[Standards] Proposed XMPP Extension: Content Types in Messages

Goffi goffi at goffi.org
Wed Jan 20 08:33:46 UTC 2016

Le mardi 19 janvier 2016, 16:49:22 XMPP Extensions Editor a écrit :
> The XMPP Extensions Editor has received a proposal for a new XEP.
> Title: Content Types in Messages
> Abstract: This specification describes a generic method whereby content in
> messages can be tagged as having a specific Internet Content Type. It also
> provides a method for sending the same content using different content
> types, as a fall-back mechanism when communicating between clients having
> different content type support.
> URL: http://xmpp.org/extensions/inbox/content-types.html


I still think this XEP is a false good idea, as I said in last week 
discussion. Here are the main reasons:

	- there are already a couple of projects using markdown through the 
standardized XHTML-IM. With this XEP, we'll have some markdown in a <content> 
element, some converted in XHTML-IM, which one should I use?

	- mardown is not a standard, and the only tentative to standardize it 
(CommonMark) is not popular for the moment (not even sure of its status at 

	- even if a standard was there, there are and will probably always be 
different flavours. In other terms, every client will tend to have slightly 
different rendering, in the opposition of what XMPP currently offers or try to 
offers (same thing on each screen in the same order).

	- beside markdown, other syntaxes will be used, each client having its 
favorite one. This will bring more fragmentation

	- today we have 2 types contents: plain text and rich (XHTML-IM). I don't 
see any reason to add on extra one, or at least a syntax which translate 
trivially to XHTML is not a good reason to add a new content for me.

	- XHTML/XHTML-IM being XML, so using the same kind of parser that what is 
already used for XMPP, it seems the natural option for rich content. If the 
goal of all this is to edit markdown, we do convert XHTML => markdown, and 
it's working reasonably well, specially for the limited set of elements that 
we have in XHTML-IM

	- I would rather see markdown put as text content (without hint or 
anything), than having extra elements with any possible syntax.

In addition I wonder what is the point of this? For instant messaging, it's 
not common to edit text, or with last message correction (and client can keep 
the last message original syntax in cache trivially). Why not doing the 
conversion markdown => XHTML-IM client side before sending the message?

For blogging, it's more natural to use XHTML, and anyway this XEP doesn't 
cover the case (blogging use PubSub, not messages).


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