Python装饰器实现方法及应用场景详解

from functools import wraps  # 最新版python引用是 import functools

def requires_auth(f):  # f 就是我们需要装饰的函数，一看就是不带参数的装饰器
  @wraps(f)   # 新版python写法 @functools.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  # 该装饰器需相关配置才能运行，这里是截取代码展示应用

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)

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"
      print(log_string)
      # 打开logfile，并写入内容
      with open(logfile, 'a') as opened_file:
        # 现在将日志打到指定的logfile
        opened_file.write(log_string + '\n')
      return func(*args, **kwargs)
    return wrapped_function
  return logging_decorator
@logit()
def myfunc1():
  pass
myfunc1()
# Output: myfunc1 was called
# 现在一个叫做 out.log 的文件出现了，里面的内容就是上面的字符串
@logit(logfile='func2.log')
def myfunc2():
  pass
myfunc2()
# Output: myfunc2 was called
# 现在一个叫做 func2.log 的文件出现了，里面的内容就是上面的字符串