Network.Gopher.Util

Helper utilities used within the library and the server which also could be useful for other application code.

Security

sanitizePath :: RawFilePath -> RawFilePath

Normalise a path and prevent directory traversal attacks.

sanitizeIfNotUrl :: RawFilePath -> RawFilePath

Use sanitizePath except if the path starts with URL: in which case the original string is returned.

dropPrivileges :: String -> IO ()

Call setGroupID and setUserID to switch to the given user and their primary group. Requires special privileges. Will raise an exception if either the user does not exist or the current user has no permission to change UID/GID.

String Encoding

asciiOrd :: Char -> Word8

ord a Word8

asciiChr :: Word8 -> Char

chr a Word8

asciiToLower :: Word8 -> Word8

Transform a Word8 to lowercase if the solution is in bounds.

uEncode :: String -> ByteString

Encode a String to a UTF-8 ByteString

uDecode :: ByteString -> String

Decode a UTF-8 ByteString to a String

Misc Helpers

stripNewline :: ByteString -> ByteString

Strip \r and \n from ByteStrings

boolToMaybe :: Bool -> a -> Maybe a

boolToMaybe True x == Just x

boolToMaybe False x == Nothing