Django: path doesn't find the right primary key in url path

Question

I'm using django2 and I get an error when I access this url: http://127.0.0.1:8000/hotes/12/access/7/update I get an error 404 "None access object was found"

To make a long story short: I want to update an object linked to another. To do so, I have to send through the link, both primary keys (12 and 7 in the url). Also, I use the generic view "UpdateView" given by Django.

This is the path concerned in my project.urls:

urlpatterns = [
    path('hotes/<int:pk>/access/<int:access_pk>/update/',views.AccessUpdateView.as_view(), name='access_update'),
    path('hotes/add',views.host_add, name='host_add'),
    path('hotes/<int:pk>/', include([
        path('edit',views.HostUpdateView.as_view(), name='host_update'),
        path('delete',views.host_delete, name='host_delete'),
    ])),
    path('hotes/<int:pk>/add/', include([
        path('access',views.access_add, name='access_add'),
        path('oncall',views.onCall_add, name='onCall_add'),
        path('network',views.network_add, name='network_add'),
    ])),
    path('hotes/<int:pk>/',views.host_view, name='host_view'),
    path('hotes/',views.hosts_view, name='hosts_view'),
    path('', views.home, name='home'),
    path('admin/', admin.site.urls),
]

I want the second primary key to be used in my view "AccessUpdateView".

This is a part of my models.py:

class Host(models.Model):
    name = models.CharField(max_length=30, unique=True)
    usage = models.CharField(max_length=30, blank=True)
    function = models.CharField(max_length=30, blank=True)
    production = models.NullBooleanField(blank=True, null=True)
    place = models.CharField(max_length=30, blank=True)
    type = models.CharField(max_length=30, blank=True)
    processor = models.DecimalField(max_digits=3, decimal_places=2, null=True, blank=True)
    storage = models.CharField(max_length=10, blank=True)
    memory = models.CharField(max_length=10, blank=True)
    dns_inner = models.CharField(max_length=50, blank=True)
    dns_extern = models.CharField(max_length=50, blank=True)
    os = models.ForeignKey(Os, null=True, related_name='hosts', on_delete=models.SET_NULL, blank=True)

class Access(models.Model):
    service = models.CharField(max_length=20)
    client_access = models.NullBooleanField(blank=True, null=True)
    ip = models.GenericIPAddressField()
    login = models.CharField(max_length=30, blank=True)
    password = models.CharField(max_length=50, blank=True)
    host = models.ForeignKey(Host, related_name='access', on_delete=models.CASCADE)

As you can see on host can have multiple access but an access in linked to only one host.

This is the view concerned:

class AccessUpdateView(UpdateView):
    model = Access
    fields = ('service','client_access','ip','login','password', )
    template_name = 'access_update.html'
    pk_url_kwarg = 'access_pk'
    context_object_name = 'access'

    def form_valid(self, form):
        access = form.save(commit=False)
        host_id = self.kwargs['pk']
        access.host_id = host_id
        access.save()
        return redirect('host_view', pk=host_id)

---

EDIT: new error when I try to access the url:

NoReverseMatch at /hotes/12/access/7/update/

Reverse for 'host_view' with arguments '('',)' not found. 1 pattern(s) tried: ['hotes\\/(?P[0-9]+)\\/$']

---

EDIT: The error was coming from "access_update.html" I removed the href in the Hote link which contained {% url host.pk %}

{% extends 'base.html' %}

{% load widget_tweaks %}

{% block title %}Modifier Acces{% endblock %}

{% block breadcrumb %}
  <li class="breadcrumb-item"><a href="{% url 'hosts_view' %}">Hotes</a></li>
  <li class="breadcrumb-item"><a href="">Hote</a></li>
  <li class="breadcrumb-item active">Modification Acces</li>
{% endblock %}

{% block contenu %}
  <form method="post" novalidate>
    {% csrf_token %}
    {% include 'includes/form.html' %}
    <button type="submit" class="btn btn-success">Modifier</button>
  </form>
{% endblock %}

The question is what is the right way to write the pk of the host in the url? (host_id doesn't work)

Answer 1

If you want to use access_pk , then you should set pk_url_kwarg = 'access_pk' in the view.

In your form_valid method, you are using host without defining it. If pk from the URL is the host id, then you can access it with self.kwargs['pk'] .

def form_valid(self, form):
    access = form.save(commit=False)
    host_id = self.kwargs['pk']
    access.host_id = host_id
    access.save()
    return redirect('host_view', pk=host_id)

Inside the template for the AccessUpdateView , you have access to access since that is the object that is being updated. If you want to use the host or its id, you should access it via access .

{% url 'host_view' access.host_id %}