+{-# LANGUAGE
+ OverloadedStrings
+ , TemplateHaskell
+ , UnicodeSyntax
+ #-}
-- |Utility functions used internally in the Lucu httpd. These
-- functions may be useful too for something else.
module Network.HTTP.Lucu.Utils
( splitBy
- , joinWith
- , trim
- , isWhiteSpace
, quoteStr
, parseWWWFormURLEncoded
+ , splitPathInfo
+ , trim
+ , liftCIAscii
+ , liftText
+ , liftMap
)
where
-
+import Control.Monad
+import Data.Ascii (Ascii, CIAscii, AsciiBuilder)
+import qualified Data.Ascii as A
+import Data.ByteString (ByteString)
+import qualified Data.ByteString.Char8 as BS
+import Data.Char
import Data.List hiding (last)
+import Data.Map (Map)
+import qualified Data.Map as M
+import Data.Monoid.Unicode
+import Data.Text (Text)
+import qualified Data.Text as T
+import Language.Haskell.TH.Lib
+import Language.Haskell.TH.Syntax
import Network.URI
import Prelude hiding (last)
+import Prelude.Unicode
--- |> splitBy (== ':') "ab:c:def"
--- > ==> ["ab", "c", "def"]
-splitBy :: (a -> Bool) -> [a] -> [[a]]
+-- |>>> splitBy (== ':') "ab:c:def"
+-- ["ab", "c", "def"]
+splitBy ∷ (a → Bool) → [a] → [[a]]
+{-# INLINEABLE splitBy #-}
splitBy isSep src
- = case break isSep src
- of (last , [] ) -> [last]
- (first, _sep:rest) -> first : splitBy isSep rest
+ = case break isSep src of
+ (last , [] ) → [last]
+ (first, _sep:rest) → first : splitBy isSep rest
+
+-- |>>> quoteStr "abc"
+-- "\"abc\""
+--
+-- >>> quoteStr "ab\"c"
+-- "\"ab\\\"c\""
+quoteStr ∷ Ascii → AsciiBuilder
+quoteStr str = A.toAsciiBuilder "\"" ⊕
+ go (A.toByteString str) (∅) ⊕
+ A.toAsciiBuilder "\""
+ where
+ go ∷ BS.ByteString → AsciiBuilder → AsciiBuilder
+ go bs ab
+ = case BS.break (≡ '"') bs of
+ (x, y)
+ | BS.null y → ab ⊕ b2ab x
+ | otherwise → go (BS.tail y) (ab ⊕ b2ab x
+ ⊕ A.toAsciiBuilder "\\\"")
--- |> joinWith ":" ["ab", "c", "def"]
--- > ==> "ab:c:def"
-joinWith :: [a] -> [[a]] -> [a]
-joinWith separator xs
- = separator `seq` xs `seq`
- foldr (++) [] $! intersperse separator xs
+ b2ab ∷ BS.ByteString → AsciiBuilder
+ b2ab = A.toAsciiBuilder ∘ A.unsafeFromByteString
--- |> trim (== '_') "__ab_c__def___"
--- > ==> "ab_c__def"
-trim :: (a -> Bool) -> [a] -> [a]
-trim p = p `seq` trimTail . trimHead
+-- |>>> parseWWWFormURLEncoded "aaa=bbb&ccc=ddd"
+-- [("aaa", "bbb"), ("ccc", "ddd")]
+parseWWWFormURLEncoded ∷ Ascii → [(ByteString, ByteString)]
+parseWWWFormURLEncoded src
+ -- THINKME: We could gain some performance by using attoparsec
+ -- here.
+ | src ≡ "" = []
+ | otherwise = do pairStr ← splitBy (\ c → c ≡ ';' ∨ c ≡ '&') (A.toString src)
+ let (key, value) = break (≡ '=') pairStr
+ return ( unescape key
+ , unescape $ case value of
+ ('=':val) → val
+ val → val
+ )
where
- trimHead = dropWhile p
- trimTail = reverse . trimHead . reverse
+ unescape ∷ String → ByteString
+ unescape = BS.pack ∘ unEscapeString ∘ map plusToSpace
--- |@'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 #-}
+ plusToSpace ∷ Char → Char
+ plusToSpace '+' = ' '
+ plusToSpace c = c
--- |> quoteStr "abc"
--- > ==> "\"abc\""
---
--- > quoteStr "ab\"c"
--- > ==> "\"ab\\\"c\""
-quoteStr :: String -> String
-quoteStr str = str `seq`
- foldr (++) "" (["\""] ++ map quote str ++ ["\""])
+-- |>>> splitPathInfo "http://example.com/foo/bar"
+-- ["foo", "bar"]
+splitPathInfo ∷ URI → [ByteString]
+splitPathInfo uri
+ = let reqPathStr = uriPath uri
+ reqPath = [unEscapeString x | x ← splitBy (≡ '/') reqPathStr, (¬) (null x)]
+ in
+ map BS.pack reqPath
+
+-- |>>> trim " ab c d "
+-- "ab c d"
+trim ∷ String → String
+trim = reverse ∘ f ∘ reverse ∘ f
where
- quote :: Char -> String
- quote '"' = "\\\""
- quote c = [c]
+ f = dropWhile isSpace
+-- |Convert a 'CIAscii' to an 'Exp' representing it as a literal.
+liftCIAscii ∷ CIAscii → Q Exp
+liftCIAscii a = [| A.toCIAscii (A.unsafeFromString $(strLit a)) |]
+ where
+ strLit ∷ CIAscii → Q Exp
+ strLit = liftString ∘ A.toString ∘ A.fromCIAscii
--- |> parseWWWFormURLEncoded "aaa=bbb&ccc=ddd"
--- > ==> [("aaa", "bbb"), ("ccc", "ddd")]
-parseWWWFormURLEncoded :: String -> [(String, String)]
-parseWWWFormURLEncoded src
- | src == "" = []
- | otherwise = do pairStr <- splitBy (\ c -> c == ';' || c == '&') src
- let (key, value) = break (== '=') pairStr
- return ( unEscapeString key
- , unEscapeString $ case value of
- ('=':val) -> val
- val -> val
- )
+-- |Convert a 'Text' to an 'Exp' representing it as a literal.
+liftText ∷ Text → Q Exp
+liftText t = [| T.pack $(strLit t) |]
+ where
+ strLit ∷ Text → Q Exp
+ strLit = liftString ∘ T.unpack
+
+-- |Convert an arbitrary 'Map' to an 'Exp' representing it as a
+-- literal, using a given key lifter and a value lifter.
+liftMap ∷ Eq k ⇒ (k → Q Exp) → (v → Q Exp) → Map k v → Q Exp
+liftMap liftK liftV m = [| M.fromAscList $(liftPairs $ M.toAscList m) |]
+ where
+ liftPairs = listE ∘ map liftPair
+ liftPair (k, v) = tupE [liftK k, liftV v]