[Standards] XEP-280 and MUC private chats

Peter Saint-Andre stpeter at stpeter.im
Tue Jul 16 21:31:22 UTC 2013

On 7/16/13 3:23 PM, Kevin Smith wrote:
> On Tue, Jul 16, 2013 at 8:02 PM, Peter Saint-Andre <stpeter at stpeter.im> wrote:
>> On 7/14/13 1:13 PM, Mathieu Pasquet wrote:
>>> On Sun, Jul 14, 2013 at 05:36:51PM +0100, Kevin Smith wrote:
>>>> On Sun, Jun 9, 2013 at 7:40 PM, Mathieu Pasquet <mathieui at mathieui.net> wrote:
>>>>> I was starting to implement carbons in poezio when I came across some
>>>>> kind of design issue that I haven’t been able to work out.
>>>>> As I understand it (and in the use case explained in the introduction),
>>>>> Carbons provide a way to minimize the nuisance of changing devices, by
>>>>> providing all the messages with 'chat' type to all the carbon-enabled
>>>>> clients.
>>>>> The requirements also state that “All clients that turn on the new
>>>>> protocol MUST be able to see all inbound chat-type messages”.
>>>>> However, in the case of private MUC messages (XEP-0045, 7.5), the
>>>>> messages are also of type 'chat', causing them to be forwarded as normal
>>>>> chat messages. But the other resources are not necessarily present on
>>>>> that MUC, so they will receive the messages just fine, as with any
>>>>> direct conversation with a fulljid, but they won’t be able to reply,
>>>>> because I believe most MUC implementations will check the fulljid and
>>>>> reply with an error.
>>>>> I can’t think of a straightforward solution to this issue, as the server
>>>>> doesn’t know about MUC, neither does the other resource.
>>>>> On the sender part, it might be solved by including a <private/> with
>>>>> each message sent through such chats, but on the receiving part, AFAIK
>>>>> there is no way to distinguish those.
>>>>> I think the XEP should cover that case, because it is rather common to
>>>>> have private conversations with people in a groupchat, and letting
>>>>> clients guess how they should handle the message is very error-prone.
>>>> Could you disco any unknown JIDs to see if they're users or MUCs?
>>>> /K
>>> Yeah, that’s what I went with (I had forgotten about it at the moment of
>>> writing that email).
>>> I think the XEP should indicate such a behavior, as a client developer
>>> might forget about this case.
>> Sounds like a positive addition. It would be good to advance this spec
>> to Draft sometime. Do you have any other feedback?
>>> Or even better, maybe the server could perform that disco, although I
>>> get that making changes to already-deployed implementations might be
>>> painful.
>> How would it work for the server to perform service discovery on your
>> behalf? (BTW, you don't need to send the disco request if you're using
>> entity capabilities / XEP-0115.)
> No?

I must be missing some context, then -- if you've received caps from
another entity, there's no need to send the disco request.

Peter Saint-Andre

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