Can I raise Http404 in a Django template tag?

Question

I have a Django application that provides template tag profile. The tag accepts a username as its argument. How should I treat the situation when there exists no User instance with the given username? Does it make sense to raise HTTP 404 inside a template tag? Or should I simply pass an empty dictionary to the template?

Answer 1

I don't think it's possible to raise a 404 from the template, and you shouldn't do it if you could. You should keep the logic and presentation separate.

You have two sound possibilities.

• Don't render anything with your template tag (fail silently)
• Raise a template error.

You don't say exactly what your template tag is doing, so I can't recommend any of the two, but the most normal thing to do with a template tag, is to fail silently.

Answer 2

I can see two ways:

Use if statement with javascript code to redirect, like

{% if profile_not_exist %}
   Javascript with redirect
{% else %}
   Generic code
{% endif %}

Or define logic in view( better way ), like

def index(request):
   if(profile_not_exist):
      indexTemplate = loader.get_template('404.html')
   else:
      indexTemplate = loader.get_template('index.html')

Answer 3

What you should do is check within your template if the user variable exists before displaying the profile tag.

Answer 4

If the page is User specific, you should get the user to @login_required before rendering that page, so that you know that the user exists.

Otherwise, by convention, you should just fail silently in the template tags.