middlewares.py 文件源码

def response_middleware(app, next_handler):
    async def handler(request):
        result = await next_handler(request)
        if not isinstance(result, Response):
            accept = request.headers.get('accept', 'application/json')
            if accept in ('application/json', '*/*'):
                if isinstance(result, ErrorResponse):
                    data, status, headers = result.data, result.status, result.headers
                    if headers:
                        # Passing both Content-Type header
                        # and content_type or charset params is forbidden
                        # (json_response already passes content_type)
                        headers.pop('content-type', None)
                else:
                    data, status, headers = result, HTTP_OK, None
                result = json_response(data, status=status, headers=headers)
            else:
                logger.error('Unable to serialize response (accept=%s)', accept)
                raise HTTPBadRequest()
        return result
    return handler