python django 自定义 装饰器

# -*-coding:utf-8-*-
__author__ = "GILANG (pleasurelong@foxmail.com)"
"""
django 自定义用于view的装饰器
"""
from functools import wraps

def object_does_not_exist(func):
    """
    不带参数的装饰器
    """
    @wraps(func)
    def returned_wrapper(request, *args, **kwargs):
        try:
            return func(request, *args, **kwargs)
        except ObjectDoesNotExist:
            raise Http404()
    return returned_wrapper

@object_does_not_exist
def detail(request):
    """
    用法
    """
    pass

############################################################################

def object_does_not_exist(redirect=None):
    """
    第一种写法：带参数的装饰器
    """
    def decorator(func):
        @wraps(func)
        def returned_wrapper(request, *args, **kwargs):
            try:
                return func(request, *args, **kwargs)
            except ObjectDoesNotExist:
                if redirect:
                    return HttpResponseRedirect(redirect)
                else:
                    raise Http404()
        return returned_wrapper
    return decorator

@object_does_not_exist(redirect='/')
def detail(request):
    pass

# 记得加个闭合括号，否则会出现类似 takes exactly 1 argument (0 given) 的错误
@object_does_not_exist()
def foo(request):
    pass

############################################################################

def object_does_not_exist(func=None, redirect=None):
    """
    第二种写法：带参数的装饰器
    第二种方法可以解决 got an unexpected keyword argument 错误。
    """
    def decorator(func):
        @wraps(func)
        def returned_wrapper(request, *args, **kwargs):
            try:
                return func(request, *args, **kwargs)
            except ObjectDoesNotExist:
                if redirect:
                    return HttpResponseRedirect(redirect)
                else:
                    raise Http404()
        return returned_wrapper

    if not func:
        def foo(func):
            return decorator(func)
        return foo

    else:
        return decorator(func)

@object_does_not_exist(redirect='/')
def detail(request):
    pass

@object_does_not_exist
def foo(request):
    pass