Subject: [httpwg/http-extensions] Cache digest and scoping (#216)

From: HTTP issue updates <[email-masked]>
Date: Tue, 26 Jul 2016 00:41:33 -0700

In the draft it is unclear what the scope the digest will cover.  Is it scoped to the hostname of the stream (authority header)?  Is the scope limited to the resources referenced in the stream and the client would have to keep a data structure around for every page?

There are a few cases where I can see issues with scoping on hostnames:
1. If a user goes to www.example.com, you might want to expand the cache digest to all of the resources for example.com.
2. The first point doesn't make sense for a site like Tumblr where there are many blogs for *.tumblr.com and creating a digest might become large.  Having a limit on the number of items in the digest and having the most used items in the cache digest might help.
3. There are also issues for sites where there are multiple domain names referenced by the stream and being served by the same connection.  This will happen with finance.yahoo.com where it has s.yimg.com resources and they are served by the same server.

For reference:
"A CACHE_DIGEST frame can be sent from a client to a server on any stream in the "open" state, and conveys a digest of the contents of the client's cache for associated stream."

---
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/httpwg/http-extensions/issues/216