Re: Client-side expanded url's

Mic Bowman (
Fri, 08 Mar 1996 08:18:10 -0500

Message-Id: <>
Subject: Re: Client-side expanded url's 
In-Reply-To: Your message of "Thu, 07 Mar 1996 08:04:37 EST."
Date: Fri, 08 Mar 1996 08:18:10 -0500
From: Mic Bowman <>

A couple years ago, Transarc built a URL translation facility to
define equivalent URLs with a preferred order for access.  Our motivation
was to make use of the caching/replication facilities of a wide-area
file system like AFS/DFS.  Given the choice of pulling a page from an
http server or the equivalent page from an afs server, I generally
prefer the afs server.

The translation worked through a series of rules not unlike the rules
that some servers have for translating incoming HTTP paths into local
file system paths.  The rules file looks something like this:

	substitution1 [frequency]
	substitution2 [frequency]

If the URL matches the pattern, then choose a substitution.  The
substitution is chosen randomly with a distribution based on the 
frequency parameter.  

In addition to enabling dual access to files available through both 
afs and http, the translation provides a nice way to access transparently 
proxy servers, ftp mirror archives, and replicated http sites.

For more information you might want to check out:


Member of Technical Staff, Lead Architect Research Group
Transarc Corporation
The Gulf Tower, 707 Grant Street
Pittsburgh, PA 15219
(412) 338-6752
(412) 338-4404 (FAX)