From 494c954cbb8dfd618f06eb51193b472a3f23f7cd Mon Sep 17 00:00:00 2001
From: Omar Roth <omarroth@protonmail.com>
Date: Sat, 9 Nov 2019 22:05:17 -0500
Subject: [PATCH] Add etag to /api/v1/annotations

---
 src/invidious.cr | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/invidious.cr b/src/invidious.cr
index 06f9e624..96c3d6e9 100644
--- a/src/invidious.cr
+++ b/src/invidious.cr
@@ -4042,7 +4042,13 @@ get "/api/v1/annotations/:id" do |env|
     annotations = response.body
   end
 
-  annotations
+  etag = sha256(annotations)[0, 16]
+  if env.request.headers["If-None-Match"]?.try &.== etag
+    env.response.status_code = 304
+  else
+    env.response.headers["ETag"] = etag
+    annotations
+  end
 end
 
 get "/api/v1/videos/:id" do |env|