[Playlist] Question on identifier content, URI and URN

[Lucas Gonze]

Thanks for digging in at this level of detail, Sebastien.

The definition we use for a URN comes from 
http://gbiv.com/protocols/uri/rev-2002/rfc2396bis.html#URLvsURN :
'The term "Uniform Resource Name" (URN) has been used historically to 
refer to both URIs under the "urn" scheme [RFC2141], which are required 
to remain globally unique and persistent even when the resource ceases 
to exist or becomes unavailable, and to any other URI with the 
properties of a name.'

Because there is a potential clash over the definition (must use "urn" 
scheme VS. is a URI which may not be a locator), the XSPF v1 spec 
explicitly defines the term:
...
2.3.1 URI, URLs and URNs

The terms URI, URL, and URN should be interpreted here as follows: a URL 
is an address of something that can be fetched by a computer; a URN is a 
name of something which may be purely an abstraction; a URI is either. 
In this document, //playlist[@xmlns], //playlist/identifier, meta[@rel], 
link[@rel], and //playlist/trackList/track/identifier are URNs, all 
other elements are URLs.

See also: RFC2396bis; URIs, URLs, and URNs: Clarifications and 
Recommendations 1.0
...

That is, we do not use RFC2141 as the basis for the definition of a URN. 
    A URN is a URI which is not necessarily a locator; any other use of 
the term URI excludes names which are not locators.

It is easy to argue that this is silly, confusing, and wrong, but there 
it is -- a spec means nothing if it can be modified at will.  Fixing 
this would touch a lot of spots, I don't believe that I could do this 
many edits without creating what is essentially a new version, and there 
aren't resources for doing a new version.

Or are there?  If the stars aligned properly I think it would be great 
to do a formal IETF working group to create a simplified, shorter and 
better-written draft.

-Lucas



> I am confused about the identifier content:
> 
> While XSPF Version 0 (http://www.xspf.org/xspf-v0.html) says that
> identifier "MUST be a legal URI" XSPF Version 1
> (http://www.xspf.org/xspf-v1.html) says it "MUST be a legal URN".
> 
> The identifiers found in the testcases "playlist-extensive.xspf"
> and "track-extensive.xspf" did not help to make this clear:
> 
> 
> <identifier>magnet:?xt=urn:sha1:YNCKHTQCWBTRNJIV4WNAE52SJUQCZO5C</identifier>
> This looks like a broken URN to me.
> 
> <identifier>http://bar.com/secondderived.xspf</identifier>
> This is a URL, not a URN.
> 
> 
> Please help me to understand this, I really need help here.
> 
> 
> Thanks in advance, Sebastian
> 
>