Django Template Tag Conditional

Question

How make a a conditional statement out of a Django Template Tag?

from django import template
from django.contrib.auth.models import User, Group

register = template.Library()

@register.simple_tag
def is_designer(user_id):
    try:
        group = Group.objects.get(
            name = "Designer",
            user = user_id
        )
        return True
    except Group.DoesNotExist:
        return False

This appears True or False in my template which is correct:

{% is_designer user.id %}

However these gives me an error "Unused 'user.id' at end of if expression.":

{% if is_designer user.id == True %} Yes {% endif %}

{% if is_designer user.id %} Yes {% endif %}

Answer 1

If you made that into an assignment tag, you could do something like

{% is_designer user.id as is_user_designer %}

{% if is_user_designer == True %} Yes {% endif %}

{% if is_user_designer %} Yes {% endif %}

Note: As of Django 1.9, assignment tags are deprecated and simple tags can store values now. See the deprecation notice in the 1.9 docs https://docs.djangoproject.com/en/1.9/howto/custom-template-tags/#assignment-tags

Answer 2

How about this one:

{% is_designer user.id as is_user_designer %}
{{ is_user_designer|yesno:"Yes," }}