1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
|
{-# LANGUAGE OverloadedStrings #-}
-----------------------------------------------------------------
-- | Module : Network.Wai.Middleware.MethodOverridePost
--
-- Changes the request-method via first post-parameter _method.
-----------------------------------------------------------------
module Network.Wai.Middleware.MethodOverridePost
( methodOverridePost
) where
import Network.Wai
import Network.HTTP.Types (parseQuery)
import Data.Monoid (mconcat, mempty)
import Data.IORef
import Data.ByteString.Lazy (toChunks)
-- | Allows overriding of the HTTP request method via the _method post string parameter.
--
-- * Looks for the Content-Type requestHeader.
--
-- * If the header is set to application/x-www-form-urlencoded
-- and the first POST parameter is _method
-- then it changes the request-method to the value of that
-- parameter.
--
-- * This middleware only applies when the initial request method is POST.
--
methodOverridePost :: Middleware
methodOverridePost app req send =
case (requestMethod req, lookup "Content-Type" (requestHeaders req)) of
("POST", Just "application/x-www-form-urlencoded") -> setPost req >>= flip app send
_ -> app req send
setPost :: Request -> IO Request
setPost req = do
body <- (mconcat . toChunks) `fmap` lazyRequestBody req
ref <- newIORef body
let rb = atomicModifyIORef ref $ \bs -> (mempty, bs)
case parseQuery body of
(("_method", Just newmethod):_) -> return $ req {requestBody = rb, requestMethod = newmethod}
_ -> return $ req {requestBody = rb}
|
