How to make Django template raise an error if a variable is missing in context

Question

I'm using Django templates in a non-Django project and I want to make sure that my templates contain no references to variables that are not in context and for that I need Django template renderer to raise an error when it sees {{ non_existent_variable }} when there is no non_existent_variable in Context.

TEMPLATE_STRING_IF_INVALID could be set to something and then we could check that this something is not in the rendered template, but that is not elegant at all.

Can I somehow without too much work override the way Context swallows missing key errors?

Answer 1

There is a Django Snippet which provides a solution:

# settings.py class InvalidVarException(object):     def __mod__(self, missing):         try:             missing_str=unicode(missing)         except:             missing_str='Failed to create string representation'         raise Exception('Unknown template variable %r %s' % (missing, missing_str))     def __contains__(self, search):         if search=='%s':             return True         return False  TEMPLATE_DEBUG=True TEMPLATE_STRING_IF_INVALID = InvalidVarException()