Почему возникает ошибка matching query does not exist?

Question

[apheyhys]

Есть модель:

class Novel(models.Model):
    slug = models.SlugField()
    title_rus = models.CharField(max_length=100)
    novel_txt = models.FileField(upload_to='uploads/books_txt', blank=True, null=True)

Представление, которое читает txt-файл, и возвращает содержание txt, а также содержание поля title_rus из модели

def novel_text(request, slug):

    get_file = Novel.objects.get(slug=slug).novel_txt    
    file_path = os.path.join('media', str(get_file))
    data_file = open(file_path, 'r')
    text = data_file.read()
    
    novels = Novel.objects.get(slug=slug).title_rus

    context = {
        'text': text,
        'novels': novels
    }

    return render(request, 'novels/text.html', context)

Шаблон

{% extends 'novels/base.html' %}
{% load staticfiles %}
{% block content %}
<div class="pricing-header px-3 py-3 pt-md-5 pb-md-4 mx-auto text-center">
<h1 class="display-4">{{ novels }}</h1>
</div>
    <div class="container">
    <div>{{ text|linebreaksbr }}</div>
        <div>
{% endblock %}

Все работает, но возникает ошибка:

Traceback (most recent call last):
  File "/home/apheyhys/PycharmProjects/jhchase/venv/lib/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/home/apheyhys/PycharmProjects/jhchase/venv/lib/python3.7/site-packages/django/core/handlers/base.py", line 126, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/apheyhys/PycharmProjects/jhchase/venv/lib/python3.7/site-packages/django/core/handlers/base.py", line 124, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/apheyhys/PycharmProjects/jhchase/novels/views.py", line 15, in novel_text
    get_file = Novel.objects.get(slug=slug).novel_txt
  File "/home/apheyhys/PycharmProjects/jhchase/venv/lib/python3.7/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/home/apheyhys/PycharmProjects/jhchase/venv/lib/python3.7/site-packages/django/db/models/query.py", line 399, in get
    self.model._meta.object_name
novels.models.Novel.DoesNotExist: Novel matching query does not exist.

Answer 1

[Вадим Шаталов]

get_file = Novel.objects.get(slug=slug).novel_txt
...
novels.models.Novel.DoesNotExist: Novel matching query does not exist.

Нет объекта в БД с таким слагом

Comments

[apheyhys]

В том то и дело, что text и novels отображаются в шаблоне, все нормально работает, но ошибка возникает.

[apheyhys]

Все разобрался, дело в urls

было

urlpatterns = [
    path('', views.novels_list, name='novels_list'),
    path('<slug>', views.novel_text, name='novel_text'),
]

А нужно

urlpatterns = [
    path('', views.novels_list, name='novels_list'),
    path('<slug:slug>', views.novel_text, name='novel_text'),
]