Django: Using ModelAdmin to default to currently logged in user

Yeah, you may have noticed that I've been working on the blog lately. Poor openclue.org got flooded with already posted RSS feeds again. This happens all to often. Sorry guys.

Anyway, this blog system has the ability to have more than one person post articles. In the past, sjohannes used to post here too. The model for articles looks something like this:

from django.contrib.auth.models import User
from django.db import models
import datetime

class Article(models.Model):
    title = models.CharField(max_length=250)
    slug = models.SlugField()
    article = models.TextField()
    pub_date = models.DateTimeField(
        default=datetime.datetime.now)
    publisher = models.ForeignKey(User)

As you can see, there's a ForeignKey to django.contrib.auth.models.User. The question here is: how do I make the publisher field default to the currently logged in user? It was harder than I thought it should be, but it can be done using hooks in the ModelAdmin for the Article model. Take a look:

class ArticleAdmin(admin.ModelAdmin):
    list_display = ('pub_date', 'publisher', 'title', 'slug')
    search_fields = ('title', 'article')
    prepopulated_fields = {
        'slug': ('title',),
    }

    def get_form(self, req, obj=None, **kwargs):
        # save the currently logged in user for later
        self.current_user = req.user
        return super(ArticleAdmin, self).get_form(req, obj, **kwargs)

    def formfield_for_dbfield(self, field, **kwargs):
        from django import forms
        from django.contrib.auth import models
        if field.name == 'publisher':
            queryset = models.User.objects.all()
            return forms.ModelChoiceField(
                queryset=queryset, initial=self.current_user.id)
        return super(ArticleAdmin, self).formfield_for_dbfield(field, **kwargs)

admin.site.register(models.Article, ArticleAdmin)

As you can see, I overload get_form for one purpose: It takes the HttpRequest as the first argument, which we can use to save the currently logged in user. The other method that's overloaded, formfield_for_dbfield is called for every field in the model, and is made for the purpose of specifying your own custom form fields (and widgets). In this case, we use the same field type that the admin would have used - ModelChoiceField and give it an initial, which is the id of the currently logged in user.

There you have it. It's a little hacky, but it's the only way I could find to do it. If you've seen a cleaner way, let me know!