Part 2: decorator

As mentioned before, the internal function of the decorator has replaced the original function (new function), so this function will missing many attributes.

 1 def is_admin(f): 2     def wrapper(*args, **kwargs): 3         if kwargs.get(‘usrename‘) != ‘admin‘: 4             raise Exception("Now allow") 5         return f(*args, **kwargs) 6     return wrapper 7  8 def foobar(username="soneone"): 9     """ DOcarzy stuff """10     pass11 12 13 >>> foobar.func_doc14 ‘ DOcarzy stuff ‘15 >>> foobar.__name__16 ‘foobar‘17 >>> @is_admin18 def foobar(username="someone"):19     """Do carzy stuff"""20     pass21 22 >>> foobar.__doc__23 >>> foobar.__name__24 ‘wrapper‘25 >>> 

 

We can use functools to solve this problem.

 1 import functools  2 def is_admin(f): 3     @functools.wraps(f) 4     def wrapper(*args, **kwargs): 5         if kwargs.get(‘usrename‘) != ‘admin‘: 6             raise Exception("Now allow") 7         return f(*args, **kwargs) 8     return wrapper 9 10 def foobar(username="soneone"):11     """ DOcarzy stuff """12     pass13 14 15 >>> foobar.__name__16 ‘foobar‘17 >>> foobar.__doc__18 ‘ DOcarzy stuff ‘19 >>> 

 

In our example, we always input the username keyword as a parameter to the decorator function to build a better solution.

UseInspect

 1 import functools 2 import inspect 3  4 def is_admin(f): 5     @functools.wraps(f) 6     def wrapper(*args, **kwargs): 7  8         func_args = inspect.getcallargs(f,*args,**kwargs) 9         print func_args10         if func_args.get(‘username‘) != ‘admin‘:11             raise Exception("Now allow")12         return f(*args, **kwargs)13     return wrapper14 15 @is_admin16 def foobar(username, type="chocolate"):17     """ DOcarzy stuff """18     pass19 20 >>> foobar(username=‘admin‘)21 {‘username‘: ‘admin‘, ‘type‘: ‘chocolate‘}22 >>> 

 

Part 2: decorator