装饰器的使用

"""
    装饰器
"""
# 需求：对以下两个功能增加权限验证.
"""
# 需要增加的功能
def verify_permissions():
    print("权限验证")

# 已有功能
def enter_background():
    verify_permissions()
    print("进入后台")

def delete_order():
    verify_permissions()
    print("删除订单")

enter_background()
delete_order()

# 缺点：增加新功能，需要修改已有功能．  [违反开闭原则]
"""

"""
# 需要增加的功能
def verify_permissions(func):
    def wrapper():
        print("权限验证")
        func()

    return wrapper

# 已有功能
def enter_background():
    print("进入后台")

def delete_order():
    print("删除订单")

# enter_background = 新功能 + 旧功能
enter_background = verify_permissions(enter_background)
delete_order = verify_permissions(delete_order)

enter_background()
delete_order()
缺点：每次拦截对已有功能(enter_background)的调用,不科学.
"""

"""
# 需要增加的功能
def verify_permissions(func):
    def wrapper():
        print("权限验证")
        func()

    return wrapper

# 已有功能
# enter_background = verify_permissions(enter_background)
@verify_permissions
def enter_background():
    print("进入后台")

@verify_permissions
def delete_order():
    print("删除订单")

enter_background()
delete_order()
缺点：如果已有功能参数不统一，则无法包装.
"""


def verify_permissions(func):
    def wrapper(*args, **kwargs):
        print("权限验证")
        func(*args, **kwargs)

    return wrapper


# 已有功能
@verify_permissions
def enter_background(login_id, pwd):
    print(login_id, pwd, "进入后台")

@verify_permissions
def delete_order(id):
    print("删除订单", id)

# enter_background = verify_permissions(enter_background)
# delete_order = verify_permissions(delete_order)

enter_background("abc", 1234)
delete_order(101)