+{-# OPTIONS_HADDOCK prune #-}
+
+-- |Manipulation of entity tags.
module Network.HTTP.Lucu.ETag
- ( ETag
- , mkETag -- Bool -> String -> ETag
- , eTagP -- Parser ETag
- , eTagListP -- Parser [ETag]
+ ( ETag(..)
+ , strongETag
+ , weakETag
+ , eTagP
+ , eTagListP
)
where
+import Control.Monad
import Network.HTTP.Lucu.Parser
-import Network.HTTP.Lucu.Parser.Http
-
+import Network.HTTP.Lucu.Parser.Http hiding (token)
+import Network.HTTP.Lucu.Utils
+-- |An entity tag is made of a weakness flag and a opaque string.
data ETag = ETag {
- etagIsWeak :: Bool
- , etagToken :: String
+ -- |The weakness flag. Weak tags looks like W\/\"blahblah\" and
+ -- strong tags are like \"blahblah\".
+ etagIsWeak :: !Bool
+ -- |An opaque string. Only characters from 0x20 (sp) to 0x7e (~)
+ -- are allowed.
+ , etagToken :: !String
} deriving (Eq)
-
instance Show ETag where
show (ETag isWeak token) = (if isWeak then
"W/"
else
"")
++
- foldr (++) "" (["\""] ++ map quote token ++ ["\""])
- where
- quote :: Char -> String
- quote '"' = "\\\""
- quote c = [c]
+ quoteStr token
+-- |This is equivalent to @'ETag' 'Prelude.False'@. If you want to
+-- generate an ETag from a file, try using
+-- 'Network.HTTP.Lucu.StaticFile.generateETagFromFile'.
+strongETag :: String -> ETag
+strongETag = ETag False
-mkETag :: Bool -> String -> ETag
-mkETag = ETag
+-- |This is equivalent to @'ETag' 'Prelude.True'@.
+weakETag :: String -> ETag
+weakETag = ETag True
eTagP :: Parser ETag
eTagP = do isWeak <- option False (string "W/" >> return True)
str <- quotedStr
- return $ mkETag isWeak str
+ return $ ETag isWeak str
eTagListP :: Parser [ETag]
eTagListP = allowEOF
- $ sepBy1 eTagP (do many sp
- char ','
- many sp)
+ $! do xs <- listOf eTagP
+ when (null xs)
+ $ fail ""
+ return xs