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Re: Whatever happened with Partial PUTs

From: Jim Luther <luther.j@apple.com>
Date: Wed, 6 Feb 2002 08:12:24 -0800
To: w3c-dist-auth@w3c.org
Message-Id: <4E55AA52-1B1C-11D6-AA84-0003934B6A22@apple.com>
I found the answer by searching through the archives some more (it was 
under PUT-RANGE).

<http://lists.w3.org/Archives/Public/ietf-http-wg/1997OctDec/0011.html> 
gives the reason why PUT-RANGE wasn't left in the HTTP 1.1 specification 
and 
<http://www.w3.org/Protocols/HTTP/Issues/BeforeLastCall.html#PUT-RANGE> 
is where PUT-RANGE was officially removed from Rev-02 of the HTTP 1.1 
spec.

I guess we'll look at using something Mac OS X client/Apple iDisk server 
specific until there's a standard way to do ranged PUTs.

- Jim Luther

On Monday, February 4, 2002, at 11:05 AM, Jim Luther wrote:

> Hi,
>
> Last week I posted something to the HTTP list (copied below) and I've 
> received no response. So this morning I searched the w3c archives and 
> found that my issue had been discussed before on this list (see 
> <http://lists.w3.org/Archives/Public/w3c-dist-
> auth/1997JanMar/thread.html> and look for "Partial Put"). However, I 
> didn't find that the issue of partial or ranged PUTs has ever been 
> resolved.
>
> As Yaron Goland said at the time 
> <http://lists.w3.org/Archives/Public/w3c-dist-
> auth/1997JanMar/0258.html>, "As anyone running on a 28.8 modem or less 
> will tell you, this isn't an optimization, this features determines if 
> the user can function." I wouldn't limit that to 28.8 modems -- with 
> large enough files, this can even affect users with fast connections.
>
> I know that mod_dav allows Content-Range headers with PUTs. However, it 
> only allows a file's existing content to be changed and for new content 
> to be appended to the end of the existing content. We also need to be 
> able to change the length of a resource without changing the content.
>
> So, what happened with this issue?
>
> Jim Luther
> Apple Computer, Inc.
>
>> From: Jim Luther <luther.j@apple.com>
>> Date: Thu Jan 31, 2002  06:13:20 PM US/Pacific
>> To: http-wg@cuckoo.hpl.hp.com
>> Subject: Ranged PUT and changing an entity's length
>>
>> Hi,
>>
>> Mac OS X has a file system which uses HTTP and the WebDAV extensions. 
>> Today, when an file entity on a DAV server is opened with write 
>> access, our file system GETs the entire entity from the server and 
>> then works with the local copy. When that entity is closed or synced, 
>> the local copy is PUT back to the server.
>>
>> I'd like to change our code so that individual write requests to the 
>> server entity are write-through to the server, but to do that, I need 
>> to be able to do a ranged PUT with the range possibly starting and 
>> ending beyond the entity's current instance-length (the current length 
>> of the entity on the server). In addition, to be able to handle seek 
>> and truncate requests, I need to be able to change the instance-length 
>> without changing any data to both to make the entity either larger or 
>> smaller.
>>
>> RFC 2616 doesn't really say how a Content-Range header might be used 
>> to specify a ranged PUT request (it only discusses how a server would 
>> use it to reply to a ranged GET), and nowhere that I can find does the 
>> RFC say how the length of an entity can be changed (although I was 
>> thinking that maybe the byte-content-range-spec in a Content-Range 
>> header could look something like "bytes */100" to set the length of an 
>> entity to 100 without changing any data).
>>
>> So, my two questions:
>>
>> 1 - Are ranged PUTs possible and if so, what should the headers look 
>> like?
>>
>> 2 - Can the length of an entity be changed and if so, what should the 
>> headers look like?
>>
>> Thanks,
>>
>> Jim Luther
>> Apple Computer
>
Received on Wednesday, 6 February 2002 11:12:26 GMT

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