NoReverseMatch URL not being found Django - django

Question

I'm probably missing something here, but I have a connect page in which the logged in user can chat to another user by clicking on a Chat? link located on each users profile.
The chat functionality is built using Django Channels and is accessed via the url pattern
site/messages/username
where username is the other_user that the current_user is chatting with.
I currently have the chat? link as
<a class='btn btn-light' href="{% url 'thread' username %}" id="chat">Chat?</a>
However that throws the error
NoReverseMatch Reverse for 'thread' not found. 'thread' is not a valid view function or pattern name.
I have tried following the docs and adding username as an arg / taking it off but I keep hitting this same error.
The chat app is included in settings.py and the urls are included in admin.py.
The connect and chat are separate apps.
Below is relevant code. Thank you for your time and help!
chat/urls.py
from django.urls import path, re_path
from .views import ThreadView, InboxView
app_name = 'chat'
urlpatterns = [
path("", InboxView.as_view()),
re_path(r"^(?P<username>[\w.#+-]+)", ThreadView.as_view(), name='thread'),
]
chat/views.py
class ThreadView(LoginRequiredMixin, FormMixin, DetailView):
template_name = 'chat/thread.html'
form_class = ComposeForm
success_url = './'
def get_queryset(self):
return Thread.objects.by_user(self.request.user)
def get_object(self):
other_username = self.kwargs.get("username")
obj, created = Thread.objects.get_or_new(self.request.user, other_username)
if obj == None:
raise Http404
return obj
def get_context_data(self, **kwargs):
context = super().get_context_data(**kwargs)
context['form'] = self.get_form()
return context
traceback
Internal Server Error: /connect/
Traceback (most recent call last):
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner
response = get_response(request)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/core/handlers/base.py", line 126, in _get_response
response = self.process_exception_by_middleware(e, request)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/core/handlers/base.py", line 124, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/contrib/auth/decorators.py", line 21, in _wrapped_view
return view_func(request, *args, **kwargs)
File "/Users/xx/xx/project/src/project/connect/views.py", line 15, in connect_home_view
return render(request, 'connect/home.html', context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/shortcuts.py", line 36, in render
content = loader.render_to_string(template_name, context, request, using=using)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/loader.py", line 62, in render_to_string
return template.render(context, request)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/backends/django.py", line 61, in render
return self.template.render(context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/base.py", line 171, in render
return self._render(context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/base.py", line 163, in _render
return self.nodelist.render(context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/base.py", line 937, in render
bit = node.render_annotated(context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/base.py", line 904, in render_annotated
return self.render(context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/loader_tags.py", line 150, in render
return compiled_parent._render(context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/base.py", line 163, in _render
return self.nodelist.render(context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/base.py", line 937, in render
bit = node.render_annotated(context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/base.py", line 904, in render_annotated
return self.render(context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/loader_tags.py", line 62, in render
result = block.nodelist.render(context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/base.py", line 937, in render
bit = node.render_annotated(context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/base.py", line 904, in render_annotated
return self.render(context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/defaulttags.py", line 209, in render
nodelist.append(node.render_annotated(context))
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/base.py", line 904, in render_annotated
return self.render(context)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/template/defaulttags.py", line 442, in render
url = reverse(view_name, args=args, kwargs=kwargs, current_app=current_app)
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/urls/base.py", line 90, in reverse
return iri_to_uri(resolver._reverse_with_prefix(view, prefix, *args, **kwargs))
File "/Users/xx/xx/project/lib/python3.7/site-packages/django/urls/resolvers.py", line 622, in _reverse_with_prefix
raise NoReverseMatch(msg)
django.urls.exceptions.NoReverseMatch: Reverse for 'thread' with arguments '('',)' not found. 1 pattern(s) tried: ['messages/(?P<username>[\\w.#+-]+)']
[2019/01/27 12:36:43] HTTP GET /connect/ 500 [0.10, 127.0.0.1:50815]

Answer 1

You're using app_name = 'chat'. This makes your app level urls available under the app namespace. See docs: https://docs.djangoproject.com/en/2.1/topics/http/urls/#url-namespaces-and-included-urlconfs
This should work:
{% url 'chat:thread' username %}

Answer 2

Since you have given your app a name in your url app_name = 'chat'
your url must have the name given
<a class='btn btn-light' href="{% url 'chat:thread' username %}" id="chat">Chat?</a>
this is called namespacing in programming