'Return a MultiDict containing all the variables from the
QUERY_STRING.'

@property
def GET(self):

    env = self.environ
    source = env.get('QUERY_STRING', '')
    if ('webob._parsed_query_vars' in env):
        (vars, qs) = env['webob._parsed_query_vars']
        if (qs == source):
            return vars
    data = []
    if source:
        data = parse_qsl_text(source)
    vars = GetDict(data, env)
    env['webob._parsed_query_vars'] = (vars, source)
    return vars
