safe cgi parameter

[Robin Becker]

I'm trying to pass xml into a cgi script and have some problems because I both
want to escape all my inputs (to avoid the possibility of an html injection
attack) and also allow my xml to be obtained in its original form.

I thought of this

from xml.sax.saxutils import escape as xmlEscape
class SafeCgiParam(str):
def __new__(cls,v):
return str.__new__(cls,xmlEscape(v))
def __init__(self,v):
self.__raw__ = v
so

>>x=SafeCgiParam('a<&>b')
print x

a&lt;&amp;&gt;b

>>print x.__raw__

a<&>b
ie always wrap the value, but access to the original is possible via __raw__.

However, if you do anything like x.strip() the original is lost. I'm not sure
that's a bad thing, but I thought I would ask what others do for this problem.
--
Robin Becker