Hi
I believe the main objection is against adding additional API to querysets.
get_object_or_404 only converts DoesNotExist into a 404 exception and
doesn't handle MultipleObjectsReturned.
I'm not the first to suggest adding an additional shortcut, e.g.
django.shortcuts.get_object_or_none which would work similarly to
get_object_or_404 (and get_list_or_404 for that matter). The existing
shortcuts use functionality from several parts of Django (the ORM and the
request/response handling) which get_object_or_none wouldn't do, but its
behavior would be so close to what get_object_or_404 is doing that it may
be alright.
OTOH even the implementation of this shortcut is so simple that I just add
it to each project when I have a need for it (I had a hard time finding it
because it comes up much less often than I thought it did). So I am not
proposing this addition personally but I wouldn't be against it either (if
that counts for anything).
Best regards,
Matthias
def get_object_or_none(klass, *args, **kwargs):
queryset = _get_queryset(klass)
if not hasattr(queryset, "get"):
klass__name = (
klass.__name__ if isinstance(klass, type) else
klass.__class__.__name__
)
raise ValueError(
"First argument to get_object_or_404() must be a Model,
Manager, "
"or QuerySet, not '%s'." % klass__name
)
try:
return queryset.get(*args, **kwargs)
except queryset.model.DoesNotExist:
return None
On Sun, Jul 10, 2022 at 10:13 PM Dave Gaeddert <dave.gaedd...@gmail.com>
wrote:
> Fair enough. To me, the `get_or_none` behavior with multiple results would
> still be to raise an exception (so it is just like `get` in that sense).
> And that’s the reason I personally don’t just see it as a shortcut for
> `filter().first()` — I have (as I’m sure others have) made the mistake
> before of *thinking* that I was using a unique query when that wasn’t
> necessarily true, so the multiple results exception has caught mistakes at
> runtime. I’d rather have that exception than use `filter().first()` and
> potentially show the wrong object to the wrong user, for example, and not
> figure out that I have a uniqueness/db problem. I like the fact that `get`
> raises those exceptions, I just think that try/except DoesNotExist/None is
> such a common behavior that a shortcut for *that* would actually be
> useful.
>
> Dave
> On Sunday, July 10, 2022 at 3:24:32 AM UTC-5 Adam Johnson wrote:
>
>> I'm also against adding get_or_none(), for the same reasons. Adding a
>> method to shortcut something that can already be done doesn't seem worth it
>> to me.
>>
>> On Sat, Jul 9, 2022 at 1:56 PM Mariusz Felisiak <felisiak...@gmail.com>
>> wrote:
>>
>>> I'm against it because it's already easily achievable and it's debatable
>>> how it should behave with many results. IMO any new method would be
>>> confusing and in the case of unique filtering `get_or_none(unique_filters)`
>>> would be an alias for `.filter(unique_filters).first()`. To me, this is
>>> duplication of an API.
>>>
>>> There are several -0 in the previous thread (Shai, Florian) and you can
>>> count -1 from me.
>>>
>>> Best,
>>> Mariusz
>>>
>>> --
>>> You received this message because you are subscribed to the Google
>>> Groups "Django developers (Contributions to Django itself)" group.
>>>
>> To unsubscribe from this group and stop receiving emails from it, send an
>>> email to django-develop...@googlegroups.com.
>>> To view this discussion on the web visit
>>> https://groups.google.com/d/msgid/django-developers/aeb9be96-ec03-48f9-ae97-2859b62a1df6n%40googlegroups.com
>>> <https://groups.google.com/d/msgid/django-developers/aeb9be96-ec03-48f9-ae97-2859b62a1df6n%40googlegroups.com?utm_medium=email&utm_source=footer>
>>> .
>>>
>> --
> You received this message because you are subscribed to the Google Groups
> "Django developers (Contributions to Django itself)" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to django-developers+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/django-developers/dbee041d-4f80-4e61-bf0a-1d6f4e2e22e6n%40googlegroups.com
> <https://groups.google.com/d/msgid/django-developers/dbee041d-4f80-4e61-bf0a-1d6f4e2e22e6n%40googlegroups.com?utm_medium=email&utm_source=footer>
> .
>
--
You received this message because you are subscribed to the Google Groups
"Django developers (Contributions to Django itself)" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to django-developers+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-developers/CANvPqgBCDjejMb_QrHpgZ%3DuZanCgCnwYb42-2-Mf8bmQ1cnL%3Dw%40mail.gmail.com.
