@method_decorator() 源码解析

# coding:utf-8
"""
作用：
原理：闭包 >> 1. 函数内部定义函数
             2.内部函数使用外部函数的变量
            3.外部函数返回内部函数的引用
带参数的函数装饰器 》》 三层

类的装饰器 >> 解决self 参数的问题
          >> 被装饰的对象是类不是函数
"""


def method_decorator(decorator, name=''):
    print("类装饰器执行了")

    def _dec(cls):
        print("真正的类装饰器生成了，并执行了")
        is_class = isinstance(cls, type)
        if is_class:
            method = getattr(cls, name)
        else:
            raise Exception("该装饰器只用来装饰类")

        def _wrapper(self, *args, **kwargs):
            @decorator
            def bound_func(*args2, **kwargs2):
                return method(self, *args2, **kwargs2)

            return bound_func(*args, **kwargs)

        setattr(cls, name, _wrapper)
        return cls

    return _dec

def my_decorator(bound_func):
    print("函数装饰器执行了")

    def real_func(*args, **kwargs):
        print("
exc decorator code before func
")
        ret = bound_func(*args, **kwargs)
        print("
exc decorator code after func
")
        return ret

    return real_func

"""
@method_decorator(decorator=my_decorator, name="get")
ViewTemp = method_decorator(decorator=my_decorator, name="get")(ViewTemp)
ViewTemp = _dec(ViewTemp)
>>> ViewTemp.get = ViewTemp._wrapper 
"""

@method_decorator(decorator=my_decorator, name="get")
class ViewTemp:
    def get(self, request):
        print("-----this is get method-----", "
request==", request)

    def post(self, request):
        print("-----this is post method----")

if __name__ == '__main__':
    """
    ViewTemp().get(request="xixixi)
    ViewTemp()._wrapper(request="xixixi)
    >>> _wrapper(self, request="xixixi)
    >>> >>> @decorator                                      my_decorator(bound_func)
    >>> >>> def bound_func(*args2, **kwargs2):              bound_func = real_func
                return method(self, *args2, **kwargs2)
            return bound_func(*args, **kwargs)     
    >>> real_func(request="xixixi)
    >>> >>> print("
exc decorator code before func
") 
    >>> >>> ret = bound_func(request="xixixi") >> bound_func(request="xixixi") >> method(self, request="xixixi)
    >>> >>> print("
exc decorator code after func
")
    >>> >>> return ret
    
    """
    ViewTemp().get(request="xixixi")
    pass