forked from yesodweb/wai
/
MethodOverridePost.hs
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/
MethodOverridePost.hs
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{-# 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)
import Data.Conduit.Lazy (lazyConsume)
import Control.Monad.Trans.Resource (ResourceT)
import Data.Conduit.List (sourceList)
-- | 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 middlware only applies when the initial request method is POST.
--
methodOverridePost :: Middleware
methodOverridePost app req = case (requestMethod req, lookup "Content-Type" (requestHeaders req)) of
("POST", Just "application/x-www-form-urlencoded") -> setPost req >>= app
_ -> app req
setPost :: Request -> ResourceT IO Request
setPost req = do
body <- lazyConsume (requestBody req)
case parseQuery (mconcat body) of
(("_method", Just newmethod):_) -> return $ req {requestBody = sourceList body, requestMethod = newmethod}
_ -> return $ req {requestBody = sourceList body}