From 33c5c3a4d2382e908f499af2a3922b93a30a12bb Mon Sep 17 00:00:00 2001
From: Ryan Barrett <git@ryanb.org>
Date: Thu, 23 Nov 2023 22:41:52 -0800
Subject: [PATCH] AP: add HEAD support to followers/ing, outbox collections

for #383
---
 activitypub.py            | 11 +++++++++--
 tests/test_activitypub.py | 10 ++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/activitypub.py b/activitypub.py
index 59fd6b3..b7c727a 100644
--- a/activitypub.py
+++ b/activitypub.py
@@ -875,7 +875,8 @@ def inbox(protocol=None, id=None):
 # source protocol in path; primarily for backcompat
 @app.get(f'/ap/web/<regex("{DOMAIN_RE}"):id>/<any(followers,following):collection>')
 # special case Web users without /ap/web/ prefix, for backward compatibility
-@app.get(f'/<regex("{DOMAIN_RE}"):id>/<any(followers,following):collection>')
+@app.route(f'/<regex("{DOMAIN_RE}"):id>/<any(followers,following):collection>',
+           methods=['GET', 'HEAD'])
 @flask_util.cached(cache, CACHE_TIME)
 def follower_collection(id, collection):
     """ActivityPub Followers and Following collections.
@@ -892,6 +893,9 @@ def follower_collection(id, collection):
     if not user:
         return f'{protocol} user {id} not found', 404
 
+    if request.method == 'HEAD':
+        return '', {'Content-Type': as2.CONTENT_TYPE}
+
     # page
     followers, new_before, new_after = Follower.fetch_page(collection, user=user)
     page = {
@@ -931,7 +935,7 @@ def follower_collection(id, collection):
 # source protocol in path; primarily for backcompat
 @app.get(f'/ap/web/<regex("{DOMAIN_RE}"):id>/outbox')
 # special case Web users without /ap/web/ prefix, for backward compatibility
-@app.get(f'/<regex("{DOMAIN_RE}"):id>/outbox')
+@app.route(f'/<regex("{DOMAIN_RE}"):id>/outbox', methods=['GET', 'HEAD'])
 @flask_util.cached(cache, CACHE_TIME)
 def outbox(id):
     """Serves a user's AP outbox.
@@ -946,6 +950,9 @@ def outbox(id):
     if not g.user:
         error(f'User {id} not found', status=404)
 
+    if request.method == 'HEAD':
+        return '', {'Content-Type': as2.CONTENT_TYPE}
+
     query = Object.query(Object.users == g.user.key)
     objects, new_before, new_after = fetch_objects(query, by=Object.updated,
                                                    user=g.user)
diff --git a/tests/test_activitypub.py b/tests/test_activitypub.py
index 79cac91..374348e 100644
--- a/tests/test_activitypub.py
+++ b/tests/test_activitypub.py
@@ -1558,6 +1558,11 @@ class ActivityPubTest(TestCase):
             'items': [ACTOR],
         }, resp.json)
 
+    def test_following_collection_head(self, *_):
+        resp = self.client.head(f'/user.com/following')
+        self.assertEqual(200, resp.status_code)
+        self.assertEqual('', resp.get_data(as_text=True))
+
     def test_outbox_fake_empty(self, *_):
         self.make_user('fake:foo', cls=Fake)
         resp = self.client.get(f'/ap/fake:foo/outbox',
@@ -1641,6 +1646,11 @@ class ActivityPubTest(TestCase):
             },
         }, resp.json)
 
+    def test_outbox_web_head(self, *_):
+        resp = self.client.head(f'/user.com/outbox')
+        self.assertEqual(200, resp.status_code)
+        self.assertEqual('', resp.get_data(as_text=True))
+
 
 class ActivityPubUtilsTest(TestCase):
     def setUp(self):