[FIXED] Django Limit Queryaset Objects by Foreign Key

Issue

Sorry for this question but I'm reasonably new to Django and it's eluding me. I am updating a system (think school) with users, classes (the teachable kind), etc. I have classes from the legacy system I want to bring into the new system, and I need to limit the list by a legacy_user_id. So far, I have this in models.py

from account.models import Profile, LegacyUser

class OldClassesManager(models.Manager):
    def get_queryset(self):
        return super().get_queryset().filter(LegacyUser.legacy_id)

class OldInstructables(models.Model):
    legacy_user_id = models.IntegerField(null=False)
    name = models.CharField(max_length=100,  blank=False)
[other stuff]

    objects = models.Manager()
    SOMETHING = OldClassesManager()

    def __str__(self):
        return self.name

And this in views.py

class OldClassList(ListView):
    model = OldInstructables

I think my problem is that I don't know what goes where I put SOMETHING. Any help or insight would be much appreciated.

Solution

You can not filter in the manager, or at least not without a method with a parameter, since models are (normally) request-unaware.

You can filter in the view with:

from django.contrib.auth.mixins import LoginRequiredMixin


class OldClassList(LoginRequiredMixin, ListView):
    model = OldInstructables

    def get_queryset(self):
        return (
            super().get_queryset().filter(legacy_user_id=self.request.user.legacy_id)
        )

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Note: You can limit views to a class-based view to authenticated users with the LoginRequiredMixin mixin ^[Django-doc].

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Note: In Django, class-based views (CBV) often have a …View suffix, to avoid a clash with the model names. Therefore you might consider renaming the view class to OldClassListView, instead of OldClassList.

Answered By - willeM_ Van Onsem