airflow/contrib/hooks/bigquery_hook.py
def next(self):
        """
        Helper method for fetchone, which returns the next row from a buffer.
        If the buffer is empty, attempts to paginate through the result set for
        the next page, and load it into the buffer.
        """
        if not self.job_id:
            return None

        if len(self.buffer) == 0:
            if self.all_pages_loaded:
                return None

            query_results = (self.service.jobs().getQueryResults(
                projectId=self.project_id,
                jobId=self.job_id,
                pageToken=self.page_token).execute(num_retries=self.num_retries))

            if 'rows' in query_results and query_results['rows']:
                self.page_token = query_results.get('pageToken')
                fields = query_results['schema']['fields']
                col_types = [field['type'] for field in fields]
                rows = query_results['rows']

                for dict_row in rows:
                    typed_row = ([
                        _bq_cast(vs['v'], col_types[idx])
                        for idx, vs in enumerate(dict_row['f'])
                    ])
                    self.buffer.append(typed_row)

                if not self.page_token:
                    self.all_pages_loaded = True

            else:
                # Reset all state since we've exhausted the results.
                self.page_token = None
                self.job_id = None
                self.page_token = None
                return None

        return self.buffer.pop(0)
def next(self):
        """
        Helper method for fetchone, which returns the next row from a buffer.
        If the buffer is empty, attempts to paginate through the result set for
        the next page, and load it into the buffer.
        """
        if not self.job_id:
            return None

        if len(self.buffer) == 0:
            if self.all_pages_loaded:
                return None

            query_results = (self.service.jobs().getQueryResults(
                projectId=self.project_id,
                jobId=self.job_id,
                pageToken=self.page_token).execute(num_retries=self.num_retries))

            if 'rows' in query_results and query_results['rows']:
                self.page_token = query_results.get('pageToken')
                fields = query_results['schema']['fields']
                col_types = [field['type'] for field in fields]
                rows = query_results['rows']

                for dict_row in rows:
                    typed_row = ([
                        _bq_cast(vs['v'], col_types[idx])
                        for idx, vs in enumerate(dict_row['f'])
                    ])
                    self.buffer.append(typed_row)

                if not self.page_token:
                    self.all_pages_loaded = True

            else:
                # Reset all state since we've exhausted the results.
                self.page_token = None
                self.job_id = None
                self.page_token = None
                return None

        return self.buffer.pop(0)
Helper method for fetchone, which returns the next row from a buffer.
        If the buffer is empty, attempts to paginate through the result set for
        the next page, and load it into the buffer.