From 9fa553bbc4afb0505c346f67cba56f7ab2db8996 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=C3=A9o=20Colombaro?= <git@colombaro.fr>
Date: Thu, 3 Nov 2022 22:50:13 +0000
Subject: [PATCH] Use proper `Cache-Control` values

---
 h5bp/web_performance/cache-control.conf | 31 ++++++-------------------
 nginx.conf                              | 28 ++++++++++++++++++++++
 2 files changed, 35 insertions(+), 24 deletions(-)

diff --git a/h5bp/web_performance/cache-control.conf b/h5bp/web_performance/cache-control.conf
index 9bb2401..38991fe 100644
--- a/h5bp/web_performance/cache-control.conf
+++ b/h5bp/web_performance/cache-control.conf
@@ -2,32 +2,15 @@
 # | Cache Control                                                      |
 # ----------------------------------------------------------------------
 
-# TBD
+# Serve resources with appropriate cache control.
 #
-# (1) TBD
-#
-# (2) TBD
-#
-# (3) TBD
+# The `Cache-Control` header field holds directives (instructions) that control
+# caching in browsers and shared caches (e.g. Proxies, CDNs).
 #
 # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control
-
-map $sent_http_content_type $cache_control {
-  # (1)
-  default           "private, must-revalidate";
-
-  # (2)
-  ~*text/html       "public, immutable";
-  ~*text/css        "public, immutable";
-  ~*text/javascript "public, immutable";
-  ~*xml             "public, immutable";
-  ~*application/pdf "public, immutable";
-
-  # (3)
-  ~*audio/          "public, immutable";
-  ~*image/          "public, immutable";
-  ~*font/           "public, immutable";
-  ~*video/          "public, immutable";
-}
+# https://www.rfc-editor.org/rfc/rfc9111.html
+# https://www.rfc-editor.org/rfc/rfc8246.html
+# https://www.iana.org/assignments/http-cache-directives/http-cache-directives.xml
+# https://cache-tests.fyi/
 
 add_header Cache-Control $cache_control;
diff --git a/nginx.conf b/nginx.conf
index 239b22e..ce36898 100644
--- a/nginx.conf
+++ b/nginx.conf
@@ -102,6 +102,34 @@ http {
   # Specify file cache expiration.
   include h5bp/web_performance/cache_expiration.conf;
 
+  # Add Cache-Control.
+  # h5bp/web_performance/cache-control.conf
+  map $sent_http_content_type $cache_control {
+    default                           "public, immutable, stale-while-revalidate";
+
+    # No content
+    ""                                "no-store";
+
+    # Manifest files
+    ~*application/manifest\+json      "public";
+    ~*text/cache-manifest             ""; # `no-cache` set by `expire`
+
+    # Assets
+    ~*image/svg\+xml                  "public, immutable, stale-while-revalidate";
+
+    # Data interchange
+    ~*application/(atom|rdf|rss)\+xml "public, stale-while-revalidate";
+
+    # Documents
+    ~*text/html                       "private, must-revalidate";
+    ~*text/markdown                   "private, must-revalidate";
+    ~*text/calendar                   "private, must-revalidate";
+
+    # Data
+    ~*json                            ""; # `no-cache` set by `expire`
+    ~*xml                             ""; # `no-cache` set by `expire`
+  }
+
   # Add X-Frame-Options for HTML documents.
   # h5bp/security/x-frame-options.conf
   map $sent_http_content_type $x_frame_options {