Custom Django template tag to look up a string username and return it as a user object.

Question

I use some third-party template tags in my Django Application (maintained elsewhere) that return a username as a string I can access in my templates like this.

{% for user in gr.user.foll.list %}

 {{user}}

Trouble is because {{user}} is returned as a string - I need to convert into a Django User Object, if it exists in the Django DB, or set a varible unRegistered if not so I can do things like:

 { user.get_profile.about }} # get profile information

So I thought I would write my first Django Template Tag so I could use it like this:

{% webapp_user_lookup user %} # my custom tag
    {% ifnot unRegistered %}
    {{ user.get_profile.about }} # get profile information - would fail with a string
    {% endifnot %}
 {% endfor %}

The code I use elsewhere to look up a user in a view is:

try:
        user = User.objects.get(username__iexact=user)
        unRegistered = False
        if not other_user.is_active:
                unRegistered = True
 except: 
        unRegistered = True

However looking at the Django Template tag examples I'm having trouble understanding how best to structure the custom template tag, to take my string username - and send back the results as an object if they exist, or set a varible if not and the original string. I'd really like to better understand how the structure works, and if I need a 'class' and if so, why. (I'm new to programming).

Answer 1

use a template filter like so:

{{username|get_user}}

in your user_template_tags.py:

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

register = template.Library()

########################

def get_user(username):
    try:
        user = User.objects.get(username__iexact=username)
    except User.DoesNotExist: 
        user = User.objects.none()
    return user

register.filter('get_user',get_user)

then in your template you can do something like:

{% with username|getuser as user %}
{% if user %}DO USER STUFF
{% else %}DO UNREGISTERED STUFF
{% endif %}
{% endwith %}