diff --git a/Network/Wai/Handler/CGI.hs b/Network/Wai/Handler/CGI.hs
--- a/Network/Wai/Handler/CGI.hs
+++ b/Network/Wai/Handler/CGI.hs
@@ -2,6 +2,8 @@
 module Network.Wai.Handler.CGI
     ( run
     , run'
+    , run''
+    , runSendfile
     ) where
 
 import Network.Wai
@@ -27,14 +29,35 @@
 run :: Application -> IO ()
 run app = do
     vars <- getEnvironment
-    run' vars System.IO.stdin System.IO.stdout app
+    let input = requestBodyHandle System.IO.stdin
+        output = B.hPut System.IO.stdout
+    run'' vars input output Nothing app
 
+runSendfile :: String -- ^ sendfile header
+            -> Application -> IO ()
+runSendfile sf app = do
+    vars <- getEnvironment
+    let input = requestBodyHandle System.IO.stdin
+        output = B.hPut System.IO.stdout
+    run'' vars input output (Just sf) app
+
 run' :: [(String, String)] -- ^ all variables
      -> System.IO.Handle -- ^ responseBody of input
      -> System.IO.Handle -- ^ destination for output
      -> Application
      -> IO ()
 run' vars inputH outputH app = do
+    let input = requestBodyHandle inputH
+        output = B.hPut outputH
+    run'' vars input output Nothing app
+
+run'' :: [(String, String)] -- ^ all variables
+     -> (Int -> Source) -- ^ responseBody of input
+     -> (B.ByteString -> IO ()) -- ^ destination for output
+     -> Maybe String -- ^ does the server support the X-Sendfile header?
+     -> Application
+     -> IO ()
+run'' vars inputH outputH xsendfile app = do
     let rmethod = B.pack $ lookup' "REQUEST_METHOD" vars
         pinfo = lookup' "PATH_INFO" vars
         qstring = lookup' "QUERY_STRING" vars
@@ -60,7 +83,7 @@
             , serverPort = serverport
             , requestHeaders = map (cleanupVarName *** B.pack) vars
             , isSecure = isSecure'
-            , requestBody = requestBodyHandle inputH contentLength
+            , requestBody = inputH contentLength
             , errorHandler = System.IO.hPutStr System.IO.stderr
             , remoteHost = B.pack remoteHost'
             , httpVersion = "1.1" -- FIXME
@@ -71,17 +94,29 @@
                 Nothing -> ("Content-Type", "text/html; charset=utf-8")
                          : h
                 Just _ -> h
-    let hPut = B.hPut outputH
+    let hPut = outputH
     hPut $ B.pack $ "Status: " ++ (show $ statusCode $ status res) ++ " "
     hPut $ statusMessage $ status res
     hPut $ B.singleton '\n'
     mapM_ (printHeader hPut) h'
-    hPut $ B.singleton '\n'
-    _ <- runEnumerator (fromResponseBody (responseBody res)) (myPut outputH) ()
-    return ()
+    case (xsendfile, responseBody res) of
+        (Just sf, ResponseFile fp) ->
+            hPut $ B.pack $ concat
+                [ sf
+                , ": "
+                , fp
+                , "\n\n"
+                , sf
+                , " not supported"
+                ]
+        _ -> do
+            hPut $ B.singleton '\n'
+            _ <- runEnumerator (fromResponseBody (responseBody res))
+                               (myPut outputH) ()
+            return ()
 
-myPut :: System.IO.Handle -> () -> B.ByteString -> IO (Either () ())
-myPut outputH _ bs = B.hPut outputH bs >> return (Right ())
+myPut :: (B.ByteString -> IO ()) -> () -> B.ByteString -> IO (Either () ())
+myPut output _ bs = output bs >> return (Right ())
 
 printHeader :: (B.ByteString -> IO ())
             -> (ResponseHeader, B.ByteString)
diff --git a/Network/Wai/Handler/Helper.hs b/Network/Wai/Handler/Helper.hs
--- a/Network/Wai/Handler/Helper.hs
+++ b/Network/Wai/Handler/Helper.hs
@@ -1,5 +1,6 @@
 module Network.Wai.Handler.Helper
     ( requestBodyHandle
+    , requestBodyFunc
     ) where
 
 import System.IO (Handle)
@@ -8,8 +9,17 @@
 import Network.Wai (Source (..))
 
 requestBodyHandle :: Handle -> Int -> Source
-requestBodyHandle _ 0 = Source $ return Nothing
-requestBodyHandle h len = Source $ do
-    bs <- B.hGet h $ min len defaultChunkSize
-    let newLen = len - B.length bs
-    return $ Just (bs, requestBodyHandle h newLen)
+requestBodyHandle h =
+    requestBodyFunc go
+  where
+    go i = Just `fmap` B.hGet h (min i defaultChunkSize)
+
+requestBodyFunc :: (Int -> IO (Maybe B.ByteString)) -> Int -> Source
+requestBodyFunc _ 0 = Source $ return Nothing
+requestBodyFunc h len = Source $ do
+    mbs <- h len
+    case mbs of
+        Nothing -> return Nothing
+        Just bs -> do
+            let newLen = len - B.length bs
+            return $ Just (bs, requestBodyFunc h $ max 0 newLen)
diff --git a/wai-extra.cabal b/wai-extra.cabal
--- a/wai-extra.cabal
+++ b/wai-extra.cabal
@@ -1,5 +1,5 @@
 Name:                wai-extra
-Version:             0.2.0
+Version:             0.2.1
 Synopsis:            Provides some basic WAI handlers and middleware.
 Description:         The goal here is to provide common features without many dependencies.
 License:             BSD3
@@ -31,7 +31,7 @@
                      Network.Wai.Middleware.Jsonp
                      Network.Wai.Zlib
                      Network.Wai.Parse
-  Other-modules:     Network.Wai.Handler.Helper
+                     Network.Wai.Handler.Helper
   ghc-options:       -Wall
   c-sources:         c/helper.c
   include-dirs:      c