From b5451e0f4df0491b50d24932c585b0771a595a1f Mon Sep 17 00:00:00 2001
From: Denis Cornehl <denis@cornehl.org>
Date: Thu, 29 Sep 2022 19:52:44 +0200
Subject: [PATCH] omit cache-control header when it would be empty

---
 src/test/mod.rs    | 17 +++++++++++------
 src/web/cache.rs   |  5 ++++-
 src/web/rustdoc.rs |  2 +-
 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/test/mod.rs b/src/test/mod.rs
index 6d0caaf23..395af6998 100644
--- a/src/test/mod.rs
+++ b/src/test/mod.rs
@@ -61,12 +61,17 @@ pub(crate) fn assert_cache_control(
     config: &Config,
 ) {
     assert!(config.cache_control_stale_while_revalidate.is_some());
-    assert_eq!(
-        res.headers()
-            .get("Cache-Control")
-            .expect("missing cache-control header"),
-        &CacheControl(cache_policy.render(config)).to_string()
-    );
+    let cache_control = res.headers().get("Cache-Control");
+
+    let expected_directives = cache_policy.render(config);
+    if expected_directives.is_empty() {
+        assert!(cache_control.is_none());
+    } else {
+        assert_eq!(
+            cache_control.expect("missing cache-control header"),
+            &CacheControl(expected_directives).to_string()
+        );
+    }
 }
 
 /// Make sure that a URL returns a status code between 200-299
diff --git a/src/web/cache.rs b/src/web/cache.rs
index 28183dc34..c01bfbae0 100644
--- a/src/web/cache.rs
+++ b/src/web/cache.rs
@@ -104,7 +104,10 @@ impl AfterMiddleware for CacheMiddleware {
             );
         }
 
-        res.headers.set(CacheControl(cache.render(config)));
+        let directives = cache.render(config);
+        if !directives.is_empty() {
+            res.headers.set(CacheControl(directives))
+        }
         Ok(res)
     }
 }
diff --git a/src/web/rustdoc.rs b/src/web/rustdoc.rs
index 16364cdf2..70396d682 100644
--- a/src/web/rustdoc.rs
+++ b/src/web/rustdoc.rs
@@ -1769,7 +1769,7 @@ mod test {
             let url = format!("http://{}/dummy", web.server_addr());
             let resp = client.get(url).send()?;
             assert_eq!(resp.status(), StatusCode::FOUND);
-            assert!(resp.headers().get("Cache-Control").unwrap().is_empty());
+            assert!(resp.headers().get("Cache-Control").is_none());
             assert!(resp
                 .headers()
                 .get("Location")