Re: bohe and delta experimentation...

"Adrien W. de Croy" <adrien@qbik.com> Sat, 19 January 2013 01:03 UTC

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From: "Adrien W. de Croy" <adrien@qbik.com>
To: Phillip Hallam-Baker <hallam@gmail.com>, James M Snell <jasnell@gmail.com>
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Date: Sat, 19 Jan 2013 01:00:31 +0000
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Subject: Re: bohe and delta experimentation...
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------ Original Message ------
From: "Phillip Hallam-Baker" <hallam@gmail.com>
>
>
>On Wed, Jan 16, 2013 at 5:07 PM, James M Snell <jasnell@gmail.com> 
>wrote:
>>After going a number of scenarios with bohe using a variety of 
>>stream-compression scenarios it's painfully obvious that there is 
>>really no way around the CRIME issue when using stream-compression. So 
>>with that, I'm turning my attention to the use of Roberto's delta 
>>encoding and exploring whether or not binary optimized values can make 
>>a significant difference (as opposed to simply dropping in 
>>huffman-encoded text everywhere).
>>
>>I'm starting with dates first...
>>
>>Right now, dates in http/1 requests are rather inefficient. The 
>>existing date-time format wastes a significant amount of space, albeit 
>>across only a relatively few headers. On the plus side, these tend to 
>>compress well, but given that the dates change frequently 
>>request-to-request, they will be short-lived in the delta context.
>
>Why do HTTP request messages have dates in them anyhow?

Date is used in caching, with Last-Modified it is used to calculate age 
of resource when served for purposes of estimating max-age for heuristic 
caching.

This presumes the same clock was used to generate Date as Last-Modified.

So I don't think we can lose it.

Adrien