Links are only regenerated after they have expired. For backward
compatibility the links are also generated when there is no expiry
or link. Every file has only one expiry timestamp for all its links.
In the future we might want to inspect the used projection, to see
whether the client needs those links at all (prevents unnecessary
regeneration), and to force inclusion of the expiry timestamp when
links are requested.
Sybren A. Stüvel
37037f3c2c