[Standards-JIG] JEP-0017 Framing: Why was it rejected?

Trejkaz Xaoza trejkaz at xaoza.net
Wed Oct 20 22:13:06 UTC 2004


On Wed, 20 Oct 2004 19:16, Justin Karneges wrote:
> As far as I know, extra character data can be present unless it is
> explicitly disallowed (or used for something else).  I assume the <stream>
> element doesn't have this restriction, else we'd all be violating the spec
> by sending those "whitespace pings".

The different there is that whitespace is ignorable when it occurs between XML 
elements (i.e., it doesn't affect the XML contents.)

> To Bob: the main argument against framing is probably just that it makes
> the protocol less clean-looking.  The notion of a streamed XML document
> that you can throw right at a SAX parser is compelling.  Sure, it is
> possible to implement specs like JEP-0017 that graft on framing, but how
> much sense does it make to skip over a piece of what is supposed to be a
> continuous document?
>
> The only pure way (in an XML sense) to have framing would be to create an
> alternative to xmpp-core that operates on a series of framed documents
> instead of a big streamed one.  JEP-0124 is one example of such a spec.

You could, yeah, potentially envisage an XMPP router which uses a more 
efficient protocol.

But actually, it's trivial to think of other ideas which don't break the XML.  
XMPP could have wrapped every element in a container which specifies how big 
it is.  Or it could have had a size attribute on each stanza which is 
optional, and can be used to hint the size of the interior of the stanza.  Or 
it could have used a new element in-between stanzas (like the text.)

But as has been mentioned, this really just makes the system easier to abuse.  
The server will still need to parse the content so that they can kick off 
malicious clients, otherwise you have a whole lot of people dropping out when 
their parsers can't cope.  I don't think this would work except possibly from 
server to server (although... then you would just get malicious servers.)

TX

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