Develop Reference

Django Admin actions don't work after redefining primary key of the model

I am using standard models.Model in Django. I changed my primary key to _id (mongo). After that, actions in Django Admin don't work anymore. For example, when I use the default Django action – Delete selected, no object is found through the query. However, no problem occurs when I edit or delete objects manually. Is there any way to fix it?
Are you sure you want to delete the selected companies? -> Summary, objects: None

Exclude UUID field from Django admin

I have a UUID field in Django 1.6 imported from django-uuidfield v0.4.0. I can't change Django versions.
id = uuidfield.UIIDField()
And all is fine, except when attempting to view the model in the Admin, when this error is displayed:
expected a character buffer object
The problem seems to be this line:
return mark_safe(force_text(value).translate(_js_escapes))
from site-packages/django/utils/functional.py
I have tried to exclude this field from the Admin view by excluding it specifically
exclude=('id',)
and by including a different field explicitly, hoping it would only process that field and not the ID field (as the docs seem to indicate).
include = ('email',)
But the error persists. It seems as if the Admin site is examining the fields anyway, ignoring any settings in the Admin setup. I have also set 'editable=False' in the model definition with no effect for the id field.
I don't need to manipulate or edit this field in any way from the admin screen, just hide it so it does not crash the admin.

I'm not sure where you are importing that from, but Django has included its own UUIDField since version 1.7. You should certainly be using that instead.

Get rid of get_profile() in a migration to Django 1.6

With Django 1.5 and the introduction of custom user models the AUTH_PROFILE_MODULE became deprecated. In my existing Django application I use the User model and I also have a Profile model with a foreign key to the User and store other stuff about the user in the profile. Currently using AUTH_PROFILE_MODULE and this is set to 'app.profile'.
So obviously, my code tends to do lots of user.get_profile() and this now needs to go away.
Now, I could create a new custom user model (by just having my profile model extend User) but then in all other places where I currently have a foreign key to a user will need to be changed also... so this would be a large migration in my live service.
Is there any way - and with no model migration - and only by creating/overriding the get_profile() function with something like my_user.userprofile_set.all()[0]) somewhere?
Anyone out there that has gone down this path and can share ideas or experiences?
If I where to do this service again now - would obviously not go this way but with a semi-large live production system I am open for short-cuts :-)

Using a profile model with a relation to the built-in User is still a totally legitimate construct for storing additional user information (and recommended in many cases). The AUTH_PROFILE_MODULE and get_profile() stuff that is now deprecated just ended up being unnecessary, given that built-in Django 1-to-1 syntax works cleanly and elegantly here.
The transition from the old usage is actually easy if you're already using a OneToOneField to User on your profile model, which is how the profile module was recommended to be set up before get_profile was deprecated.
class UserProfile(models.Model):
user = OneToOneField(User, related_name="profile")
# add profile fields here, e.g.,
nickname = CharField(...)
# usage: no get_profile() needed. Just standard 1-to-1 reverse syntax!
nickname = request.user.profile.nickname
See here if you're not familiar with the syntactic magic for OneToOneField's that makes this possible. It ends up being a simple search and replace of get_profile() for profile or whatever your related_name is (auto related name in the above case would be user_profile). Standard django reverse 1-1 syntax is actually nicer than get_profile()!
Change a ForeignKey to a OneToOneField
However, I realize this doesn't answer your question entirely. You indicate that you used a ForeignKey to User in your profile module rather than a OneToOne, which is fine, but the syntax isn't as simple if you leave it as a ForeignKey, as you note in your follow up comment.
Assuming you were using your ForeignKey in practice as an unique foreign key (essentially a 1-to-1), given that in the DB a OneToOneField is just a ForeignKey field with a unique=True constraint, you should be able to change the ForeignKey field to a OneToOneField in your code without actually having to make a significant database migration or incurring any data loss.
Dealing with South migration
If you're using South for migrations, the code change from the previous section may confuse South into deleting the old field and creating a new one if you do a schemamigration --auto, so you may need to manually edit the migration to do things right. One approach would be to create the schemamigration and then blank out the forwards and backwards methods so it doesn't actually try to do anything, but so it still freezes the model properly as a OneToOneField going forward. Then, if you want to do things perfectly, you should add the unique constraint to the corresponding database foreign key column as well. You can either do this manually with SQL, or via South (by either editing the migration methods manually, or by setting unique=True on the ForeignKey and creating a first South migration before you switch it to a OneToOneField and do a second migration and blank out the forwards/backwards methods).

Django admin - Create a complex filter on User model

I have a field Foo with a ForeignKey that points to User. I need to create filter in the admin that only displays User that have at least one Foo. This would be easy with the development version of Django, but I am stuck with the 1.3.
I have seen here how to add a custom filter using the undocumented FilterSpec class. My problem is that it requires to modify the User model. I could inherit from User, but I already ave a setup where additional data is put into a Profile model wiith a one-to.one link to User.
Is there a less intrusive way to add a custom filter to the User model?

You can actually use the foreign key relation backwards in an ORM query.
User.objects.filter(foo__isnull=False)

Improving Performance of Django ForeignKey Fields in Admin

By default, Django's admin renders ForeignKey fields in admin as a select field, listing every record in the foreign table as an option. In one admin-accessible model, I'm referencing the User model as a ForeignKey, and since I have thousands of users Django is populating the select with thousands of options. This is causing the admin page to load incredibly slowly, and the select is not very useful since it can take a while to scroll through thousands of options to find the one you want.
What's the best way to change the rendering of this field in order to improve page load and usability? I'd like the select field to be replaced with some sort of button to launch a search form popup, or a text field that searches keywords via Ajax to find the Id for the specific User they want to associate. Does admin have anything like this builtin, or would I have to write this from scratch?

Add raw_id_fields to your model to only show the ID instead of a dropdown.

You're right, Cerin, the cause of the slowdown is because Django is populating the <select> element with too many options. You might want to use an autocomplete element instead.
Interestingly, Django 2.0 has introduced a new feature on the admin site, called autocomplete_fields, which I think you will find useful in this case. It uses AJAX.
class ExampleAdmin(models.ModelAdmin):
autocomplete_fields = ['example_field_user']

You can use one of the few autocomplete apps for Django. Check them at Django Packages.
There's also django-extensions that have ForeignKeyAutocompleteAdmin that fit your needs pretty well.

Another option is to add readonly_fields instead of raw_id_fields