> {-# LANGUAGE TypeFamilies, QuasiQuotes, TemplateHaskell, MultiParamTypeClasses, OverloadedStrings #-}
> import Yesod
> import qualified Data.ByteString.Char8 as S8
> import qualified Data.Text as T
> data Echo = Echo
> mkYesod "Echo" [parseRoutes|
> / Homepage GET POST
> |]
> instance Yesod Echo where approot _ = ""
> getHomepage :: Handler RepHtml
> getHomepage = defaultLayout $ do
> setTitle "Upload a file"
> addHamlet [hamlet|
> <form method=post action=. enctype=multipart/form-data>
> File name:
> <input type=file name=file
> <input type=submit
> |]
> postHomepage :: Handler [(ContentType, Content)]
> postHomepage = do
> (_, files) <- runRequestBody
> fi <- maybe notFound return $ lookup "file" files
> return [(S8.pack $ T.unpack $ fileContentType fi, toContent $ fileContent fi)]
> main :: IO ()
> main = warpDebug 3000 Echo
To avoid warnings
> _ignored :: Widget
> _ignored = undefined