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Re: Examining the 'no server modification' requirement

From: Brad Porter <bwporter@yahoo.com>
Date: Thu, 10 Jan 2008 22:36:42 -0800 (PST)
To: Mark Nottingham <mnot@yahoo-inc.com>
Cc: "WAF WG \(public\)" <public-appformats@w3.org>
Message-ID: <691012.23164.qm@web53509.mail.re2.yahoo.com>

So basically if servers, browsers, and proxies all need to be update to support the caching and protocol extensions?

(Sent from mobile device)

On Jan 10, 2008, at 10:15 PM, Mark Nottingham <mnot@yahoo-inc.com> wrote:

On 11/01/2008, at 4:46 PM, Brad Porter wrote:

The no-server-modification requirement originally arose in the voice browser working group due to the practical experience of the participant companies that in many large IT-based companies, the website environment is a shared environment that supports segmented ownership of documents and content, but not segmented ownership of website configuration.  Given this is a per-resource policy, it made sense to associate the policy meta-data directly with the resource.  This is why the original NOTE only focused on the Processing Instruction and did not include the HTTP headers.

Further, there are a number of cases that voice browser working group participants identified where the resources are static and can be properly cached.  Proper HTTP caching was heavily used for static-only content in the voice browser realm given the tighter response time requirements expected on the phone.  Therefore, requiring server validation would potentially require sites to invoke a dynamic pathway for static XML data, or worse eliminate effective caching altogether.

That's the beauty of the server-side model; it works very well with caching.

E.g., if the request is

GET /foo HTTP/1.1
Host: www.example.com
Referer-Root: http://other.example.org/

The response could be

HTTP/1.1 200 OK
Cache-Control: max-age=3600
Vary: Referer-Root


which tells a cache that it can serve that response to other clients, *as long as* they send the same Referer-Root header. The cache ends up enforcing the server's policy on its behalf, without any new software.


Mark Nottingham       mnot@yahoo-inc.com
Received on Friday, 11 January 2008 06:36:59 UTC

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