Easiest way to add {{ variable }} from different related model in one template - django

Question

I got a question. I'm wondering what's the easiest way to add different {{ variable }} from different related model in one template.
I'd like to add some information related to seller rating:
def total_seller_ratings(self):
return self.seller.rating_seller.count()
def avg_seller_ratings(self):
return self.seller.annotate(avg_ratesugar=Avg('rating_seller__ratesugar')).order_by('-avg_ratesugar')
Create a template tag from Middleware? Or is any fastes solution to add another model on my view?
I got a main view for my main page:
#Channel MAIN PAGE
#method_decorator(login_required(login_url='/cooker/login'),name="dispatch")
class ChannelMainPage(generic.DetailView, FormMixin):
model = Channel
context_object_name = 'channel'
template_name = 'channel_detail.html'
form_class = ChannelChatForm
def get_context_data(self, **kwargs):
context = super(ChannelMainPage, self).get_context_data(**kwargs)
context['form'] = self.get_form()
return context
def form_valid(self, form):
if form.is_valid():
form.instance.channel = self.object
form.instance.user = self.request.user
form.save()
return super(ChannelMainPage, self).form_valid(form)
else:
return super(ChannelMainPage, self).form_invalid(form)
def post(self,request,*args,**kwargs):
self.object = self.get_object()
form = self.get_form()
if form.is_valid():
return self.form_valid(form)
else:
return self.form_valid(form)
def get_success_url(self):
return reverse('channel:channel_detail',kwargs={"slug":self.object.slug})
models.py
class Channel(models.Model):
consumer = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="channel_consumer", blank=True, null=True)
name = models.CharField(max_length=10)
seller = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="channel_seller")
image = models.ImageField(null=True,blank=True,default='user/user-128.png', upload_to='channel/')
date_created = models.DateTimeField(auto_now_add=True)
is_active = models.BooleanField('Make it happen', default=False)
class Rating(models.Model):
channel = models.OneToOneField(Channel,on_delete=models.CASCADE,related_name="rating_channel")
consumer = models.ForeignKey(settings.AUTH_USER_MODEL, blank=True, null=True, on_delete=models.CASCADE,related_name='rating_consumer')
seller = models.ForeignKey(settings.AUTH_USER_MODEL, blank=True, null=True, on_delete=models.CASCADE,related_name='rating_seller')
is_rated = models.BooleanField('Already rated', default=True)
comment = models.TextField(max_length=200)
publishing_date = models.DateTimeField(auto_now_add=True)
ratesugar = models.IntegerField(validators=[MinValueValidator(1), MaxValueValidator(5)])
def __str__(self):
return self.channel.name

Answer 1

One place to add it is on the Model class. This is already available as a variable within the context (see generic.Detailview.get_context_data). It is named "object" and can then be accessed through the templating mechanics.
class Channel(models.Model):
consumer = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="channel_consumer", blank=True, null=True)
name = models.CharField(max_length=10)
seller = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="channel_seller")
image = models.ImageField(null=True,blank=True,default='user/user-128.png', upload_to='channel/')
date_created = models.DateTimeField(auto_now_add=True)
is_active = models.BooleanField('Make it happen', default=False)
def some_method():
pass
template.html
<div>{{ object.some_method() }}</div>
Finally, on the discussion (code design) of which model to place the desired methods on...
If you want to calculate the average over ALL ratings it belongs on the User model.
If you want an average over the ratings over a given channel then it belongs on the Channel model.
Good luck.
PS. Don't forget to prefetch_related to have avoid slow queries!