Re: [squid-users] ETag support for html files

fre 2006-06-02 klockan 13:10 -0400 skrev sknipe@tucows.com:

> Could you please verify the following. When ETag is used
> for .html pages, the caching seems to be at the Browser
> level. Does Squid play a role in the if-none-match with
> ETags?

Caching is still done at the proxy. ETag changes nothing of that. What
ETag does is only to allow the use of If-None-Match which is a stronger
cache validation than If-Modified-Since, allowing detection of object
changes within the same second or when an object is replaced by an older
object.. (i.e. restored from backup or similar).

> Is there a way to have an HTTP/1.1 or HTTP/1.x response
> generated for IE?

Squid is HTTP/1.0. It can't respond with HTTP/1.1 as it does not yet
support transfer-encoding and a few other critical HTTP/1.1 components
wich MUST be supported to announce HTTP/1.1. Responding with HTTP/1.1
without supporting HTTP/1.1 would result in a lot of problems as the
transfer encoding changes the HTTP/1.1 message format (it's not just
some added header or other trivial change..)

Clients are not supposed to make many other differences in their
behavior because of this other than to not use transfer encoding. Using
If-None-Match within HTTP/1.0 is fine and even required by the HTTP/1.1
specification, but should for completeness be combined with a
If-Modified-Since in case the server or proxy does not support
If-None-Match. Please note that this is even the case if the server is
HTTP/1.1 as supporting If-None-Match is optional. See RFC2616 (HTTP/1.1)
section 13.3.4 "Rules for When to Use Entity Tags and Last-Modified
Dates" for a detailed description on when to use what and the reasoning
behind this..

Regards
Henrik