Re: [Ietf-message-headers] Re: I-DAction:draft-saintandre-header-pres-00.txt

SM wrote:

> At 01:56 07-11-2007, Peter Saint-Andre wrote: 

 [...]

>> What are "these schemes"? What is the category under which it is
>> perceived that the im: scheme and the pres: scheme are the same? Again,
>> according to RFC 2779, RFC 3859, and RFC 3860, these are separate and
>> distinct domains of functionality, which just happen to often be
>> implemented and deployed in the same systems or services.
>
> You are viewing the im: scheme and the pres: scheme from the point of 
> view of their RFCs which is different from the functionality offered 
> by the mail header.  In a previous email, you mentioned a generic 
> solution.  My point is that it is better to have a generic mail header 
> to encompass pres:, im: and other schemes that would use URIs in such 
> a manner.

+1. I don't see why 2 nearly identical header fields are needed.

I also don't see any particular reason for prohibiting direct use of 
XMPP or SIP URIs here. There is no need in extra resolution step if an 
email author only supports one type of IM application.

Regarding the recommended syntax: it is worth considering syntax used by 
List-Archive/List-Unsubscribe/... (RFC 2369) header fields, which are 
surrounded by '<' and '>', e.g.:

List-Archive: <http://www.imc.org/ietf-imapext/mail-archive/>

> We could have, for example, the following header:
>
> Contact-ID: pres:juliet <at> example.com; im:juliet <at> example.com
>
> The MUA would process the header to determine whether there is a 
> presence URI or IM URI and take appropriate action.