Unable to save object with images while using FormWizard in Django 1.7 and Python 3.4

[Frankline]

​Hi all​,

I am having a problem saving a Django form using the FormWizard while using Django 1.7 and Python 3.4. Below is my code:

models.py

...
class Advert(models.Model):
    ... # Some irelevant code removed for brevity
    owner = models.ForeignKey(settings.AUTH_USER_MODEL, db_index=True, blank=False, null=False)
    title = models.CharField(_("Title"), max_length=120)
    description = models.TextField(_("Description"), default='')
    category = models.ForeignKey(AdCategory, db_index=True, related_name='ad_category', verbose_name=_('Category'))
    status = models.IntegerField(choices=ADVERT_STATES, default=0)
    adtype = models.IntegerField(choices=ADTYPES, default=1)
    price = models.DecimalField(_('Price'), max_digits=12, decimal_places=2, blank=True, default=0,
                            help_text=_('Price'), validators=[MinValueValidator(0)])
                            
...
class AdvertImage(models.Model):

    def generate_new_filename(instance, filename):
        IMAGE_UPLOAD_DIR = "advert_images"
        old_fname, extension = os.path.splitext(filename)
        return '%s/%s%s' % (IMAGE_UPLOAD_DIR, uuid.uuid4().hex, extension)    
    
    advert = models.ForeignKey(Advert, related_name='images')
    image = models.ImageField(upload_to=generate_new_filename, null=True, blank=True)

forms.py

from django.forms.models import inlineformset_factory
from django import forms
from django.forms import ModelForm, RadioSelect, TextInput

from .models import Advert, AdvertImage


class AdvertCategoryForm(ModelForm):

    class Meta:
        model = Advert
        fields = ('category',)


class AdvertDetailsForm(ModelForm):

    class Meta:
        model = Advert
        fields = ('title', 'description', 'location', 'adtype', 'price')


class AdvertImageForm(ModelForm):

    class Meta:
        model = AdvertImage
        fields = ('image',)

AdvertImageFormset = inlineformset_factory(Advert, AdvertImage, fields=('image',), can_delete=False, extra=3, max_num=3)


FORMS = [("ad_category", AdvertCategoryForm),
         ("ad_details", AdvertDetailsForm),
         ("ad_images", AdvertImageFormset)]

TEMPLATES = {"ad_category": "adverts/advert_category_step.html",
             "ad_details": "adverts/advert_details_step.html",
             "ad_images": "adverts/advert_images_step.html"}

views.py

...
class AdvertWizard(LoginRequiredMixin, SessionWizardView):

    form_list = FORMS
    file_storage = FileSystemStorage(location=os.path.join(settings.MEDIA_ROOT))

    def get_template_names(self):
        return [TEMPLATES[self.steps.current]]

    ...

    def done(self, form_list, **kwargs):
        advert = Advert()
        """for form in form_list:
            for field, value in form.cleaned_data.iteritems():
                setattr(advert, field, value)"""

        form_dict = {}
        for form in form_list:
            form_dict.update(form.cleaned_data)

        advert.owner = self.request.user
        advert.save()
        redirect(advert)

​The problem occurs in the done method while saving the form:

ValueError at /ads/new
dictionary update sequence element #0 has length 3; 2 is required
Request Method:
POST
Request URL:
http://localhost:8000/ads/new
Django Version:
1.7.1
Exception Type:
ValueError
Exception Value:
dictionary update sequence element #0 has length 3; 2 is required
Exception Location:
/home/frank/Projects/python/django/pet_store/src/petstore/apps/adverts/views.py in done, line 147
Python Executable:
/home/frank/.virtualenvs/petstore/bin/python
Python Version:
3.4.0
/home/frank/Projects/python/django/pet_store/src/petstore/apps/adverts/views.py in done
            form_dict.update(form.cleaned_data)
 ...
▶ Local vars

However, when I replace the following code:

form_dict = {}
        for form in form_list:
            form_dict.update(form.cleaned_data)

with this one

for form in form_list:
    for field, value in form.cleaned_data.iteritems():
        setattr(advert, field, value)

I now get the following error:

AttributeError at /ads/new
'dict' object has no attribute 'iteritems'
Request Method:
POST
Request URL:
http://localhost:8000/ads/new
Django Version:
1.7.1
Exception Type:
AttributeError
Exception Value:
'dict' object has no attribute 'iteritems'
Exception Location:
/home/frank/Projects/python/django/pet_store/src/petstore/apps/adverts/views.py in done, line 140
Python Executable:
/home/frank/.virtualenvs/petstore/bin/python
Python Version:
3.4.0
Python Path:
['/home/frank/Projects/python/django/pet_store/src/petstore',
 '/home/frank/.virtualenvs/petstore/lib/python3.4',
 '/home/frank/.virtualenvs/petstore/lib/python3.4/plat-x86_64-linux-gnu',
 '/home/frank/.virtualenvs/petstore/lib/python3.4/lib-dynload',
 '/usr/lib/python3.4',
 '/usr/lib/python3.4/plat-x86_64-linux-gnu',
 '/home/frank/.virtualenvs/petstore/lib/python3.4/site-packages'
Server time:
Thu, 22 Jan 2015 19:25:22 +0300

Probably this has to do with the images that have been added through inlineformset, and the lack of iteritems method in Python 3.4.

How can I fix this to be able to save the object along with the images through Django's FormWizard?

Thanks

P.S.: Apologies for the long post.

[Collin Anderson]

Hi,

Use items() instead of iteritems().

Collin