CODEWITHSUNDEEP
djangodjango-modelsdjango-forms
Nader
Nader

Reputation: 77

ValueError at /posts/create/15/: Cannot assign "<Group: Group 2>": "Post.group" must be a "Group" instance

I am writing the create method for a post, which belongs to a group and a user. I keep getting this error, although this is how it's done in the documentation and every other source i've looked at. here are the relevant files:

models.py

from django.db import models
from django.contrib.auth.models import User, Group


class Post(models.Model):
    title = models.CharField(max_length=255, unique=True)
    body = models.TextField()
    likes_total = models.IntegerField(default=0)
    pub_date = models.DateTimeField()
    author = models.ForeignKey(User, on_delete=models.CASCADE)
    group = models.ForeignKey(Group, on_delete=models.CASCADE)


def __str__(self):
    return self.name

def summary(self):
    # return the 1st 100 chars
    return self.body[:100]

def pub_date_pretty(self):
    # strftime is how to break down time
    return self.pub_date.strftime('%b %e %Y')

posts.urls.py

from . import views
from django.urls import path


app_name = 'posts'

urlpatterns = [
    path('create/<int:group_id>/', views.create, name='create'),
]

posts.views.py

def create(request, group_id):
    group = get_object_or_404(Group, pk= group_id)
    if request.method == 'POST':
        if request.POST['body']:
            post = Post()
            post.title = request.POST['title']
            post.body = request.POST['body']
            post.pub_date = timezone.datetime.now()
            post.author = request.user
            post.group = group
            post.save()
            return redirect('/groups/' + str(group_id))

        else:
            return render(request, 'groups/detail.html', {'group':group})

    else:
        return render(request, 'groups/detail.html', {'group':group})

the error is thrown when I am saving the group to the post (post.group = group), although this the method that ive learned. Hope someone can figure this out. thanks!!

Upvotes: 1

Views: 693

Answers (1)

solarissmoke
solarissmoke

Reputation: 31474

You seem to have mixed up two different Group models. In your model you have:

from django.contrib.auth.models import User, Group

and in your view you have:

from groups.models import Group

These are completely different classes, which is why you get an error telling you that you can't assign groups.models.Group to what should be a auth.models.Group.

I'm not sure which you intend it to be, but you need to use the same class in both places.

Upvotes: 4

Related Questions