> Subject: Caching Proxy Caching server
> Date: Thu, 6 Apr 2000 00:22:49 -0700 (PDT)
> From: David LeBlanc <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED]
>
> Hi all;
> I have the chance to use TclHttpd in a project and i'd like to use it as
> follows:
>
> INTERNET <-> tclhttpd <-> browser with tclhttpd caching all pages called
> for by the browser for later offline viewing.
>
> Is this possible? Is it difficult? Has anyone done it before?
Is certainly is possible, and not particularly difficult.
Combining the tclhttpd with the http package gives you most
of what you need.
Building a fully-featured, general-purpose, HTTP/1.1 compliant
caching proxy server would certainly involve a reasonable
amount of engineering, but it's not rocket science.
Recently I built a system using tclhttpd that handled all of
the interactions with the browser, but connected via HTTP
with a SAP R/3 system out the backend. Let me assure you that
the tclhttpd component was the easy part ;-)
A caching server simply needs to stuff the downloaded data
into a Tcl array (for in-memory caching) or into a file
for long-term caching. It can look at the HTTP headers to
determine if the document should/shouldn't be cached,
expiry time, etc. The only hard part would be running
a "thread" to expire stale documents, and checking for
freshness with HEAD queries.
Cheers,
Steve Ball
--
Steve Ball | Swish XML Editor | Training & Seminars
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