Django: Multiple URL parameters

Question

I'm making a study app that involves flashcards. It is divided into subjects. Each subject (biology, physics) has a set of decks (unitone, unittwo). Each deck has a set of cards (terms and definitions). I want my URLs to look like localhost:8000/biology/unitone/ but I have trouble putting two URL parameters in one URL.

models.py

class Subject(models.Model):
    subject_name = models.CharField(max_length=100)
    description = models.TextField()

    def __str__(self):
        return self.subject_name

    def get_absolute_url(self):
        return reverse('card:index')

class Deck(models.Model):
    deck_name = models.CharField(max_length=100)
    subject = models.ForeignKey(Subject, on_delete=models.CASCADE)

    def __str__(self):
        return self.deck_name

class Card(models.Model):
    term = models.CharField(max_length=100)
    definition = models.TextField()
    deck = models.ForeignKey(Deck, on_delete=models.CASCADE)

    def __str__(self):
        return self.term

views.py

class IndexView(generic.ListView):
   template_name = 'card/index.html'
   context_object_name = 'subjects'

   def get_queryset(self):
       return Subject.objects.all()

class SubjectView(DetailView):
    model = Subject
    slug_field = "subject"
    template_name = 'card/subject.html'

class DeckView(DetailView):
    model = Deck
    slug_field = "deck"
    template_name = 'card/deck.html'

urls.py

# localhost:8000/subjects/1 (biology)
url(r'^subjects/(?P<pk>[0-9]+)/$', views.SubjectView.as_view(), name='subject')


# localhost:8000/subjects/1/1 (biology/unitone)
url(r'^subjects/(?P<pk>[0-9]+)/(?P<pk>[0-9]+)/$', views.DeckView.as_view(), name='deck'),

The second URL in urls.py is what I'm having trouble with. It's not a valid URL.

Answer 1

You can't have multiple parameters with the same name. You have to give each parameter a unique name, eg:

url(r'^subjects/(?P<pk>[0-9]+)/(?P<deck>[0-9]+)/$', views.DeckView.as_view(), name='deck'),

In the DeckView you can then access them as self.kwargs['pk'] and self.kwargs['deck'] .

Answer 2

there's a way by rewriting the DetailViews

urls.py

url(r'^subjects/(?P<subjects>\w+)/(?P<deck>\w+)/$', views.DeckView.as_view(), name='deck'),

views.py

class DeckView(DetailView):
    model = Deck
    # slug_field = "deck" # you don't need it 
    template_name = 'card/deck.html'


    def get_object(self, subjects, deck):
        subject_obj = Subject.objects.filter(subject_name=subjects).first()
        obj = Deck.objects.filter(subject=subject_obj,deck_name=deck).first()
        return obj


    def get(self, request, subjects, deck):
        self.object = self.get_object(subjects, deck)
        context = self.get_context_data(object=self.object)
        return self.render_to_response(context)

then access localhost:8000/subjects/biology/unitone/