Getting 'QuerySet' object has no attribute '_meta' error while serializing list of models

Question

I understand this particular error message

'QuerySet' object has no attribute '_meta'

has been discussed a lot on StackOverflow and I have gone through lots of the answers provided but each is unique and didn't solve my problem.

So, I have a list of filtered model objects I'm getting from a database:

questions_by_category = Question.objects.filter(category=category_id)

I want to save this list in the session like this:

request.session["questions"] = json.dumps(model_to_dict(questions_by_category))

but I'm getting the error message specifically from this line:

model_to_dict(questions_by_category)

This is the model class:

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    correct_answer = models.CharField(max_length=20)
    publication_date = models.DateTimeField('date_published', default=django
                                            .utils.timezone.now)
    question_hint = models.CharField(max_length=200, default='hint')
    question_thumbnail = models.ImageField(upload_to='gallery', height_field=None, width_field=None,
                                           max_length=100,
                                           default='images/pyramid.jpg')
    category = models.ForeignKey(QuestionCategory, on_delete=models.SET_NULL, null=True)
    difficulty_level = models.IntegerField(default=10)

    def was_published_recently(self):
        return self.publication_date >= timezone.now() - datetime.timedelta(days=1)

    class Meta:
        db_table = 'question'

    def __str__(self):
        return self.question_text

    def serialize(self):
        return self.__dict__

And the view:

def question(request, category_name, category_id):
    questions_by_category = Question.objects.filter(category=category_id)
    current_question = questions_by_category.iterator().__next__()
    choice = current_question.choice_set.get()

    form = ChoiceForm(request.POST)

    request.session["questions"] = json.dumps(model_to_dict(questions_by_category))

    context = {
        'question': current_question, 'choice': choice, 'form': form
    }

    return render(request, 'quiz/question.html', context)

EDIT

This the other view where I intend to modify the list:

def accept_choice(request):
global data
if request.method == 'POST':
    data = request.POST.get('choiceRadioGroup')
    print('Selected data: ' + str(data))

return render(request, 'quiz/question.html', {'data': 'data'}

The goal here (which is starting to appear messy) is to select accept a choice from the question view, on next button click, accept_choice is called, and the next question id displayed. My intention is to keep track of the current question by maintaining the list of questions in a session.

I'd really appreciate an explanation on what I'm doing wrong and the right way to go about this.

Because model_to_dict, as the name implies, expects a model, not a queryset. — Daniel Roseman, Apr 29 '19 at 11:57
But why are you doing any of this? Why are you trying to save a queryset to the session? And why are you trying to do that by converting it to a dict? And why are you then trying to convert it to a JSON string? — Daniel Roseman, Apr 29 '19 at 11:58
@DanielRoseman I'm kind of new to this hence the confusion. I'm trying to save the list in the session because I to access the list (after removing or adding items) from different views — Ojonugwa Jude Ochalifu, Apr 29 '19 at 12:00
have a look here: https://stackoverflow.com/questions/7811556/how-do-i-convert-a-django-queryset-into-list-of-dicts — Preston, Apr 29 '19 at 12:14
I would probably look at saving just the question IDs, rather than the whole queryset. How do your other views which modify this list look? — Daniel Roseman, Apr 29 '19 at 12:15

Getting 'QuerySet' object has no attribute '_meta' error while serializing list of models

0 Answers0