Menu
By definition, a decorator is a function that takes another function and extends the behavior of the latter function without explicitly modifying it.
Decorators can be chained A Decorator function is used only to format the output of another function dec keyword is used for decorating a function Decorators always return None”
A decorator is a design pattern in Python that allows a user to add new functionality to an existing object without modifying its structure. Decorators are usually called before the definition of a function you want to decorate.
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.
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With