Get request parameters for redirect url.

def get_redirect_args(self, request, callback):
        "Get request parameters for redirect url."
        callback = request.build_absolute_uri(callback)
        args = {
            'client_id': self.provider.consumer_key,
            'redirect_uri': callback,
            'response_type': 'code',
        }
        state = self.get_application_state(request, callback)
        if state is not None:
            args['state'] = state
            request.session[self.session_key] = state
        return args