As part of a Sitecore upgrade to v10 we also upgraded to
Dianoga V5.4.1. This site uses output/HTML cache extensively. We need to support browsers with and without
webp support. The WebP CDN config mentions this:
<!-- Generate a unique HTML cache key for renderings since the links will have query string extension=webp -->
This seems to happen correctly i.e. if a browser supports webp the
extension=webp querystring is added and otherwise it is not. The issue I'm running into is that these URLs are part of renderings which get cached in the output cache and are not always correct when returned from cache, e.g. initially a rendering was requested and cached by a browser which does not support webp, and then it gets returned to a browser with webp support.
Prior to this upgrade Dianoga did not add this extension, and returned correct webp/original image based on the browsers
accept request header (the CDN is configured to use this for unique cache key). This there a way in Dianoga v5 to get the same behavior, or is there a different configuration to make this work?