How to retrieve data from a model "function" with model.objects.values()? - django

Question

this is my model
class ArtWork(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.PROTECT)
title = models.CharField(max_length=40)
desc = models.TextField(max_length=100)
image = models.ImageField(upload_to=get_post_filename, null=True, blank=True)
category = models.ForeignKey('Category', null=True, blank=True, on_delete=models.SET_NULL)
album = models.OneToOneField('PostImages', related_name='model',
blank=True, null=True, on_delete=models.PROTECT)
# identifier
private_unique_id = models.CharField(max_length=200, blank=True, unique=True, default=uuid.uuid4)
public_unique_id = models.CharField(max_length=200, blank=True, unique=True, default=uuid.uuid4)
def __str__(self):
return self.title
def get_ratings(self):
like = Vote.objects.filter(artwork=self, like=True, nope=False).count()
nope = Vote.objects.filter(artwork=self, nope=True, like=False).count()
return like, nope
I'd like to get the ArtWork model function "get_ratings" in views with "values" filter
in views.py
if request.is_ajax():
posts = ArtWork.objects.filter(active=True)
data = serializers.serialize("json", posts, fields=('image', 'title', 'desc','get_ratings'))
return JsonResponse(data, content_type='application/json', safe=False)
posts = ArtWork.objects.filter(active=True).only('get_ratings').values('image', 'title', 'desc',)
return render(request, 'Home.html', {'posts': posts[:3]})
what I want to do is basically return for ajax request in views a list of objects including the results of the function
any help is appreciated, thanks in advance.

Answer 1

If you are trying to create new Artwork object, I'd do it like this:
class ArtWork(models.Model):
title = models.CharField(max_length=40)
...
#classmethod
def get_ratings(cls, field1):
like = Vote.objects.filter(artwork=self, like=True, nope=False).count()
nope = Vote.objects.filter(artwork=self, nope=True, like=False).count()
return like, nope
then, import it in your view:
from <app_name>.models import ArtWork
.....
ArtWork.get_rating()
This works for me, hope this help you too.

Answer 2

You should use custom managers to apply methods to QuerySets.
class ArtWorkManager(models.Manager):
def get_ratings(self):
like = Vote.objects.filter(artwork=self, like=True, nope=False).count()
nope = Vote.objects.filter(artwork=self, nope=True, like=False).count()
return like, nope
also, you should add the below line to Artwork model:
objects = ArtWorkManager()
Check this link for custom managers.