troeger / opensubmit

        raise PermissionDenied(

            "Withdrawal for this assignment is no longer possible, or you are unauthorized to access that submission.")

    if "confirm" in request.POST:

        submission.state = Submission.WITHDRAWN

        submission.save()

        messages.info(request, 'Submission successfully withdrawn.')

        return redirect('dashboard')

    else:

        return render(request, 'withdraw.html', {'submission': submission})

@lti_provider(consumer_lookup=lti_secret, site_url=MAIN_URL)

@require_POST

def lti(request, post_params, consumer_key, *args, **kwargs):

    '''

        Entry point for LTI consumers.

        This view is protected by the BLTI package decorator,

        which performs all the relevant OAuth signature checking.

        It also makes sure that the LTI consumer key and secret were ok.

        The latter ones are supposed to be configured in the admin interface.

        We can now trust on the provided data to be from the LTI provider.

        If everything worked out, we store the information the session for

        the Python Social passthrough provider, which is performing

        user creation and database storage.

    '''

    data = {}

    data['ltikey'] = post_params.get('oauth_consumer_key')

        user creation and database storage.

    '''

    data = {}

    data['ltikey'] = post_params.get('oauth_consumer_key')

    # None of them is mandatory

    data['id'] = post_params.get('user_id', None)

    data['username'] = post_params.get('custom_username', None)

    data['last_name'] = post_params.get('lis_person_name_family', None)

    data['email'] = post_params.get('lis_person_contact_email_primary', None)

    data['first_name'] = post_params.get('lis_person_name_given', None)

    request.session[passthrough.SESSION_VAR] = data

    return redirect(reverse('social:begin', args=['lti']))