Support for multiple representations for a URL

[dasch]

In some cases it makes sense to have multiple resources for the same URL, e.g. one for logged-in and one for anonymous users. I believe the spec supports this, as e.g. If-None-Match can contain a list of ETags.

I propose the following change:

1. Rather than merely selecting the first matching cache entry for a request, get all matching entries.
2. If one of them is still fresh, respond with that immediately.
3. Otherwise – if they all need to be validated – collect the ETags and pass them all to the application in If-None-Match.
4. If the application responds with 304, select the entry with the ETag found in the 304 response.

This would allow the application to control exactly what is returned to the client.

[dasch]

(Also, I'd be happy to implement this if you agree with the design.)

[grosser]

@rtomayko

[ioquatix]

Boop +1

[grosser]

Sounds good ... @dasch want to make a PR ? ( I'm the maintainer now 😭 )

[dasch]

@grosser we've switched to caching with Nginx in the meantime :-x I probably won't have time to look at this in the short term, but it shouldn't be too difficult.