Django Model Not Updating

I'm trying to count the amount of times a user visits a page: models.py: class Request(models.Model): user = models.ForeignKey(User) view = models.CharField(max_length = 25

Solution 1:

You could do something like this:

models.py

classRequest(models.Model):
    user = models.ForeignKey(User)
    view = models.CharField(max_length = 250)
    visits = models.PositiveIntegerField(default=0)

views.py

def daygaps(request,*a, **kw):

    request_counter = Request.objects.get_or_create(
        user = request.user, view = 'daygaps')

    request_counter.visits += 1 # or =F('visits')+1 to avoid a race condition as suggested by Moses Koledoye
    request_counter.save()

OR

models.py

classRequest(models.Model):
    user = models.ForeignKey(User)
    view = models.CharField(max_length = 250)
    visits = models.PositiveIntegerField(default=1)

views.py

def daygaps(request,*a, **kw):

    updated_count = Request.objects\
        .filter(user= request.user, view='daygaps')\
        .update(visits=F('visits')+1)

    if not updated_count:
        Request.objects.create(user= request.user, view='daygaps')

which avoids race conditions too and has an added advantage of not having to retrieve the object.

In general, I guess the second one is better if the update is simple enough to be implemented with F expressions.

Solution 2:

Instead of using filter and indexing the list returned by the QuerySet, you could simply use .get to return the object:

from django.db.models import F

def daygaps(request,*a, **kw):
    ...
    request_counter = Request.objects.get(
        user__username = request.user.username, view = 'daygaps')
    request_counter.visits = F('visits') + 1
    request_counter.save()

You can wrap the logic in a try/except to handle DoesNotExist exceptions.

The F expression helps you manage race conditions. Read more: Updating attributes based on existing fields