[glue-wg] New Endpoint and Service types

[Paul Millar]

Hi Stephen,

On 06/03/14 12:22, stephen.burke at stfc.ac.uk wrote:
> Paul Millar [mailto:paul.millar at desy.de] said:
>> SupportedProfile=http://webdav.org/
>>
>> (or however we choose to label WebDAV support).
>
> I don't see that as an appropriate use of the attribute - that should
> be a URL you can follow to get information, not a selection
> parameter.

Later on, I proposed:

	http://www.ietf.org/rfc/rfc4918.txt

This is a precise definition of the additional semantics supported by 
the endpoint.

Would that be better?

> Textual matching against a URL is vulnerable to both
> format variations, e.g. in the number of / characters, and changes in
> the URL itself.

Note that GLUE-2 defines the type of attribute as URI.  If you don't 
like it, we need to change GLUE-2 to not use URI as a type!

More practically, as LDAP doesn't support URI as a type then the LDAP 
binding must define a URI canonicalisation so that a text search is not 
ambiguous.  That the LDAP binding doesn't define this canonicalisation 
is a problem that should be fixed.


> A URL is something which is basically a free-form
> string aside from syntax constraints,

(Isn't that an oxymoron?  If there are syntax constraints then it isn't 
free-form ;-)


> not a specifier that can be defined precisely.

I disagree.  Taking what you say at face value, we should remove all 
URIs as attribute types in the specification!

An URL is perfectly valid identifier.  What might be missing is how to 
describe a URL in LDAP, but that's a separate issue.

> In any case, we already have an attribute to
> publish additional subsidiary types, namely InterfaceExtension.

I'm perfectly happy if we publish WebDAV as an InterfaceExtension rather 
than a SupportedProfile.

GLUE-2 says nothing about how these should be used (it defines 
SupportedProfile as a profile and InterfaceExtension as an extension!)


>> For us, the value is a constant.  If the URL happens to be a
>> pointer to where the semantics are described then all the better!
>
> This pretty much says that you agree that this is an abuse of the
> attribute!

I don't follow: which part of GLUE-2 spec. says this usage is an abuse?

Cheers,

Paul.