/r/ handler: include Accept header in flask cache key

requires pending bug fix https://github.com/pallets-eco/flask-caching/pull/431

redirect.py

@@ -90,6 +90,18 @@ def redir(to):
     logger.info(f'redirecting to {to}')
     return redirect(to, code=301)
 
+# offically-supported-monkey-patch flask_caching to include Accept header in
+# cache key:
+# https://flask-caching.readthedocs.io/en/latest/api.html#flask_caching.Cache.cached
+# requires this pending bug fix:
+# https://github.com/pallets-eco/flask-caching/pull/431
+orig_cache_key = redir.make_cache_key
+
+def accept_header_cache_key(*args, **kwargs):
+    return f'{orig_cache_key(*args, **kwargs)}  {request.headers.get("Accept")}'
+
+redir.make_cache_key = accept_header_cache_key
+
 
 def convert_to_as2(url, domain):
     """Fetch a URL as HTML, convert it to AS2, and return it.

requirements.txt

@@ -4,6 +4,7 @@ git+https://github.com/snarfed/oauth-dropins.git#egg=oauth_dropins
 git+https://github.com/snarfed/granary.git#egg=granary
 git+https://github.com/snarfed/negotiator.git@py3#egg=negotiator
 git+https://github.com/dvska/gdata-python3.git#egg=gdata
+git+https://github.com/snarfed/flask-caching.git@fix-97#egg=Flask-Caching
 
 beautifulsoup4==4.11.1
 brevity==0.2.17
@@ -20,7 +21,6 @@ feedgen==0.9.0
 feedparser==6.0.10
 fixtures==4.0.1
 Flask==2.2.2
-Flask-Caching==2.0.1
 flask-gae-static==1.0
 google-api-core==2.11.0
 google-auth==2.15.0

tests/test_redirect.py

@@ -6,6 +6,7 @@ from unittest.mock import patch
 from granary import as2
 from oauth_dropins.webutil.testutil import requests_response
 
+from app import app, cache
 import common
 from models import User
 from .test_webmention import REPOST_HTML, REPOST_AS2
@@ -50,6 +51,22 @@ class RedirectTest(testutil.TestCase):
     def test_as2_ld(self):
         self._test_as2(common.CONTENT_TYPE_AS2_LD)
 
+    def test_accept_header_cache_key(self):
+        app.config['CACHE_TYPE'] = 'SimpleCache'
+        cache.init_app(app)
+        self.client = app.test_client()
+
+        got = self.client.get('/r/https://foo.com/bar')
+        self.assertEqual(301, got.status_code)
+        self.assertEqual('https://foo.com/bar', got.headers['Location'])
+
+        self._test_as2(common.CONTENT_TYPE_AS2)
+
+        got = self.client.get('/r/https://foo.com/bar',
+                              headers={'Accept': 'text/html'})
+        self.assertEqual(301, got.status_code)
+        self.assertEqual('https://foo.com/bar', got.headers['Location'])
+
     @patch('requests.get')
     def _test_as2(self, accept, mock_get):
         """Currently mainly for Pixelfed.