Configurable Cache Duration for Outdated Transformed Blobs

Added a new configuration property delivery.outdated-transformed-blob-cache-duration to control how long outdated or yet unknown transformed blobs are to be cached in a multi-CAE scenario (cae.single-node=false). Before this fix, CAE send a cache-control header with max-age of 0 seconds. This value is now configurable. Consider that a yet unknown cache should not be cached for long because the CDN should ideally cache the correct transformed blob for a given URL. The cases to cover are that (1) either a more up-to-date CAE generated the link and the CAE answering the request for the transformed blob does not yet know about the updated blob and (2) a client has stored a very old version of a transformed blob URL for which the blob data is no longer cached by the CDN. A CAE cannot distinguish between these two cases but serves the currently (either outdated or newer) known transformed blob. The new configuration property allows projects to optimize for scenario (1) or (2) by setting a (1) short duration or (2) a long duration.

Configuration example:

# Set cache duration to 1 hour
delivery.outdated-transformed-blob-cache-duration=1h

Upgrade Information

(CMS-28032)

Third-Party Update: commons-io 2.19.0

Apache Commons IO has been updated to 2.19.0.

(CMS-27839)