PayPal: Patch API client to cache access tokens (#2600)

src/pretix/plugins/paypal/api.py

@@ -0,0 +1,53 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020 Raphael Michel and contributors
+# Copyright (C) 2020-2021 rami.io GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
+# <https://www.gnu.org/licenses/>.
+#
+import hashlib
+import json
+
+from django.core.cache import cache
+from paypalrestsdk.api import Api as VendorApi
+
+
+class Api(VendorApi):
+    def get_token_hash(self, authorization_code=None, refresh_token=None, headers=None):
+        if not authorization_code and not refresh_token:
+            checksum = hashlib.sha256(self.basic_auth().encode()).hexdigest()
+            cache_key_hash = f'pretix_paypal_token_hash_{checksum}'
+            cache_key_request_at = f'pretix_paypal_token_request_at_{checksum}'
+            token_hash = cache.get(cache_key_hash)
+            if token_hash:
+                token_request_at = cache.get(cache_key_request_at)
+                if token_request_at:
+                    self.token_hash = json.loads(token_hash)
+                    self.token_request_at = token_request_at
+                    self.validate_token_hash()
+                    if self.token_hash is not None:
+                        return self.token_hash
+
+            t = super().get_token_hash(authorization_code, refresh_token, headers)
+
+            if self.token_hash:
+                cache.set(cache_key_hash, json.dumps(self.token_hash), 3600 * 4)
+                cache.set(cache_key_request_at, self.token_request_at, 3600 * 4)
+
+            return t
+
+        return super().get_token_hash(authorization_code, refresh_token, headers)

src/pretix/plugins/paypal/payment.py

@@ -58,6 +58,7 @@ from pretix.base.payment import BasePaymentProvider, PaymentException
 from pretix.base.services.mail import SendMailException
 from pretix.base.settings import SettingsSandbox
 from pretix.multidomain.urlreverse import build_absolute_uri
+from pretix.plugins.paypal.api import Api
 from pretix.plugins.paypal.models import ReferencedPayPalObject
 
 logger = logging.getLogger('pretix.plugins.paypal')
@@ -197,7 +198,7 @@ class Paypal(BasePaymentProvider):
 
     def init_api(self):
         if self.settings.connect_client_id and not self.settings.secret:
-            paypalrestsdk.set_config(
+            paypalrestsdk.api.__api__ = Api(
                 mode="sandbox" if "sandbox" in self.settings.connect_endpoint else 'live',
                 client_id=self.settings.connect_client_id,
                 client_secret=self.settings.connect_secret_key,
@@ -205,10 +206,11 @@ class Paypal(BasePaymentProvider):
                 openid_client_secret=self.settings.connect_secret_key
             )
         else:
-            paypalrestsdk.set_config(
+            paypalrestsdk.api.__api__ = Api(
                 mode="sandbox" if "sandbox" in self.settings.get('endpoint') else 'live',
                 client_id=self.settings.get('client_id'),
-                client_secret=self.settings.get('secret'))
+                client_secret=self.settings.get('secret')
+            )
 
     def payment_is_valid_session(self, request):
         return (request.session.get('payment_paypal_id', '') != ''