module Network.Wai.Routing.Predicate.Query
( Query (..)
, HasQuery (..)
) where
import Data.ByteString (ByteString)
import Data.ByteString.From
import Data.Monoid
import Network.HTTP.Types.Status
import Network.Wai.Routing.Error
import Network.Wai.Routing.Internal
import Network.Wai.Routing.Predicate.Predicate
import Network.Wai.Routing.Request
newtype Query a = Query ByteString
instance (FromByteString a) => Predicate (Query a) Req where
type FVal (Query a) = Error
type TVal (Query a) = a
apply (Query x) =
let msg = "Missing query '" <> x <> "'." in
rqApply (lookupQuery x) readValues (err status400 msg)
newtype HasQuery = HasQuery ByteString
instance Predicate HasQuery Req where
type FVal HasQuery = Error
type TVal HasQuery = ()
apply (HasQuery x) r =
if null (lookupQuery x r)
then F (err status400 ("Missing query '" <> x <> "'."))
else T 0 ()