Does Django have a way to open a HTTP long poll connection?
Solution 1:
Have a look at Django / Comet (Push): Least of all evils? or The latest recommendation for Comet in Python? - COMET is another name for "ajax long-polling".
Apparently the most common approach is not doing it directly in django but with the help of an additional daemon (probably because e.g. Apache doesn't do well with lots of long-living connections). Nowadays nodejs+socketio is pretty popular for this (and it can even use WebSockets) - you just need to find a nice way to pass data between the two things. If it's unidirectional (e.g. just broadcasts to all connected clients) a redis pubsub queue is not a bad option for this.
But http://code.google.com/p/django-orbited/ is probably the most djangoish solution.
Solution 2:
For the future readers :)
I created a simple long polling django class views using Gevent, you can find it on github on https://github.com/tbarbugli/django_longpolling or get it from pypi (django_longpolling)
EDIT: I did some further experiment / deployment with django long polling / async workers and I can say that if possible opting to an external daemon is a very good choice, especially if you use the db (when using async worker you need a db connection pool or you are going to have the amount of worker connections bound to your db connection limits which is not desiderable).