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Re: Idea to reduce web traffic

From: Yves Lafon <ylafon@w3.org>
Date: Thu, 5 Feb 2004 16:10:14 +0100 (MET)
To: Clóvis Wichoski <clovis_wichoski@uol.com.br>
Cc: www-jigsaw@w3.org
Message-ID: <Pine.GSO.4.58.0402051552330.22327@gnenaghyn.vaevn.se>

On Thu, 29 Jan 2004, Clóvis Wichoski wrote:

> For example:
> The client request Index.html that is in your local Jigsaw cache and
> returns quickly, in this page has a login form with action /servlet/
> that the local Jigsaw forward to an online WebServer (Apache+Tomcat).

> 1) I don't need that for every request to static content to check the
> WebServer if this page has changed, for static content, I like to run a
> method like, updateAllCacheNow(). but this situation is for some sites,
> don't for all.

Do you want Jigsaw to forward everything and act as a surrogate proxy or
just used as a connector for some spaces like /servlet/ ?
> 2) for this maybe I use MirrorFrame? or MirrorFrame don't work with
> dynamic contents?

MirrorFrame is the one to use in the second case describer. MirrorFrame
mirrors part of a web site and don't really care if the content is dynamic
or not.

> 3) I need to Implement my own ProxyFrame and CacheFilter, or this
> already can be done by Jigsaw?

It should be there, but if there is something it can't do, it can be

> 4) If I need to Implement there is a way to get the Sequence diagram or
> idea of a request on Jigsaw? (how  ProxyFrame and CacheFilter works from
> request to response)

The processing model is defined at

Note that there are two different cache filters, one server side and one
client side.
The client-side one is the one to use in the general case for proxies and
mirrors, as it act as an HTTP/1.1 compliant cache. Most probably the
static content will stay in the cache and the dynamic will be always
forwarded (provided they are served with proper HTTP headers)

> The idea is to reduce the web traffic, for example, think that in one
> page I have 30 images, for all images, the browser cache, request to
> Jigsaw Proxy if image changed, then Jigsaw Proxy request to WebServer if
> image changed, and only when WebServer reply to JigSaw Proxy the Jigsaw
> reply to Browser that image isn't changed, then the image is displayed.

Hum so it is a HTTP/1.1 proxy/cache compliancy issue (in that case only
the ProxyFrame and the CacheFilter). When the browser ask for a new
version, the cache will compare the request with what's in the cache and
the expiration timeand based on that will serve it directly of get it form
the uptream server.

> On browser I can't change this behavior but on Jigsaw I can, but I need
> some help, before start, to assure that I don't already make a know
> feature of Jigsaw.

Well, if the browser is in Java, you can reuse Jigsaw's HTTP stack (and
proxy/cache) in place of the default one.

Yves Lafon - W3C
"Baroula que barouleras, au tiéu toujou t'entourneras."
Received on Thursday, 5 February 2004 10:12:22 UTC

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