Page not found (404) in Django webapp

Question

Am building a CRM application and thing was going fine until I got this roadblock Page not found (404) Request Method: GET Request URL: http://127.0.0.1:8000/leads//update/

I have tried tweaking the templates and even the view file but to no avail, Here are the views files for the CRUD aspect

class LeadListView(ListView):
   template_name = 'lead_list.html'
   queryset = Lead.objects.all()
   context_object_name = 'leads'


class LeadDetailView(DetailView):
   template_name = 'leads/lead_detail.html'
   queryset = Lead.objects.all()
   context_object_name = 'leads'


class LeadCreateView(CreateView):
   template_name = 'leads/lead_create.html'
   form_class = LeadModelForm

   def get_success_url(self):
      return reverse('leads:lead_list')


class LeadUpdateView(UpdateView):
   template_name = 'leads/lead_update.html'
   form_class = LeadModelForm
   queryset = Lead.objects.all()

   def get_success_url(self):
      return reverse('leads:lead_list')

And here is the HTML template for detail view

<div class="lg:w-1/2 w-full lg:pr-10 lg:py-6 mb-6 lg:mb-0">
            <h2 class="text-sm title-font text-gray-500 tracking-widest">LEAD</h2>
            <h1 class="text-gray-900 text-3xl title-font font-medium mb-4">{{ leads.first_name }} {{ leads.last_name }}</h1>
            <div class="flex mb-4">
                <a href="{% url 'leads:lead_detail' leads.pk %}" class="flex-grow text-indigo-500 border-b-2 border-indigo-500 py-2 text-lg px-1">
                    Overview
                </a>
                <a class="flex-grow border-b-2 border-gray-300 py-2 text-lg px-1">
                    Reviews
                </a>
                <a href="/leads/{{ lead.pk }}/update/" class="flex-grow border-b-2 border-gray-300 py-2 text-lg px-1">
                    Update Details
                </a>
            </div>
            <p class="leading-relaxed mb-4">Fam locavore kickstarter distillery. Mixtape chillwave tumeric sriracha taximy chia microdosing tilde DIY. XOXO fam inxigo juiceramps cornhole raw denim forage brooklyn. Everyday carry +1 seitan poutine tumeric. Gastropub blue bottle austin listicle pour-over, neutra jean.</p>
            <div class="flex border-t border-gray-200 py-2">
                <span class="text-gray-500">Age</span>
                <span class="ml-auto text-gray-900">{{ lead.age }}</span>
            </div>
            <div class="flex border-t border-gray-200 py-2">
                <span class="text-gray-500">Size</span>
                <span class="ml-auto text-gray-900">Medium</span>
            </div>
            <div class="flex border-t border-b mb-6 border-gray-200 py-2">
                <span class="text-gray-500">Quantity</span>
                <span class="ml-auto text-gray-900">4</span>
            </div>
            <div class="flex">
                <span class="title-font font-medium text-2xl text-gray-900">$58.00</span>
                <button class="flex ml-auto text-white bg-indigo-500 border-0 py-2 px-6 focus:outline-none hover:bg-indigo-600 rounded">Button</button>
                <button class="rounded-full w-10 h-10 bg-gray-200 p-0 border-0 inline-flex items-center justify-center text-gray-500 ml-4">
                    <svg fill="currentColor" stroke-linecap="round" stroke-linejoin="round" stroke-width="2" class="w-5 h-5" viewBox="0 0 24 24">
                        <path d="M20.84 4.61a5.5 5.5 0 00-7.78 0L12 5.67l-1.06-1.06a5.5 5.5 0 00-7.78 7.78l1.06 1.06L12 21.23l7.78-7.78 1.06-1.06a5.5 5.5 0 000-7.78z"></path>
                    </svg>
                </button>
            </div>
        </div>

And this is for the update view

div class="lg:w-1/2 w-full lg:pr-10 lg:py-6 mb-6 lg:mb-0">
            <h2 class="text-sm title-font text-gray-500 tracking-widest">LEAD</h2>
            <h1 class="text-gray-900 text-3xl title-font font-medium mb-4">{{ leads.first_name }} {{ leads.last_name }}</h1>
            <div class="flex mb-4">
                <a href="{% url 'leads:lead_detail' lead.pk %}" class="flex-grow text-indigo-500 border-b-2 border-indigo-500 py-2 text-lg px-1">
                    Overview
                </a>
                <a class="flex-grow border-b-2 border-gray-300 py-2 text-lg px-1">
                    Reviews
                </a>
                <a href="/leads/{{ lead.pk }}/update/" class="flex-grow border-b-2 border-gray-300 py-2 text-lg px-1">
                    Update Details
                </a>
            </div>
            <form method="post">
                {% csrf_token %}
                {{ form.as_p }}
                <button type="submit">Submit</button>
            </form>
            <a href="{% url 'leads:lead_delete' lead.pk %}" class="mt-3 flex ml-auto text-white bg-indigo-500 border-0 py-2 px-6 focus:outline-none hover:bg-indigo-600 rounded">
                Delete
            </a>
        </div>

And I found nothing wrong here with the urls.py file

from django.urls import path
from .views import (
    lead_list, lead_detail, lead_create, lead_update, lead_delete,
    LeadListView, LeadDetailView, LeadCreateView, LeadUpdateView
)

app_name = 'leads'

urlpatterns = [
    path('', LeadListView.as_view(), name='lead_list'),
    path('<int:pk>/', LeadDetailView.as_view(), name='lead_detail'),
    path('<int:pk>/update/', LeadUpdateView.as_view(), name='lead_update'),
    path('<int:pk>/delete/', lead_delete, name='lead_delete'),
    path('create/', LeadCreateView.as_view(), name='lead_create'),
]

Below is the link that is broken and where am I trying to get to

Answer 1

You are using the context_object_name = leads in your LeadDetailView. However, in your detail template, you are referencing the object of interest with lead. So, in the URL in your template, {{ lead.pk }} won't be rendered correctly since the lead variable is not defined.

It seems it will work if you fix the value of context_object_name.

About the 404 status code of the response, that's simply because you haven't specified any parameter as the pk parameter. So the URL won't match with any of the URL patterns you have specified in your urls.py file.