Create a custom happstack response code

Question

I have been trying to create a custom happstack response the 405 "Method not allowed" so if someone calls the API with a POST or PUT method they will get this response. I am new to happstack. Any ideas how I can do that?

Answer 1

Well the ok :: (FilterMonad Response m) => a -> m a function is implemented as [src]:

ok :: (FilterMonad Response m) => a -> m a
ok = resp 200

So it is the same way like you would write an ok response, except that you should use resp :: (FilterMonad Response m) => Int -> b -> m b with a custom return code.

For example:

resp 405 "Method not allowed"

So we can for example block PUT and POST requests with something like:

main :: IO ()
main = simpleHTTP nullConf $ msum
         [ do method GET
              ok $ "This is allowed.\n"
         , do method PUT
              (resp 405) $ "Method not allowed"
         , do method POST
              (resp 405) $ "Method not allowed"
         ]