django: saving a query set to session

Question

I am trying to save query result obtained in one view to session, and retrieve it in another view, so I tried something like below:

def default (request):
    equipment_list = Equipment.objects.all()

    request.session['export_querset'] = equipment_list

However, this gives me

TypeError at /calbase/

<QuerySet [<Equipment: A>, <Equipment: B>, <Equipment: C>]> is not JSON serializable

I am wondering what does this mean exactly and how should I go about it? Or maybe there is alternative way of doing what I want besides using session?

Answer 1

If this is what you are saving:

 equipment_list = Equipment.objects.all()

You shouldn't or wouldn't need to use sessions. Why? Because this is a simple query without any filtering. equipment_list would be common to all the users. This can quite easily be saved in the cache

 from django.core.cache import cache

 equipment_list = cache.get('equipment_list')
 if not equipment_list:
     equipment_list = Equipment.objects.all()
     cache.set('equipment_list',equipment_list)

Note that a queryset can be saved in the cache without it having to be converted to values first.

Update:
One of the other answers mention that a querysets are not json serializable. That's only applicable when you are trying to pass that off as a json response. Isn't applicable when you are trying to cache it because django.core.cache does not use json serialization it uses pickling.