[Standards] Fwd: [TechReview] Review of XEP-0234, 0260 and 0261.

Peter Saint-Andre stpeter at stpeter.im
Tue Aug 17 11:52:46 UTC 2010

On 8/17/10 5:37 AM, Matthew Wild wrote:
> On 17 August 2010 05:21, Peter Saint-Andre <stpeter at stpeter.im> wrote:
>> I'm forwarding this old message to the Standards list for further
>> discussion. Expect follow-ups soon.
>> /psa
>> -------- Original Message --------
>> Subject: [TechReview] Review of XEP-0234, 0260 and 0261.
>> Date: Fri, 28 May 2010 14:53:14 +0200
>> From: Steffen Larsen <zooldk at gmail.com>
>> Reply-To: XSF Technical Review Team <techreview at xmpp.org>
>> To: XSF Technical Review Team <techreview at xmpp.org>
>> CC: XMPP Extension Discussion List <standards at xmpp.org>
>> Hi All,
>> Me, Joe and Ali have spend some time last week to review the XEPs
>> described in the subject.
>> Here is our summary of XEP-0234 (which I also mailed earlier to the tech
>> list):
>> Hash transfer in section 3. has a poor wording: "At any time, the
>> hosting entity can communicate the hash of the file to the receiving
>> entity".
>> We believe that it should be changed to "At any time (during the session
>> life-time or before the session terminates)".
>> That will make it more unambiguous that it can only be done in the right
>> state (that is in a session that is not terminated yet).
>> The <file> tag has a size attribute, but the unit is not explained
>> anywhere. Its only in XEP-0096 chapter 3 it is explained that the unit
>> is bytes. It is the same with the hash attribute. In XEP-0234, it is not
>> visible that it is the MD5 checksum that is used as algorithm.
>> In XEP-0234 it does not look like that we can do resumable downloads of
>> files. In XEP-0096 it looks like that there is defined an optional
>> <range> element. If ranged queries are to be implemented, we could do
>> that as a transport options/transport features (XEP-0260/0261). But it
>> seems like that this feature is left out at present time.
> Just a quick note that if we add ranges, we should make sending the
> hash with the session-initiate a SHOULD. Otherwise the receiving
> client has no way to judge whether it is the same file except by the
> filename and size.
> Also I've had bad experience (as a user) with transfer resumption thus
> far... I think some clients just ignore the range, and send from 0,
> causing the range-supporting recipient to receive the start of the
> file twice. So either we make range support mandatory, or we need some
> way for the initiator to announce it.

If anything, I'd prefer to remove ranges from XEP-0096. Do any clients
support them?


Peter Saint-Andre

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