Python的装饰器用法学习笔记

def run():
  print "I'm run."

def run():
  print time.ctime()
  print "I'm run."
  print time.ctime()

def count(func):
  def wrapper():
    print time.ctime()
    ret = func()
    print time.ctime()
    return ret
  return wrapper

@count
def run():
  print "I'm run."

      # print '2015-4-10'

def now():
  print '2015-4-10'
f = now
f()  

now.__name__    # print 'now'
f.__name__     # print 'now'

print f       # print '<function now at 0x000000000213A908>'
print now      # print '<function now at 0x000000000213A908>'

def log(func):
  def wrapper(*args, **kwargs):
    print "call %s()" % func.__name__
    return func(*args, **kwargs)
  return wrapper

@log
def now():
  print '2015-4-10'

now()        # print 'call now()'

# 没有使用前
now.__name__    # print 'now'
# 使用后
now.__name__    # print 'wrapper'

def log(func):
  @functools.wraps(func)
  def wrapper(*args, **kwargs):
    ...

def login(level):
  def _deco(func):
    def wrapper(*args, **kwargs):
      if level >= 5:
        print '用户 VIP 等级 %d' % int(level-5)
      else:
        print '用户 屌丝 等级 %d' % abs(level-5)
      return func(*args, **kwargs)
    return wrapper
  return _deco

@login(5)
def user(username):
  print 'welcome, %s' % username

# 用户vip 等级0
# welcome, mink
user('mink')

class A(object):
  def __init__(self, func):
    self.func = func

  def __call__(self):
    return self.func() ** 2

@A
def foo():
  return 10

print foo()   # print 100