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Re: proposal for issue #178

From: Roy T. Fielding <fielding@gbiv.com>
Date: Mon, 7 Jun 2010 13:02:05 -0700
Message-Id: <8744BB96-25EB-4910-81B5-5B77CB7C03C5@gbiv.com>
To: "'HTTP Working Group'" <ietf-http-wg@w3.org>
On Jun 7, 2010, at 8:05 AM, David Morris wrote:
> On Mon, 7 Jun 2010, Daniel Stenberg wrote:
> 
>> On Tue, 8 Jun 2010, Adrien de Croy wrote:
>> 
>>> I don't see any point in having an integrity check for a message containing
>>> only a partial range.  Surely you want to accumulate the entire entity by
>>> piecing together all the parts, and then you use the MD5 to check the total.
>> 
>> Imagine downloading a large file in many small chunks from many different
>> servers.
>> 
>> In the end, you might sit there with a huge file with a bad checksum without
>> being able to pinpoint the single small chunk that had the error. So now you
>> need to redownload the whole thing again, instead of just regetting the small
>> chunk that contained the error.
> 
> Fact of the matter is that the probablitly of getting one chunk in error 
> is very low in comparison with the origin servers being out of sync being 
> the reason for the error. Without an MD5 for the whole entity there is no
> was to check the complete entity for correctness.
> 
> It should have been clear from the beginning that the MD5 applied to the
> whole entity.

No, Content-MD5 is a MIME header field for message content.  Always has been.

....Roy
Received on Monday, 7 June 2010 20:02:35 GMT

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