Disable conversion of HEAD method to GET

Author: aspettl

Diff for: nginx.conf

@@ -240,6 +240,16 @@ echo "Docker configured with HTTPS_PROXY=$scheme://$http_host/"
         proxy_ignore_client_abort on;
         proxy_cache_revalidate on;
 
+        # Avoid conversion of HEAD method to GET
+        proxy_cache_convert_head off;
+        # HEAD requests are to be cached separately from GET, so they need a different cache key.
+        # To avoid a breaking change in cache keys (which would invalidate existing caches), we keep the normal URI
+        # for GET requests as key, but use a prefix for HEAD.
+        set $docker_proxy_cache_prefix "";
+        if ($request_method = HEAD) {
+            set $docker_proxy_cache_prefix "HEAD:";
+        }
+
         # Hide/ignore headers from caching. S3 especially likes to send Expires headers in the past in some situations.
         proxy_hide_header      Set-Cookie;
         proxy_ignore_headers   X-Accel-Expires Expires Cache-Control Set-Cookie;
@@ -303,7 +313,7 @@ echo "Docker configured with HTTPS_PROXY=$scheme://$http_host/"
             proxy_cache cache;
             # But we store the result with the cache key of the original request URI
             # so that future clients don't need to follow the redirect too
-            proxy_cache_key $original_uri;
+            proxy_cache_key $docker_proxy_cache_prefix$original_uri;
         }
 
         # by default, dont cache anything.

Diff for: nginx.manifest.common.conf

@@ -3,6 +3,6 @@
     add_header X-Docker-Registry-Proxy-Cache-Type "$docker_proxy_request_type";
     proxy_pass https://$targetHost;
     proxy_cache cache;
-    proxy_cache_key   $uri;
+    proxy_cache_key   $docker_proxy_cache_prefix$uri;
     proxy_intercept_errors on;
     error_page 301 302 307 = @handle_redirects;