Django raising 404 with a message

Question

I like to raise 404 with some error message at different places in the script eg: Http404(\"some error msg: %s\" %msg) So, in my urls.py I included:

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Answer 1

In general, 404 error is "page not found" error - it should not have customizable messages, simply because it should be raised only when a page is not found.

You can return a TemplateResponse with status parameter set to 404

Answer 2

if you want to raise some sort of static messages for a particular view , you can do as follows:-

from django.http import Http404

def my_view(request):
  raise Http404("The link seems to be broken")

Answer 3

I figured out a solution for Django 2.2 (2019) after a lot of the middleware changed. It is very similar to Muhammed's answer from 2013. So here it is:

middleware.py

from django.http import Http404, HttpResponse

class CustomHTTP404Middleware:
    def __init__(self, get_response):
        self.get_response = get_response
        # One-time configuration and initialization.

    def __call__(self, request):
        # Code to be executed for each request before the view (and later middleware) are called.
        response = self.get_response(request)
        # Code to be executed for each request/response after the view is called.
        return response

    def process_exception(self, request, exception):
        if isinstance(exception, Http404):
            message = f"""
                {exception.args},
                User: {request.user},
                Referrer: {request.META.get('HTTP_REFERRER', 'no referrer')}
            """
            exception.args = (message,)

Also, add this last to your middleware in settings.py: 'app.middleware.http404.CustomHTTP404Middleware',

Answer 4

In my case, I wanted to take some action (e.g. logging) before returning a custom 404 page. Here is the 404 handler that does it.

def my_handler404(request, exception):
    logger.info(f'404-not-found for user {request.user} on url {request.path}')
    return HttpResponseNotFound(render(request, "shared/404.html"))

Note that HttpResponseNotFound is required. Otherwise, the response's HTTP status code is 200.

Answer 5

Raise an Http404 exception inside a view. It's usually done when you catch a DoesNotExist exception. For example:

from django.http import Http404

def article_view(request, slug):
    try:
        entry = Article.objects.get(slug=slug)
    except Article.DoesNotExist:
        raise Http404()
    return render(request, 'news/article.html', {'article': entry, })

Even better, use get_object_or_404 shortcut:

from django.shortcuts import get_object_or_404

def article_view(request):
    article = get_object_or_404(MyModel, pk=1)
    return render(request, 'news/article.html', {'article': entry, })

If you'd like to customize the default 404 Page not found response, put your own template called 404.html to the templates folder.

Answer 6

Yes we can show specific exception message when raise Http404.

Pass some exception message like this

raise Http404('Any kind of message ')

Add 404.html page into templates directory.

templates/404.html

{{exception}}