Django Form: Only show manytomany objects from logged in user

Question

The current problem is that my form shows the logged in user all Portfolios ever created. The form should only show portfolios that the logged-in user created.

Something like this:

associated_portfolios manytomany field = ...objects.filter(user=user_id)

I'm not sure if this should be implemented in the forms.py or views.py and if so how. I've been going through the django documentation and found 'formfield_for_manytomany' but not sure if this is only meant for admin.

Models.py

class Portfolio(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    name = models.CharField(max_length=20)
    description = models.CharField(max_length=250, blank=True, null=True)

class Post(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    title = models.CharField(max_length=50)
    body = RichTextUploadingField(blank=True, null=True)
    associated_portfolios = models.ManyToManyField(Portfolio, blank=True)
    created_on = models.DateField(auto_now_add=True, editable=False)

Views.py

class PostCreate(CreateView):
    model = Post
    form_class = PostCreateForm

    def formfield_for_manytomany(self, db_field, request, **kwargs):
        self.fields['associated_portfolios'] = Portfolio.objects.filter(user=self.request.user)
        return super().formfield_for_manytomany(db_field, request, using=self.using, **kwargs)

forms.py

class PortfolioCreateForm(ModelForm):
    class Meta:
        model = Portfolio
        fields = ['user', 'name', 'description']    

class PostCreateForm(ModelForm):
    class Meta:
        model = Post
        fields = ['user', 'title', 'body', 'category', 'associated_portfolios']

Greg Kaleka · Accepted Answer · 2020-02-20T16:14:03.840

2

Since you're using a ModelForm, the associated_protfolios field will be a ModelMultipleChoiceField [docs]. This field has a queryset attribute [docs]. We want to modify that attribute.

Django's CreateView has a method get_form, which in this case will grab your PostCreateForm. This is a good spot to filter the field's queryset, since we have access to the user:

class PostCreate(CreateView):
    model = Post
    form_class = PostCreateForm

    def get_form(self, *args, **kwargs):
        form = super().get_form(*args, **kwargs)  # Get the form as usual
        user = self.request.user
        form.fileds['associated_portfolios'].queryset = Portfolio.objects.filter(user=user)
        return form

edited Feb 20 '20 at 16:14

answered Feb 19 '20 at 16:02

Greg Kaleka

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Really interesting approach. Thanks for the help. Currently getting AttributeError: 'PostCreateForm' object has no attribute 'fileds' - would it be right to try to add the queryset inside of the forms? associated_portfolios = forms.ModelChoiceField(queryset=... – Alex Winkler Feb 20 '20 at 11:09
Ahh! Just realized 'fileds' was a typo! Talk about tunnel vision. Your solution worked! Thanks a lot! Quick question why use form = super().get_form(*args, **kwargs) and not form = PostCreateForm() – Alex Winkler Feb 20 '20 at 11:17
1

Glad it worked! In this case, there's no difference (you can look at the docs for CreateView's get_form method and see it just returns an instance of `form_class` if one is given), except that calling `super().get_form()` is more DRY. If you were to change your form class name, you would only need to change it in one spot, rather than two if you used `form = PostCreateForm()`. Also, it's a best practice in cases like this. Sometimes there are other implementation details you might miss if you don't call super. – Greg Kaleka Feb 20 '20 at 16:12

score 0 · Answer 2 · answered Feb 19 '20 at 09:25

Did you try this

self.fields['associated_portfolios'] = Post.objects.filter(associated_portfolios__portfolio__user=request.user)

OR

user_posts = Post.objects.filter(user=request.user)
self.fields['associated_portfolios'] = user_posts.associated_portfolios.all()

read more about M2M relationships querying here, because I think your problem may be with it.

Also, I'm not sure about your actual data maybe it's right and it gives a correct result as filtering Portfolio model against current user to get its objects looks right for me, but anyway double check everything again.

And as a final note, add related_name to your model fields so you can use it easily for reverse relations rather than going with Django's default naming, it will be clearer and give a better understanding.

Thanks for the attempt at a solution! Unfortunately, no luck with those solutions and ya I've read up and down that M2M Django doc but there's no examples on how to filter the fields. — Alex Winkler, Feb 19 '20 at 09:37

Django Form: Only show manytomany objects from logged in user

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