[Standards] Domain & JID Aliasing

Thu Feb 1 16:07:33 CST 2007

> Tim Brennan schrieb:
>> Unless there's some way a redirect solution could be made to work  
>> somehow with existing clients (e.g. if the redirect was wrapped in  
>> a <message> in such a way that we expect most clients to display  
>> the error message to the end user telling them to use the  
>> different address).  Maybe existing clients do the right thing  
>> with <gone>, but I doubt it.
>
> The "<message/>" of the gone error is in the <text>...</text>  
> element of the error stanza, no? Most clients I know should present  
> the text contained in this element.

Many only display the text element to the user if it's in a message  
stanza.  If, for instance, a client gets a presence error ('Remote  
server unavailable'), many will will display it in my status log, but  
will NOT pop up a messagebox from that user and display the text.   
(After all, it'd be really annoying if they did, considering how many  
little personal jabber servers go offline periodically!)

Given that, I think Tim's point about wrapping it in <message/> was  
that it's the only way you could be backwards compatible in  
redirects.  At least, and still have the user informed for certain.  
For instance, if someone tried to send a <presence/> of type  
subscribe to 'tim.brennan at zimba.com' and got back:

<presence from='tim.brennan at zimba.com' type='error' id='cli12'> </ 
presence><error type='modify' code='400'><gone  
xmlns='urn:ietf:params:xml:xmpp-stanzas'>tim at zimba.com</ 
gone><text>Hi, this is the server at Zimba.com!  I see that you're  
trying to subscribe to tim.brennan's presence, but tim.brennan is  
merely an alias for the user tim at zimba.com; please add tim at zimba.com  
to your roster instead.  Thanks!</text></error></presence>

<message to='sparks at jabber.org/Trillian' from='tim.brennan at zimba.com'  
id='redir01'><body>Hi, this is the server at Zimba.com!  I see that  
you're trying to subscribe to tim.brennan's presence, but tim.brennan  
is merely an alias for the user tim at zimba.com; please add  
tim at zimba.com to your roster instead.  Thanks!</body></message>

...which would display something more-or-less workable on  
everything.  Downside, it's a) ugly, and b) leads to an extraneous  
message on any client that DOES understand <gone/>.  And c) it makes  
aliases pretty darn pointless anyway.

Realistically, using 'redirects' in this manner would be the  
equivalent of e-mailing 'tim.brennan at zimba.com' and getting an e-mail  
in reply saying, "Hi!  You tried to e-mail tim.brennan at zimba.com.  I  
know who this is, but his real e-mail is tim at zimba.com.  Rather than  
forwarding the message on silently, I'm going to be exceedingly  
annoying and tell you to resend it with a different 'to' address!   
Have a nice day!"

At which point, there's really no purpose in having the aliases in  
general other than if someone's trying to guess/remember a JID.   
Hence why (as ugly as it might be), I think for servers that want to  
support aliasing, the 'right thing' from a usability standpoint is  
the silent internal translation.

-- 
Rachel Blackman <rcb at ceruleanstudios.com>
Trillian Messenger - http://www.trillian.cc/