URL decode text input in fastcgi server, including %uXXXX sequences.

1 files changed, 18 insertions, 0 deletions

diff --git a/src/server/URLEncoding.hs b/src/server/URLEncoding.hs
new file mode 100644
index 000000000..ad5fb0dd9
--- /dev/null
+++ b/src/server/URLEncoding.hs
@@ -0,0 +1,18 @@
+module URLEncoding where
+
+import Data.Bits (shiftL, (.|.))
+import Data.Char (chr,digitToInt,isHexDigit)
+
+
+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