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Re: DIFF method

From: Werner Donné <werner.donne@re.be>
Date: Mon, 20 Mar 2006 14:46:57 +0100
Message-ID: <441EB251.6000609@re.be>
To: Geoffrey M Clemm <geoffrey.clemm@us.ibm.com>
Cc: ietf-dav-versioning@w3.org, webdav <w3c-dist-auth@w3.org>

Geoffrey M Clemm wrote:
> 
> I wasn't questioning the desirability (from a client's perspective) of
> having a DIFF method, but was just pointing out that the challenge is
> to come up with a standard result format that more than one server will
> be willing/able to produce.

I don't see why there should be a standard result format. There are by
definition many, because there are many content types. For some a diff
may even not be possible. There can also be several result formats
for the same content type. That is a matter of representation.

> 
> Cheers,
> Geoff

Regards,

Werner.

> 
> Werner wrote on 03/20/2006 08:24:55 AM:
> 
>> Geoffrey M Clemm wrote:
>> > The only interesting thing about a DIFF method is the format of its
> result.
>> > There was such a wide variation in the different formats that diff
> tools
>> > use for different types of resources that it didn't appear to be
> something
>> > on which we could get consensus.  There are some standards for diff
> formats,
>> > e.g., http://www.ietf.org/rfc/rfc3284.txt?number=3284 (The VCDIFF
> Generic
>> > Differencing and Compression Data Format) and some new ones being
>> > proposed, e.g.,
> http://www.ietf.org/internet-drafts/draft-ietf-simple-xcap-diff-03.txt
>>
>> The diff calculation itself can require software that can't be distributed
>> to clients, because of licensing limitations, programming language,
> resources
>> or whatever. Note that it can be more than just a diff of text files. I
>> will use DeltaXML, for example, which is specialised in calculating
> the diff
>> between two XML documents. It inserts mark-up in its own namespace in the
>> resulting document.
>>
>> The format can also be converted on the fly, depending on the "Accept"
>> request header. I could convert it to PDF, again with tools that are only
>> available on the server.
>>
>> > Cheers,
>> > Geoff
>>
>> Regards,
>>
>> Werner.
>>
>> >
>> > Werner wrote on 03/20/2006 04:28:34 AM:
>> >> Shouldn't there be a DIFF method? Calculating the difference between
>> >> two versions may be a very specialised operation for some document
>> >> formats. The software or resources to accomplish it may not be
> available
>> >> to clients.
>>
>> --
>> Werner Donné  --  Re
>> Engelbeekstraat 8
>> B-3300 Tienen
>> tel: (+32) 486 425803   e-mail: werner.donne@re.be
>>

-- 
Werner Donné  --  Re
Engelbeekstraat 8
B-3300 Tienen
tel: (+32) 486 425803	e-mail: werner.donne@re.be
Received on Monday, 20 March 2006 13:46:41 GMT

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