James Snell wrote:
I really don't want to be going down the road of requiring HTTP header equivalents in the Atom feed, etc. All I want is the ability to specify a hash of whatever it is that is being linked to. It could work in both link and content elements and one could easily use the Content-MD5 header to verify whether or not the resource referenced has been modified since the time it was included in the Entry.
The URI and the length of the file do not guarantee that the content
has not changed and yes, I had considered this as a possible non-core
extension but wanted to float it as a core item first.
The level of accuracy you're looking for can't be achieved without specifying which HTTP request headers can influence the content returned (e.g. "Accept"), and what their values must be in order to receive the content with the hash given. For example, content negotiation could be really handy for podcasts (mp3, aac, ogg, wma).
Robert Sayre
