NoReverseMatch at /tickets/1/comments/new/ Reverse for 'ticket-detail' not found. 'ticket-detail' is not a valid view function or pattern name.

Using Django Templates & Frontend
1

Trying to create a separate comments app for my ticket project but still trying to use templates that are in the ticket app. I suspect that I got this error because the comments app is not finding the template within the ticket app and tried using reverse inside the get_absolute_url method but it is still not working and I don’t know where to go from here.

Here is my models.py

class Comment(models.Model):
    ticket = models.ForeignKey(Ticket, related_name='comments', on_delete=models.CASCADE, null=True)
    title = models.CharField(max_length=20)
    content = models.TextField()
    date_posted = models.DateTimeField(default=timezone.now)
    author = models.ForeignKey(User, on_delete=models.CASCADE)
    
    def __str__(self):
        return self.title
    
    def get_absolute_url(self):
        return reverse('tickets: ticket-detail', kwargs={'pk': self.ticket_id})

main urls.py

urlpatterns = [
    path('admin/', admin.site.urls),
    path('', include('users.urls')),
    path('', include(('tickets.urls', 'tickets'), namespace='tickets')),
    path('', include('comments.urls')),
]

if settings.DEBUG:
    urlpatterns += static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)

comments urls.py

urlpatterns = [
    path('tickets/<int:pk>/', CommentListView.as_view(), name='comment-home'),
    path('tickets/<int:pk>/comments/new/', CommentCreateView.as_view(), name='comment-create'),
    path('tickets/comments/<int:pk>/update/', CommentUpdateView.as_view(), name='comment-update'),
    path('tickets/comments/<int:pk>/delete/', CommentDeleteView.as_view(), name='comment-delete'),
]
2

The error you’re showing has nothing to do with the templates.

You have:

First (although I don’t think it’s the problem here) you have an unnecessary space between “tickets” and “ticket-detail”. I’d remove that space.

However, you’re referencing a url named “ticket-detail”, but I don’t see a url defined by that name in what you’ve posted. What url is supposed to be used?

Also, in the future, it will be helpful if you posted the complete tracebacks you receive.

3

tickets urls.py

from django.urls import path
from .views import (
    TicketListView,
    TicketDetailView,
    TicketCreateView,
    TicketUpdateView,
    TicketDeleteView,
    UserTicketListView,
)
from . import views

urlpatterns = [
    path('', TicketListView.as_view(), name='ticket-home'),
    path('user/<str:username>', UserTicketListView.as_view(), name='user-tickets'),
    path('tickets/<int:pk>/', TicketDetailView.as_view(), name='ticket-detail'),
    path('tickets/new/', TicketCreateView.as_view(), name='ticket-create'),
    path('tickets/<int:pk>/update/', TicketUpdateView.as_view(), name='ticket-update'),
    path('tickets/<int:pk>/delete/', TicketDeleteView.as_view(), name='ticket-delete'),
    path('about/', views.about, name='tickets-about'),
]

traceback

Request Method: POST
Request URL: http://localhost:5000/tickets/1/comments/new/

Django Version: 4.0.1
Python Version: 3.10.0
Installed Applications:
['tickets.apps.TicketsConfig',
 'users.apps.UsersConfig',
 'comments.apps.CommentsConfig',
 'demo.apps.DemoConfig',
 'crispy_forms',
 'django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']





Request Method: POST
Request URL: http://localhost:5000/tickets/1/comments/new/

Django Version: 4.0.1
Python Version: 3.10.0
Installed Applications:
['tickets.apps.TicketsConfig',
 'users.apps.UsersConfig',
 'comments.apps.CommentsConfig',
 'demo.apps.DemoConfig',
 'crispy_forms',
 'django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback (most recent call last):
  File "C:\Users\mikha\bug_env\lib\site-packages\django\core\handlers\exception.py", line 47, in inner
    response = get_response(request)
  File "C:\Users\mikha\bug_env\lib\site-packages\django\core\handlers\base.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "C:\Users\mikha\bug_env\lib\site-packages\django\views\generic\base.py", line 69, in view
    return self.dispatch(request, *args, **kwargs)
  File "C:\Users\mikha\bug_env\lib\site-packages\django\contrib\auth\mixins.py", line 71, in dispatch
    return super().dispatch(request, *args, **kwargs)
  File "C:\Users\mikha\bug_env\lib\site-packages\django\views\generic\base.py", line 101, in dispatch
    return handler(request, *args, **kwargs)
  File "C:\Users\mikha\bug_env\lib\site-packages\django\views\generic\edit.py", line 174, in post
    return super().post(request, *args, **kwargs)
  File "C:\Users\mikha\bug_env\lib\site-packages\django\views\generic\edit.py", line 144, in post
    return self.form_valid(form)
  File "C:\Users\mikha\issuetracker\comments\views.py", line 38, in form_valid
    return super().form_valid(form)
  File "C:\Users\mikha\bug_env\lib\site-packages\django\views\generic\edit.py", line 128, in form_valid
    return super().form_valid(form)
  File "C:\Users\mikha\bug_env\lib\site-packages\django\views\generic\edit.py", line 59, in form_valid
    return HttpResponseRedirect(self.get_success_url())
  File "C:\Users\mikha\bug_env\lib\site-packages\django\views\generic\edit.py", line 118, in get_success_url
    url = self.object.get_absolute_url()
  File "C:\Users\mikha\issuetracker\comments\models.py", line 18, in get_absolute_url
    return reverse('tickets:ticket-detail', kwargs={'pk': self.ticket_id})
  File "C:\Users\mikha\bug_env\lib\site-packages\django\urls\base.py", line 86, in reverse
    return resolver._reverse_with_prefix(view, prefix, *args, **kwargs)
  File "C:\Users\mikha\bug_env\lib\site-packages\django\urls\resolvers.py", line 729, in _reverse_with_prefix
    raise NoReverseMatch(msg)

Exception Type: NoReverseMatch at /tickets/1/comments/new/
Exception Value: Reverse for 'ticket-detail' with keyword arguments '{'pk': None}' not found. 1 pattern(s) tried: ['tickets/(?P<pk>[0-9]+)/\\Z']

Removing the space creates a different error

4

Yep, you fixed one problem and uncovered a different one.

This is your definition for ticket-detail:

Now, notice what the error is telling you:

That named URL needs a parameter (<int:pk>) in order to generate the URL.

But, what are you passing it?

And so it’s not working.