Added a payment provider for free products

doc/development/api/payment.rst

@@ -66,6 +66,8 @@ The provider class
 
    .. automethod:: checkout_form
 
+   .. automethod:: is_allowed
+
    .. autoattribute:: checkout_form_fields
 
    .. automethod:: checkout_prepare

src/locale/de/LC_MESSAGES/django.po

@@ -8,7 +8,7 @@ msgstr ""
 "Project-Id-Version: 1\n"
 "Report-Msgid-Bugs-To: \n"
 "POT-Creation-Date: 2015-06-21 19:18+0000\n"
-"PO-Revision-Date: 2015-06-21 21:19+0100\n"
+"PO-Revision-Date: 2015-06-23 09:51+0100\n"
 "Last-Translator: Raphael Michel <michel@rami.io>\n"
 "Language-Team: Raphael Michel <michel@rami.io>\n"
 "Language: de\n"
@@ -1483,7 +1483,7 @@ msgstr "Als nicht bezahlt markieren"
 #: pretix/control/templates/pretixcontrol/order/refund.html:4
 #: pretix/control/templates/pretixcontrol/order/refund.html:8
 msgid "Refund order"
-msgstr "Bestellung erstatteten"
+msgstr "Bestellung erstatten"
 
 #: pretix/control/templates/pretixcontrol/order/index.html:42
 #: pretix/presale/templates/pretixpresale/event/order.html:65

src/pretix/base/payment.py

@@ -2,15 +2,19 @@ from collections import OrderedDict
 from decimal import Decimal
 from django import forms
 from django.contrib import messages
+from django.db.models import Sum, Q
+from django.dispatch import receiver
 
 from django.forms import Form
 from django.http import HttpRequest
 from django.template.loader import get_template
 from django.utils.translation import ugettext_lazy as _
 from pretix.base.forms import SettingsForm
-from pretix.base.models import Order
+from pretix.base.models import Order, CartPosition
+from pretix.base.services.orders import mark_order_paid
 
 from pretix.base.settings import SettingsSandbox
+from pretix.base.signals import register_payment_providers
 
 
 class BasePaymentProvider:
@@ -154,6 +158,16 @@ class BasePaymentProvider:
         form.fields = self.checkout_form_fields
         return form
 
+    def is_allowed(self, request: HttpRequest) -> bool:
+        """
+        You can use this method to disable this payment provider for certain groups
+        of users, products or other criteria. If this method returns ``False``, the
+        user will not be able to select this payment method.
+
+        The default implementation always returns ``True``.
+        """
+        return True
+
     def checkout_form_render(self, request: HttpRequest) -> str:
         """
         When the user selects this provider as his prefered payment method,
@@ -243,7 +257,7 @@ class BasePaymentProvider:
         containing an URL the user will be redirected to. If you are done with your process
         you should return the user to the order's detail page.
 
-        If the payment is completed, you should call ``pretix.bsae.services.orders.mark_order_paid(order, provider, info)``
+        If the payment is completed, you should call ``pretix.base.services.orders.mark_order_paid(order, provider, info)``
         with ``provider`` being your :py:attr:`identifier` and ``info`` being any string
         you might want to store for later usage. Please note, that if you want to store
         something inside ``order.payment_info``, please do it after the ``mark_order_paid`` call,
@@ -345,3 +359,67 @@ class BasePaymentProvider:
         order.mark_refunded()
         messages.success(request, _('The order has been marked as refunded. Please transfer the money '
                                     'back to the buyer manually.'))
+
+
+class FreeOrderProvider(BasePaymentProvider):
+
+    @property
+    def is_enabled(self) -> bool:
+        return True
+
+    @property
+    def identifier(self) -> str:
+        return "free"
+
+    def checkout_confirm_render(self, request) -> str:
+        return _("No payment is required as this order only includes products which are free of charge.")
+
+    def order_pending_render(self, request: HttpRequest, order: Order) -> str:
+        pass
+
+    def checkout_is_valid_session(self, request: HttpRequest) -> bool:
+        return True
+
+    @property
+    def verbose_name(self) -> str:
+        return _("Free of charge")
+
+    def checkout_perform(self, request: HttpRequest, order: Order):
+        mark_order_paid(order, 'free')
+
+    @property
+    def settings_form_fields(self) -> dict:
+        return {}
+
+    def order_control_refund_render(self, order: Order) -> str:
+        return ''
+
+    def order_control_refund_perform(self, request: HttpRequest, order: Order) -> "bool|str":
+        """
+        Will be called if the event administrator confirms the refund.
+
+        This should transfer the money back (if possible). You can return an URL the
+        user should be redirected to if you need special behaviour or None to continue
+        with default behaviour.
+
+        On failure, you should use Django's message framework to display an error message
+        to the user.
+
+        The default implementation sets the Orders state to refunded and shows a success
+        message.
+
+        :param request: The HTTP request
+        :param order: The order object
+        """
+        order.mark_refunded()
+        messages.success(request, _('The order has been marked as refunded.'))
+
+    def is_allowed(self, request: HttpRequest) -> bool:
+        return CartPosition.objects.current.filter(
+            Q(user=request.user) & Q(event=request.event)
+        ).aggregate(sum=Sum('price'))['sum'] == 0
+
+
+@receiver(register_payment_providers)
+def register_payment_provider(sender, **kwargs):
+    return FreeOrderProvider

src/pretix/base/signals.py

@@ -29,6 +29,7 @@ class EventPluginSignal(django.dispatch.Signal):
             # Find the Django application this belongs to
             searchpath = receiver.__module__
             app = None
+            mod = None
             while "." in searchpath:
                 try:
                     if apps.is_installed(searchpath):
@@ -37,8 +38,8 @@ class EventPluginSignal(django.dispatch.Signal):
                     pass
                 searchpath, mod = searchpath.rsplit(".", 1)
 
-            # Only fire receivers from active plugins
+            # Only fire receivers from active plugins and core modules
-            if app.name in sender.get_plugins():
+            if (searchpath, mod) == ("pretix", "base") or (app and app.name in sender.get_plugins()):
                 if not hasattr(app, 'compatibility_errors') or not app.compatibility_errors:
                     response = receiver(signal=self, sender=sender, **named)
                     responses.append((receiver, response))

src/pretix/control/views/event.py

@@ -136,7 +136,9 @@ class PaymentSettings(EventPermissionRequiredMixin, TemplateView, SingleObjectMi
             )
             provider.settings_content = provider.settings_content_render(self.request)
             provider.form.prepare_fields()
-            providers.append(provider)
+            if provider.settings_content or provider.form.fields:
+                # Exclude providers which do not provide any settings
+                providers.append(provider)
         return providers
 
     def get_context_data(self, *args, **kwargs) -> dict:

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

@@ -35,16 +35,17 @@
                 </div>
             </div>
         </div>
-        {# TODO: Question answers #}
         <div class="row-fluid">
             <div class="panel panel-primary">
                 <div class="panel-heading">
+                    {% if payment_provider.identifier != "free" %}
                     <div class="pull-right">
                         <a href="{% url "presale:event.checkout.payment" organizer=request.event.organizer.slug  event=request.event.slug %}">
                             <span class="fa fa-edit"></span>
                             {% trans "Modify" %}
                         </a>
                     </div>
+                    {% endif %}
                     <h3 class="panel-title">
                         {% trans "Payment" %}
                     </h3>
@@ -57,7 +58,7 @@
         <div class="row checkout-button-row">
 			<div class="col-md-4">
 				<a class="btn btn-block btn-default btn-lg"
-	   					href="{{ view.get_payment_url }}">
+	   					href="{{ view.get_previous_url }}">
 					{% trans "Go back" %}
 				</a>
 			</div>

src/pretix/presale/views/checkout.py

@@ -153,7 +153,7 @@ class PaymentDetails(EventViewMixin, CartDisplayMixin, EventLoginRequiredMixin,
         responses = register_payment_providers.send(self.request.event)
         for receiver, response in responses:
             provider = response(self.request.event)
-            if not provider.is_enabled:
+            if not provider.is_enabled or not provider.is_allowed(self.request):
                 continue
             fee = provider.calculate_fee(self._total_order_value)
             providers.append({
@@ -178,6 +178,12 @@ class PaymentDetails(EventViewMixin, CartDisplayMixin, EventLoginRequiredMixin,
         messages.error(self.request, _("Please select a payment method."))
         return self.get(request, *args, **kwargs)
 
+    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
@@ -208,6 +214,7 @@ class OrderConfirm(EventViewMixin, CartDisplayMixin, EventLoginRequiredMixin, Ch
         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
@@ -225,7 +232,9 @@ class OrderConfirm(EventViewMixin, CartDisplayMixin, EventLoginRequiredMixin, Ch
         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.checkout_is_valid_session(request):
+        if not self.payment_provider.checkout_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:
@@ -348,3 +357,7 @@ class OrderConfirm(EventViewMixin, CartDisplayMixin, EventLoginRequiredMixin, Ch
         )
         OrderPosition.transform_cart_positions(cartpos, order)
         return order
+
+    def get_previous_url(self):
+        if self.payment_provider != "free":
+            return self.get_payment_url()