From 524eb92a9eeaca940d4bf73d7592e2e87df8652c Mon Sep 17 00:00:00 2001
From: Patrick Gansterer <paroga@paroga.com>
Date: Fri, 9 Oct 2026 08:18:16 +0200
Subject: [PATCH] feat(header): add CAPSULE_PROTOCOL standard header (RFC 9297)

---
 benches/src/header_map/basic.rs | 1 +
 src/header/mod.rs               | 1 +
 src/header/name.rs              | 6 ++++++
 tests/header_map.rs             | 1 +
 tests/header_map_fuzz.rs        | 1 +
 5 files changed, 10 insertions(+)

diff --git a/benches/src/header_map/basic.rs b/benches/src/header_map/basic.rs
index 8c198a026..40d4c720d 100644
--- a/benches/src/header_map/basic.rs
+++ b/benches/src/header_map/basic.rs
@@ -537,6 +537,7 @@ const STD: &'static [HeaderName] = &[
     AUTHORIZATION,
     CACHE_CONTROL,
     CACHE_STATUS,
+    CAPSULE_PROTOCOL,
     CDN_CACHE_CONTROL,
     CONNECTION,
     CONTENT_DISPOSITION,
diff --git a/src/header/mod.rs b/src/header/mod.rs
index 1a5f1ede6..15d802ff1 100644
--- a/src/header/mod.rs
+++ b/src/header/mod.rs
@@ -70,6 +70,7 @@ pub use self::name::{
     AUTHORIZATION,
     CACHE_CONTROL,
     CACHE_STATUS,
+    CAPSULE_PROTOCOL,
     CDN_CACHE_CONTROL,
     CONNECTION,
     CONTENT_DISPOSITION,
diff --git a/src/header/name.rs b/src/header/name.rs
index d3e38a214..eff5e2dfe 100644
--- a/src/header/name.rs
+++ b/src/header/name.rs
@@ -350,6 +350,12 @@ standard_headers! {
     /// See [RFC 9211](https://www.rfc-editor.org/rfc/rfc9211.html).
     (CacheStatus, CACHE_STATUS, b"cache-status");
 
+    /// Indicates whether the Capsule Protocol is in use for a request or
+    /// response.
+    ///
+    /// See [RFC 9297](https://www.rfc-editor.org/rfc/rfc9297.html).
+    (CapsuleProtocol, CAPSULE_PROTOCOL, b"capsule-protocol");
+
     /// Specifies directives that allow origin servers to control the behavior of CDN caches
     /// interposed between them and clients separately from other caches that might handle the
     /// response.
diff --git a/tests/header_map.rs b/tests/header_map.rs
index 67505c2eb..da2e5accd 100644
--- a/tests/header_map.rs
+++ b/tests/header_map.rs
@@ -388,6 +388,7 @@ const STD: &'static [HeaderName] = &[
     AUTHORIZATION,
     CACHE_CONTROL,
     CACHE_STATUS,
+    CAPSULE_PROTOCOL,
     CDN_CACHE_CONTROL,
     CONNECTION,
     CONTENT_DISPOSITION,
diff --git a/tests/header_map_fuzz.rs b/tests/header_map_fuzz.rs
index 14f172d0f..3c9712d9e 100644
--- a/tests/header_map_fuzz.rs
+++ b/tests/header_map_fuzz.rs
@@ -273,6 +273,7 @@ fn gen_header_name(g: &mut StdRng) -> HeaderName {
         header::AUTHORIZATION,
         header::CACHE_CONTROL,
         header::CACHE_STATUS,
+        header::CAPSULE_PROTOCOL,
         header::CDN_CACHE_CONTROL,
         header::CONNECTION,
         header::CONTENT_DISPOSITION,