Django signal emitting once, received twice -- Why?

Question

I'm working with Django signals, but they seem to be received twice, even if emitted once. Here's the code I'm working with (it's a simple wrapper to use Uploadify with Django)...

# Signal-emitting code... emits whenever a file upload is received
# ----------------------------------------------------------------
upload_recieved = django.dispatch.Signal(providing_args=['data'])

def upload(request, *args, **kwargs):
    if request.method == 'POST':
        if request.FILES:
            print 'sending signal'
            upload_recieved.send(sender='uploadify', data=request.FILES['Filedata'])
    return HttpResponse('True')

# Signal-receiving code...
# ----------------------------------------------------------------    
def upload_received_handler(sender, data, **kwargs):
    print 'upload received handler'

print 'connecting signal'
upload_recieved.connect(upload_received_handler)

(I just noticed my signal is spelled wrong)

I'm sure you noticed the print statements in there. On the console, this is what it's showing:

(server starts)
connecting signal

...

sending signal
upload received handler
upload received handler     # << == where is this 2nd one coming from?
127.0.0.1 - - [25/Sep/2009 07:28:22] "POST /uploadify/upload/ HTTP/1.1" 200 -

(also odd is why does Django report the page POST after the signals are fired?)

Answer 1

you can check "created" argument in your function that you are connecting with signal which returns True and False respectively. Created will be True only when a new object is created.

def task_feedback_status_handler(sender, instance, created, **kwargs):
    if created:
        do something
post_save.connect(task_feedback_status_handler, sender=Feedback)