Why does a MultiValueDictKeyError occur when voting in the polls plugin for Django CMS?

Question

Django

I'm learning Django CMS, I tried to create a polls plugin for Django CMS 3.2.0 based on the standard django-polls application. Followed instructions in official docks . All code is copied from there. But after placing the plugin on the main page of my project, I see only the question itself and the radio buttons by the number of answers, but I do not see the text of the answers. After selecting one of the answers and pressing the Vote button, I get an error page. Here is the traceback:

Environment:
Request Method: POST
Request URL: localhost:8000/en/polls/2/vote
Django Version: 1.8.7
Python Version: 2.7.10
Installed Applications:
('djangocms_admin_style',
'django.contrib.auth',
'django .contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.admin',
'django.contrib.sites',
'django.contrib.sitemaps',
'django.contrib.staticfiles',
'django.contrib .messages',
'debug_toolbar',
'cms',
'menus',
'sekizai',
'treebeard',
'djangocms_text_ckeditor',
'djangocms_style',
'djangocms_column',
'filer',
'easy_thumbnails'
' cmsplugin_filer_image '
' cmsplugin_filer_file '
' cmsplugin_filer_folder '
'
cmsplugin_filer_teaser ' ', 'polls_plugin') Installed Middleware: ('cms.middleware.utils.ApphookReloadMiddleware', 'django.contrib.sessions.middleware.SessionMiddleware', 'django.middleware.csrf.CsrfViewMiddleware', 'django.contrib.auth.middleware .AuthenticationMiddleware', 'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.locale.LocaleMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
'debug_toolbar.middleware.DebugToolbarMiddleware',
'cms.middleware.user.CurrentUserMiddleware',
'cms .middleware.page.CurrentPageMiddleware',
'cms.middleware.toolbar.ToolbarMiddleware',
'cms.middleware.language.LanguageCookieMiddleware')
Traceback:
File "C:\Users\Fox\Envs\fatdiet\lib\site-packages\django \core\handlers\base.py" in get_response
132. response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:\Users\Fox\Envs\fatdiet\lib\site-packages\django\contrib\auth\decorators.py" in _wrapped_view
22. return view_func(request, *args, **kwargs)
File "C:\Users\Fox\Envs\fatdiet\lib\site-packages\django\views\generic\base.py" in view
71. return self. dispatch(request, *args, **kwargs)
File "C:\Users\Fox\Envs\fatdiet\lib\site-packages\django\views\generic\base.py" in dispatch
89. return handler(request, * args, **kwargs)
File "C:\Users\Fox\Envs\fatdiet\lib\site-packages\polls\views.py" in post
26. choice = Choice.objects.get(id=request.POST[' choice_pk'])
File "C:\Users\Fox\Envs\fatdiet\lib\site-packages\django\utils\datastructures.py" in __getitem__
322. raise MultiValueDictKeyError(repr(key))
Exception Type:MultiValueDictKeyError at /ru/polls/2/vote/
Exception Value: "'choice_pk'"

Here is the code from \site-packages\polls\views.py where the error is raised:

from django.views.generic import DetailView, ListView, RedirectView
from django.core.urlresolvers import reverse_lazy
from django.contrib import messages
from django.utils.translation import ugettext_lazy as _

from polls.models import Choice, Poll, Vote


class PollListView(ListView):
    model = Poll


class PollDetailView(DetailView):
    model = Poll

    def get_context_data(self, **kwargs):
        context = super(PollDetailView, self).get_context_data(**kwargs)
        context['poll'].votable = self.object.can_vote(self.request.user)
        return context


class PollVoteView(RedirectView):
    def post(self, request, *args, **kwargs):
        poll = Poll.objects.get(id=kwargs['pk'])
        user = request.user
        choice = Choice.objects.get(id=request.POST['choice_pk'])
        Vote.objects.create(poll=poll, user=user, choice=choice)
        messages.success(request, _("Thanks for your vote."))
        return super(PollVoteView, self).post(request, *args, **kwargs)

    def get_redirect_url(self, **kwargs):
        return reverse_lazy('polls:detail', args=[kwargs['pk']])

And here is the code from poll_plugin.html (taken from the as is docs):

<h1>{{ instance.poll.question }}</h1>

<form action="{% url 'polls:vote' instance.poll.id %}" method="post" name="form">
    {% csrf_token %}
    <div class="form-group">
        {% for choice in instance.poll.choice_set.all %}
            <div class="radio">
                <label>
                    <input type="radio" name="choice" value="{{ choice.id }}">
                    {{ choice.choice_text }}
                </label>
            </div>
        {% endfor %}
    </div>
    <input type="submit" value="Vote" />
</form>

If you write {{ choice }} instead of {{ choice.choice_text }}, then the text of the questions is visible, but the error remains when voting.
I've been digging into the code of the django-polls application and in the code of my plugin for the second day and I can't solve the problem in any way. What am I doing wrong?

Answer 1

I found the first step of the solution :)
I had to write name="choice_pk" in the input attributes and output the text as {{choice.choice}} . Apparently, the polls version has been updated and changed.
True, the second error got out, now when voting I get:

IntegrityError at /ru/polls/2/vote/
columns user_id, poll_id are not unique

I will now investigate this issue.