From 719fec0828ae52579dc11a708821701b3a09fbc1 Mon Sep 17 00:00:00 2001
From: Ana Gelez <ana@gelez.xyz>
Date: Thu, 25 Jun 2020 22:26:44 +0200
Subject: [PATCH] Add a comment

---
 src/template_utils.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/template_utils.rs b/src/template_utils.rs
index 25c703a36..0b1268492 100644
--- a/src/template_utils.rs
+++ b/src/template_utils.rs
@@ -63,6 +63,9 @@ impl<'r> Responder<'r> for Ructe {
         let etag = format!("{:x}", hasher.finish());
         if r.headers()
             .get("If-None-Match")
+            // This check matches both weak and strong ETags
+            // NGINX (and maybe other software) sometimes sends ETags with a
+            // "W/" prefix, that we ignore here
             .any(|s| s[1..s.len() - 1] == etag || s[3..s.len() - 1] == etag)
         {
             Response::build()