装饰器(Decorators)是 Python 的一个重要部分。简单地说：他们是修改其他函数的功能的函数。为其他函数添加附加功能，不改变原函数代码及调用方式
创建装饰器
# 定义一个接收函数的方法，在此方法内创建一个函数，并返回该函数
def a_decorators(a_function):
def my_decorators_func():
print("I am doing some boring work before executing my_decorators_func()")
a = a_function()
print("I am doing some after work before executing my_decorators_func()")
return a
return my_decorators_func
使用wraps修饰
from functools import wraps
def a_decorators(a_function):
@wraps(a_function)
def my_decorators_func():
print("I am doing some boring work before executing my_decorators_func()")
a = a_function()
print("I am doing some after work before executing my_decorators_func()")
return a
return my_decorators_func
使用装饰器
用法1
@a_decorators
def do_some_thing():
...
用法2
a_new_func = a_decorators(do_some_thing)
a_new_func()
带参数的装饰器
def a_decorators_args(flag=True):
def a_decorators(a_function):
def my_decorators_func(name):
if flag:
print("I am doing some boring work before executing a_function()")
a = a_function(name)
print("I am doing some after work after executing a_function()")
return a
return my_decorators_func
return a_decorators
@a_decorators_args(False)
def a_function(name):
print(name)
if __name__ == '__main__':
a_function('bai')
使用场景
授权(Authorization)
from functools import wraps
def requires_auth(f):
@wraps(f)
def decorated(*args, **kwargs):
auth = request.authorization
if not auth or not check_auth(auth.username, auth.password):
authenticate()
return f(*args, **kwargs)
return decorated
日志(Logging)
`
from functools import wraps
def logit(func):
@wraps(func)
def with_logging(*args, **kwargs):
print(func.__name__ + " was called")
return func(*args, **kwargs)
return with_logging
@logit
def addition_func(x):
"""Do some math."""
return x + x
result = addition_func(4)
`
