Question

I have:

class Profile(models.Model):
    user = models.OneToOneField(User)
    birthday = models.DateField(null=True)
    gender = models.CharField(max_length=140)  
    profile_picture = models.URLField()

class Follow(models.Model):
    follower = models.ForeignKey(User, related_name="who_follows")
    followed = models.ForeignKey(User, related_name="who_is_followed")
    follow_time = DateTimeField(auto_now=True)

So what should be ProfileResource in order that I can get followers_count? Or can I POST that user has a new follower?

My ProfileResource is:

class ProfileResource(ModelResource):
    followers_count = Follow.objects.filter(followed=)
    class Meta:
        queryset = User.objects.all()
        resource_name = 'profile'
        filtering = {
            'username': ALL,
        }

Is it the best way? Or I should use it like:

class Profile(models.Model):
    user = models.OneToOneField(User)
    birthday = models.DateField(null=True)
    gender = models.CharField(max_length=140)  
    profile_picture = models.URLField()
    followers = ToManyField('self')
    following = ToManyField('self')

Answer 1

You should be able to get a count of followers via a attribute. Try something like:

class Profile(models.Model):
    ...
    def followers_count(self):
        return self.user.who_is_followed.all().count()

class ProfileResource(ModelResource):
    followers_count = fields.CharField(attribute='followers_count')
    ...