http.py

    def get(self):
        key = self._load_request_as_json().get('key')
        is_metadata_request = self._load_request_as_json().get('metadata')
        response = self.sam.get(key=key).resource()

        if hasattr(response.data, 'metadata_key'):
            if is_metadata_request:
                response = cyclone.web.escape.json_encode({'metadata_key':response.data.metadata_key})
            elif response.data.metadata_key:
                response = cyclone.web.escape.json_encode({'done':True})
            elif not response.data.metadata_key:
                response = cyclone.web.escape.json_encode({'done':False})
            self.set_header('Content-Type', 'application/json')
            self.finish(response)

maneiro o código!