Is Django post_save signal asynchronous?

Question

I have a like function which is just like social networks like or thumbs up function; the user clicks the star / heart / whatever to mark the content as liked.I

Answer 1

Also look into celery (or more specifically django-celery). It is an async task scheduler / handler. So your post_save signal handler creates a task, which is picked up and executed through celery. That way you still have your speedy application, while the heavy lifting is performed async, even on a different machine or batch of machines.

Answer 2

The async-signals package (https://github.com/nyergler/async-signals) abstracts this issue. You call an async signal function; if Celery is present the package uses it to issue the signal asynchronously from a worker; and if Celery is not available the package sends the signal in the traditional synchronous way.

Answer 3

Hm, first of all signals in Django are not asynchronous. For your particular case I think post_save is the wrong way to go. The most straightforward way is simply to fire an ajax request to view which do your like action and don't wait for the response. Instead modify your view/html directly after you fired the request.

That would of course require that you know beforehand that your user is allowed to like this item and that your request will not fail.

Answer 4

What you want is a thread. They're very easy to use. You just subclass threading.Thread and write a run method:

import threading

class LikeThread(threading.Thread):
    def __init__(self, user, liked, **kwargs):
        self.user = user
        self.liked = liked
        super(LikeThread, self).__init__(**kwargs)

    def run(self):
        # long running code here

Then, when your ready to do the task, you fire it off with:

LikeThread(request.user, something).start()

The rest of your view code or whatever will resume and return the response, and the thread will happily do its work until it's done and then end itself.

See full documentation: http://docs.python.org/library/threading.html