RDF for e-mail metadata? Hmm.

by Uche Ogbuji

Related link: http://www.ietf.org/internet-drafts/draft-klyne-message-xml-00.txt



I've always been a proponent of RDF in reasonable circs: i.e. in closed systems where authorities are clear. But ocasionally I come across the usage that makes me wonder whether it is madness, genius, or both.



The idea of encoding e-mail messages in XML is not new. Several years ago, Jonathan Borden developed XML Mail Transport Protocol (XMTP) for representation of RFC 822 and MIME in XML. I thouht Jonathan might have also experimented with an RDF variation on this, but the relevant Web page is down right now, so I'm not sure.



Graham Klyne's Interet Draft is much more comprehensive than XMTP. Though it's in RDF/XML, it tries to keep the RDFisms as disceet as possible. Nevertheless, the question is whether the following works for an XML e-mail representation:




<emx:Message
xmlns:emx='URN:ietf:params:email-xml:'
xmlns:rfc822='URN:ietf:params:rfc822:'>
<rfc822:from>
<emx:Address>
<emx:adrs>mailto:Christopher.Robin@GreenDoor.org</emx:adrs>
<emx:name>Christopher Robin</emx:name>
</emx:Address>
</rfc822:from>
<rfc822:to>
<emx:Address>
<emx:adrs>mailto:Pooh@PoohCorner.100Aker.org</emx:adrs>
<emx:name>Winnie the Pooh</emx:name>
</emx:Address>
</rfc822:to>
<rfc822:subject>Re: Woozle hunting</rfc822:subject>
<emx:content type='text/plain'>
You're the Best Bear in All the World
</emx:content>
</emx:Message>


I'll have to chew on it a bit to decide. "It's too verbose" comments ae too facile: remember that the aim here is more machine accessibility than human readibility.



5 Comments

anonymous2
2003-03-14 02:12:27
email xml
okay this is something that has puzzled me for a while. To say that it doesn't matter that a reperesentation of email as xml is too verbose because it is meant to be machine accessible supposes that email is not machine accessible as of now, which of course it isn't as regards the meaning of the message, as regards the from, to, etc. etc. headers and all other things relating to the standard it is very accessible. For this reason the translation of the legacy structure of email to an xml structure seems to give benefits only in the context of decreasing the number of tools that one has to be familiar with, unless of course there is addressed the possibility of adding markup into the content of the message in such a way as to increase semantic richness. In such a scenario (the really interesting one in my opinion) the verbosity of a standard can become quite a sticking point.
uche
2003-03-15 11:24:13
email xml
Current MIME is somewhat accessible to machines, but not in a way that is easy to integrate into other data, nor in a way that is easy to extend, especially for metadata notaton. The richness of the systems (such as blogs) that have appeared once extensible alternatives to flat machine formats have been established is, I think, instructive.


Of course, all this is a matter for as much philosophical debate as technical.

danja
2003-03-15 15:58:41
hmm...
Heh - does the web (semantic or otherwise) come into the category of "closed systems where authorities are clear."?


Regarding Graham's format - interesting approach, seems sensible to reuse the semantics of the rfc rather than bend DC, foaf etc to fit.


There's a good question near "anonymous"'s comment - how much of the machine friendliness needs to come from the syntax, and how important is the format? Surely the model should be enough - i.e. forget RDF/XML, use MIME data but directly as RDF, according to an interpretation like Graham's. Plug the mail interface directly into your system. If you *must* serialize it to an external form, it's still worth asking: is RDF/XML the most appropriate?

anonymous2
2003-03-17 12:09:35
Exercise in futility
What a waste of time :-)


Why do you guys get going with what you already have instead of those intellectual mastu..., er, whatever?-)


Proof that MIME is machine readable: ZOE

uche
2003-03-18 11:49:37
Exercise in futility
I'm not quite sure I understand your point, but to the extent that I do, I think you might have to consider that some of the people who work on these matters are very successful and productive. If you think such matters are a waste of time, I wonder why you would spend your own time on a weblog discussing them.


--Uche