"]
-                                           , methods resDelete ["DELETE"]
-                                           ]
-
-      methods :: (ResourceDef -> Maybe a) -> [String] -> [String]
-      methods f xs = case f def of
-                       Just _  -> xs
-                       Nothing -> []
-
-      processException :: Config -> Exception -> IO ()
-      processException conf exc
-          = do let abo = case exc of
-                           ErrorCall    msg  -> Abortion InternalServerError [] msg
-                           IOException  ioE  -> Abortion InternalServerError [] $ formatIOE ioE
-                           DynException dynE -> case fromDynamic dynE of
-                                                  Just (abo :: Abortion) -> abo
-                                                  Nothing
-                                                      -> Abortion InternalServerError []
-                                                         $ show exc
-                           _                 -> Abortion InternalServerError [] $ show exc
+      rsrc ∷ Request → Maybe (Resource ())
+      rsrc req
+          = case reqMethod req of
+              GET    → resGet
+              HEAD   → case resHead of
+                          Just r  → Just r
+                          Nothing → resGet
+              POST   → resPost
+              PUT    → resPut
+              DELETE → resDelete
+              _      → error $ "Unknown request method: " ⧺ show (reqMethod req)
+
+      notAllowed ∷ Resource ()
+      notAllowed
+          = setStatus MethodNotAllowed
+            *>
+            (setHeader "Allow" $ A.fromAsciiBuilder
+                               $ joinWith ", "
+                               $ map A.toAsciiBuilder allowedMethods)
+
+      allowedMethods ∷ [Ascii]
+      allowedMethods = nub $ concat [ methods resGet    ["GET"]
+                                    , methods resHead   ["GET", "HEAD"]
+                                    , methods resPost   ["POST"]
+                                    , methods resPut    ["PUT"]
+                                    , methods resDelete ["DELETE"]
+                                    ]
+
+      methods ∷ Maybe a → [Ascii] → [Ascii]
+      methods m xs
+          | isJust m  = xs
+          | otherwise = []
+
+      toAbortion ∷ SomeException → Abortion
+      toAbortion e
+          = case fromException e of
+              Just abortion → abortion
+              Nothing       → Abortion InternalServerError (∅) (Just $ T.pack $ show e)
+
+      processException ∷ SomeException → IO ()
+      processException exc
+          = do let abo = toAbortion exc
                -- まだ DecidingHeader 以前の状態だったら、この途中終了
                -- を應答に反映させる餘地がある。さうでなければ stderr
                -- にでも吐くしか無い。
-               state <- atomically $ readItr itr itrState id
-               if state <= DecidingHeader then
-                   flip runReaderT itr
-                      $ do setStatus $ aboStatus abo
-                           -- FIXME: 同じ名前で複數の値があった時は、こ
-                           -- れではまずいと思ふ。
-                           mapM_ (\ (name, value) -> setHeader name value) $ aboHeaders abo
-                           setHeader "Content-Type" "application/xhtml+xml"
-                           output $ aboPage conf abo
-                 else
-                   hPutStrLn stderr $ show abo
-
-               flip runReaderT itr $ driftTo Done
-
-      formatIOE :: IOError -> String
-      formatIOE ioE = if isUserError ioE then
-                          ioeGetErrorString ioE
-                      else
-                          show ioE
+               state ← atomically $ readTVar itrState
+               res   ← atomically $ readTVar itrResponse
+               if state ≤ DecidingHeader then
+                   flip runRes itr $
+                       do setStatus $ aboStatus abo
+                          mapM_ (uncurry setHeader) $ fromHeaders $ aboHeaders abo
+                          output $ LT.encodeUtf8 $ abortPage itrConfig itrRequest res abo
+               else
+                   when (cnfDumpTooLateAbortionToStderr itrConfig)
+                       $ hPutStrLn stderr $ show abo
+               runRes (driftTo Done) itr