Fix duplicate CORS headers for tile fallbacks

nginx/default.conf

@@ -6,20 +6,19 @@ server {
     root /var/lib/arma-tiles;
     etag on;
 
+    # Keep these at server level. Named fallback locations inherit them, so each
+    # response has exactly one CORS value instead of the invalid "*, *".
+    add_header Cache-Control "public, max-age=86400, stale-while-revalidate=604800" always;
+    add_header Access-Control-Allow-Origin "*" always;
+    add_header Access-Control-Allow-Methods "GET, HEAD, OPTIONS" always;
+    add_header Access-Control-Allow-Headers "Origin, Range, Accept" always;
+
     # Public API is x/y/z. try_files performs an internal lookup at z/x/y.png.
     location ~ ^/tiles/(?<tile_x>[0-9]+)/(?<tile_y>[0-9]+)/(?<tile_z>[0-9]+)$ {
         if ($request_method = OPTIONS) {
-            add_header Access-Control-Allow-Origin "*" always;
-            add_header Access-Control-Allow-Methods "GET, HEAD, OPTIONS" always;
-            add_header Access-Control-Allow-Headers "Origin, Range, Accept" always;
-            add_header Content-Length 0;
             return 204;
         }
         try_files /tiles/$tile_z/$tile_x/$tile_y.png @callback_provider_tile;
-        add_header Cache-Control "public, max-age=86400, stale-while-revalidate=604800" always;
-        add_header Access-Control-Allow-Origin "*" always;
-        add_header Access-Control-Allow-Methods "GET, HEAD, OPTIONS" always;
-        add_header Access-Control-Allow-Headers "Origin, Range, Accept" always;
     }
 
     # A callback-provider base layer fills transparent edges when configured.