ETag

[Lucu.git] / Network / HTTP / Lucu / ETag.hs

diff --git a/Network/HTTP/Lucu/ETag.hs b/Network/HTTP/Lucu/ETag.hs
index 0341f5ac382b245638575477b0474ec0b1fafe40..056f14fa4c8f847512abd93c1cf4af62de25006d 100644 (file)
--- a/Network/HTTP/Lucu/ETag.hs
+++ b/Network/HTTP/Lucu/ETag.hs
@@ -1,46 +1,70 @@
+{-# LANGUAGE
+    OverloadedStrings
+  , UnicodeSyntax
+  #-}
+{-# OPTIONS_HADDOCK prune #-}
+
+-- |Manipulation of entity tags.
 module Network.HTTP.Lucu.ETag
-    ( ETag
-    , mkETag    -- Bool -> String -> ETag
-    , eTagP     -- Parser ETag
-    , eTagListP -- Parser [ETag]
-    )
-    where
+    ( ETag(..)
 
-import           Network.HTTP.Lucu.Parser
-import           Network.HTTP.Lucu.Parser.Http
+    , printETag
 
+    , strongETag
+    , weakETag
+    , eTagP
+    , eTagListP
+    )
+    where
+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
 
+-- |An entity tag is made of a weakness flag and a opaque string.
 data ETag = ETag {
-      etagIsWeak :: Bool
-    , 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]
-
+      -- |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  ∷ !Ascii
+    } deriving (Eq, Show)
 
-mkETag :: Bool -> String -> ETag
-mkETag = ETag
+-- |Convert an 'ETag' to 'Ascii'.
+printETag ∷ ETag → Ascii
+printETag et
+    = A.fromAsciiBuilder $
+      ( ( if etagIsWeak et then
+              A.toAsciiBuilder "W/"
+          else
+              (∅)
+        )
+        ⊕
+        quoteStr (etagToken et) )
 
+-- |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 ∷ Ascii → ETag
+strongETag = ETag False
 
-eTagP :: Parser ETag
-eTagP = do isWeak <- option False (string "W/" >> return True)
-           str    <- quotedStr
-           return $ mkETag isWeak str
+-- |This is equivalent to @'ETag' 'Prelude.True'@.
+weakETag ∷ Ascii → ETag
+weakETag = ETag True
 
+eTagP ∷ Parser ETag
+eTagP = try $
+        do isWeak ← option False (string "W/" ≫ return True)
+           str    ← quotedStr
+           return $ ETag isWeak str
 
-eTagListP :: Parser [ETag]
-eTagListP = allowEOF
-            $ sepBy1 eTagP (do many sp
-                               char ','
-                               many sp)
+eTagListP ∷ Parser [ETag]
+eTagListP = do xs ← listOf eTagP
+               when (null xs) $
+                   fail "empty list of ETags"
+               return xs