Re: Clarification on use of Content-Location header

fre 2010-05-14 klockan 12:36 -0700 skrev Roy T. Fielding:

> All schemes are dereferenceable, including urn, info, and tag.

Are they?

Quote from the tag scheme specification RFC4151:

        There is no authoritative resolution mechanism for tags.  Unlike
        most other URIs, tags can only be used as identifiers, and are
        not designed to support resolution.  If authoritative resolution
        is a desired feature, a different URI scheme should be used.

Some of the  URN name spaces have similar issues.

Also still have not quite understood what makes tag differ from an urn
name space but that's not an httpbis topic. I guess the difference is in
namespace resolution where URN namespaces generally need to be defined
and have a meaning but tag is just abstract identifiers with no
requirement on any defined meaning.

Also the messiness of tag etc does not change the general rule with
respect to use of other schemes in HTTP Content-Location, just makes tag
a bit impractical to be used in Content-Location.


Received on Friday, 14 May 2010 20:09:48 UTC