From 941e018055c65b6193b0c674bae71f298c126cb6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20L=C3=BCck?= <christian@clue.engineering>
Date: Mon, 14 Sep 2026 13:18:03 +0200
Subject: [PATCH] Add `Cache-Control` header to cache static files for 1 day

---
 Dockerfile             |  2 +-
 README.md              |  2 --
 tests/integration.bash | 12 ++++++++++++
 www/.htaccess          |  3 +++
 4 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 2e02778..8a04f87 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -18,7 +18,7 @@ COPY www/ www/
 RUN vendor/bin/sculpin generate
 
 FROM php:8.1-apache
-RUN ln -s /etc/apache2/mods-available/rewrite.load /etc/apache2/mods-enabled
+RUN ln -s /etc/apache2/mods-available/rewrite.load /etc/apache2/mods-available/headers.load /etc/apache2/mods-enabled
 COPY --from=build /app/build/ /var/www/html/
 HEALTHCHECK --start-period=1m --start-interval=0.1s --interval=1h \
     CMD ["curl", "-I", "--no-progress-meter", "http://localhost/"]
diff --git a/README.md b/README.md
index eafbecb..3f12a8c 100644
--- a/README.md
+++ b/README.md
@@ -61,8 +61,6 @@ directory behind your favorite web server (Apache + PHP-FPM etc.).
 Additionally, this should be deployed behind a reverse proxy (nginx) or CDN (Bunny CDN)
 that is responsible for HTTPS certificate handling and forcing HTTPS redirects.
 
-Additionally, Apache has been configured to cache static files for 1 day.
-
 The live website is deployed by pushing the contents of the `build/` directory to
 the `live` branch like this:
 
diff --git a/tests/integration.bash b/tests/integration.bash
index d33e299..a81fe94 100755
--- a/tests/integration.bash
+++ b/tests/integration.bash
@@ -20,6 +20,7 @@ match() {
 curl -v $base/
 match "HTTP/.* 200"
 match -iE "Content-Type: text/html(;.*)?$"
+match -iE "Cache-Control: max-age=86400$"
 
 curl -v $base/index.html
 match "HTTP/.* 302"
@@ -34,6 +35,7 @@ match "HTTP/.* 404"
 curl -v $base/blog
 match "HTTP/.* 200"
 match -iE "Content-Type: text/html(;.*)?$"
+match -iE "Cache-Control: max-age=86400$"
 
 curl -v $base/blog.html
 match "HTTP/.* 302"
@@ -99,4 +101,14 @@ curl -v $base/contact/
 match "HTTP/.* 302"
 match -iE "Location: $redir/contact$"
 
+curl -v $base/posts.atom
+match "HTTP/.* 200"
+match -iE "Content-Type: application/atom\+xml$"
+match -iE "Cache-Control: max-age=86400$"
+
+curl -v $base/src/tailwind.min.css
+match "HTTP/.* 200"
+match -iE "Content-Type: text/css$"
+match -iE "Cache-Control: max-age=86400$"
+
 echo "OK ($n)"
diff --git a/www/.htaccess b/www/.htaccess
index 4aeb120..0f764de 100644
--- a/www/.htaccess
+++ b/www/.htaccess
@@ -60,3 +60,6 @@ Redirect /psocksd-0.3.4.phar https://github.com/clue/psocksd/releases/download/v
 Redirect /psocksd-0.3.3.phar https://github.com/clue/psocksd/releases/download/v0.3.3/psocksd.phar
 Redirect /psocksd-0.3.2.phar https://github.com/clue/psocksd/releases/download/v0.3.2/psocksd.phar
 Redirect /psocksd-0.3.1.phar https://github.com/clue/psocksd/releases/download/v0.3.1/psocksd.phar
+
+# all files should be cached for 1 day, otherwise any intermediaries may apply their own caching rules
+Header set Cache-Control "max-age=86400"