Display user name in reference to user id in django template

Question

I expect this is an easy question. For some reason, I don't have a solution yet.

I have an object set from django reversion: version_list. Each object in the set has a user id attached to it. How do I grab the user names that correspond to the user ID's?

To try to be clearer, if each object in version_list has a name, date, and user id, how can I join the version_list set with the user table to figure out what user id goes with which name? This is done in the view, or the template?

Answer 1

I think you're looking for a simple template tag.

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

register = template.Library()

@register.simple_tag
def get_username_from_userid(user_id):
    try:
        return User.objects.get(id=user_id).username
    except User.DoesNotExist:
        return 'Unknown'

Which you would use like:

{% for version in version_list %}
  {% get_username_from_userid version.user_id %}
{% endfor %}

Answer 2

Unless this is for some sort of legacy compatibility, you should really change your schema to use a ForeignKey(User). The data should be the same for this column, so if you already have a lot of stuff you don't want to lose in your database just update the model field to

user = models.ForeignKey(User)

and you won't even have to alter the table if the field is already called user_id.

As for getting the user's name, this is always done at the template level but it depends on whether you want a full name (Casey Stark) or a username (caseywstark).

Use {{ user }} to display the username and {{ user.get_full_name }} to display a full name. The second method calls the get_full_name function of the User object inside your template. Just keep in mind that you must set user.first_name and user.last_name in order for this to not return an empty string.

{% for version in version_list %}
    {{ version.user }} wrote version {{ version }}
{% endfor %}

Answer 3

Does the version object has a user property (i.e., ForeignKey) or is it just an integer field? If it's a user foreign key, you should be able to say:

{% for v in version_list %}
{{ v.user.get_full_name }}
{% endfor %}

Otherwise you're going to need to add a function/ property to your version objects that looks up the related user, like

from django.contrib.auth.models import User

def related_user(self):
    try:
        return User.objects.get(pk=self.user_id)
    except User.DoesNotExist:
        return None

And then in your template:

{% for v in version_list %}
{{ v.related_user.get_full_name }}
{% endfor %}