From 178b5ccde372feae2171cdaa6d480cef0e63fb38 Mon Sep 17 00:00:00 2001
From: Ryan Barrett <git@ryanb.org>
Date: Mon, 8 Jan 2024 07:53:09 -0800
Subject: [PATCH] /convert: handle missing protocols

fixes https://console.cloud.google.com/errors/detail/CLHg5u_DuYGWaw;time=P30D?project=bridgy-federated
---
 convert.py            | 10 ++++++++--
 tests/test_convert.py |  7 +++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/convert.py b/convert.py
index 05bb52e..4fed879 100644
--- a/convert.py
+++ b/convert.py
@@ -35,8 +35,10 @@ def convert(dest, _, src=None):
         :func:`convert_source_path_redirect`
     """
     if src:
+        src_cls = PROTOCOLS.get(src)
+        if not src_cls:
+            error(f'No protocol found for {src}', status=404)
         logger.info(f'Overriding any domain protocol with {src}')
-        src_cls = PROTOCOLS[src]
     else:
         src_cls = Protocol.for_request(fed=Protocol)
     if not src_cls:
@@ -108,4 +110,8 @@ def convert_source_path_redirect(src, dest, _):
         request.url = request.url.replace(f'/{src}/', '/')
         return convert(dest, None, src)
 
-    return redirect(subdomain_wrap(PROTOCOLS[src], new_path), code=301)
+    proto = PROTOCOLS.get(src)
+    if not proto:
+        error(f'No protocol found for {src}', status=404)
+
+    return redirect(subdomain_wrap(proto, new_path), code=301)
diff --git a/tests/test_convert.py b/tests/test_convert.py
index be5e347..dc2bc48 100644
--- a/tests/test_convert.py
+++ b/tests/test_convert.py
@@ -330,3 +330,10 @@ A ☕ reply
         self.assert_multiline_equals(HTML, resp.get_data(as_text=True),
                                      ignore_blanks=True)
 
+    def test_missing_protocols(self):
+        resp = self.client.get('/convert/https:/user.com/post')
+        self.assertEqual(404, resp.status_code)
+
+        resp = self.client.get('/convert/https:/user.com/post',
+                               base_url='https://fed.brid.gy/')
+        self.assertEqual(404, resp.status_code)