The cache-control header should specify a 'max-age' directive to inform proxies of the XML's cacheability

The 6 year old patch to xmlsitemap.pages.inc does not apply to the latest xmlsitemap 7.x-2.x-dev and if still applicable needs a reroll.

Checking patch xmlsitemap.pages.inc...
error: while searching for:
    exit;
  }

  $headers += array(
    'Content-type' => 'text/xml; charset=utf-8',
    //'Content-length' => filesize($file),
    'Last-modified' => $last_modified,
    'Etag' => $etag,
    'Expires' => gmdate(DATE_RFC1123, $mtime + variable_get('xmlsitemap_minimum_lifetime', 0)),
    'Cache-Control' => 'must-revalidate',
    'X-Robots-Tag' => 'noindex, follow',
  );


error: patch failed: xmlsitemap.pages.inc:79
error: xmlsitemap.pages.inc: patch does not apply

Reroll: Commented line in the $headers array was removed.

Do we also need to fix this in D8?

Looks like it.

A reroll for 7.x

On #3521048: /sitemap.xml reverse proxy cache issue – cache-control header should be configurable in admin UI, @kepesv suggested adding a UI to set the cache-control value, and @bmunslow provided a patch, although that explicitly sets a no-cache header.

should this be against 2.x ?

@loze yes you're probably right - because 8.x-1.6 is a more recent release than 2.0.0, I assumed that was the active version.

Have opened MR 75 against 2.x, but haven't tested that branch fully yet

Having applied this patch, we have observed odd behaviour where incomplete sitemap pages are cached in Cloudflare.