Django CreateView is not saving object

Question

I'm practicing django Class-Based-View with a basic blog application. For some reason, however, the CreateView for my Post model is not saving the post inside the database.

models.py

class Post(models.Model):
    user = models.ForeignKey(User)
    post_title = models.CharField(max_length=200)
    post_content = models.CharField(max_length=500)
    post_date = models.DateTimeField('date posted')

forms.py

class PostForm(forms.ModelForm):
    class Meta:
        model = Post
        exclude = ('user', 'post_date')

views.py

class PostCreate(CreateView):
    template_name = 'app_blog/post_save_form.html'
    model = Post
    form_class = PostForm

    def form_valid(self, form):
        form.instance.user = self.request.user
        form.instance.post_date = datetime.now()
        return super(PostCreate, self).form_valid(form)

It displays content without generating any error, but when I check the admin page, the post created by the CreateView is not saved in the database.. Any idea..??

Thanks

Answer 1

One tip: don't use exclude when defining forms, use fields, is more secure and the recommended way to do it.

The redirect is defined by get_success_url method. If you have in your model the method get_absolute_url CreateView will redirect to that URL, otherwise you can always override get_success_url in your view.

Using get_absolute_url:

class Post(models.Model):
    user = models.ForeignKey(User)
    post_title = models.CharField(max_length=200)
    post_content = models.CharField(max_length=500)
    post_date = models.DateTimeField('date posted')

    @permalink
    def get_absolute_url(self):
        return ('myurlname', (), {'myparam': something_useful})

Using get_success_url:

class PostCreate(CreateView):
    template_name = 'app_blog/post_save_form.html'
    model = Post
    form_class = PostForm

    def form_valid(self, form):
        form.instance.user = self.request.user
        form.instance.post_date = datetime.now()
        form.save()
        return super(PostCreate, self).form_valid(form)

    def get_success_url(self):
        return reverse('myurlname', args=(somethinguseful,))

I think you will find this page very useful when working with CBVs: http://ccbv.co.uk/projects/Django/1.5/django.views.generic.edit/CreateView/

Answer 2

the problem is that you are excluding fields that are mandatory, so it won't pass through your form validation.

You should pass this fields hidden with some default value, let the use fill them, set them to null=True or populate them before you access form_valid

Answer 3

I came across this question today after many years but those answer seems not correctly.

The main issue here is the form.instance is None for CreateView. So my approach is below as suggestion form django docs:

def form_valid(self, form):
    instance = form.save(commit=False)
    instance.user = self.request.user
    instance.post_date = datetime.now()
    instance.save()
    return redirect(self.get_success_url())