Add payment provider PayPal

src/pretix/plugins/paypal/__init__.py

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+from django.apps import AppConfig
+from django.utils.translation import ugettext_lazy as _
+from pretix.base.plugins import PluginType
+
+
+class PaypalApp(AppConfig):
+    name = 'pretix.plugins.paypal'
+    verbose_name = _("Stripe")
+
+    class PretixPluginMeta:
+        type = PluginType.PAYMENT
+        name = _("PayPal")
+        author = _("the pretix team")
+        version = '1.0.0'
+        description = _("This plugin allows you to receive payments via PayPal")
+
+    def ready(self):
+        from . import signals  # NOQA
+
+
+default_app_config = 'pretix.plugins.paypal.PaypalApp'

src/pretix/plugins/paypal/payment.py

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+from collections import OrderedDict
+import json
+import logging
+from django.contrib import messages
+from django.core.urlresolvers import reverse
+from django.template import Context
+from django.template.loader import get_template
+from django.utils.functional import cached_property
+from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import ugettext as __
+from django import forms
+
+import paypalrestsdk
+
+from pretix.base.payment import BasePaymentProvider
+
+
+logger = logging.getLogger('pretix.plugins.paypal')
+
+
+class Paypal(BasePaymentProvider):
+
+    identifier = 'paypal'
+    verbose_name = _('PayPal')
+    settings_form_fields = OrderedDict([
+        ('client_id',
+         forms.CharField(
+             label=_('Client ID'),
+             required=False
+         )),
+        ('endpoint',
+         forms.CharField(
+             label=_('Endpoint'),
+             initial='api.paypal.com',
+             required=False
+         )),
+        ('secret',
+         forms.CharField(
+             label=_('Secret'),
+             required=False
+         ))
+    ])
+    checkout_form_fields = OrderedDict([
+    ])
+
+    def init_api(self):
+        paypalrestsdk.set_config(
+            mode="sandbox" if "sandbox" in self.settings.get('endpoint') else 'live',
+            client_id=self.settings.get('client_id'),
+            client_secret=self.settings.get('secret'))
+
+    def checkout_is_valid_session(self, request):
+        return (request.session.get('payment_paypal_id', '') != ''
+                and request.session.get('payment_paypal_payer', '') != '')
+
+    def checkout_form_render(self, request) -> str:
+        template = get_template('pretixplugins/paypal/checkout_payment_form.html')
+        ctx = Context({'request': request, 'event': self.event, 'settings': self.settings})
+        return template.render(ctx)
+
+    def checkout_prepare(self, request, cart):
+        self.init_api()
+        items = []
+        for cp in cart['positions']:
+            items.append({
+                "name": cp.item.name,
+                "description": str(cp.variation) if cp.variation else "",
+                "quantity": cp.count,
+                "price": str(cp.price),
+                "currency": request.event.currency
+            })
+        if cart['payment_fee']:
+            items.append({
+                "name": __('Payment method fee'),
+                "description": "",
+                "quantity": 1,
+                "currency": request.event.currency,
+                "price": str(cart['payment_fee'])
+            })
+        payment = paypalrestsdk.Payment({
+            'intent': 'sale',
+            'payer': {
+                "payment_method": "paypal",
+            },
+            "redirect_urls": {
+                "return_url": request.build_absolute_uri(reverse('plugins:paypal.return')),
+                "cancel_url": request.build_absolute_uri(reverse('plugins:paypal.abort')),
+            },
+            "transactions": [
+                {
+                    "item_list": {
+                        "items": items
+                    },
+                    "amount": {
+                        "currency": request.event.currency,
+                        "total": str(cart['total'])
+                    },
+                    "description": __('Event tickets for %s') % request.event.name
+                }
+            ]
+        })
+        return self._create_payment(request, payment)
+
+    def _create_payment(self, request, payment):
+        if payment.create():
+            if payment.state not in ('created', 'approved', 'pending'):
+                messages.error(request, _('We had trouble communicating with PayPal'))
+                logger.error('Invalid payment state: ' + str(payment))
+                return
+            request.session['payment_paypal_id'] = payment.id
+            request.session['payment_paypal_event'] = self.event.id
+            for link in payment.links:
+                if link.method == "REDIRECT" and link.rel == "approval_url":
+                    return str(link.href)
+        else:
+            messages.error(request, _('We had trouble communicating with PayPal'))
+            logger.error('Error on creating payment: ' + str(payment.error))
+
+    def checkout_confirm_render(self, request) -> str:
+        """
+        Returns the HTML that should be displayed when the user selected this provider
+        on the 'confirm order' page.
+        """
+        template = get_template('pretixplugins/paypal/checkout_payment_confirm.html')
+        ctx = Context({'request': request, 'event': self.event, 'settings': self.settings})
+        return template.render(ctx)
+
+    def checkout_perform(self, request, order) -> str:
+        """
+        Will be called if the user submitted his order successfully to initiate the
+        payment process.
+
+        It should return a custom redirct URL, if you need special behaviour, or None to
+        continue with default behaviour.
+
+        On errors, it should use Django's message framework to display an error message
+        to the user (or the normal form validation error messages).
+
+        :param order: The order object
+        """
+        if (request.session.get('payment_paypal_id', '') == ''
+                or request.session.get('payment_paypal_payer', '') == ''):
+            messages.error(request, _('We were unable to process your payment. See below for details on how to '
+                                      'proceed.'))
+
+        self.init_api()
+        payment = paypalrestsdk.Payment.find(request.session.get('payment_paypal_id'))
+        if str(payment.transactions[0].amount.total) != str(order.total) or payment.transactions[1].amount.currency != \
+                self.event.currency:
+            messages.error(request, _('We were unable to process your payment. See below for details on how to '
+                                      'proceed.'))
+            logger.error('Value mismatch: Order %s vs payment %s' % (order.id, str(payment)))
+            return
+
+        return self._execute_payment(payment, request, order)
+
+    def _execute_payment(self, payment, request, order):
+        payment.execute({"payer_id": request.session.get('payment_paypal_payer')})
+
+        if payment.state == 'pending':
+            messages.warning(request, _('PayPal has not yet approved the payment. We will inform you as soon as the '
+                                        'payment completed.'))
+            order = order.clone()
+            order.payment_info = str(payment)
+            order.save()
+            return
+
+        if payment.state != 'approved':
+            messages.error(request, _('We were unable to process your payment. See below for details on how to '
+                                      'proceed.'))
+            logger.error('Invalid state: %s' % str(payment))
+            return
+
+        order.mark_paid('paypal', str(payment))
+        messages.success(request, _('We successfully received your payment. Thank you!'))
+        return None
+
+    def order_pending_render(self, request, order) -> str:
+        retry = True
+        try:
+            if order.payment_info and json.loads(order.payment_info)['state'] != 'pending':
+                retry = False
+        except KeyError:
+            pass
+        template = get_template('pretixplugins/paypal/pending.html')
+        ctx = Context({'request': request, 'event': self.event, 'settings': self.settings,
+                       'retry': retry, 'order': order})
+        return template.render(ctx)

src/pretix/plugins/paypal/signals.py

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+from django.dispatch import receiver
+
+from pretix.base.signals import register_payment_providers
+
+from .payment import Paypal
+
+
+@receiver(register_payment_providers)
+def register_payment_provider(sender, **kwargs):
+    return Paypal

src/pretix/plugins/paypal/templates/pretixplugins/paypal/checkout_payment_confirm.html

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+{% load i18n %}
+
+<p>{% blocktrans trimmed %}
+    The total amount listed above will be withdrawn from your PayPal acocunt after the
+    confirmation of your purchase.
+{% endblocktrans %}</p>

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

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+{% load i18n %}
+
+<p>{% blocktrans trimmed %}
+    After you clicked continue, we will redirect you to PayPal to fill in your payment
+    details. You will then be redirected back here to review and confirm your order.
+{% endblocktrans %}</p>

src/pretix/plugins/paypal/templates/pretixplugins/paypal/pending.html

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+{% load i18n %}
+
+{% if retry %}
+    <p>{% blocktrans trimmed %}
+        Our attempt to execute your Payment via PayPal has failed. Please try again or contact us.
+    {% endblocktrans %}</p>
+    <p>
+        <a href="{% url "plugins:paypal.retry" order=order.code %}" class="btn btn-default">{% trans "Try again" %}</a>
+    </p>
+{% else %}
+    <p>{% blocktrans trimmed %}
+        We're waiting for an answer from PayPal regarding your payment. Please contact us, if this
+        takes more than a few hours.
+    {% endblocktrans %}</p>
+{% endif %}

src/pretix/plugins/paypal/urls.py

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+from django.conf.urls import url, include
+
+from .views import success, abort, retry
+
+
+urlpatterns = [
+    url(r'^paypal/', include([
+        url(r'^abort/$', abort, name='paypal.abort'),
+        url(r'^return/$', success, name='paypal.return'),
+        url(r'^retry/(?P<order>[^/]+)/', retry, name='paypal.retry')
+    ])),
+]

src/pretix/plugins/paypal/views.py

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+import logging
+from django.contrib import messages
+from django.contrib.auth.decorators import login_required
+from django.core.urlresolvers import reverse
+from django.shortcuts import redirect
+import paypalrestsdk
+from pretix.base.models import Event, Order
+from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import ugettext as __
+from pretix.base.settings import SettingsSandbox
+from pretix.plugins.paypal.payment import Paypal
+
+
+logger = logging.getLogger('pretix.plugins.paypal')
+
+
+@login_required
+def success(request):
+    pid = request.GET.get('paymentId')
+    token = request.GET.get('token')
+    payer = request.GET.get('PayerID')
+    if pid == request.session['payment_paypal_id']:
+        request.session['payment_paypal_token'] = token
+        request.session['payment_paypal_payer'] = payer
+        try:
+            event = Event.objects.current.get(identity=request.session['payment_paypal_event'])
+            return redirect(reverse('presale:event.checkout.confirm', kwargs={
+                'event': event.slug,
+                'organizer': event.organizer.slug,
+            }))
+        except Event.DoesNotExist:
+            pass  # TODO: Handle this
+    else:
+        pass  # TODO: Handle this
+
+
+@login_required
+def abort(request):
+    messages.error(request, _('It looks like you cancelled the PayPal payment'))
+    try:
+        event = Event.objects.current.get(identity=request.session['payment_paypal_event'])
+        return redirect(reverse('presale:event.checkout.payment', kwargs={
+            'event': event.slug,
+            'organizer': event.organizer.slug,
+        }))
+    except Event.DoesNotExist:
+        pass  # TODO: Handle this
+
+
+@login_required
+def retry(request, order):
+    try:
+        order = Order.objects.current.get(
+            user=request.user,
+            code=order,
+        )
+    except Order.DoesNotExist:
+        return  # TODO: Handle this
+
+    provider = Paypal(order.event)
+    provider.init_api()
+
+    if 'token' in request.GET:
+        if 'PayerID' in request.GET:
+            payment = paypalrestsdk.Payment.find(request.session.get('payment_paypal_id'))
+            provider._execute_payment(payment, request, order)
+        else:
+            messages.error(request, _('It looks like you cancelled the PayPal payment'))
+    else:
+        payment = paypalrestsdk.Payment({
+            'intent': 'sale',
+            'payer': {
+                "payment_method": "paypal",
+            },
+            "redirect_urls": {
+                "return_url": request.build_absolute_uri(reverse('plugins:paypal.retry', kwargs={
+                    'order': order.code
+                })),
+                "cancel_url": request.build_absolute_uri(reverse('plugins:paypal.retry', kwargs={
+                    'order': order.code
+                })),
+            },
+            "transactions": [
+                {
+                    "item_list": {
+                        "items": [
+                            {
+                                "name": 'Order %s' % order.code,
+                                "quantity": 1,
+                                "price": str(order.total),
+                                "currency": order.event.currency
+                            }
+                        ]
+                    },
+                    "amount": {
+                        "currency": order.event.currency,
+                        "total": str(order.total)
+                    },
+                    "description": __('Event tickets for %s') % order.event.name
+                }
+            ]
+        })
+        resp = provider._create_payment(request, payment)
+        if resp:
+            return redirect(resp)
+
+    return redirect(reverse('presale:event.order', kwargs={
+        'event': order.event.slug,
+        'organizer': order.event.organizer.slug,
+        'order': order.code,
+    }))