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接【简明】彻底搞清楚Python的装饰器，我们继续介绍类装饰器+带参数的装饰+多装饰器，顾名思义类装饰器就是类闭包。
定义一个类装饰器
需求：实现一个类装饰器，能够在方法执行时打印日志，并且发送通知到指定地方。
from functools import wraps class logAndNotify(object): # 初始化，定义日志路径 def __init__(self,logfile='service.log'): self.logfile = logfile # 使类成为可调用对象 def __call__(self,func): @wraps(func) def wrap_func(*args,**kwargs): info = func.__name__+'was called' # 实现写日志 with open(self.logfile,'a') as f: f.write(info+'\n') # 实现通知 self.notify() return func(*args,**kwargs) return wrap_func def notify(self): print('notify has been send...') @logAndNotify() def sayHi(name): print('hello',name,'!') res = sayHi('phyger') print(res) 复制代码
执行结果：
➜ RemoteWorking git:(master) ✗ /usr/bin/python3 /root/RemoteWorking/test/test.py notify has been send... hello phyger ! None 复制代码
类装饰器功能扩展
如果我们想要在此类装饰器的基础上，增加发送邮件的功能，就可以利用类的继承特性来实现。
from functools import wraps class logAndNotify(object): # 初始化，定义日志路径 def __init__(self, logfile="service.log"): self.logfile = logfile # 使类成为可调用对象 def __call__(self, func): @wraps(func) def wrap_func(*args, **kwargs): info = func.__name__ + "was called" # 实现写日志 with open(self.logfile, "a") as f: f.write(info + "\n") # 实现通知 self.notify() return func(*args, **kwargs) return wrap_func def notify(self): print("notify has been send...") class NewWarp(logAndNotify): # 初始化邮件地址 def __init__(self, email_address='phyger@qq.com', *args, **kwargs): self.email_address = email_address super(NewWarp,self).__init__(*args, **kwargs) # 重写notify方法 def notify(self): print("notify has been send...") print('email sended...to',self.email_address) @NewWarp() def sayHi(name): print("hello", name, "!") res = sayHi("phyger") print(res) 复制代码
执行结果：
➜ RemoteWorking git:(master) ✗ /usr/bin/python3 /root/RemoteWorking/test/test.py notify has been send... email sended...to phyger@qq.com hello phyger ! None 复制代码
带参数的装饰器
当我们需要根据不同的场景对函数进行不同的装饰操作的时候，我们需要使用到带参数的装饰器。
例：日志级别控制
import logging from functools import wraps def logg(level): def mid(func): @wraps(func) def inner(*args, **kwargs): # log设置 #logging.basicConfig(format=' %(asctime)s - %(levelname)s -%(message)s') logging.basicConfig(format = '"%(asctime)s - %(filename)s[line:%(lineno)d] - %(levelname)s: %(message)s"') logger = logging.getLogger() logger.setLevel(level) # logger打印 logger.info('{} start...'.format(func.__name__)) logger.error('{} errors...'.format(func.__name__)) logger.warn('{} warnning...'.format(func.__name__)) logger.debug('{}end...'.format(func.__name__)) return func(*args, **kwargs) return inner return mid @logg(level='DEBUG') def sayHi(name): print('hi,',name) @logg(level='INFO') def sayBye(name): print('bye',name) sayHi(name='phyger') sayBye(name='phyger') 复制代码
执行输出：
➜ RemoteWorking git:(master) ✗ /usr/bin/python3 /root/RemoteWorking/test/test.py "2020-10-31 11:23:42,161 - test.py[line:15] - INFO: sayHi start..." "2020-10-31 11:23:42,161 - test.py[line:16] - ERROR: sayHi errors..." "2020-10-31 11:23:42,162 - test.py[line:17] - WARNING: sayHi warnning..." "2020-10-31 11:23:42,162 - test.py[line:18] - DEBUG: sayHiend..." hi, phyger "2020-10-31 11:23:42,162 - test.py[line:15] - INFO: sayBye start..." "2020-10-31 11:23:42,162 - test.py[line:16] - ERROR: sayBye errors..." "2020-10-31 11:23:42,162 - test.py[line:17] - WARNING: sayBye warnning..." bye phyger 复制代码
可以看到：
- 当设置最高级别ERROR的时候，所有级别的日志都打印。
- 当设置INFO级别的的时候，DEBUG最低级别的日志不打印。
多装饰器
当有多个不能够耦合的功能需要在函数上增加时，我们需要使用多个装饰器，怎么用呢？
例：实现日志和发送通知的分离
import logging from functools import wraps def wrap1(func): def inner1(*args, **kwargs): print('start') func(*args, **kwargs) print('end') return True return inner1 def wrap2(func): def inner2(*args, **kwargs): print("msg has sended...") func(*args, **kwargs) return True return inner2 @wrap1 @wrap2 def sayHi(name): print('hi',name) sayHi(name='phyher') 复制代码
执行输出：
➜ RemoteWorking git:(master) ✗ /usr/bin/python3 /root/RemoteWorking/test/test.py start msg has sended... hi phyher end
