Python 类方法classmethod 示例

#https://github.com/pavlov99/json-rpc/blob/master/jsonrpc/manager.pyimport jsonimport loggingfrom .utils import is_invalid_paramsfrom .exceptions import (    JSONRPCInvalidParams,    JSONRPCInvalidRequest,    JSONRPCInvalidRequestException,    JSONRPCMethodNotFound,    JSONRPCParseError,    JSONRPCServerError,    JSONRPCDispatchException,)from .jsonrpc1 import JSONRPC10Responsefrom .jsonrpc2 import (    JSONRPC20BatchRequest,    JSONRPC20BatchResponse,    JSONRPC20Response,)from .jsonrpc import JSONRPCRequestlogger = logging.getLogger(__name__)class JSONRPCResponseManager(object):    """ JSON-RPC response manager.    Method brings syntactic sugar into library. Given dispatcher it handles    request (both single and batch) and handles errors.    Request could be handled in parallel, it is server responsibility.    :param str request_str: json string. Will be converted into        JSONRPC20Request, JSONRPC20BatchRequest or JSONRPC10Request    :param dict dispather: dict<function_name:function>.    """    RESPONSE_CLASS_MAP = {        "1.0": JSONRPC10Response,        "2.0": JSONRPC20Response,    }    @classmethod    def handle(cls, request_str, dispatcher):        if isinstance(request_str, bytes):            request_str = request_str.decode("utf-8")        try:            json.loads(request_str)        except (TypeError, ValueError):            return JSONRPC20Response(error=JSONRPCParseError()._data)        try:            request = JSONRPCRequest.from_json(request_str)        except JSONRPCInvalidRequestException:            return JSONRPC20Response(error=JSONRPCInvalidRequest()._data)        return cls.handle_request(request, dispatcher)    @classmethod    def handle_request(cls, request, dispatcher):        """ Handle request data.        At this moment request has correct jsonrpc format.        :param dict request: data parsed from request_str.        :param jsonrpc.dispatcher.Dispatcher dispatcher:        .. versionadded: 1.8.0        """        rs = request if isinstance(request, JSONRPC20BatchRequest) \            else [request]        responses = [r for r in cls._get_responses(rs, dispatcher)                     if r is not None]        # notifications        if not responses:            return        if isinstance(request, JSONRPC20BatchRequest):            return JSONRPC20BatchResponse(*responses)        else:            return responses[0]    @classmethod    def _get_responses(cls, requests, dispatcher):        """ Response to each single JSON-RPC Request.        :return iterator(JSONRPC20Response):        .. versionadded: 1.9.0          TypeError inside the function is distinguished from Invalid Params.        """        for request in requests:            def response(**kwargs):                return cls.RESPONSE_CLASS_MAP[request.JSONRPC_VERSION](                    _id=request._id, **kwargs)            try:                method = dispatcher[request.method]            except KeyError:                output = response(error=JSONRPCMethodNotFound()._data)            else:                try:                    result = method(*request.args, **request.kwargs)                except JSONRPCDispatchException as e:                    output = response(error=e.error._data)                except Exception as e:                    data = {                        "type": e.__class__.__name__,                        "args": e.args,                        "message": str(e),                    }                    logger.exception("API Exception: {0}".format(data))                    if isinstance(e, TypeError) and is_invalid_params(                            method, *request.args, **request.kwargs):                        output = response(                            error=JSONRPCInvalidParams(data=data)._data)                    else:                        output = response(                            error=JSONRPCServerError(data=data)._data)                else:                    output = response(result=result)            finally:                if not request.is_notification:                    yield output