From b516d919995f3bf36045263376628ff0aa298095 Mon Sep 17 00:00:00 2001
From: Michael Telatynski <7t3chguy@gmail.com>
Date: Tue, 11 Jul 2023 09:18:50 +0100
Subject: [PATCH] Add `Server` to Access-Control-Expose-Headers header (#15908)

---
 changelog.d/15908.misc | 1 +
 synapse/http/server.py | 2 +-
 tests/test_server.py   | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)
 create mode 100644 changelog.d/15908.misc

diff --git a/changelog.d/15908.misc b/changelog.d/15908.misc
new file mode 100644
index 000000000..3ab8674e0
--- /dev/null
+++ b/changelog.d/15908.misc
@@ -0,0 +1 @@
+Add `Server` to Access-Control-Expose-Headers header.
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 933172c87..e411ac7e6 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -910,7 +910,7 @@ def set_cors_headers(request: SynapseRequest) -> None:
         )
         request.setHeader(
             b"Access-Control-Expose-Headers",
-            b"Synapse-Trace-Id",
+            b"Synapse-Trace-Id, Server",
         )
 
 
diff --git a/tests/test_server.py b/tests/test_server.py
index e266c06a2..dc491e06e 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -268,7 +268,7 @@ class OptionsResourceTests(unittest.TestCase):
         )
         self.assertEqual(
             channel.headers.getRawHeaders(b"Access-Control-Expose-Headers"),
-            [b"Synapse-Trace-Id"],
+            [b"Synapse-Trace-Id, Server"],
         )
 
     def _check_cors_msc3886_headers(self, channel: FakeChannel) -> None: