Files
gf-core/src/server/URLEncoding.hs
hallgren 550db69caa Fix UTF-8 decoding problem in gf -server
The package network-2.4.1.1 thoughlessly introduced a backward incompatible
change to the function Network.URI.unEscapeString, see

    f2168b1f89

This also affects the function Network.Shed.Httpd.queryToArguments, which is
used in GFServer.hs.

To remain compatible with older and newer versions of the network package,
we need to stay clear of queryToArguments and unEscapeString. A replacement
function has been added to server/URLEncoding.hs.
2013-06-13 08:23:48 +00:00

62 lines
1.9 KiB
Haskell

module URLEncoding(urlDecodeUnicode,decodeQuery) where
import Data.Bits (shiftL, (.|.))
import Data.Char (chr,digitToInt,isHexDigit)
-- | Decode hexadecimal escapes
urlDecodeUnicode :: String -> String
urlDecodeUnicode [] = ""
urlDecodeUnicode ('%':'u':x1:x2:x3:x4:s)
| all isHexDigit [x1,x2,x3,x4] =
chr ( digitToInt x1 `shiftL` 12
.|. digitToInt x2 `shiftL` 8
.|. digitToInt x3 `shiftL` 4
.|. digitToInt x4) : urlDecodeUnicode s
urlDecodeUnicode ('%':x1:x2:s) | isHexDigit x1 && isHexDigit x2 =
chr ( digitToInt x1 `shiftL` 4
.|. digitToInt x2) : urlDecodeUnicode s
urlDecodeUnicode (c:s) = c : urlDecodeUnicode s
--------------------------------------------------------------------------------
type Query = [(String,String)]
-- | Decode application/x-www-form-urlencoded
decodeQuery :: String -> Query
decodeQuery = map (aboth decode . breakAt '=') . chopList (breakAt '&')
aboth f (x,y) = (f x,f y)
-- | Decode "+" and hexadecimal escapes
decode [] = []
decode ('%':'u':d1:d2:d3:d4:cs)
| all isHexDigit [d1,d2,d3,d4] = chr(fromhex4 d1 d2 d3 d4):decode cs
decode ('%':d1:d2:cs)
| all isHexDigit [d1,d2] = chr(fromhex2 d1 d2):decode cs
decode ('+':cs) = ' ':decode cs
decode (c:cs) = c:decode cs
fromhex4 d1 d2 d3 d4 = 256*fromhex2 d1 d2+fromhex2 d3 d4
fromhex2 d1 d2 = 16*digitToInt d1+digitToInt d2
-- From hbc-library ListUtil ---------------------------------------------------
-- Repeatedly extract (and transform) values until a predicate hold. Return the list of values.
unfoldr :: (a -> (b, a)) -> (a -> Bool) -> a -> [b]
unfoldr f p x | p x = []
| otherwise = y:unfoldr f p x'
where (y, x') = f x
chopList :: ([a] -> (b, [a])) -> [a] -> [b]
chopList f l = unfoldr f null l
breakAt :: (Eq a) => a -> [a] -> ([a], [a])
breakAt _ [] = ([], [])
breakAt x (x':xs) =
if x == x' then
([], xs)
else
let (ys, zs) = breakAt x xs
in (x':ys, zs)