+ # First check duplicate parameters
+ for param in ('client_id', 'response_type', 'redirect_uri', 'scope', 'state'):
+ try:
+ duplicate_params = request.duplicate_params
+ except ValueError:
+ raise errors.InvalidRequestFatalError(description='Unable to parse query string', request=request)
+ if param in duplicate_params:
+ raise errors.InvalidRequestFatalError(description='Duplicate %s parameter.' % param, request=request)
+