Question

As an example:

def get_booking(f=None):     print "Calling get_booking Decorator"     def wrapper(request, **kwargs):         booking = _get_booking_from_session(request)         if booking == None:             # we don't have a booking in our session.             return HttpRedirect('/')         else:             return f(request=request, booking=booking, **kwargs)     return wrapper  @get_booking def do_stuff(request, booking):     # do stuff here 

The problem I am having is, the @get_booking decorator is being called even before I called the function that I am decorating.

Output on start:

Calling get_booking Decorator Calling get_booking Decorator Calling get_booking Decorator Calling get_booking Decorator Calling get_booking Decorator Calling get_booking Decorator Calling get_booking Decorator Calling get_booking Decorator Calling get_booking Decorator Calling get_booking Decorator [26/Oct/2008 19:54:04] "GET /onlinebooking/?id=1,2 HTTP/1.1" 302 0 [26/Oct/2008 19:54:05] "GET /onlinebooking/ HTTP/1.1" 200 2300 [26/Oct/2008 19:54:05] "GET /site-media/css/style.css HTTP/1.1" 200 800 [26/Oct/2008 19:54:05] "GET /site-media/css/jquery-ui-themeroller.css HTTP/1.1" 200 25492 

I haven’t even made a call to a function that is decorated at this point.

I am just getting started with decorators, so maybe I am missing something.

Answer 1

I believe python decorators are just syntactic sugar.

@foo def bar ():     pass 

is the same thing as

def bar ():     pass bar = foo(bar) 

As you can see, foo is being called even though bar has not been called. This is why you see the output from your decorator function. Your output should contain a single line for every function you applied your decorator to.