Refactored checkout steps

src/pretix/base/payment.py

@@ -3,7 +3,7 @@ from decimal import Decimal
 
 from django import forms
 from django.contrib import messages
-from django.db.models import Sum
+from django.db.models import Q, Sum
 from django.dispatch import receiver
 from django.forms import Form
 from django.http import HttpRequest
@@ -402,7 +402,9 @@ class FreeOrderProvider(BasePaymentProvider):
         pass
 
     def payment_is_valid_session(self, request: HttpRequest) -> bool:
-        return True
+        return CartPosition.objects.current.filter(
+            Q(session=request.session.session_key) & Q(event=request.event)
+        ).aggregate(sum=Sum('price'))['sum'] == 0
 
     @property
     def verbose_name(self) -> str:

src/pretix/presale/checkoutflow.py

@@ -0,0 +1,335 @@
+from django.contrib import messages
+from django.core.exceptions import ValidationError
+from django.core.urlresolvers import reverse
+from django.core.validators import EmailValidator
+from django.db.models import Q, Sum
+from django.http import HttpResponseNotAllowed
+from django.shortcuts import redirect
+from django.utils import translation
+from django.utils.functional import cached_property
+from django.utils.translation import ugettext_lazy as _
+from django.views.generic.base import TemplateResponseMixin
+
+from pretix.base.models import CartPosition
+from pretix.base.services.orders import OrderError, perform_order
+from pretix.base.signals import register_payment_providers
+from pretix.presale.forms.checkout import ContactForm
+from pretix.presale.signals import checkout_flow_steps
+from pretix.presale.views import CartMixin
+from pretix.presale.views.questions import QuestionsViewMixin
+
+
+class BaseCheckoutFlowStep:
+    def __init__(self, event):
+        self.event = event
+        self.request = None
+
+    @property
+    def identifier(self):
+        raise NotImplementedError()
+
+    @property
+    def priority(self):
+        return 100
+
+    def is_applicable(self, request):
+        return True
+
+    def is_completed(self, request, warn=False):
+        raise NotImplementedError()
+
+    def get_next_applicable(self, request):
+        if self._next:
+            if not self._next.is_applicable(request):
+                return self._next.get_next_applicable(request)
+            return self._next
+
+    def get_prev_applicable(self, request):
+        if self._previous:
+            if not self._previous.is_applicable(request):
+                return self._previous.get_prev_applicable(request)
+            return self._previous
+
+    def get(self, request):
+        return HttpResponseNotAllowed([])
+
+    def post(self, request):
+        return HttpResponseNotAllowed([])
+
+    def get_step_url(self):
+        return reverse(
+            'presale:event.checkout',
+            kwargs={
+                'event': self.event.slug,
+                'organizer': self.event.organizer.slug,
+                'step': self.identifier
+            }
+        )
+
+    def get_prev_url(self, request):
+        prev = self.get_prev_applicable(request)
+        if not prev:
+            return reverse('presale:event.index', kwargs={
+                'event': self.request.event.slug,
+                'organizer': self.request.event.organizer.slug
+            })
+        else:
+            return prev.get_step_url()
+
+    def get_next_url(self, request):
+        n = self.get_next_applicable(request)
+        if not n:
+            return reverse('presale:event.checkout.confirm', kwargs={
+                'event': self.request.event.slug,
+                'organizer': self.request.event.organizer.slug
+            })
+        else:
+            return n.get_step_url()
+
+
+def get_checkout_flow(event):
+    flow = list([step(event) for step in DEFAULT_FLOW])
+    for receiver, response in checkout_flow_steps.send(event):
+        step = response(event=event)
+        if step.priority > 1000:
+            raise ValueError('Plugins are not allowed to define a priority greater than 1000')
+        flow.append(step)
+
+    # Sort by priority
+    flow.sort(key=lambda p: p.priority)
+
+    # Create a double-linked-list for esasy forwards/backwards traversal
+    last = None
+    for step in flow:
+        step._previous = last
+        if last:
+            last._next = step
+        last = step
+    return flow
+
+
+class TemplateFlowStep(TemplateResponseMixin, BaseCheckoutFlowStep):
+    template_name = ""
+
+    def get_context_data(self, **kwargs):
+        kwargs.setdefault('step', self)
+        kwargs.setdefault('event', self.event)
+        kwargs.setdefault('prev_url', self.get_prev_url(self.request))
+        return kwargs
+
+    def render(self, **kwargs):
+        context = self.get_context_data(**kwargs)
+        return self.render_to_response(context)
+
+    def get(self, request):
+        self.request = request
+        return self.render()
+
+    def post(self, request):
+        self.request = request
+        return self.render()
+
+    def is_completed(self, request, warn=False):
+        raise NotImplementedError()
+
+    @property
+    def identifier(self):
+        raise NotImplementedError()
+
+
+class QuestionsStep(QuestionsViewMixin, CartMixin, TemplateFlowStep):
+    priority = 50
+    identifier = "questions"
+    template_name = "pretixpresale/event/checkout_questions.html"
+
+    def is_applicable(self, request):
+        return True
+
+    @cached_property
+    def contact_form(self):
+        return ContactForm(data=self.request.POST if self.request.method == "POST" else None,
+                           initial={
+                               'email': self.request.session.get('email', '')
+                           })
+
+    def post(self, request):
+        self.request = request
+        failed = not self.save() or not self.contact_form.is_valid()
+        if failed:
+            messages.error(request,
+                           _("We had difficulties processing your input. Please review the errors below."))
+            return self.render()
+        request.session['email'] = self.contact_form.cleaned_data['email']
+        return redirect(self.get_next_url(request))
+
+    def is_completed(self, request, warn=False):
+        self.request = request
+        try:
+            emailval = EmailValidator()
+            if 'email' not in request.session:
+                if warn:
+                    messages.warning(request, _('Please enter a valid e-mail address.'))
+                return False
+            emailval(request.session.get('email'))
+        except ValidationError:
+            if warn:
+                messages.warning(request, _('Please enter a valid e-mail address.'))
+            return False
+
+        for cp in self.positions:
+            answ = {
+                aw.question_id: aw.answer for aw in cp.answers.all()
+            }
+            for q in cp.item.questions.all():
+                if q.required and q.identity not in answ:
+                    if warn:
+                        messages.warning(request, _('Please fill in answers to all required questions.'))
+                    return False
+            if cp.item.admission and self.request.event.settings.get('attendee_names_required', as_type=bool) \
+                    and cp.attendee_name is None:
+                if warn:
+                    messages.warning(request, _('Please fill in answers to all required questions.'))
+                return False
+        return True
+
+    def get_context_data(self, **kwargs):
+        ctx = super().get_context_data(**kwargs)
+        ctx['forms'] = self.forms
+        ctx['contact_form'] = self.contact_form
+        return ctx
+
+
+class PaymentStep(QuestionsViewMixin, CartMixin, TemplateFlowStep):
+    priority = 200
+    identifier = "payment"
+    template_name = "pretixpresale/event/checkout_payment.html"
+
+    @cached_property
+    def _total_order_value(self):
+        return CartPosition.objects.current.filter(
+            Q(session=self.request.session.session_key) & Q(event=self.request.event)
+        ).aggregate(sum=Sum('price'))['sum']
+
+    @cached_property
+    def provider_forms(self):
+        providers = []
+        responses = register_payment_providers.send(self.request.event)
+        for receiver, response in responses:
+            provider = response(self.request.event)
+            if not provider.is_enabled or not provider.is_allowed(self.request):
+                continue
+            fee = provider.calculate_fee(self._total_order_value)
+            providers.append({
+                'provider': provider,
+                'fee': fee,
+                'form': provider.payment_form_render(self.request)
+            })
+        return providers
+
+    def post(self, request):
+        self.request = request
+        for p in self.provider_forms:
+            if p['provider'].identifier == request.POST.get('payment', ''):
+                request.session['payment'] = p['provider'].identifier
+                resp = p['provider'].checkout_prepare(
+                    request, self.get_cart(payment_fee=p['provider'].calculate_fee(self._total_order_value)))
+                if isinstance(resp, str):
+                    return redirect(resp)
+                elif resp is True:
+                    return redirect(self.get_next_url(request))
+                else:
+                    return self.render()
+        messages.error(self.request, _("Please select a payment method."))
+        return self.render()
+
+    def get_context_data(self, **kwargs):
+        ctx = super().get_context_data(**kwargs)
+        ctx['providers'] = self.provider_forms
+        ctx['selected'] = self.request.POST.get('payment', self.request.session.get('payment', ''))
+        return ctx
+
+    @cached_property
+    def payment_provider(self):
+        responses = register_payment_providers.send(self.request.event)
+        for receiver, response in responses:
+            provider = response(self.request.event)
+            if provider.identifier == self.request.session['payment']:
+                return provider
+
+    def is_completed(self, request, warn=False):
+        self.request = request
+        if 'payment' not in request.session or not self.payment_provider:
+            if warn:
+                messages.error(request, _('The payment information you entered was incomplete.'))
+            return False
+        if not self.payment_provider.payment_is_valid_session(request) or \
+                not self.payment_provider.is_enabled or \
+                not self.payment_provider.is_allowed(request):
+            if warn:
+                messages.error(request, _('The payment information you entered was incomplete.'))
+            return False
+        return True
+
+    def is_applicable(self, request):
+        self.request = request
+        if self._total_order_value == 0:
+            request.session['payment'] = 'free'
+            return False
+        return True
+
+
+class ConfirmStep(CartMixin, TemplateFlowStep):
+    priority = 1001
+    identifier = "confirm"
+    template_name = "pretixpresale/event/checkout_confirm.html"
+
+    def is_applicable(self, request):
+        return True
+
+    def is_completed(self, request, warn=False):
+        pass
+
+    def get_context_data(self, **kwargs):
+        ctx = super().get_context_data(**kwargs)
+        ctx['cart'] = self.get_cart(answers=True)
+        ctx['payment'] = self.payment_provider.checkout_confirm_render(self.request)
+        ctx['payment_provider'] = self.payment_provider
+        return ctx
+
+    @cached_property
+    def payment_provider(self):
+        responses = register_payment_providers.send(self.request.event)
+        for receiver, response in responses:
+            provider = response(self.request.event)
+            if provider.identifier == self.request.session['payment']:
+                return provider
+
+    def post(self, request):
+        self.request = request
+        try:
+            order = perform_order(self.request.event, self.payment_provider, self.positions,
+                                  email=request.session.get('email', None),
+                                  locale=translation.get_language())
+        except OrderError as e:
+            messages.error(request, str(e))
+            return redirect(self.get_step_url())
+        else:
+            # Message is delivered via GET parameter
+            # messages.success(request, _('Your order has been placed.'))
+            resp = self.payment_provider.payment_perform(request, order)
+            return redirect(resp or self.get_order_url(order))
+
+    def get_order_url(self, order):
+        return reverse('presale:event.order', kwargs={
+            'event': self.request.event.slug,
+            'organizer': self.request.event.organizer.slug,
+            'order': order.code,
+            'secret': order.secret
+        }) + '?thanks=yes'
+
+
+DEFAULT_FLOW = (
+    QuestionsStep,
+    PaymentStep,
+    ConfirmStep
+)

src/pretix/presale/forms/checkout.py

@@ -4,7 +4,7 @@ from django.utils.translation import ugettext_lazy as _
 from pretix.base.models import Question
 
 
-class GuestForm(forms.Form):
+class ContactForm(forms.Form):
     email = forms.EmailField(label=_('E-mail'))
 
 

src/pretix/presale/signals.py

@@ -6,3 +6,8 @@ This signal is sent out to include code into the HTML <head> tag
 html_head = EventPluginSignal(
     providing_args=["request"]
 )
+
+"""
+This signal is sent out to retrieve pages for the checkout flow
+"""
+checkout_flow_steps = EventPluginSignal()

src/pretix/presale/templates/pretixpresale/event/checkout_confirm.html

@@ -10,7 +10,8 @@
         <div class="panel panel-primary cart">
             <div class="panel-heading">
                 <div class="pull-right">
-                    <a href="{% url "presale:event.index" organizer=request.event.organizer.slug  event=request.event.slug %}">
+                    <a href="
+                    {% url "presale:event.index" organizer=request.event.organizer.slug  event=request.event.slug %}">
                         <span class="fa fa-edit"></span>
                         {% trans "Modify" %}
                     </a>
@@ -39,12 +40,12 @@
             <div class="panel panel-primary">
                 <div class="panel-heading">
                     {% if payment_provider.identifier != "free" %}
-                    <div class="pull-right">
+                        <div class="pull-right">
-                        <a href="{% url "presale:event.checkout.payment" organizer=request.event.organizer.slug  event=request.event.slug %}">
+                            <a href="{% url "presale:event.checkout" step="payment" organizer=request.event.organizer.slug  event=request.event.slug %}">
-                            <span class="fa fa-edit"></span>
+                                <span class="fa fa-edit"></span>
-                            {% trans "Modify" %}
+                                {% trans "Modify" %}
-                        </a>
+                            </a>
-                    </div>
+                        </div>
                     {% endif %}
                     <h3 class="panel-title">
                         {% trans "Payment" %}
@@ -54,20 +55,41 @@
                     {{ payment }}
                 </div>
             </div>
-        </div>
+            <div class="row-fluid">
-        <div class="row checkout-button-row">
+                <div class="panel panel-primary panel-contact">
-			<div class="col-md-4">
+                    <div class="panel-heading">
-				<a class="btn btn-block btn-default btn-lg"
+                        <div class="pull-right">
-	   					href="{{ view.get_previous_url }}">
+                            <a href="{% url "presale:event.checkout" step="questions" organizer=request.event.organizer.slug  event=request.event.slug %}">
-					{% trans "Go back" %}
+                                <span class="fa fa-edit"></span>
-				</a>
+                                {% trans "Modify" %}
-			</div>
+                            </a>
-            <div class="col-md-4 col-md-offset-4">
+                        </div>
-                <button class="btn btn-block btn-primary btn-lg" type="submit">
+                        <h3 class="panel-title">
-                    {% trans "Place binding order" %}
+                            {% trans "Contact information" %}
-                </button>
+                        </h3>
+                    </div>
+                    <div class="panel-body">
+                        <dl class="dl-horizontal">
+                            <dt>{% trans "E-mail address" %}</dt>
+                            <dd>{{ request.session.email }}</dd>
+                        </dl>
+                    </div>
+                </div>
+            </div>
+            <div class="row checkout-button-row">
+                <div class="col-md-4">
+                    <a class="btn btn-block btn-default btn-lg"
+                            href="{{ prev_url }}">
+                        {% trans "Go back" %}
+                    </a>
+                </div>
+                <div class="col-md-4 col-md-offset-4">
+                    <button class="btn btn-block btn-primary btn-lg" type="submit">
+                        {% trans "Place binding order" %}
+                    </button>
+                </div>
+                <div class="clearfix"></div>
             </div>
-            <div class="clearfix"></div>
         </div>
     </form>
 {% endblock %}

src/pretix/presale/templates/pretixpresale/event/checkout_payment.html

@@ -34,7 +34,7 @@
         <div class="row checkout-button-row">
             <div class="col-md-4">
                 <a class="btn btn-block btn-default btn-lg"
-                        href="{{ view.get_previous_url }}">
+                        href="{{ prev_url }}">
                     {% trans "Go back" %}
                 </a>
             </div>

src/pretix/presale/templates/pretixpresale/event/checkout_questions.html

@@ -8,6 +8,20 @@
     <form class="form-horizontal" method="post">
         {% csrf_token %}
         <div class="panel-group" id="questions_accordion">
+            <div class="panel panel-default">
+                <div class="panel-heading">
+                    <h4 class="panel-title">
+                        <a data-toggle="collapse" href="#contact" data-parent="#questions_accordion">
+                            <strong>{% trans "Contact information" %}</strong>
+                        </a>
+                    </h4>
+                </div>
+                <div id="contact" class="panel-collapse collapsed in">
+                    <div class="panel-body">
+                        {% bootstrap_form contact_form layout="horizontal" %}
+                    </div>
+                </div>
+            </div>
             {% for form in forms %}
                 <div class="panel panel-default">
                     <div class="panel-heading">
@@ -22,7 +36,7 @@
                         </h4>
                     </div>
                     <div id="cp{{ form.pos.identity }}"
-                            class="panel-collapse collapsed {% if forloop.counter0 == 0 %}in{% endif %}">
+                            class="panel-collapse collapsed in">
                         <div class="panel-body">
                             {% bootstrap_form form layout="horizontal" %}
                         </div>
@@ -33,7 +47,7 @@
         <div class="row checkout-button-row">
             <div class="col-md-4">
                 <a class="btn btn-block btn-default btn-lg"
-                        href="{{ view.get_index_url }}">
+                        href="{{ prev_url }}">
                     {% trans "Go back" %}
                 </a>
             </div>

src/pretix/presale/urls.py

@@ -11,11 +11,9 @@ urlpatterns = [
         url(r'^$', pretix.presale.views.event.EventIndex.as_view(), name='event.index'),
         url(r'^cart/add$', pretix.presale.views.cart.CartAdd.as_view(), name='event.cart.add'),
         url(r'^cart/remove$', pretix.presale.views.cart.CartRemove.as_view(), name='event.cart.remove'),
-        url(r'^checkout$', pretix.presale.views.checkout.CheckoutStart.as_view(), name='event.checkout.start'),
+        url(r'^checkout/$', pretix.presale.views.checkout.CheckoutView.as_view(), name='event.checkout.start'),
-        url(r'^checkout/payment$', pretix.presale.views.checkout.PaymentDetails.as_view(),
+        url(r'^checkout/(?P<step>[^/]+)/$', pretix.presale.views.checkout.CheckoutView.as_view(),
-            name='event.checkout.payment'),
+            name='event.checkout'),
-        url(r'^checkout/confirm$', pretix.presale.views.checkout.OrderConfirm.as_view(),
-            name='event.checkout.confirm'),
         url(r'^order/(?P<order>[^/]+)/(?P<secret>[A-Za-z0-9]+)/$', pretix.presale.views.order.OrderDetails.as_view(),
             name='event.order'),
         url(r'^order/(?P<order>[^/]+)/(?P<secret>[A-Za-z0-9]+)/cancel$',

src/pretix/presale/views/__init__.py

@@ -32,7 +32,7 @@ class LoginRequiredMixin:
         return login_required(view)
 
 
-class CartDisplayMixin:
+class CartMixin:
     @cached_property
     def positions(self):
         """

src/pretix/presale/views/checkout.py

@@ -1,275 +1,37 @@
 from django.contrib import messages
 from django.core.urlresolvers import reverse
-from django.db.models import Q, Sum
+from django.http import Http404
-from django.http import HttpRequest
 from django.shortcuts import redirect
-from django.utils import translation
-from django.utils.functional import cached_property
 from django.utils.translation import ugettext_lazy as _
-from django.views.generic import TemplateView
+from django.views.generic import View
 
-from pretix.base.models import CartPosition, OrderPosition, QuestionAnswer
+from pretix.presale.checkoutflow import get_checkout_flow
-from pretix.base.services.orders import OrderError, perform_order
+from pretix.presale.views import CartMixin
-from pretix.base.signals import register_payment_providers
-from pretix.presale.forms.checkout import QuestionsForm
-from pretix.presale.views import CartDisplayMixin, EventViewMixin
 
 
-class CheckoutView(TemplateView):
+class CheckoutView(CartMixin, View):
-
+    def dispatch(self, request, *args, **kwargs):
-    def get_payment_url(self):
+        self.request = request
-        return reverse('presale:event.checkout.payment', kwargs={
-            'event': self.request.event.slug,
-            'organizer': self.request.event.organizer.slug,
-        })
-
-    def get_confirm_url(self):
-        return reverse('presale:event.checkout.confirm', kwargs={
-            'event': self.request.event.slug,
-            'organizer': self.request.event.organizer.slug,
-        })
-
-    def get_questions_url(self):
-        return reverse('presale:event.checkout.start', kwargs={
-            'event': self.request.event.slug,
-            'organizer': self.request.event.organizer.slug,
-        })
-
-    def get_index_url(self):
-        return reverse('presale:event.index', kwargs={
-            'event': self.request.event.slug,
-            'organizer': self.request.event.organizer.slug
-        })
-
-    def get_order_url(self, order):
-        return reverse('presale:event.order', kwargs={
-            'event': self.request.event.slug,
-            'organizer': self.request.event.organizer.slug,
-            'order': order.code,
-            'secret': order.secret
-        }) + '?thanks=yes'
-
-
-class QuestionsViewMixin:
-    @cached_property
-    def forms(self):
-        """
-        A list of forms with one form for each cart cart position that has questions
-        the user can answer. All forms have a custom prefix, so that they can all be
-        submitted at once.
-        """
-        formlist = []
-        for cr in self.positions:
-            cartpos = cr if isinstance(cr, CartPosition) else None
-            orderpos = cr if isinstance(cr, OrderPosition) else None
-            form = QuestionsForm(event=self.request.event,
-                                 prefix=cr.identity,
-                                 cartpos=cartpos,
-                                 orderpos=orderpos,
-                                 data=(self.request.POST if self.request.method == 'POST' else None))
-            form.pos = cartpos or orderpos
-            if len(form.fields) > 0:
-                formlist.append(form)
-        return formlist
-
-    def save(self):
-        failed = False
-        for form in self.forms:
-            # Every form represents a CartPosition or OrderPosition with questions attached
-            if not form.is_valid():
-                failed = True
-            else:
-                # This form was correctly filled, so we store the data as
-                # answers to the questions / in the CartPosition object
-                for k, v in form.cleaned_data.items():
-                    if k == 'attendee_name':
-                        form.pos = form.pos.clone()
-                        form.pos.attendee_name = v if v != '' else None
-                        form.pos.save()
-                    elif k.startswith('question_') and v is not None:
-                        field = form.fields[k]
-                        if hasattr(field, 'answer'):
-                            # We already have a cached answer object, so we don't
-                            # have to create a new one
-                            if v == '':
-                                field.answer.delete()
-                            else:
-                                field.answer = field.answer.clone()
-                                field.answer.answer = v
-                                field.answer.save()
-                        elif v != '':
-                            QuestionAnswer.objects.create(
-                                cartposition=(form.pos if isinstance(form.pos, CartPosition) else None),
-                                orderposition=(form.pos if isinstance(form.pos, OrderPosition) else None),
-                                question=field.question,
-                                answer=v
-                            )
-        return not failed
-
-
-class CheckoutStart(EventViewMixin, CartDisplayMixin, QuestionsViewMixin, CheckoutView):
-    template_name = "pretixpresale/event/checkout_questions.html"
-
-    def post(self, *args, **kwargs):
-        failed = not self.save()
-        if failed:
-            messages.error(self.request,
-                           _("We had difficulties processing your input. Please review the errors below."))
-            return self.get(*args, **kwargs)
-        return redirect(self.get_payment_url())
-
-    def get(self, *args, **kwargs):
         if not self.positions:
-            messages.error(self.request,
+            messages.error(request, _("Your cart is empty"))
-                           _("Your cart is empty"))
+            return redirect(reverse('presale:event.index', kwargs={
-            return redirect(self.get_index_url())
+                'organizer': self.request.event.organizer.slug,
+                'event': self.request.event.slug
+            }))
 
-        if not self.forms:
+        flow = get_checkout_flow(self.request.event)
-            # Nothing to do here
+        for step in flow:
-            if self.request.GET.get('back', 'false') == 'true':
+            if not step.is_applicable(request):
-                return redirect(self.get_index_url())
-            return redirect(self.get_payment_url())
-
-        return super().get(*args, **kwargs)
-
-    def get_context_data(self, **kwargs):
-        ctx = super().get_context_data(**kwargs)
-        ctx['forms'] = self.forms
-        return ctx
-
-
-class PaymentDetails(EventViewMixin, CartDisplayMixin, CheckoutView):
-    template_name = "pretixpresale/event/checkout_payment.html"
-
-    @cached_property
-    def _total_order_value(self):
-        return CartPosition.objects.current.filter(
-            Q(session=self.request.session.session_key) & Q(event=self.request.event)
-        ).aggregate(sum=Sum('price'))['sum']
-
-    @cached_property
-    def provider_forms(self):
-        providers = []
-        responses = register_payment_providers.send(self.request.event)
-        for receiver, response in responses:
-            provider = response(self.request.event)
-            if not provider.is_enabled or not provider.is_allowed(self.request):
                 continue
-            fee = provider.calculate_fee(self._total_order_value)
+            if 'step' not in kwargs:
-            providers.append({
+                return redirect(step.get_step_url())
-                'provider': provider,
+            is_selected = (step.identifier == kwargs.get('step', ''))
-                'fee': fee,
+            if not is_selected and not step.is_completed(request, warn=not is_selected):
-                'form': provider.payment_form_render(self.request),
+                return redirect(step.get_step_url())
-            })
+            if is_selected:
-        return providers
+                if request.method.lower() in self.http_method_names:
-
+                    handler = getattr(step, request.method.lower(), self.http_method_not_allowed)
-    def post(self, request, *args, **kwargs):
-        for p in self.provider_forms:
-            if p['provider'].identifier == request.POST.get('payment', ''):
-                request.session['payment'] = p['provider'].identifier
-                resp = p['provider'].checkout_prepare(
-                    request, self.get_cart(payment_fee=p['provider'].calculate_fee(self._total_order_value)))
-                if isinstance(resp, str):
-                    return redirect(resp)
-                elif resp is True:
-                    return redirect(self.get_confirm_url())
                 else:
-                    return self.get(request, *args, **kwargs)
+                    handler = self.http_method_not_allowed
-        messages.error(self.request, _("Please select a payment method."))
+                return handler(request)
-        return self.get(request, *args, **kwargs)
+        raise Http404()
-
-    def get(self, request, *args, **kwargs):
-        if self._total_order_value == 0:
-            request.session['payment'] = 'free'
-            return redirect(self.get_confirm_url())
-        return super().get(request, *args, **kwargs)
-
-    def get_context_data(self, **kwargs):
-        ctx = super().get_context_data(**kwargs)
-        ctx['providers'] = self.provider_forms
-        ctx['selected'] = self.request.POST.get('payment', self.request.session.get('payment', ''))
-        return ctx
-
-    def get_previous_url(self):
-        return self.get_questions_url() + "?back=true"
-
-
-class OrderConfirm(EventViewMixin, CartDisplayMixin, CheckoutView):
-    template_name = "pretixpresale/event/checkout_confirm.html"
-
-    def __init__(self, *args, **kwargs):
-        self.msg_some_unavailable = False
-        super().__init__(*args, **kwargs)
-
-    def get_context_data(self, **kwargs):
-        ctx = super().get_context_data(**kwargs)
-        ctx['cart'] = self.get_cart(answers=True)
-        ctx['payment'] = self.payment_provider.checkout_confirm_render(self.request)
-        ctx['payment_provider'] = self.payment_provider
-        return ctx
-
-    @cached_property
-    def payment_provider(self):
-        responses = register_payment_providers.send(self.request.event)
-        for receiver, response in responses:
-            provider = response(self.request.event)
-            if provider.identifier == self.request.session['payment']:
-                return provider
-
-    def check_process(self, request):
-        if len(self.positions) == 0:
-            messages.warning(request, _('Your cart is empty.'))
-            return redirect(self.get_index_url())
-        if 'payment' not in request.session or not self.payment_provider:
-            messages.error(request, _('The payment information you entered was incomplete.'))
-            return redirect(self.get_payment_url())
-        if not self.payment_provider.payment_is_valid_session(request) or \
-                not self.payment_provider.is_enabled or \
-                not self.payment_provider.is_allowed(request):
-            messages.error(request, _('The payment information you entered was incomplete.'))
-            return redirect(self.get_payment_url())
-        for cp in self.positions:
-            answ = {
-                aw.question_id: aw.answer for aw in cp.answers.all()
-            }
-            for q in cp.item.questions.all():
-                if q.required and q.identity not in answ:
-                    messages.warning(request, _('Please fill in answers to all required questions.'))
-                    return redirect(self.get_questions_url())
-            if cp.item.admission and self.request.event.settings.get('attendee_names_required', as_type=bool) \
-                    and cp.attendee_name is None:
-                messages.warning(request, _('Please fill in answers to all required questions.'))
-                return redirect(self.get_questions_url())
-
-    def get(self, request, *args, **kwargs):
-        self.request = request
-        return self.check_process(request) or super().get(request, *args, **kwargs)
-
-    def error_message(self, msg, important=False):
-        if not self.msg_some_unavailable or important:
-            self.msg_some_unavailable = True
-            messages.error(self.request, msg)
-
-    def post(self, request, *args, **kwargs):
-        self.request = request
-        return self.check_process(request) or self.perform_order(request)
-
-    def perform_order(self, request: HttpRequest):
-        try:
-            order = perform_order(self.request.event, self.payment_provider, self.positions,
-                                  email=request.session.get('guest_email', None),
-                                  locale=translation.get_language())
-        except OrderError as e:
-            messages.error(request, str(e))
-            return redirect(self.get_confirm_url())
-        else:
-            # Message is delivered via GET parameter
-            # messages.success(request, _('Your order has been placed.'))
-            resp = self.payment_provider.payment_perform(request, order)
-            return redirect(resp or self.get_order_url(order))
-
-    def get_previous_url(self):
-        if self.payment_provider.identifier != "free":
-            return self.get_payment_url()
-        else:
-            return self.get_questions_url() + "?back=true"

src/pretix/presale/views/event.py

@@ -1,10 +1,10 @@
 from django.db.models import Count
 from django.views.generic import TemplateView
 
-from pretix.presale.views import CartDisplayMixin, EventViewMixin
+from pretix.presale.views import CartMixin, EventViewMixin
 
 
-class EventIndex(EventViewMixin, CartDisplayMixin, TemplateView):
+class EventIndex(EventViewMixin, CartMixin, TemplateView):
     template_name = "pretixpresale/event/index.html"
 
     def get_context_data(self, **kwargs):

src/pretix/presale/views/order.py

@@ -14,8 +14,8 @@ from pretix.base.services.tickets import generate
 from pretix.base.signals import (
     register_payment_providers, register_ticket_outputs,
 )
-from pretix.presale.views import CartDisplayMixin, EventViewMixin
+from pretix.presale.views import CartMixin, EventViewMixin
-from pretix.presale.views.checkout import QuestionsViewMixin
+from pretix.presale.views.questions import QuestionsViewMixin
 
 
 class OrderDetailMixin:
@@ -44,7 +44,7 @@ class OrderDetailMixin:
         })
 
 
-class OrderDetails(EventViewMixin, OrderDetailMixin, CartDisplayMixin, TemplateView):
+class OrderDetails(EventViewMixin, OrderDetailMixin, CartMixin, TemplateView):
     template_name = "pretixpresale/event/order.html"
 
     def get(self, request, *args, **kwargs):

src/pretix/presale/views/questions.py

@@ -0,0 +1,61 @@
+from django.utils.functional import cached_property
+
+from pretix.base.models import CartPosition, OrderPosition, QuestionAnswer
+from pretix.presale.forms.checkout import QuestionsForm
+
+
+class QuestionsViewMixin:
+    @cached_property
+    def forms(self):
+        """
+        A list of forms with one form for each cart cart position that has questions
+        the user can answer. All forms have a custom prefix, so that they can all be
+        submitted at once.
+        """
+        formlist = []
+        for cr in self.positions:
+            cartpos = cr if isinstance(cr, CartPosition) else None
+            orderpos = cr if isinstance(cr, OrderPosition) else None
+            form = QuestionsForm(event=self.request.event,
+                                 prefix=cr.identity,
+                                 cartpos=cartpos,
+                                 orderpos=orderpos,
+                                 data=(self.request.POST if self.request.method == 'POST' else None))
+            form.pos = cartpos or orderpos
+            if len(form.fields) > 0:
+                formlist.append(form)
+        return formlist
+
+    def save(self):
+        failed = False
+        for form in self.forms:
+            # Every form represents a CartPosition or OrderPosition with questions attached
+            if not form.is_valid():
+                failed = True
+            else:
+                # This form was correctly filled, so we store the data as
+                # answers to the questions / in the CartPosition object
+                for k, v in form.cleaned_data.items():
+                    if k == 'attendee_name':
+                        form.pos = form.pos.clone()
+                        form.pos.attendee_name = v if v != '' else None
+                        form.pos.save()
+                    elif k.startswith('question_') and v is not None:
+                        field = form.fields[k]
+                        if hasattr(field, 'answer'):
+                            # We already have a cached answer object, so we don't
+                            # have to create a new one
+                            if v == '':
+                                field.answer.delete()
+                            else:
+                                field.answer = field.answer.clone()
+                                field.answer.answer = v
+                                field.answer.save()
+                        elif v != '':
+                            QuestionAnswer.objects.create(
+                                cartposition=(form.pos if isinstance(form.pos, CartPosition) else None),
+                                orderposition=(form.pos if isinstance(form.pos, OrderPosition) else None),
+                                question=field.question,
+                                answer=v
+                            )
+        return not failed

src/static/pretixpresale/less/event.less

@@ -67,6 +67,9 @@
         }
     }
 }
+.panel-contact dl {
+    margin-bottom: 0;
+}
 .panel-primary .panel-heading a {
     color: white;
 }

src/tests/presale/test_checkout.py

@@ -31,25 +31,13 @@ class CheckoutTestCase(TestCase):
 
         self.client.get('/%s/%s/' % (self.orga.slug, self.event.slug))
         self.session_key = self.client.cookies.get(settings.SESSION_COOKIE_NAME).value
+        self._set_session('email', 'admin@localhost')
 
     def test_empty_cart(self):
-        response = self.client.get('/%s/%s/checkout' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.get('/%s/%s/checkout/' % (self.orga.slug, self.event.slug), follow=True)
         self.assertRedirects(response, '/%s/%s/' % (self.orga.slug, self.event.slug),
                              target_status_code=200)
 
-    def test_no_questions(self):
-        CartPosition.objects.create(
-            event=self.event, session=self.session_key, item=self.ticket,
-            price=23, expires=now() + timedelta(minutes=10)
-        )
-        CartPosition.objects.create(
-            event=self.event, session=self.session_key, item=self.ticket,
-            price=20, expires=now() + timedelta(minutes=10)
-        )
-        response = self.client.get('/%s/%s/checkout' % (self.orga.slug, self.event.slug), follow=True)
-        self.assertRedirects(response, '/%s/%s/checkout/payment' % (self.orga.slug, self.event.slug),
-                             target_status_code=200)
-
     def test_questions(self):
         q1 = Question.objects.create(
             event=self.event, question='Age', type=Question.TYPE_NUMBER,
@@ -69,7 +57,7 @@ class CheckoutTestCase(TestCase):
             event=self.event, session=self.session_key, item=self.ticket,
             price=20, expires=now() + timedelta(minutes=10)
         )
-        response = self.client.get('/%s/%s/checkout' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.get('/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug), follow=True)
         doc = BeautifulSoup(response.rendered_content)
 
         self.assertEqual(len(doc.select('input[name=%s-question_%s]' % (cr1.identity, q1.identity))), 1)
@@ -78,23 +66,25 @@ class CheckoutTestCase(TestCase):
         self.assertEqual(len(doc.select('input[name=%s-question_%s]' % (cr2.identity, q2.identity))), 1)
 
         # Not all required fields filled out, expect failure
-        response = self.client.post('/%s/%s/checkout' % (self.orga.slug, self.event.slug), {
+        response = self.client.post('/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug), {
             '%s-question_%s' % (cr1.identity, q1.identity): '42',
             '%s-question_%s' % (cr2.identity, q1.identity): '',
             '%s-question_%s' % (cr1.identity, q2.identity): 'Internet',
             '%s-question_%s' % (cr2.identity, q2.identity): '',
+            'email': 'admin@localhost'
         }, follow=True)
         doc = BeautifulSoup(response.rendered_content)
         self.assertGreaterEqual(len(doc.select('.has-error')), 1)
 
         # Corrected request
-        response = self.client.post('/%s/%s/checkout' % (self.orga.slug, self.event.slug), {
+        response = self.client.post('/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug), {
             '%s-question_%s' % (cr1.identity, q1.identity): '42',
             '%s-question_%s' % (cr2.identity, q1.identity): '23',
             '%s-question_%s' % (cr1.identity, q2.identity): 'Internet',
             '%s-question_%s' % (cr2.identity, q2.identity): '',
+            'email': 'admin@localhost'
         }, follow=True)
-        self.assertRedirects(response, '/%s/%s/checkout/payment' % (self.orga.slug, self.event.slug),
+        self.assertRedirects(response, '/%s/%s/checkout/payment/' % (self.orga.slug, self.event.slug),
                              target_status_code=200)
 
         cr1 = CartPosition.objects.current.get(identity=cr1.identity)
@@ -111,22 +101,24 @@ class CheckoutTestCase(TestCase):
             event=self.event, session=self.session_key, item=self.ticket,
             price=23, expires=now() + timedelta(minutes=10)
         )
-        response = self.client.get('/%s/%s/checkout' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.get('/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug), follow=True)
         doc = BeautifulSoup(response.rendered_content)
         self.assertEqual(len(doc.select('input[name=%s-attendee_name]' % cr1.identity)), 1)
 
         # Not all required fields filled out, expect failure
-        response = self.client.post('/%s/%s/checkout' % (self.orga.slug, self.event.slug), {
+        response = self.client.post('/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug), {
             '%s-attendee_name' % cr1.identity: '',
+            'email': 'admin@localhost'
         }, follow=True)
         doc = BeautifulSoup(response.rendered_content)
         self.assertGreaterEqual(len(doc.select('.has-error')), 1)
 
         # Corrected request
-        response = self.client.post('/%s/%s/checkout' % (self.orga.slug, self.event.slug), {
+        response = self.client.post('/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug), {
             '%s-attendee_name' % cr1.identity: 'Peter',
+            'email': 'admin@localhost'
         }, follow=True)
-        self.assertRedirects(response, '/%s/%s/checkout/payment' % (self.orga.slug, self.event.slug),
+        self.assertRedirects(response, '/%s/%s/checkout/payment/' % (self.orga.slug, self.event.slug),
                              target_status_code=200)
 
         cr1 = CartPosition.objects.current.get(identity=cr1.identity)
@@ -139,15 +131,16 @@ class CheckoutTestCase(TestCase):
             event=self.event, session=self.session_key, item=self.ticket,
             price=23, expires=now() + timedelta(minutes=10)
         )
-        response = self.client.get('/%s/%s/checkout' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.get('/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug), follow=True)
         doc = BeautifulSoup(response.rendered_content)
         self.assertEqual(len(doc.select('input[name=%s-attendee_name]' % cr1.identity)), 1)
 
         # Not all fields filled out, expect success
-        response = self.client.post('/%s/%s/checkout' % (self.orga.slug, self.event.slug), {
+        response = self.client.post('/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug), {
             '%s-attendee_name' % cr1.identity: '',
+            'email': 'admin@localhost'
         }, follow=True)
-        self.assertRedirects(response, '/%s/%s/checkout/payment' % (self.orga.slug, self.event.slug),
+        self.assertRedirects(response, '/%s/%s/checkout/payment/' % (self.orga.slug, self.event.slug),
                              target_status_code=200)
 
         cr1 = CartPosition.objects.current.get(identity=cr1.identity)
@@ -161,17 +154,17 @@ class CheckoutTestCase(TestCase):
             event=self.event, session=self.session_key, item=self.ticket,
             price=23, expires=now() + timedelta(minutes=10)
         )
-        response = self.client.get('/%s/%s/checkout/payment' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.get('/%s/%s/checkout/payment/' % (self.orga.slug, self.event.slug), follow=True)
         doc = BeautifulSoup(response.rendered_content)
         self.assertEqual(len(doc.select('input[name=payment]')), 2)
-        response = self.client.post('/%s/%s/checkout/payment' % (self.orga.slug, self.event.slug), {
+        response = self.client.post('/%s/%s/checkout/payment/' % (self.orga.slug, self.event.slug), {
             'payment': 'banktransfer'
         }, follow=True)
-        self.assertRedirects(response, '/%s/%s/checkout/confirm' % (self.orga.slug, self.event.slug),
+        self.assertRedirects(response, '/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug),
                              target_status_code=200)
 
     def test_premature_confirm(self):
-        response = self.client.get('/%s/%s/checkout/confirm' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.get('/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug), follow=True)
         self.assertRedirects(response, '/%s/%s/' % (self.orga.slug, self.event.slug),
                              target_status_code=200)
 
@@ -182,8 +175,8 @@ class CheckoutTestCase(TestCase):
             price=23, expires=now() + timedelta(minutes=10)
         )
 
-        response = self.client.get('/%s/%s/checkout/confirm' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.get('/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug), follow=True)
-        self.assertRedirects(response, '/%s/%s/checkout/payment' % (self.orga.slug, self.event.slug),
+        self.assertRedirects(response, '/%s/%s/checkout/payment/' % (self.orga.slug, self.event.slug),
                              target_status_code=200)
 
         self._set_session('payment', 'banktransfer')
@@ -191,8 +184,8 @@ class CheckoutTestCase(TestCase):
         self.event.settings.set('attendee_names_asked', True)
         self.event.settings.set('attendee_names_required', True)
 
-        response = self.client.get('/%s/%s/checkout/confirm' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.get('/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug), follow=True)
-        self.assertRedirects(response, '/%s/%s/checkout' % (self.orga.slug, self.event.slug),
+        self.assertRedirects(response, '/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug),
                              target_status_code=200)
 
         cr1 = cr1.clone()
@@ -204,16 +197,21 @@ class CheckoutTestCase(TestCase):
         )
         self.ticket.questions.add(q1)
 
-        response = self.client.get('/%s/%s/checkout/confirm' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.get('/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug), follow=True)
-        self.assertRedirects(response, '/%s/%s/checkout' % (self.orga.slug, self.event.slug),
+        self.assertRedirects(response, '/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug),
                              target_status_code=200)
 
         q1 = q1.clone()
         q1.required = False
         q1.save()
-        response = self.client.get('/%s/%s/checkout/confirm' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.get('/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug), follow=True)
         self.assertEqual(response.status_code, 200)
 
+        self._set_session('email', 'invalid')
+        response = self.client.get('/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug), follow=True)
+        self.assertRedirects(response, '/%s/%s/checkout/questions/' % (self.orga.slug, self.event.slug),
+                             target_status_code=200)
+
     def _set_session(self, key, value):
         session = self.client.session
         session[key] = value
@@ -226,7 +224,7 @@ class CheckoutTestCase(TestCase):
         )
         self._set_session('payment', 'banktransfer')
 
-        response = self.client.post('/%s/%s/checkout/confirm' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.post('/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug), follow=True)
         doc = BeautifulSoup(response.rendered_content)
         self.assertEqual(len(doc.select(".thank-you")), 1)
         self.assertFalse(CartPosition.objects.current.filter(identity=cr1.identity).exists())
@@ -240,7 +238,7 @@ class CheckoutTestCase(TestCase):
         )
         self._set_session('payment', 'banktransfer')
 
-        response = self.client.post('/%s/%s/checkout/confirm' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.post('/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug), follow=True)
         doc = BeautifulSoup(response.rendered_content)
         self.assertEqual(len(doc.select(".thank-you")), 1)
         self.assertFalse(CartPosition.objects.current.filter(identity=cr1.identity).exists())
@@ -257,7 +255,7 @@ class CheckoutTestCase(TestCase):
         )
         self._set_session('payment', 'banktransfer')
 
-        response = self.client.post('/%s/%s/checkout/confirm' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.post('/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug), follow=True)
         doc = BeautifulSoup(response.rendered_content)
         self.assertEqual(len(doc.select(".alert-danger")), 1)
         cr1 = CartPosition.objects.current.get(identity=cr1.identity)
@@ -276,7 +274,7 @@ class CheckoutTestCase(TestCase):
         )
         self._set_session('payment', 'banktransfer')
 
-        response = self.client.post('/%s/%s/checkout/confirm' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.post('/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug), follow=True)
         doc = BeautifulSoup(response.rendered_content)
         self.assertEqual(len(doc.select(".alert-danger")), 1)
         self.assertEqual(CartPosition.objects.current.filter(session=self.session_key).count(), 1)
@@ -291,9 +289,9 @@ class CheckoutTestCase(TestCase):
         )
         self._set_session('payment', 'banktransfer')
 
-        response = self.client.post('/%s/%s/checkout/confirm' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.post('/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug), follow=True)
         doc = BeautifulSoup(response.rendered_content)
-        self.assertEqual(len(doc.select(".alert-danger")), 1)
+        self.assertGreaterEqual(len(doc.select(".alert-danger")), 1)
         self.assertFalse(CartPosition.objects.current.filter(identity=cr1.identity).exists())
 
     def test_confirm_expired_unavailable(self):
@@ -305,19 +303,20 @@ class CheckoutTestCase(TestCase):
         )
         self._set_session('payment', 'banktransfer')
 
-        response = self.client.post('/%s/%s/checkout/confirm' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.post('/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug), follow=True)
         doc = BeautifulSoup(response.rendered_content)
-        self.assertEqual(len(doc.select(".alert-danger")), 1)
+        self.assertGreaterEqual(len(doc.select(".alert-danger")), 1)
         self.assertFalse(CartPosition.objects.current.filter(identity=cr1.identity).exists())
 
     def test_confirm_completely_unavailable(self):
         self.quota_tickets.items.remove(self.ticket)
-        CartPosition.objects.create(
+        cr1 = CartPosition.objects.create(
             event=self.event, session=self.session_key, item=self.ticket,
             price=23, expires=now() - timedelta(minutes=10)
         )
         self._set_session('payment', 'banktransfer')
 
-        response = self.client.post('/%s/%s/checkout/confirm' % (self.orga.slug, self.event.slug), follow=True)
+        response = self.client.post('/%s/%s/checkout/confirm/' % (self.orga.slug, self.event.slug), follow=True)
         doc = BeautifulSoup(response.rendered_content)
-        self.assertEqual(len(doc.select(".alert-danger")), 1)
+        self.assertGreaterEqual(len(doc.select(".alert-danger")), 1)
+        self.assertFalse(CartPosition.objects.current.filter(identity=cr1.identity).exists())