python-18 装饰器

柯里化

装饰器

import datetime
import time

def logger(fn):
    def wrapper(*args, **kwargs):
        print('before +++++++++++++++++++')
        start = datetime.datetime.now()
        ret = fn(*args, **kwargs)
        delta = (datetime.datetime.now() - start).total_seconds()
        print('{} took {}s'.format(fn.__name__, delta))
        return ret 
    return wrapper

@logger  # logger 1 个参数 add = logger(add) => add = wrapper
def add(x, y):
    time.sleep(2)
    return x + y

print(add(10, 11))

文档字符串

def copy_properties(src, dest):
    dest.__name__ = src.__name__
    dest.__doc__ = src.__doc__

def logger(fn):
    def wrapper(*args, **kwargs):
        """wrapper function doc"""
        print('brfore ++++++++')
        ret = fn(*args, **kwargs)
        print('alter +++++++++')
        return ret
#     wrapper.__name__ = fn.__name__
#     wrapper.__doc__ = fn.__doc__
    copy_properties(fn, wrapper)
    
    return wrapper

#@logger
def add(x, y):
    """add function doc"""
    return x + y 

print(add(10, 11))
print(add.__name__, add.__doc__)

def copy_properties(src):
    def _copy(dest):
        dest.__name__ = src.__name__
        dest.__doc__ = src.__doc__
        return dest
    return _copy
    
def logger(fn):
    @copy_properties(fn)
    def wrapper(*args, **kwargs):
        """wrapper function doc"""
        print('brfore ++++++++')
        ret = fn(*args, **kwargs)
        print('alter +++++++++')
        return ret
#     wrapper.__name__ = fn.__name__
#     wrapper.__doc__ = fn.__doc__
    #copy_properties(fn)(wrapper)
    
    return wrapper

@logger
def add(x, y):
    """add function doc"""
    return x + y 

print(add(10, 11))
print(add.__name__, add.__doc__)

又做一层柯里化

from functools import update_wrapper, wraps
import time

def savedb(name, delta):
    print('存入数据库')
    pass 

def logger(duration=5, x=lambda name, delta:print("{} took {}s. slowly".format(name, delta))):
    def inner(fn):
        @wraps(fn)
        def wrapper(*args, **kwargs):
            start = datetime.datetime.now()
            ret = fn(*args, **kwargs)
            delta = (datetime.datetime.now() - start).total_seconds()
            if delta > duration:
                x(fn.__name__, delta)
                
            return ret
        return wrapper
    return inner

@logger(x=savedb)
def add(x, y):
    time.sleep(6)
    return x + y
        

functools模块

类型注解

友好提示，不影响执行