I certainly understand not wanting to allow an option to reduce the cache length, as many would probably want. But I have the opposite request: an option to extend the caching beyond the normal (30 days?) length?

My use case is images that are stored in github repos, where the URL includes a specific git commit hash, such as this one:

https://raw.githubusercontent.com/getify/You-Dont-Know-JS/06de0535b240f0d5be8971fbb93d474f0195f767/up%20%26%20going/fig1.png

These images, at these kinds of URLs, will never change, by virtue of how git works. If they change, the URL itself changes. They could be deleted, but that's a separate issue (the in-progress feature for an API to remove from cache).

For some reason, github (via their "raw.githubusercontent" CDN) returns very short caching headers, so it ends up creating unnecessary loads if I link that image for users. I can route these URLs through your service and now there's 30-day caching headers being applied, which is much better for users.

But ideally, I could add an option like "cache-forever" or "long-cache" or something like that, where the image caching header will be 1 year (or even longer), for cases where it's known that the image will never change.

Is this something you would consider adding?