Re: HTTP 'HASH' Method

A "hash" method would require the webserver to cache the md5/sha1 values in order to minimize disk access (computing cache on big files is using a lot of time). 

I'd suggest to use a kind of hash based on the inode number, the file size and modification time. This would just require a call to stat() and return the same value until the file gets changed. 

What ? It already exists and is called "E-Tag" ? Wow, I guess someone thought about it before me. 

So, your large network which tend to use caching extensively just have to send a request with HEAD query, or even better - a head with a If-Modified-Since header, and you're saved. 

----- Message Original ----- 
De: "chown" <elfius@gmail.com> 
A: ietf-http-wg@w3.org 
Sent: vendredi 25 mai 2007 06 h 36 (GMT+0100) Europe/Berlin 
Sujet: HTTP 'HASH' Method 

I think a 'HASH' method should be implemented into HTTP, whereby the server responds with a hash (md5/sha) of the requested resource. This would be a godsend for large networks which tend to use caching extensively, because caching-proxy servers could verify the source hasn't changed while creating a minimal amount of traffic, thereby allow the amount of time the proxy stores cache to be be greatly increased only at the cost of hard drive space. 
Not only would this benefit caching applications, but as I'm sure you could imagine, it could be used in may other fields, especially security.