[Standards] Questions pertaining to upcoming resubmission of Real Time Text standard (0.0.2)

Dave Cridland dave at cridland.net
Mon May 16 16:24:46 UTC 2011


On Mon May 16 17:05:51 2011, Joe Hildebrand wrote:
> On 5/12/11 12:22 AM, "Mark Rejhon" <markybox at gmail.com> wrote:
> 
> > -- Using numbered sufix "urn:xmpp:rtt:0"
> > ADVANTAGE: Versioning by incrementing the final number;
> > DISADVANTAGE: Many parser libraries make it difficult to provide
> > forward/backward compatibility because they look for an exact  
> xmlns value.
> > (Example: Smack Java library).  I.e. an application would only  
> work with a
> > specific exact 'xmlns'
> 
> That is a feature.  If the version number gets incremented, your
> implementation will need to process the protocols independently if  
> you want
> to have both active at the same time.  If you're able to share code  
> between
> them, that's an implementation detail, but as far as XMPP is  
> concerned, they
> are effectively two completely separate protocol extensions.

Right - you can (and should, where possible) avoid incrementing the  
version number, such as when an update is a superset of the original  
protocol, or unchanged.

But when required syntax or behaviour changes to the point where  
interoperability would fail, you can avoid tricky situations by  
minting a new namespace from within a parent metanamespace[1], and so  
avoid any experimental protocol leakage or "deployed base" issues  
from having any serious effects.

Dave.

[1] - Yes, I did just make that up. I can only apologise.
-- 
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