RE: [xri] Media Type parameters

["Gabe Wachob" <gabe.wachob@amsoft.net>]

The problem is that these are media-type parameters, and are used in
multiple places. Its specified in RFC 2045. 

Its interesting that these libraries are treating ; as a separator - the
query string is a sort of no-man's land for specs. There was a sort of de
facto spec because CGI specified how to parse the querystring for the
purpose of passing parameters.

The note you refer to (b.2.2 of the HTML 4.01 spec) is talking about how to
encode a parameter list in HTML (though I think it may apply to XML as
well). The use of ';' instead of & is NOT very common) - so I wonder why you
are seeing this behavior in PHP and Ruby... Granted, its relatively rare to
see ; in the querystring so it may just be that people don't run across this
issue very often.

While I'm deeply sympathetic to implementation issues, I'm really worried
about making the spec change like this (we'd have to change the way we
communicate parameters to media types) - besides breaking current
implementations, I'm worried about the complication of carrying around these
media type parameters separately from the media types themselves (for
example, in the Accept: header of an HTTP request). 

I'm surprised by this issue, btw. 

	-Gabe

> -----Original Message-----
> From: Victor Grey [mailto:victor@idcommons.org]
> Sent: Wednesday, August 15, 2007 10:41 AM
> To: xri@lists.oasis-open.org
> Subject: [xri] Media Type parameters
> 
> Section 3.3 of WD11 defines a set of media type parameters that can
> be used to further specify a media type.
> 
> When a proxy resolver receives these media type parameters in a URI
> query string, as opposed to an Accept header, the issue arises that
> the semicolon is recommended by the W3C as an alternative field
> separator in query strings <http://www.w3.org/TR/1999/REC-
> html401-19991224/appendix/notes.html#h-B.2.2>, and most
> implementations seem to work this way (verified in PHP and Ruby on
> Rails).
> 
> So for example, when parsing the query string in the following URI:
> http://xri.net/=drummond?_xrd_r=application/xrds
> +xml;sep=true;nodefault=type&_xrd_t=http://openid.net/signon/1.1
> 
> rather than an "_xrd_t" field and an "_xrd_r" field with two
> parameters attached, four distinct field-value pairs will be returned:
> 
> _xrd_r=application/xrds xml
> sep=true
> nodefault=type
> _xrd_t=http://openid.net/signon/1.1
> 
> I'd suggest therefore that a set of more distinct names be defined
> for media type parameters when used in a query string, something like
> "_xrd_r_nodefault" instead of "nodefault".
> 
> =vg