python杂记-5(装饰器)

时间:2023-03-09 16:34:04
python杂记-5(装饰器)

1、被装饰的函数有参数(一个参数):

def w1(func):
def inner(arg):
# 验证1
# 验证2
# 验证3
return func(arg)
return inner @w1
def f1(arg):
print(f1)

2、被装饰的函数有参数(两个参数):

def w1(func):
def inner(arg1,arg2):
# 验证1
# 验证2
# 验证3
return func(arg1,arg2)
return inner @w1
def f1(arg1,arg2):
print(f1)
 

3、被装饰的函数有参数(三个参数):

def w1(func):
def inner(arg1,arg2,arg3):
# 验证1
# 验证2
# 验证3
return func(arg1,arg2,arg3)
return inner @w1
def f1(arg1,arg2,arg3):
print(f1)

4、装饰具有处理n个参数的函数的装饰器:

def w1(func):
def inner(*args, **kwargs):
# 验证1
# 验证2
# 验证3
return func(*args, **kwargs) return inner @w1
def f1(arg1, arg2, arg3):
print(f1)

5、一个函数可以被多个装饰器装饰:

def w2(func):
def inner(*args, **kwargs):
# 验证1
# 验证2
# 验证3
return func(*args, **kwargs) return inner @w1
@w2
def f1(arg1, arg2, arg3):
print(f1)

6、更牛逼的装饰器:

#!/usr/bin/env python
# -*- coding: utf-8 -*- def Before(request, kargs):
print('before') def After(request, kargs):
print('after') def Filter(before_func, after_func):
def outer(main_func):
def wrapper(request, kargs): before_result = before_func(request, kargs)
if (before_result != None):
return before_result; main_result = main_func(request, kargs)
if (main_result != None):
return main_result; after_result = after_func(request, kargs)
if (after_result != None):
return after_result; return wrapper return outer @Filter(Before, After)
def Index(request, kargs):
print('index')

7、functools.wraps

上述的装饰器虽然已经完成了其应有的功能,即:装饰器内的函数代指了原函数,注意其只是代指而非相等,原函数的元信息没有被赋值到装饰器函数内部。例如:函数的注释信息

def outer(func):
def inner(*args, **kwargs):
print(inner.__doc__) # None
return func()
return inner @outer
def function():
"""
asdfasd
:return:
"""
print('func')

如果使用@functools.wraps装饰装饰器内的函数,那么就会代指元信息和函数。

def outer(func):
@functools.wraps(func)
def inner(*args, **kwargs):
print(inner.__doc__) # None
return func()
return inner @outer
def function():
"""
asdfasd
:return:
"""
print('func')