Re: SHOULD/MUST fragment identifier definition question

On 10 Dec 2012, at 19:36, Stéphane Corlosquet <scorlosquet@gmail.com> wrote:

> 
> 
> On Mon, Dec 10, 2012 at 8:10 AM, Henry Story <henry.story@bblfish.net> wrote:
> A question to supporters of SHOULD/MUST:
> 
> This is to be found in the terminology section:
> 
> for MUST:
> http://dvcs.w3.org/hg/WebID/raw-file/d21603d3972a/spec/identity-respec.html#terminology
> [[
> A WebID is a URI with an http or https scheme, which contains a  URI fragment identifier (i.e. a #id ) and which uniquely denotes an Agent (Person, Organization, Group, Device, etc.). The URI without the fragment identifier denotes the WebID Profile page.
> ]]
> should the text contain a MUST there, or is the above strong enough?
> 
> for SHOULD:
> http://dvcs.w3.org/hg/WebID/raw-file/http-hash-uri-should/spec/identity-respec.html#terminology
> [[
> A WebID is a URI with an HTTP or HTTPS scheme which uniquely denotes an Agent (Person, Organization, Group, Device, etc.). This URI SHOULD include a fragment identifier (a string after a "#" character).
> ]]
> 
> Does a hash URI require a string after the hash character?
> 
> Facebook for example does not have such a string as you can see here:
> 
>   curl -H "Accept: text/turtle" http://graph.facebook.com/bblfish
> 
> Also is the terminology section the normative one?
> 
> Yes, it is.
> 
> The ABNF for URI [1] does not prevent the fragment from being empty, so empty frag hash URIs are legal. Note however that in javascript in the browser you can't use window.location.hash to know whether it's a hash URI or not because it returns the empty string whether you have a hash with the empty frag ID or or no hash at all (you'd have to parse windown.location manually, but I'm not sure if people would think to do that). Also, I would not be surprised if some APIs generating URIs out there would not append a hash unless a frag string is passed in, but that doesn't concern us and doesn't mean we have to disallow the empty frag. It does look odd and people might be tempted to remove it thinking it's useless. Having an explicit fragid makes it obvious that it is intended and it's not a mistake, but that's just usability, nothing that needs to be required in our spec. I'm of two minds about this: Henry, what change do you propose exactly? what would you remove from the definition? we could say "A WebID is a URI which contains a fragment identifier or ends with '#'".

Mhh, perhaps that's just solved by considering the # as having an empty string fragment... I had not thought of that... In that case it is easier to leave the text as is. ( I have removed the ( eg. text in the questionair definitions ) )

> 
> Steph.
> PS:
> 
> [1] http://tools.ietf.org/html/rfc3986#appendix-A

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