Getting information from Django custom signal receiver

问题

This is my second question today actually but what I want to know...Is it possible to retrieve information from a signal handler.

I have a list of items, call it list and each item is in AppA. Each item has a couple of characteristics which are saved in a different app, AppB.

So, I figured that I could maybe create a dictionary, dict and iterate over the items in list. In each iteration, I was hoping to send a signal to AppB and retrieve the information, i.e. have something like

def blob(request):
    dict = {}
    for item in list:
        signal.send(sender=None, id=item.id)
        dict[item] = (char1, char2)
    ...some html request

My signal handler looks something like this:

def handler(sender, id, **kwargs):
    model2 = Model2.objects.get(id=id)
    a = model2.char1
    b = model2.char2
    return (a, b)

Then I was hoping to be able to just produce a list of the items and their characteristics in the webpage...THe problem is that obviously the signal sender has to send the signal, and get the information back which I want....is that even possible :S?

Currently, I get an error saying "global name 'char1' is not defined....and I have imported the handlers and signals into the view.py where blob resides....so is my problem just unsolvable? / Should it clearly be solved in another way? Or have I almost certainly made a stupid error with importing stuff?

回答1:

This wasn't actually so tricky. Thought I should perhaps post how it was solved. In my views, I actually wrote

    response_list=signal.send(sender=None, list=list_of_items)

I then iterated over my response_list, adding the items to a fresh list like so:

    snippets = []
    for response in response_list:
    logger.error(response)
    snippets.append(response[1])

And could then call the responses in snippets like a dictionary in my template. When I asked the question, I didn't appreciate that I could equate something with the signal sending...

来源：https://stackoverflow.com/questions/17555175/getting-information-from-django-custom-signal-receiver