Using a lazy value in a queryset filter?

[Sylvain]

Hello,

I’m trying to use the current language of the user in a queryset, but the value gets resolved outside of the request-response cycle. I thought this could work since querysets are lazy, but I guess that doesn’t make the values they use lazy. Here’s an example of what I’m talking about:

from django.utils.translation import get_language

class MyManager(models.Manager):

    def get_queryset(self):

        return super().get_queryset().filter(language=get_language())

class MyModel(models.Model):

    ...

    objects = MyManager()

Using this in a code path that’s in the request-response cycle works (eg. in a view), but using it in a form definition doesn’t (I get the default language instead of the one from the request):

class MyForm(forms.Form):

    option = forms.ModelChoiceField(queryset=MyModel.objects.all())

Is there a way to get this working without having to move the queryset call to the form __init__? Using django.utils.functional.lazy doesn’t work either because the value needs to be resolved in the filter.

Thanks!

Sylvain

[Ryan Nowakowski]

On Sun, Jun 12, 2022 at 11:46:44AM -0700, Sylvain wrote:
> Hello,
>
> I’m trying to use the current language of the user in a queryset, but the
> value gets resolved outside of the request-response cycle. I thought this
> could work since querysets are lazy, but I guess that doesn’t make the
> values they use lazy. Here’s an example of what I’m talking about:
>
> from django.utils.translation import get_language
>
> class MyManager(models.Manager):
> def get_queryset(self):
> return super().get_queryset().filter(language=get_language())
>
> class MyModel(models.Model):
> ...
> objects = MyManager()
>
> Using this in a code path that’s in the request-response cycle works (eg.
> in a view), but using it in a form definition doesn’t (I get the default
> language instead of the one from the request):
>
> class MyForm(forms.Form):
> option = forms.ModelChoiceField(queryset=MyModel.objects.all())

Can you post how you're using the form? Are you using the form in a
view? Can you post the view code?

[Sylvain]

The form is used in a view, yes, like so:

def objects_list(request):

    if request.method == "POST" and "delete" in request.POST:

        delete_form = MyForm(data=request.POST)

        if delete_form.is_valid():

            if delete_form.cleaned_data["confirm"]:

                delete_form.save()

                return redirect(...)

            else:

                return render(request, "delete_confirm.html", {"form": delete_form})

    ...