Allow payment providers to define custom form fields / templates

src/pretix/base/payment.py

@@ -1,5 +1,9 @@
 from decimal import Decimal
 
+from django.forms import Form
+from django.template import Context
+from django.template.loader import get_template
+
 from pretix.base.settings import SettingsSandbox
 
 
@@ -50,6 +54,41 @@ class BasePaymentProvider:
     def settings_form_fields(self) -> dict:
         """
         A dictionary. The keys should be (unprefixed) EventSetting keys,
-        the values should be corresponding django form fields
+        the values should be corresponding django form fields.
+
+        We suggest returning a collections.OrderedDict object instead of a dict.
         """
         raise NotImplementedError()
+
+    @property
+    def checkout_form_fields(self) -> dict:
+        """
+        A dictionary. The keys should be unprefixed field names,
+        the values should be corresponding django form fields.
+
+        We suggest returning a collections.OrderedDict object instead of a dict.
+        """
+        # TODO: Proper handling of required=True fields in HTML
+        return {}
+
+    def checkout_form(self, request) -> Form:
+        """
+        Returns the Form object of the form that should be displayed when the
+        user selects this provider as his payment method.
+        """
+        form = Form(
+            data=(request.POST if request.method == 'POST' else None),
+            prefix='payment_%s' % self.identifier
+        )
+        form.fields = self.checkout_form_fields
+        return form
+
+    def checkout_form_render(self, request) -> str:
+        """
+        Returns the HTML of the form that should be displayed when the user
+        selects this provider as his payment method.
+        """
+        form = self.checkout_form(request)
+        template = get_template('pretixpresale/event/checkout_payment_form_default.html')
+        ctx = Context({'request': request, 'form': form})
+        return template.render(ctx)

src/pretix/control/templates/pretixcontrol/event/payment.html

@@ -24,6 +24,8 @@
 						{%  bootstrap_form provider.form layout='horizontal' %}
 					</div>
 				</div>
+            {% empty %}
+                <em>{% trans "There are no payment providers available. Please go to the plugin settings and activate one or more payment plugins." %}</em>
 			{% endfor %}
 		</fieldset>
         <div class="form-group submit-group">

src/pretix/plugins/banktransfer/payment.py

@@ -1,4 +1,6 @@
 from collections import OrderedDict
+from django.template import Context
+from django.template.loader import get_template
 from django.utils.translation import ugettext_lazy as _
 from django import forms
 
@@ -16,3 +18,8 @@ class BankTransfer(BasePaymentProvider):
              required=False
          ))
     ])
+
+    def checkout_form_render(self, request) -> str:
+        template = get_template('pretixplugins/banktransfer/checkout_payment_form.html')
+        ctx = Context({'request': request, 'event': self.event, 'settings': self.settings})
+        return template.render(ctx)

src/pretix/plugins/banktransfer/templates/pretixplugins/banktransfer/checkout_payment_form.html

@@ -0,0 +1,10 @@
+{% load i18n %}
+
+<p>{% blocktrans trimmed %}
+    After completing your purchase, we will ask you to transfer the money to the following
+    bank account, using a personal reference code.
+{% endblocktrans %}</p>
+
+<address>
+    {{ settings.bank_details|linebreaksbr }}
+</address>

src/pretix/plugins/stripe/payment.py

@@ -10,3 +10,10 @@ class Stripe(BasePaymentProvider):
     verbose_name = _('Credit Card via Stripe')
     settings_form_fields = OrderedDict([
     ])
+    checkout_form_fields = OrderedDict([
+        ('cc_number',
+         forms.CharField(
+             label=_('Credit card number'),
+             required=False
+         ))
+    ])

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

@@ -23,6 +23,7 @@
                     </div>
                     <div id="payment_{{ p.provider.identifier }}" class="panel-collapse collapse">
                         <div class="panel-body form-horizontal">
+                            {{ p.form }}
                         </div>
                     </div>
                 </div>

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

@@ -0,0 +1,2 @@
+{% load bootstrap3 %}
+{% bootstrap_form form layout='horizontal' %}

src/pretix/presale/views/checkout.py

@@ -218,6 +218,7 @@ class PaymentDetails(EventViewMixin, CartDisplayMixin, EventLoginRequiredMixin,
             providers.append({
                 'provider': provider,
                 'fee': fee,
+                'form': provider.checkout_form_render(self.request),
             })
         return providers