Python decorators a simple example

Python decorators are a wonderful syntax for wrapping one function in another. I had a bit of trouble understanding the documentation, which often seems to involve talking about the history of how the syntax evolved rather than cutting to the chase and giving a simple example.

Specifically, I wanted to know how to get access to the arguments to the function I'm decorating in the decorator. Here's my example, at the top is the output:

"""
Example decorator that gets function arguments.

>>> decotest.py

>in mydecorator
>Function decorateme has been wrapped
> args = hello this is request
> kwargs = {}
>request = hello this is request
decorateme got request = hello this is request
>finished wrapped function
"""

def mydecorator(f):
   print ">in mydecorator"
   def wrapper(*args, **kwargs):
       print ">Function %s has been wrapped" % f.__name__
       print "> args = %s" % args
       print "> kwargs = %s" % kwargs
       request = args[0]
       print ">request = %s" % request
       f(*args, **kwargs)
       print ">finished wrapped function"
   return wrapper
     

def test():
   request = "hello this is request"
   decorateme(request)
 
@mydecorator
def decorateme(request):
   print "decorateme got request = %s" % request
 
if __name__ == "__main__":
   test()