Django: signal when user logs in?

You can use a signal like this (I put mine in models.py)

from django.contrib.auth.signals import user_logged_indef do_stuff(sender, user, request, **kwargs):    whatever...user_logged_in.connect(do_stuff)

See django docs: https://docs.djangoproject.com/en/dev/ref/contrib/auth/#module-django.contrib.auth.signals and here http://docs.djangoproject.com/en/dev/topics/signals/

In addition to @PhoebeB answer:you can also use @receiver decorator like this:

from django.contrib.auth.signals import user_logged_infrom django.dispatch import receiver@receiver(user_logged_in)def post_login(sender, user, request, **kwargs):    ...do your stuff..

And if you put it into signals.py in your app dir, then add this to apps.py:

class AppNameConfig(AppConfig):    ...    def ready(self):        import app_name.signals

One option might be to wrap Django's login/logout views with your own. For example:

from django.contrib.auth.views import login, logoutdef my_login(request, *args, **kwargs):    response = login(request, *args, **kwargs)    #fire a signal, or equivalent    return responsedef my_logout(request, *args, **kwargs):    #fire a signal, or equivalent    return logout(request, *args, **kwargs)

You then use these views in your code rather than Django's, and voila.

With regards to querying login status, it's pretty simple if you have access to the request object; simply check request's user attribute to see if they're a registered user or the anonymous user, and bingo. To quote the Django documentation:

if request.user.is_authenticated():    # Do something for logged-in users.else:    # Do something for anonymous users.

If you don't have access to the request object, then determining if the current user is logged in is going to be difficult.

Edit:

Unfortunately, you'll never be able to get User.is_logged_in() functionality - it's a limitation of the HTTP protocol. If you make a few assumptions, however, you might be able to get close to what you want.

First, why can't you get that functionality? Well, you can't tell the difference between someone closing the browser, or someone spending a while on a page before fetching a new one. There's no way to tell over HTTP when someone actually leaves the site or closes the browser.

So you have two options here that aren't perfect:

1. Use Javascript's unload event to catch when a user is leaving a page. You'd have to write some careful logic to make sure you aren't logging out a user when they're still navigating your site, however.
2. Fire the logout signal whenever a user logs in, just to be sure. Also create a cron job that runs fairly often to flush out expired sessions -- when an expired session is deleted, check that the session's user (if it's not anonymous) has no more active sessions, in which case you fire the logout signal.

These solutions are messy and not ideal, but they're the best you can do, unfortunately.