+ = req `seq` res `seq`
+ case resStatus res of
+ -- 1xx は body を持たない
+ -- 2xx の body は補完しない
+
+ -- 3xx
+ MovedPermanently
+ -> txt ("The resource at " ++ path ++ " has been moved to ")
+ <+>
+ eelem "a" += sattr "href" loc
+ += txt loc
+ <+>
+ txt " permanently."
+
+ Found
+ -> txt ("The resource at " ++ path ++ " is currently located at ")
+ <+>
+ eelem "a" += sattr "href" loc
+ += txt loc
+ <+>
+ txt ". This is not a permanent relocation."
+
+ SeeOther
+ -> txt ("The resource at " ++ path ++ " can be found at ")
+ <+>
+ eelem "a" += sattr "href" loc
+ += txt loc
+ <+>
+ txt "."
+
+ TemporaryRedirect
+ -> txt ("The resource at " ++ path ++ " is temporarily located at ")
+ <+>
+ eelem "a" += sattr "href" loc
+ += txt loc
+ <+>
+ txt "."
+
+ -- 4xx
+ BadRequest
+ -> txt "The server could not understand the request you sent."
+
+ Unauthorized
+ -> txt ("You need a valid authentication to access " ++ path)
+
+ Forbidden
+ -> txt ("You don't have permission to access " ++ path)
+
+ NotFound
+ -> txt ("The requested URL " ++ path ++ " was not found on this server.")
+
+ Gone
+ -> txt ("The resource at " ++ path ++ " was here in past times, but has gone permanently.")
+
+ RequestEntityTooLarge
+ -> txt ("The request entity you sent for " ++ path ++ " was too big to accept.")
+
+ RequestURITooLarge
+ -> txt "The request URI you sent was too big to accept."
+
+ -- 5xx
+ InternalServerError
+ -> txt ("An internal server error has occured during the process of your request to " ++ path)
+
+ ServiceUnavailable
+ -> txt "The service is temporarily unavailable. Try later."
+
+ _ -> none
+
+
+ where
+ path :: String
+ path = let uri = reqURI $! fromJust req
+ in
+ uriPath uri
+
+ loc :: String
+ loc = fromJust $! getHeader "Location" res
+
+{-# SPECIALIZE getMsg :: Maybe Request -> Response -> IOSArrow b XmlTree #-}
\ No newline at end of file