Django 404 (Page Not Found)

1. What Happens on a 404 Error?

If you request a URL that does not exist, Django shows a 404 error. Try this in your browser:

You will see one of two results:

1. The default Django 404 page.
2. The Django debug page if DEBUG = True.

2. Set DEBUG = False and Allowed Hosts

Open settings.py and edit these lines:

Now, visiting 127.0.0.1:8000/masfdfg/ will show the built-in 404 page.

3. Customize the 404 Template

Django looks for 404.html in your templates folder. If it exists, Django will use it for 404 errors.

Create 404.html in members/templates/:

Now, visiting 127.0.0.1:8000/masfdfg/ will show your custom 404 page.

4. Reset DEBUG to True

After testing, reset DEBUG = True in settings.py to continue development:

5. Exercises (10 Q&A)

1. Q: What happens when you visit a non-existent URL with DEBUG = True?
   A: Django shows the debug page with detailed error information.
2. Q: What happens when DEBUG = False?
   A: Django shows the 404 template page or a default "Not Found" message.
3. Q: Where should you put the custom 404 page?
   A: In the templates folder, named 404.html.
4. Q: How do you make Django allow your local host when DEBUG = False?
   A: Set ALLOWED_HOSTS = ['*'] for development.
5. Q: What HTML elements can you use in 404.html?
   A: Any HTML elements to display a friendly message.
6. Q: Can you customize 404.html differently for production?
   A: Yes, you can include images, styling, and helpful navigation links.
7. Q: Why should you reset DEBUG = True after testing?
   A: To continue seeing detailed debug errors during development.
8. Q: Does Django automatically create 404.html?
   A: No, Django provides a default template if 404.html does not exist.
9. Q: Can you link back to the main page from 404.html?
   A: Yes, you can add a hyperlink to improve user navigation.
10. Q: How can you test your 404 page locally?
    A: Visit a random URL that doesn’t exist, like 127.0.0.1:8000/randompage/.