OverloadedStrings
, UnicodeSyntax
#-}
-{-# OPTIONS_HADDOCK prune #-}
-
-- |Manipulation of entity tags.
module Network.HTTP.Lucu.ETag
( ETag(..)
-
+ , parseETag
, printETag
, strongETag
, eTagListP
)
where
+import Control.Applicative
import Control.Monad
-import Control.Monad.Unicode
import Data.Ascii (Ascii)
import qualified Data.Ascii as A
import Data.Attoparsec.Char8
import Data.Monoid.Unicode
import Network.HTTP.Lucu.Parser.Http hiding (token)
import Network.HTTP.Lucu.Utils
+import Prelude.Unicode
-- |An entity tag is made of a weakness flag and a opaque string.
data ETag = ETag {
⊕
quoteStr (etagToken et) )
+-- |Parse 'Etag' from an 'Ascii'. This functions throws an exception
+-- for parse error.
+parseETag ∷ Ascii → ETag
+parseETag str
+ = let p = do et ← eTagP
+ endOfInput
+ return et
+ bs = A.toByteString str
+ in
+ case parseOnly p bs of
+ Right et → et
+ Left err → error ("unparsable ETag: " ⧺ A.toString str ⧺ ": " ⧺ err)
+
-- |This is equivalent to @'ETag' 'Prelude.False'@. If you want to
-- generate an ETag from a file, try using
-- 'Network.HTTP.Lucu.StaticFile.generateETagFromFile'.
weakETag = ETag True
eTagP ∷ Parser ETag
-eTagP = do isWeak ← option False (string "W/" ≫ return True)
+eTagP = do isWeak ← option False (string "W/" *> return True)
str ← quotedStr
return $ ETag isWeak str