From f7bf9868689403c457b4f733db8eb98193d4ff42 Mon Sep 17 00:00:00 2001
From: Ryan Barrett <git@ryanb.org>
Date: Fri, 20 Dec 2024 09:52:20 -0800
Subject: [PATCH] redirect https://bsky.brid.gy/hashtag/TAG to
 https://bsky.app/search?q=#TAG

for #1634, thanks @Tamschi!
---
 atproto.py            | 20 ++++++++++++++++----
 tests/test_atproto.py | 13 +++++++++++++
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/atproto.py b/atproto.py
index 2b7d650a..d7a56bed 100644
--- a/atproto.py
+++ b/atproto.py
@@ -23,7 +23,7 @@
 )
 import brevity
 import dag_json
-from flask import abort, request
+from flask import abort, redirect, request
 from google.cloud import dns
 from google.cloud.dns.resource_record_set import ResourceRecordSet
 from google.cloud import ndb
@@ -36,9 +36,11 @@
 from oauth_dropins.webutil import util
 from oauth_dropins.webutil.appengine_config import ndb_client
 from oauth_dropins.webutil.appengine_info import DEBUG
-from oauth_dropins.webutil.flask_util import cloud_tasks_only, get_required_param
+from oauth_dropins.webutil import flask_util
+from oauth_dropins.webutil.flask_util import get_required_param
 from oauth_dropins.webutil.models import StringIdModel
 from oauth_dropins.webutil.util import add, json_dumps, json_loads
+from werkzeug.exceptions import NotFound
 
 import common
 from common import (
@@ -50,7 +52,7 @@
     SUPERDOMAIN,
     USER_AGENT,
 )
-import flask_app
+from flask_app import app
 import ids
 from models import Follower, Object, PROTOCOLS, Target, User
 from protocol import Protocol
@@ -1054,7 +1056,7 @@ def send_chat(*, msg, from_repo, to_did):
     return True
 
 
-@cloud_tasks_only(log=False)
+@flask_util.cloud_tasks_only(log=False)
 def poll_chat_task():
     """Polls for incoming chat messages for our protocol bot users.
 
@@ -1106,3 +1108,13 @@ def poll_chat_task():
     # done!
     bot.put()
     return 'OK'
+
+
+@app.get(f'/hashtag/<hashtag>')
+@flask_util.headers(common.CACHE_CONTROL)
+def hashtag_redirect(hashtag):
+    if (util.domain_from_link(request.host_url) ==
+            f'{ATProto.ABBREV}{common.SUPERDOMAIN}'):
+        return redirect(f'https://bsky.app/search?q=%23{hashtag}')
+
+    raise NotFound()
diff --git a/tests/test_atproto.py b/tests/test_atproto.py
index 87fbcb68..3d38f603 100644
--- a/tests/test_atproto.py
+++ b/tests/test_atproto.py
@@ -2697,3 +2697,16 @@ def test_poll_atproto_chat_messages(self, mock_get, mock_create_task):
                          received_at='1900-04-04T00:04:04Z')
 
         self.assertEqual('dunn', fa.key.get().atproto_last_chat_log_cursor)
+
+    def test_hashtag_redirect(self):
+        resp = self.get('/hashtag/foo', base_url='https://bsky.brid.gy')
+        self.assert_equals(302, resp.status_code)
+        self.assert_equals('https://bsky.app/search?q=%23foo',
+                           resp.headers['Location'])
+
+        # only on bsky subdomain
+        resp = self.get('/hashtag/foo')
+        self.assert_equals(404, resp.status_code)
+
+        resp = self.get('/hashtag/foo', base_url='https://web.brid.gy')
+        self.assert_equals(404, resp.status_code)