ACTION-750: Investigate how to add multiple property/values to the URI

We agreed [1] that the format for the Via header comment would be:
1. a URI of the form: http://www.w3.org/2008/04/ct
or
2. a URI to a POWDER resource that describes the capabilities of the proxy

I was to investigate if we could use the first form to define multiple 
values such as "I'm active and intend to transform" or any value that 
could be used to describe the CT-proxy.

In short, we can't, and I suggest we keep it simple...

A property such as:
   http://www.w3.org/2008/04/ct#active
is an opaque identifier.

A property such as:
   http://www.w3.org/2008/04/ct#(active,intend_to_recode)
is another opaque identifier, and (whatever the syntax to link both 
"properties" may be) doesn't mean "active" and "intend_to_recode". We 
may say it's another property that indeed means "active" and 
"intend_to_recode" but then:
   http://www.w3.org/2008/04/ct#(intend_to_recode,active)
would be a different property!

The good way to express several properties would be to define the format 
as a list of properties, but then the problem is the size of the string, 
too long for a comment in an HTTP header:
 
http://www.w3.org/2008/04/ct#active,http://www.w3.org/2008/04/ct#intend_to_recode

You may reply that we should then just use a prefix for the namespace:
   ct:active,ct:intend_to_recode
where "ct" is bound to "http://www.w3.org/2008/04/ct", but:
- the binding between "ct" and "http://www.w3.org/2008/04/ct" would have 
to be defined somewhere nearby, leading to a really complicated format 
for a mere comment.
- that's a CURIE-like syntax and CURIE [2] is far from being a 
recommendation.


As a side note, note that a proxy vendor may decide to use the comment 
for something else than a URI to a POWDER resource, and that's perfectly 
fine.

Francois.

[1] http://www.w3.org/2008/04/29-bpwg-minutes.html#item02
[2] http://www.w3.org/TR/2008/WD-curie-20080506/

Received on Monday, 26 May 2008 12:25:56 UTC