編程方式產生的一類

Question

我有大約20個方法重定向到一個包裝方法採用原始方法，以及的參數的其餘部分的方法：

class my_socket(parent): 

    def _in(self, method, *args, **kwargs): 
     # do funky stuff 

    def recv(self, *args, **kwargs): 
     return self._in(super().recv, *args, **kwargs) 

    def recv_into(self, *args, **kwargs): 
     return self._in(super().recv_into, *args, **kwargs) 

    # and so on... 

我怎麼可以添加更多的這些方法編程？這是關於據我得到的一切纔開始找錯了：通過類的定義，還是其他什麼東西，感覺更自然內分配

for method in 'recv', 'recvfrom', 'recvfrom_into', 'recv_into', ...: 
    setattr(my_socket, method, ???) 

我能做到這一點？

class my_socket(parent): 

    def makes_recv_methods(name): 
     # wraps call to name 

    def recv_meh = makes_recv_methods('recv_meh') 

我寧願使用__get__和朋友時，可能在魔術函數從types。

Answer 1

我會通過運行一些代碼在類定義完成後從列表中生成方法來實現這一點 - 您可以將其放入裝飾器中。

import functools 

def wrap_method(cls, name): 
    # This unbound method will be pulled from the superclass. 
    wrapped = getattr(cls, name) 
    @functools.wraps(wrapped) 
    def wrapper(self, *args, **kwargs): 
     return self._in(wrapped.__get__(self, cls), *args, **kwargs) 
    return wrapper 

def wrap_methods(cls): 
    for name in cls.WRAP_ATTRS: 
     setattr(cls, name, wrap_method(cls, name)) 
    return cls 

@wrap_methods 
class my_socket(parent_class): 
    WRAP_ATTRS = ['recv', 'recvfrom'] # ... + more method names 

    def _in(self, method, *args, **kwargs): 
     # do funky stuff 

Answer 2

威爾伯福斯提案工作，但僅使用OOP一個簡單的方法：你可以使用cog

def wrap_method(wrapped): 
    @functools.wraps(wrapped) 
    def wrapper(self, *args, **kwargs): 
     return self._in(wrapped.__get__(self, cls), *args, **kwargs) 
    return wrapper 

class Parent: 

    def _in(self, method, *args, **kwargs): 
     return method(*args, **kwargs) 


    @wrap_method 
    def recv(self, *args, **kwargs): 
     return # whatever 

    @wrap_method 
    def recv_into(self, *args, **kwargs): 
     return # whatever 

class MySocket(Parent): 

    def _in(self, method, *args, **kwargs): 
     # do funky stuff 

Answer 3

。

class MySocket(Parent): 
"""[[[cog 
import cog 
l = ['in','out'] 
for item in l: 
    cog.outl("def _{0}(self, method, *args, **kwargs):".format(item)) 

]]]""" 
#[[[end]]] 

這樣做很容易被更新，不觸及結束註釋之外的代碼的附加優勢，並在必要時你可以玩弄生成的代碼。

我已經成功地使用cog在另一個項目上生成樣板，與非生成的代碼混合在一起。它開始將一個輸入文件的指令讀入字典中。然後，對於樣板的每一部分，它都使用字典的那一部分來知道要寫什麼。

我在一個位置編輯指令文件，而不是樣板中的20個不同位置。

Answer 4

我想擴大接受的答案。我想可能有很長的修飾器方法列表應用於很長的方法列表。

import functools 


def wrap_method(cls, name, wrapper_method_name): 
    # This unbound method will be pulled from the superclass. 
    wrapped = getattr(cls, name, wrapper_method_name) 

    @functools.wraps(wrapped) 
    def wrapper(self, *args, **kwargs): 
     wrapper_method = getattr(self, wrapper_method_name) 
     return wrapper_method(wrapped.__get__(self, cls), *args, **kwargs) 

    return wrapper 


def wrap_methods(cls): 
    for wrapper_method_name in cls.WRAPPER_METHOD_NAMES: 
     for name in cls.WRAPPED_METHODS: 
      setattr(cls, name, wrap_method(cls, name, wrapper_method_name)) 
    return cls 

這裏是一個包裝原

@wrap_methods 
class WrappedConnection(BaseConnection): 
    """ 
    This class adds some quality-of-life improvements to the BaseConnection class. 
    -WRAPPED_METHODS are wrapped by WRAPPER_METHOD_NAMES 
    -wrappers can be toggled on and off. 

    example: 
    connection = WrappedConnection(show_messages=True, log_errors=False, keep_authenticated=False) 

    default: 
    connection = WrappedConnection(show_messages=False, log_errors=True, keep_authenticated=True) 
    """ 
    WRAPPER_METHOD_NAMES = ['log_errors', 'keep_authenticated', 'show_messages'] 
    WRAPPED_METHODS = ['a_method', 'b_method', 'c_method', 'd_method'] 
    MESSAGE_OVERRIDE_MAP = {"a_method": "a_method_message_override_attribute", 
          "b_method": "b_method_message_override_attribute"} 

    def keep_authenticated(self, method, *args, **kwargs): 
     """ 
     If the session has expired, the session is re-authenticated. The incident is logged by the default logger. 
     This option can be turned off by setting keep_authenticated during initialization of a WrappedConnection object. 
     - connection = WrappedConnection(keep_authenticated=False) # why would you ever do this 


     :param method: (method) method to be wrapped 
     :param args: (args) passed args 
     :param kwargs: (kwargs) passed kwargs 
     :return: (method) method wrapped by @keep_authenticated 
     """ 
     response, expired_session = method(*args, **kwargs), None 
     if response["errors"] and self._keep_authenticated: 
      expired_session = list(filter(lambda x: 'expired session' in x, response["errors"])) 
     if expired_session: 
      self.__init__() 
      logging.info('Session has been re-authenticated.') 
      response = method(*args, **kwargs) 
     return response 

    def log_errors(self, method, *args, **kwargs): 
     """ 
     If there is an error the incident is logged. This option can be turned off by setting log_errors 
     during initialization of a WrappedConnection object. 
     - connection = WrappedConnection(log_errors=False) 

     :param method: (method) method to be wrapped 
     :param args: (args) passed args 
     :param kwargs: (kwargs) passed kwargs 
     :return: (method) method wrapped by @log_errors 
     """ 
     response = method(*args, **kwargs) 
     if response["errors"] and self._log_errors: 
      errors = response["errors"] 
      logging.error(errors) 
     return response 

    def show_messages(self, method, *args, **kwargs): 
     """ 
     Shows the xml that is sent during the request. This option can be turned on by setting show_messages during 
     initialization of a WrappedConnection object. 
     - connection = WrappedConnection(show_messages=True) 

     :param method: (method) method to be wrapped 
     :param args: (args) passed args 
     :param kwargs: (kwargs) passed kwargs 
     :return: (method) method wrapped by @show_messages 
     """ 
     response = method(*args, **kwargs) 
     if self._show_messages: 
      message_override_attr = WrappedConnection.MESSAGE_OVERRIDE_MAP.get(method.__name__) 
      if message_override_attr: 
       message_override = getattr(self, message_override_attr) 
       print(BeautifulSoup(message_override, "xml").prettify()) 
      else: 
       self._show_message(method.__name__, *args, **kwargs) 
     return response 

    def __init__(self, *args, keep_authenticated=True, log_errors=True, show_messages=False, **kwargs): 
     super(WrappedConnection, self).__init__(*args, **kwargs) 
     self._keep_authenticated = keep_authenticated 
     self._log_errors = log_errors 
     self._show_messages = show_messages