How to use URL regexp to match exact date of a post in Django?

Question

I'm developing a website and blog for myself using Django. I'm using Python 3.8 and Django 3.0 and I've been having a lot of trouble trying to include the date of post creation in the URL. While I was finally able to get my URL to look something like: "mywebsite.com/blog/2020/mm/dd/.html", I am not getting a 404 if I change any part of the date.

For example if I manually change the URL to: mywebsite.com/blog/2021/mm/dd/.html, the webpage still loads without presenting an error. Can someone help me figure out where I can edit the code to correct this issue? Something where I can issue a 404 if the URL isn't exactly what is pulled from the datetime field? My models.py, views.py, and URLs.py are attached below:

Models.py

class Blog(models.Model):
    title = models.CharField(max_length=500, help_text='Title of the Blog Post')
    author = models.ForeignKey(Author, on_delete=models.SET_NULL, null=True)
    **created_on = models.DateTimeField(auto_now_add=True)
    updated_on = models.DateTimeField(auto_now=True)
    content = models.TextField(help_text='Content of the Blog Post')
    topic = models.ManyToManyField(Topic, help_text='Topic of this Blog Post')

slug = models.SlugField(
    null=False, 
    unique=True,
    max_length=500,
    editable=False,
)

class Meta:
    ordering = ['-created_on']

def __str__(self):
    return self.title

def get_absolute_url(self):
    kwargs = {
    'year': self.**created_on.strftime("%Y"),
    'month': self.**created_on.strftime("%m"),
    'day': self.**created_on.strftime("%d"),
    'slug': self.slug,
    }
    return reverse('blog-detail', kwargs=kwargs)

def save(self, *args, **kwargs):
    self.slug = slugify(self.title, allow_unicode=True)
    super(Blog, self).save(*args, **kwargs)

Views.py

class BlogListView(ListView):
    model = Blog
    template_name = 'blog_list.html'

class BlogDetailView(DetailView):
    model = Blog
    context_name = 'blog-detail'
    **year_url_kwarg = 'year'
    slug_url_kwarg = 'slug'
    **month_url_kwarg = 'month'
    **day_url_kwarg = 'day'

URLs.py

urlpatterns = [
    path('index/',views.index, name='index'),
    **re_path(r'^blog/(?P\d{4})/(?P\d{2})/(?P\d{2})/(?P[-\w]+)$', views.BlogDetailView.as_view(), name='blog-detail'),
    re_path(r'^blog/$',views.BlogListView.as_view(), name='blog_main'),

]

I put ** in the code to draw attention to relevant fields. Thank you for taking the time to reading through and trying to help me with this!

user_67579 · Answer

You can filter by overriding the .get_queryset(…) method [Django-doc]:

class BlogDetailView(DetailView):
    model = Blog
    context_name = 'blog-detail'

    def get_queryset(self, *args, **kwargs):
        return super().get_queryset(*args, **kwargs).filter(
            created_on__year=self.kwargs['year'],
            created_on__month=self.kwargs['month'],
            created_on__day=self.kwargs['day']
        )

Note: I would advise using an name for context_name that is a valid Python identifier, so not something with a hyphen. While it might work in the template engine, it is possible that later they slightly change the "grammar" of the Django template engine.

How to use URL regexp to match exact date of a post in Django?

1 Answers