+{-# LANGUAGE
+ BangPatterns
+ , UnicodeSyntax
+ #-}
+-- |Utility functions used internally in the Lucu httpd. These
+-- functions may be useful too for something else.
module Network.HTTP.Lucu.Utils
- ( splitBy -- (a -> Bool) -> [a] -> [[a]]
- , trim -- (a -> Bool) -> [a] -> [a]
- , noCaseEq -- String -> String -> Bool
- , isWhiteSpace -- Char -> Bool
+ ( splitBy
+ , joinWith
+ , trim
+ , isWhiteSpace
+ , quoteStr
+ , parseWWWFormURLEncoded
)
where
+import Control.Monad
+import Data.List hiding (last)
+import Network.URI
+import Prelude hiding (last)
+import Prelude.Unicode
-import Data.Char
-import Data.List
-
-
+-- |> splitBy (== ':') "ab:c:def"
+-- > ==> ["ab", "c", "def"]
splitBy :: (a -> Bool) -> [a] -> [[a]]
-splitBy isSeparator src
- = case break isSeparator src
- of (last , [] ) -> last : []
- (first, sep:rest) -> first : splitBy isSeparator rest
+splitBy isSep src
+ = case break isSep src
+ of (last , [] ) -> [last]
+ (first, _sep:rest) -> first : splitBy isSep rest
+-- |> joinWith ":" ["ab", "c", "def"]
+-- > ==> "ab:c:def"
+joinWith :: [a] -> [[a]] -> [a]
+joinWith = (join .) . intersperse
+-- |> trim (== '_') "__ab_c__def___"
+-- > ==> "ab_c__def"
trim :: (a -> Bool) -> [a] -> [a]
-trim p = trimTail . trimHead
+trim !p = trimTail . trimHead
where
trimHead = dropWhile p
trimTail = reverse . trimHead . reverse
+-- |@'isWhiteSpace' c@ is 'Prelude.True' iff c is one of SP, HT, CR
+-- and LF.
+isWhiteSpace :: Char -> Bool
+isWhiteSpace ' ' = True
+isWhiteSpace '\t' = True
+isWhiteSpace '\r' = True
+isWhiteSpace '\n' = True
+isWhiteSpace _ = False
+{-# INLINE isWhiteSpace #-}
-noCaseEq :: String -> String -> Bool
-noCaseEq a b
- = (map toLower a) == (map toLower b)
+-- |> quoteStr "abc"
+-- > ==> "\"abc\""
+--
+-- > quoteStr "ab\"c"
+-- > ==> "\"ab\\\"c\""
+quoteStr :: String -> String
+quoteStr !str = concat (["\""] ++ map quote str ++ ["\""])
+ where
+ quote :: Char -> String
+ quote '"' = "\\\""
+ quote c = [c]
-isWhiteSpace :: Char -> Bool
-isWhiteSpace = flip elem " \t\r\n"
+-- |> parseWWWFormURLEncoded "aaa=bbb&ccc=ddd"
+-- > ==> [("aaa", "bbb"), ("ccc", "ddd")]
+parseWWWFormURLEncoded ∷ String → [(String, String)]
+parseWWWFormURLEncoded src
+ | null src = []
+ | otherwise = do pairStr ← splitBy (\ c → c ≡ ';' ∨ c ≡ '&') src
+ let (key, value) = break (≡ '=') pairStr
+ return ( unescape key
+ , unescape $ case value of
+ ('=':val) → val
+ val → val
+ )
+ where
+ unescape ∷ String → String
+ unescape = unEscapeString ∘ map plusToSpace
+
+ plusToSpace ∷ Char → Char
+ plusToSpace '+' = ' '
+ plusToSpace c = c