模板

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from functools import wraps
def decorator(f):
    @warps(f):
    def decorated(*args, **kwargs):
        print('This is decorated')
        return f(*args, **kwargs)
    return decorated

@decorator
def func():
    print('This is func')

使用场景

  • 授权(Authorization)

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    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

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    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)
    # Output: addition_func was called

    函数中嵌入装饰器

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from functools import wraps

def logit(logfile='out.log'):
    def logging_decorator(func):
        @wraps(func)
        def wrapped_function(*args, **kwargs):
            log_string = func.__name__ + " was called"
            with open(logfile, 'a') as opened_file:
                opened_file.write(log_string + '\n')
            return func(*args, **kwargs)
        return wrapped_function
    return logging_decorator

@logit()
def func1():
    pass

@logit(logfile='func2.log')
def func2():
    pass

装饰器类

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from functools import wraps

class logit:
    def __init__(self, logfile='out.log'):
        self.logfile = logfile
    
    def __call__(self, func):
        @wraps(func)
        def wrapped_function(*args, **kwargs):
            log_string = func.__name__ + " was called"
            with open(logfile, 'a') as opened_file:
                opened_file.write(log_string + '\n')
            self.notify()
            return func(*args, **kwargs)
        return wrapped_function
    
    def notify(self):
        pass

@logit()
def func1():
    pass

@logit(logfile='func2.log')
def func2():
    pass