[Standards] RDFa ? Re: Call for Experience: Advancement of XEP-0071 (XHTML-IM) to Final

Ralph Meijer ralphm at ik.nu
Wed Oct 3 19:53:50 UTC 2012


On 2012-10-03 20:25, Andreas Kuckartz wrote:
> A correction. I wrote:
>
>> RDFa does not require any additional elements but only support for
>> these four attributes (the 'a' in RDFa stands for attributes):
>> vocab, property, resource, typeof
>
> I forgot a few, but that does not change the argument.

Hi Andreas!

While I'm sure we could alter XEP-0071 to add support for RDFa, I have 
to wonder why that is desirable.

As I see it, the main purpose of having XEP-0071 was to standardize 
existing efforts to have light *presentational* mark-up for instant 
messages. In practice, a client would mostly use a chat UI element with 
a few helper widgets for adding styles (like bold) and URLs. One 
wouldn't typically write HTML directly.

As an aside, I have personally gone as far as patching Gajim to further 
restrict the allowed elements and styles (mainly because of iChat and 
Adium).

RDFa, on the other hand, would likely be for marking up a message 
*semantically*. Standard practice in XMPP is to just add a new child 
element to the <message/> stanza for that. I.e. as a sibling of <body/> 
and (in this case) <html/>. You could simply add RDF/XML constructs, 
while keeping our restrictions on the use of XML namespace prefixes in mind.

For non-IM purposes, I have used embedded Atom Entry documents (as 
Publish-Subscribe payloads), using link elements for denoting triples.

I also have to note that we have traditionally shied away from using 
all-encompassing vocabularies in favor of application-specific ones. 
E.g. XEP-0080 defines its own way to record addresses and geo-location 
information, instead of using an existing gazillion page RFC. :-)

In any case, I'd welcome alternative points of view, of course.

-- 
ralphm



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