X-Git-Url: https://git.cielonegro.org/gitweb.cgi?a=blobdiff_plain;ds=sidebyside;f=Network%2FHTTP%2FLucu%2FResource%2FTree.hs;h=de19e0470deb3f4951080895998939df1e5294c1;hb=d4c76b57333f7dc59aad618ac5b40873577e9a58;hp=bb12dd0ee5c49bb7c3fdce0d58c6e090626eaeb0;hpb=15aa04a569fb13fb0793389f78f52b0255083cef;p=Lucu.git

diff --git a/Network/HTTP/Lucu/Resource/Tree.hs b/Network/HTTP/Lucu/Resource/Tree.hs
index bb12dd0..de19e04 100644
--- a/Network/HTTP/Lucu/Resource/Tree.hs
+++ b/Network/HTTP/Lucu/Resource/Tree.hs
@@ -1,9 +1,11 @@
--- #prune
+{-# OPTIONS_HADDOCK prune #-}
 
 -- | Repository of the resources in httpd.
 module Network.HTTP.Lucu.Resource.Tree
     ( ResourceDef(..)
     , ResTree
+    , FallbackHandler
+
     , mkResTree    -- [ ([String], ResourceDef) ] -> ResTree
 
     , findResource -- ResTree -> URI -> Maybe ([String], ResourceDef)
@@ -16,7 +18,6 @@ import           Control.Concurrent.STM
 import           Control.Exception
 import           Control.Monad
 import qualified Data.ByteString.Char8 as C8
-import           Data.Dynamic
 import           Data.List
 import qualified Data.Map as M
 import           Data.Map (Map)
@@ -29,12 +30,20 @@ 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)
 
 
+-- |'FallbackHandler' is an extra resource handler for resources which
+-- can't be statically located somewhere in the resource tree. The
+-- Lucu httpd first search for a resource in the tree, and then call
+-- fallback handlers to ask them for a resource. If all of the
+-- handlers returned 'Prelude.Nothing', the httpd responds with 404
+-- Not Found.
+type FallbackHandler = [String] -> 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
@@ -55,7 +64,7 @@ data ResourceDef = ResourceDef {
     -- 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
-    -- resource is like a CGI script.
+    -- resources are like CGI scripts.
     , resIsGreedy         :: !Bool
     -- | A 'Network.HTTP.Lucu.Resource.Resource' to be run when a GET
     -- request comes for the resource path. If 'resGet' is Nothing,
@@ -89,13 +98,13 @@ data ResourceDef = ResourceDef {
     , resDelete           :: !(Maybe (Resource ()))
     }
 
--- | 'ResTree' is an opaque structure which is a map from resource
--- path to 'ResourceDef'.
-type ResTree    = ResNode -- root だから Map ではない
+-- |'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 String ResNode
 data ResNode    = ResNode !(Maybe ResourceDef) !ResSubtree
 
--- | 'mkResTree' converts a list of @(path, def)@ to a 'ResTree' e.g.
+-- |'mkResTree' converts a list of @(path, def)@ to a 'ResTree' e.g.
 --
 -- @
 --   mkResTree [ ([]        , 'Network.HTTP.Lucu.StaticFile.staticFile' \"\/usr\/include\/stdio.h\" ) -- \/
@@ -103,7 +112,7 @@ data ResNode    = ResNode !(Maybe ResourceDef) !ResSubtree
 --             ]
 -- @
 mkResTree :: [ ([String], ResourceDef) ] -> ResTree
-mkResTree list = list `seq` processRoot list
+mkResTree xs = xs `seq` processRoot xs
     where
       processRoot :: [ ([String], ResourceDef) ] -> ResTree
       processRoot list
@@ -112,12 +121,12 @@ mkResTree list = list `seq` processRoot list
             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
+                  ResTree (ResNode Nothing children)
               else
                   -- "/" がある。
                   let (_, def) = last roots
                   in 
-                    ResNode (Just def) children
+                    ResTree (ResNode (Just def) children)
 
       processNonRoot :: [ ([String], ResourceDef) ] -> ResSubtree
       processNonRoot list
@@ -139,27 +148,33 @@ mkResTree list = list `seq` processRoot list
               subtree
 
 
-findResource :: ResTree -> URI -> Maybe ([String], ResourceDef)
-findResource (ResNode rootDefM subtree) uri
-    = let pathStr = uriPath uri
-          path    = [x | x <- splitBy (== '/') pathStr, x /= ""]
-      in
-        if null path then
-            do def <- rootDefM
-               return (path, def)
-        else
-            walkTree subtree path []
+findResource :: ResTree -> [FallbackHandler] -> URI -> IO (Maybe ([String], ResourceDef))
+findResource (ResTree (ResNode rootDefM subtree)) fbs uri
+    = do let pathStr     = uriPath uri
+             path        = [x | x <- splitBy (== '/') pathStr, x /= ""]
+             foundInTree = if null path then
+                               do def <- rootDefM
+                                  return (path, def)
+                           else
+                               walkTree subtree path []
+         if isJust foundInTree then
+             return foundInTree
+           else
+             fallback path fbs
     where
       walkTree :: ResSubtree -> [String] -> [String] -> Maybe ([String], ResourceDef)
 
-      walkTree subtree (name:[]) soFar
-          = case M.lookup name subtree of
+      walkTree _ [] _
+          = error "Internal error: should not reach here."
+
+      walkTree tree (name:[]) soFar
+          = case M.lookup name tree of
               Nothing               -> Nothing
               Just (ResNode defM _) -> do def <- defM
                                           return (soFar ++ [name], def)
 
-      walkTree subtree (x:xs) soFar
-          = case M.lookup x subtree of
+      walkTree tree (x:xs) soFar
+          = case M.lookup x tree of
               Nothing                      -> Nothing
               Just (ResNode defM children) -> case defM of
                                                 Just (ResourceDef { resIsGreedy = True })
@@ -167,6 +182,13 @@ findResource (ResNode rootDefM subtree) uri
                                                           return (soFar ++ [x], def)
                                                 _   -> walkTree children xs (soFar ++ [x])
 
+      fallback :: [String] -> [FallbackHandler] -> IO (Maybe ([String], 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 def itr
@@ -194,6 +216,7 @@ runResource def itr
               POST   -> resPost def
               PUT    -> resPut def
               DELETE -> resDelete def
+              _      -> undefined
 
       notAllowed :: Resource ()
       notAllowed = do setStatus MethodNotAllowed
@@ -212,17 +235,14 @@ runResource def itr
                        Just _  -> xs
                        Nothing -> []
 
-      processException :: Exception -> IO ()
+      toAbortion :: SomeException -> Abortion
+      toAbortion e = case fromException e of
+                       Just abortion -> abortion
+                       Nothing       -> Abortion InternalServerError emptyHeaders (Just (show e))
+
+      processException :: SomeException -> IO ()
       processException exc
-          = do let abo = case exc of
-                           ErrorCall    msg  -> Abortion InternalServerError emptyHeaders $ Just msg
-                           IOException  ioE  -> Abortion InternalServerError emptyHeaders $ Just $ formatIOE ioE
-                           DynException dynE -> case fromDynamic dynE of
-                                                  Just (abo :: Abortion) -> abo
-                                                  Nothing
-                                                      -> Abortion InternalServerError emptyHeaders
-                                                         $ Just $ show exc
-                           _                 -> Abortion InternalServerError emptyHeaders $ Just $ show exc
+          = do let abo = toAbortion exc
                    conf = itrConfig itr
                -- 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
@@ -240,9 +260,3 @@ runResource def itr
                             $ hPutStrLn stderr $ show abo
 
                flip runRes itr $ driftTo Done
-
-      formatIOE :: IOError -> String
-      formatIOE ioE = if isUserError ioE then
-                          ioeGetErrorString ioE
-                      else
-                          show ioE