Fixed treatment of unicode characters in URIs.

* Added stringToURI to Shared.  This is used in the HTML
  writer for all URIs.  It properly URI-encodes high
  characters (> 127), leaving everything else (including
  symbols and spaces) the same.

* Modified unsanitaryURI to allow UTF8 characters in a URI.
  (First, we convert the URI to URI-encoded octets, then we
  pass through parseURIReference.)
  This resolves gitit Issue #99. Previously
  '[abc](http://gitit.net/测试)' would not be rendered as
  a link when --sanitize was selected.

1 files changed, 17 insertions, 1 deletions

diff --git a/src/Text/Pandoc/Shared.hs b/src/Text/Pandoc/Shared.hs
index f093ddbee..2c1d3ab71 100644
--- a/src/Text/Pandoc/Shared.hs
+++ b/src/Text/Pandoc/Shared.hs
@@ -43,6 +43,7 @@ module Text.Pandoc.Shared (
                      stripFirstAndLast,
                      camelCaseToHyphenated,
                      toRomanNumeral,
+                     stringToURI,
                      wrapped,
                      wrapIfNeeded,
                      wrappedTeX,
@@ -114,7 +115,7 @@ import Text.ParserCombinators.Parsec
 import Text.PrettyPrint.HughesPJ ( Doc, fsep, ($$), (<>), empty, isEmpty, text, nest )
 import qualified Text.PrettyPrint.HughesPJ as PP
 import Text.Pandoc.CharacterReferences ( characterReference )
-import Data.Char ( toLower, toUpper, ord, isLower, isUpper, isAlpha,
+import Data.Char ( toLower, toUpper, ord, chr, isLower, isUpper, isAlpha,
                    isPunctuation )
 import Data.List ( find, isPrefixOf, intercalate )
 import Network.URI ( parseURI, URI (..), isAllowedInURI )
@@ -130,7 +131,12 @@ import System.IO.UTF8
 import Data.Generics
 import qualified Control.Monad.State as S
 import Control.Monad (join)
+import Data.ByteString (unpack)
+import Data.Word (Word8)
+import Data.ByteString.UTF8 (fromString)
+import Text.Printf (printf)
 import Paths_pandoc (getDataFileName)
+
 --
 -- List processing
 --
@@ -228,6 +234,16 @@ toRomanNumeral x =
               _ | x >= 1    -> "I" ++ toRomanNumeral (x - 1)
               _             -> ""
 
+-- | Escape unicode characters in a URI.  This means converting
+-- them to UTF-8, then URI-encoding the octets.  We leave everything
+-- else the same, assuming that the user has already escaped
+-- special characters like & and %.
+stringToURI :: String -> String
+stringToURI = concatMap encodeOctet . unpack . fromString
+  where encodeOctet :: Word8 -> String
+        encodeOctet x | x > 127 = printf "%%%2x" x
+        encodeOctet x = [chr (fromIntegral x)]
+
 -- | Wrap inlines to line length.
 wrapped :: Monad m => ([Inline] -> m Doc) -> [Inline] -> m Doc
 wrapped listWriter sect = (mapM listWriter $ splitBy Space sect) >>=