[web2py] getting nested attributes with cas_auth.py

[Tim Korb]

I'm using gluon/contrib/login_methods/cas_auth.py to authenticate against 
our campus CAS server.  Our server returns most of the interesting values 
nested within a single "cas:attributes" node, which is not parsed by 
cas_auth.py.  I modified cas_auth.py (starting around line 110) to pull all 
"cas:" subnodes into the "res" structure, ignoring the three spurious ones 
(see below).  It seems to work, but I'm wondering if there is a more direct 
way to achieve the same thing.

Tim

            import xml.parsers.expat as expat

            res = dict()

            def start_element(name, attrs):
                global key
                if name.startswith('cas:'):
                    key = name[4:].encode('utf8')

            def char_data(value):
                global key
                if key in ['attributes', 'serviceResponse', 
'authenticationSuccess']:
                    return
                if key in res:
                    if isinstance(res[key], list):
                        res[key].append(value)
                    else:
                        res[key] = [res[key], value]
                else:
                    res[key] = value

            parser = expat.ParserCreate()
            parser.StartElementHandler = start_element
            parser.CharacterDataHandler = char_data

            try:
                parser.Parse(data)
                return res
            except expat.ExpatError: pass
            return None # fallback