Fix #103 -- Implement Stripe Connect (#836)

* ...

* Upgrade Stripe API client

* Implement account choice

* Add disconnect and fix tests

src/pretix/plugins/stripe/forms.py

@@ -0,0 +1,20 @@
+from django import forms
+from django.utils.translation import ugettext_lazy as _
+
+
+class StripeKeyValidator():
+    def __init__(self, prefix):
+        assert isinstance(prefix, str)
+        assert len(prefix) > 0
+        self._prefix = prefix
+
+    def __call__(self, value):
+        if not value.startswith(self._prefix):
+            raise forms.ValidationError(
+                _('The provided key "%(value)s" does not look valid. It should start with "%(prefix)s".'),
+                code='invalid-stripe-secret-key',
+                params={
+                    'value': value,
+                    'prefix': self._prefix,
+                },
+            )

src/pretix/plugins/stripe/payment.py

@@ -10,8 +10,12 @@ from django.conf import settings
 from django.contrib import messages
 from django.core import signing
 from django.template.loader import get_template
-from django.utils.translation import ugettext, ugettext_lazy as _
+from django.urls import reverse
+from django.utils.crypto import get_random_string
+from django.utils.http import urlquote
+from django.utils.translation import pgettext, ugettext, ugettext_lazy as _
 
+from pretix import __version__
 from pretix.base.models import Event, Quota, RequiredAction
 from pretix.base.payment import BasePaymentProvider, PaymentException
 from pretix.base.services.mail import SendMailException
@@ -19,6 +23,7 @@ from pretix.base.services.orders import mark_order_paid, mark_order_refunded
 from pretix.base.settings import SettingsSandbox
 from pretix.helpers.urls import build_absolute_uri as build_global_uri
 from pretix.multidomain.urlreverse import build_absolute_uri
+from pretix.plugins.stripe.forms import StripeKeyValidator
 from pretix.plugins.stripe.models import ReferencedStripeObject
 
 logger = logging.getLogger('pretix.plugins.stripe')
@@ -36,24 +41,6 @@ class RefundForm(forms.Form):
     )
 
 
-class StripeKeyValidator():
-    def __init__(self, prefix):
-        assert isinstance(prefix, str)
-        assert len(prefix) > 0
-        self._prefix = prefix
-
-    def __call__(self, value):
-        if not value.startswith(self._prefix):
-            raise forms.ValidationError(
-                _('The provided key "%(value)s" does not look valid. It should start with "%(prefix)s".'),
-                code='invalid-stripe-secret-key',
-                params={
-                    'value': value,
-                    'prefix': self._prefix,
-                },
-            )
-
-
 class StripeSettingsHolder(BasePaymentProvider):
     identifier = 'stripe_settings'
     verbose_name = _('Stripe')
@@ -65,17 +52,69 @@ class StripeSettingsHolder(BasePaymentProvider):
         self.settings = SettingsSandbox('payment', 'stripe', event)
 
     def settings_content_render(self, request):
-        return "<div class='alert alert-info'>%s<br /><code>%s</code></div>" % (
-            _('Please configure a <a href="https://dashboard.stripe.com/account/webhooks">Stripe Webhook</a> to '
-              'the following endpoint in order to automatically cancel orders when charges are refunded externally '
-              'and to process asynchronous payment methods like SOFORT.'),
-            build_global_uri('plugins:stripe:webhook')
-        )
+        if self.settings.connect_client_id and not self.settings.secret_key:
+            # Use Stripe connect
+            if not self.settings.connect_user_id:
+                request.session['payment_stripe_oauth_event'] = request.event.pk
+                if 'payment_stripe_oauth_token' not in request.session:
+                    request.session['payment_stripe_oauth_token'] = get_random_string(32)
+
+                return (
+                    "<p>{}</p>"
+                    "<a href='https://connect.stripe.com/oauth/authorize?response_type=code&client_id={}&state={}"
+                    "&scope=read_write&redirect_uri={}' class='btn btn-primary btn-lg'>{}</a>"
+                ).format(
+                    _('To accept payments via Stripe, you will need an account at Stripe. By clicking on the '
+                      'following button, you can either create a new Stripe account connect pretix to an existing '
+                      'one.'),
+                    self.settings.connect_client_id,
+                    request.session['payment_stripe_oauth_token'],
+                    urlquote(build_global_uri('plugins:stripe:oauth.return')),
+                    _('Connect with Stripe')
+                )
+            else:
+                return (
+                    "<button formaction='{}' class='btn btn-danger'>{}</button>"
+                ).format(
+                    reverse('plugins:stripe:oauth.disconnect', kwargs={
+                        'organizer': self.event.organizer.slug,
+                        'event': self.event.slug,
+                    }),
+                    _('Disconnect from Stripe')
+                )
+        else:
+            return "<div class='alert alert-info'>%s<br /><code>%s</code></div>" % (
+                _('Please configure a <a href="https://dashboard.stripe.com/account/webhooks">Stripe Webhook</a> to '
+                  'the following endpoint in order to automatically cancel orders when charges are refunded externally '
+                  'and to process asynchronous payment methods like SOFORT.'),
+                build_global_uri('plugins:stripe:webhook')
+            )
 
     @property
     def settings_form_fields(self):
-        d = OrderedDict(
-            [
+        if self.settings.connect_client_id and not self.settings.secret_key:
+            # Stripe connect
+            if self.settings.connect_user_id:
+                fields = [
+                    ('connect_user_name',
+                     forms.CharField(
+                         label=_('Stripe account'),
+                         disabled=True
+                     )),
+                    ('endpoint',
+                     forms.ChoiceField(
+                         label=_('Endpoint'),
+                         initial='live',
+                         choices=(
+                             ('live', pgettext('stripe', 'Live')),
+                             ('test', pgettext('stripe', 'Testing')),
+                         ),
+                     )),
+                ]
+            else:
+                return {}
+        else:
+            fields = [
                 ('publishable_key',
                  forms.CharField(
                      label=_('Publishable key'),
@@ -94,6 +133,9 @@ class StripeSettingsHolder(BasePaymentProvider):
                          StripeKeyValidator('sk_'),
                      ),
                  )),
+            ]
+        d = OrderedDict(
+            fields + [
                 ('ui',
                  forms.ChoiceField(
                      label=_('User interface'),
@@ -146,7 +188,6 @@ class StripeSettingsHolder(BasePaymentProvider):
                  )),
             ] + list(super().settings_form_fields.items())
         )
-
         d.move_to_end('_enabled', last=False)
         return d
 
@@ -175,9 +216,28 @@ class StripeMethod(BasePaymentProvider):
         places = settings.CURRENCY_PLACES.get(self.event.currency, 2)
         return int(order.total * 10 ** places)
 
+    @property
+    def api_kwargs(self):
+        if self.settings.connect_client_id and self.settings.connect_user_id:
+            if self.settings.get('endpoint', 'live') == 'live':
+                kwargs = {
+                    'api_key': self.settings.connect_secret_key,
+                    'stripe_account': self.settings.connect_user_id
+                }
+            else:
+                kwargs = {
+                    'api_key': self.settings.connect_test_secret_key,
+                    'stripe_account': self.settings.connect_user_id
+                }
+        else:
+            kwargs = {
+                'api_key': self.settings.secret_key,
+            }
+        return kwargs
+
     def _init_api(self):
-        stripe.api_version = '2017-06-05'
-        stripe.api_key = self.settings.get('secret_key')
+        stripe.api_version = '2018-02-28'
+        stripe.set_app_info("pretix", version=__version__, url="https://pretix.eu")
 
     def checkout_confirm_render(self, request) -> str:
         template = get_template('pretixplugins/stripe/checkout_payment_confirm.html')
@@ -199,7 +259,8 @@ class StripeMethod(BasePaymentProvider):
                     'code': order.code
                 },
                 # TODO: Is this sufficient?
-                idempotency_key=str(self.event.id) + order.code + source
+                idempotency_key=str(self.event.id) + order.code + source,
+                **self.api_kwargs
             )
         except stripe.error.CardError as e:
             if e.json_body:
@@ -330,7 +391,7 @@ class StripeMethod(BasePaymentProvider):
             return
 
         try:
-            ch = stripe.Charge.retrieve(payment_info['id'])
+            ch = stripe.Charge.retrieve(payment_info['id'], **self.api_kwargs)
             ch.refunds.create()
             ch.refresh()
         except (stripe.error.InvalidRequestError, stripe.error.AuthenticationError, stripe.error.APIConnectionError) \
@@ -426,7 +487,7 @@ class StripeCC(StripeMethod):
 
         if request.session['payment_stripe_token'].startswith('src_'):
             try:
-                src = stripe.Source.retrieve(request.session['payment_stripe_token'])
+                src = stripe.Source.retrieve(request.session['payment_stripe_token'], **self.api_kwargs)
                 if src.type == 'card' and src.card and src.card.three_d_secure == 'required':
                     request.session['payment_stripe_order_secret'] = order.secret
                     source = stripe.Source.create(
@@ -521,6 +582,7 @@ class StripeGiropay(StripeMethod):
                         'hash': hashlib.sha1(order.secret.lower().encode()).hexdigest(),
                     })
                 },
+                **self.api_kwargs
             )
             return source
         finally:
@@ -577,6 +639,7 @@ class StripeIdeal(StripeMethod):
                     'hash': hashlib.sha1(order.secret.lower().encode()).hexdigest(),
                 })
             },
+            **self.api_kwargs
         )
         return source
 
@@ -618,6 +681,7 @@ class StripeAlipay(StripeMethod):
                     'hash': hashlib.sha1(order.secret.lower().encode()).hexdigest(),
                 })
             },
+            **self.api_kwargs
         )
         return source
 
@@ -676,6 +740,7 @@ class StripeBancontact(StripeMethod):
                         'hash': hashlib.sha1(order.secret.lower().encode()).hexdigest(),
                     })
                 },
+                **self.api_kwargs
             )
             return source
         finally:
@@ -746,6 +811,7 @@ class StripeSofort(StripeMethod):
                     'hash': hashlib.sha1(order.secret.lower().encode()).hexdigest(),
                 })
             },
+            **self.api_kwargs
         )
         return source
 

src/pretix/plugins/stripe/signals.py

@@ -1,5 +1,7 @@
 import json
+from collections import OrderedDict
 
+from django import forms
 from django.core.urlresolvers import resolve
 from django.dispatch import receiver
 from django.template.loader import get_template
@@ -7,8 +9,10 @@ from django.utils.translation import ugettext_lazy as _
 
 from pretix.base.settings import settings_hierarkey
 from pretix.base.signals import (
-    logentry_display, register_payment_providers, requiredaction_display,
+    logentry_display, register_global_settings, register_payment_providers,
+    requiredaction_display,
 )
+from pretix.plugins.stripe.forms import StripeKeyValidator
 from pretix.presale.signals import html_head
 
 
@@ -86,3 +90,44 @@ def pretixcontrol_action_display(sender, action, request, **kwargs):
 
 
 settings_hierarkey.add_default('payment_stripe_method_cc', True, bool)
+
+
+@receiver(register_global_settings, dispatch_uid='stripe_global_settings')
+def register_global_settings(sender, **kwargs):
+    return OrderedDict([
+        ('payment_stripe_connect_client_id', forms.CharField(
+            label=_('Stripe Connect: Client ID'),
+            required=False,
+            validators=(
+                StripeKeyValidator('ca_'),
+            ),
+        )),
+        ('payment_stripe_connect_secret_key', forms.CharField(
+            label=_('Stripe Connect: Secret key'),
+            required=False,
+            validators=(
+                StripeKeyValidator('sk_live_'),
+            ),
+        )),
+        ('payment_stripe_connect_publishable_key', forms.CharField(
+            label=_('Stripe Connect: Publishable key'),
+            required=False,
+            validators=(
+                StripeKeyValidator('pk_live_'),
+            ),
+        )),
+        ('payment_stripe_connect_test_secret_key', forms.CharField(
+            label=_('Stripe Connect: Secret key (test)'),
+            required=False,
+            validators=(
+                StripeKeyValidator('sk_test_'),
+            ),
+        )),
+        ('payment_stripe_connect_test_publishable_key', forms.CharField(
+            label=_('Stripe Connect: Publishable key (test)'),
+            required=False,
+            validators=(
+                StripeKeyValidator('pk_test_'),
+            ),
+        )),
+    ])

src/pretix/plugins/stripe/urls.py

@@ -2,7 +2,9 @@ from django.conf.urls import include, url
 
 from pretix.multidomain import event_url
 
-from .views import ReturnView, redirect_view, refund, webhook
+from .views import (
+    ReturnView, oauth_disconnect, oauth_return, redirect_view, refund, webhook,
+)
 
 event_patterns = [
     url(r'^stripe/', include([
@@ -15,5 +17,8 @@ event_patterns = [
 urlpatterns = [
     url(r'^control/event/(?P<organizer>[^/]+)/(?P<event>[^/]+)/stripe/refund/(?P<id>\d+)/',
         refund, name='refund'),
+    url(r'^control/event/(?P<organizer>[^/]+)/(?P<event>[^/]+)/stripe/disconnect/',
+        oauth_disconnect, name='oauth.disconnect'),
     url(r'^_stripe/webhook/$', webhook, name='webhook'),
+    url(r'^_stripe/oauth_return/$', oauth_return, name='oauth.return'),
 ]

src/pretix/plugins/stripe/views.py

@@ -2,6 +2,7 @@ import hashlib
 import json
 import logging
 
+import requests
 import stripe
 from django.contrib import messages
 from django.core import signing
@@ -17,10 +18,11 @@ from django.views.decorators.clickjacking import xframe_options_exempt
 from django.views.decorators.csrf import csrf_exempt
 from django.views.decorators.http import require_POST
 
-from pretix.base.models import Order, Quota, RequiredAction
+from pretix.base.models import Event, Order, Quota, RequiredAction
 from pretix.base.payment import PaymentException
 from pretix.base.services.locking import LockTimeoutException
 from pretix.base.services.orders import mark_order_paid, mark_order_refunded
+from pretix.base.settings import GlobalSettingsObject
 from pretix.control.permissions import event_permission_required
 from pretix.multidomain.urlreverse import eventreverse
 from pretix.plugins.stripe.models import ReferencedStripeObject
@@ -44,6 +46,60 @@ def redirect_view(request, *args, **kwargs):
     return r
 
 
+def oauth_return(request, *args, **kwargs):
+    if 'payment_stripe_oauth_event' not in request.session:
+        messages.error(request, _('An error occured during connecting with Stripe, please try again.'))
+        return redirect(reverse('control:index'))
+
+    event = get_object_or_404(Event, pk=request.session['payment_stripe_oauth_event'])
+
+    if request.GET.get('state') != request.session['payment_stripe_oauth_token']:
+        messages.error(request, _('An error occured during connecting with Stripe, please try again.'))
+        return redirect(reverse('control:event.settings.payment.provider', kwargs={
+            'organizer': event.organizer.slug,
+            'event': event.slug,
+            'provider': 'stripe_settings'
+        }))
+
+    gs = GlobalSettingsObject()
+
+    try:
+        resp = requests.post('https://connect.stripe.com/oauth/token', data={
+            'grant_type': 'authorization_code',
+            'client_secret': (
+                gs.settings.payment_stripe_connect_secret_key or gs.settings.payment_stripe_connect_test_secret_key
+            ),
+            'code': request.GET.get('code')
+        })
+        data = resp.json()
+
+        if 'error' not in data:
+            account = stripe.Account.retrieve(
+                data['stripe_user_id'],
+                api_key=gs.settings.payment_stripe_connect_secret_key or gs.settings.payment_stripe_connect_test_secret_key
+            )
+    except:
+        logger.exception('Failed to obtain OAuth token')
+        messages.error(request, _('An error occured during connecting with Stripe, please try again.'))
+    else:
+        if 'error' in data:
+            messages.error(request, _('Stripe returned an error: {}').format(data['error_description']))
+        else:
+            messages.success(request, _('Your Stripe account is now connected to pretix. You can change the settings in '
+                                        'detail below.'))
+            event.settings.payment_stripe_publishable_key = data['stripe_publishable_key']
+            # event.settings.payment_stripe_connect_access_token = data['access_token'] we don't need it, right?
+            event.settings.payment_stripe_connect_refresh_token = data['refresh_token']
+            event.settings.payment_stripe_connect_user_id = data['stripe_user_id']
+            event.settings.payment_stripe_connect_user_name = account['business_name']
+
+    return redirect(reverse('control:event.settings.payment.provider', kwargs={
+        'organizer': event.organizer.slug,
+        'event': event.slug,
+        'provider': 'stripe_settings'
+    }))
+
+
 @csrf_exempt
 @require_POST
 def webhook(request, *args, **kwargs):
@@ -80,7 +136,7 @@ def charge_webhook(event, event_json, charge_id):
     prov = StripeCC(event)
     prov._init_api()
     try:
-        charge = stripe.Charge.retrieve(charge_id)
+        charge = stripe.Charge.retrieve(charge_id, **prov.api_kwargs)
     except stripe.error.StripeError:
         logger.exception('Stripe error on webhook. Event data: %s' % str(event_json))
         return HttpResponse('Charge not found', status=500)
@@ -135,7 +191,7 @@ def source_webhook(event, event_json, source_id):
     prov = StripeCC(event)
     prov._init_api()
     try:
-        src = stripe.Source.retrieve(source_id)
+        src = stripe.Source.retrieve(source_id, **prov.api_kwargs)
     except stripe.error.StripeError:
         logger.exception('Stripe error on webhook. Event data: %s' % str(event_json))
         return HttpResponse('Charge not found', status=500)
@@ -169,6 +225,24 @@ def source_webhook(event, event_json, source_id):
     return HttpResponse(status=200)
 
 
+@event_permission_required('can_change_event_settings')
+@require_POST
+def oauth_disconnect(request, **kwargs):
+    del request.event.settings.payment_stripe_publishable_key
+    del request.event.settings.payment_stripe_connect_access_token
+    del request.event.settings.payment_stripe_connect_refresh_token
+    del request.event.settings.payment_stripe_connect_user_id
+    del request.event.settings.payment_stripe_connect_user_name
+    request.event.settings.payment_stripe__enabled = False
+    messages.success(request, _('Your Stripe account has been disconnected.'))
+
+    return redirect(reverse('control:event.settings.payment.provider', kwargs={
+        'organizer': request.event.organizer.slug,
+        'event': request.event.slug,
+        'provider': 'stripe_settings'
+    }))
+
+
 @event_permission_required('can_view_orders')
 @require_POST
 def refund(request, **kwargs):
@@ -219,7 +293,7 @@ class ReturnView(StripeOrderView, View):
     def get(self, request, *args, **kwargs):
         prov = self.pprov
         prov._init_api()
-        src = stripe.Source.retrieve(request.GET.get('source'))
+        src = stripe.Source.retrieve(request.GET.get('source'), **prov.api_kwargs)
         if src.client_secret != request.GET.get('client_secret'):
             messages.error(self.request, _('Sorry, there was an error in the payment process. Please check the link '
                                            'in your emails to continue.'))