Attribute Exchange pre-draft 5

[Rowan Kerr]

On 2-Apr-07, at 5:27 PM, Josh Hoyt wrote:
> I'm thinking about differentiating between an attribute that's not
> available and an attribute that *is* available, but its value is "".
> I. e. difference between a null pointer, and a pointer to an empty
> string.

That was part of why I had the idea of adding one or two extra
response values... to know whether a user released the attribute
(and whether it was supported by the OP).

By looking at the namespace RDFs for the OP as you suggested,
the RP should be able to decide whether the value is supported
by the OP, then if it's blank AND supported, then the only thing
the RP can't be sure about is whether or not the user released it.

If the RP really needs a value, they can prompt the user for
it after getting the AX response and it doesn't really matter
whether the OP supports it or not. (Unless you're going to
maybe try and Store it back to the OP later on).

But prompting users twice for the same value (for lack of any
way to know the cause of a blank value) might be an annoying
experience.


-Rowan