W3C home > Mailing lists > Public > public-xg-webid@w3.org > December 2011

Re: neither FCNS nor FOAFSSL can read a new foaf card (hosted in Azure). RDFa validators at W3C and RDFachecker say its fine...

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Wed, 28 Dec 2011 13:53:19 -0500
Message-ID: <4EFB659F.7050503@openlinksw.com>
To: public-xg-webid@w3.org
On 12/28/11 10:33 AM, Peter Williams wrote:
> Look at two cases in http://tinyurl.com/ck5j6bv
>
> FOR THIS COMMUNITY, is my site behaving correctly on issuing a 400 
> error, for a GET that, on the wire, bears a fragment?

If URL+#me crosses the wire (as it does in the Windows realm) you are 
basically asking the server to provide access to a resource at what is 
more than likely a non existent address. Thus, expect a 404 re. Linked 
Data servers.  A Linked Data Server is works on the premise of each 
unambiguously named data object being associated with a descriptor 
resource at an address. The association is managed by the Linked Data 
Server since it oversees the handling or URIs (be they names or addresses).

The thing about WebID is that the SAN must hold a de-referencable Name. 
Not a de-referencable Address. As per prior comments, there has to be > 
1 level of indirection re. this form of data access by reference. 
Without this level of indirection we end up conflating Object Identity 
with Object Representation when using HTTP URIs.

To conclude, if you control what goes over the wire, then understand 
that the Linked Data server is going to ultimately perform Name/Address 
disambiguation. Thus, what you GET will be treated as a URL to which a 
re-write is applied i.e., the URL+#me will be treated as a valid address 
to which a 200 OK would be expected, but a 404 will occur.

Now #me across the wire is a legacy issue arising from what I hear was a 
typo, so in reality, a Linked Data Server could have an additional rule 
whereby the GET URL is now a proper generic URI. Net effect (in our 
case) would be to no longer use the FROM Clause in our SPARQL and just 
place the URI we receive in the Subject slot of our query pattern.

Conclusion: the fragment id over the wire handling in Windows (solely) 
has lead to the confusion we have today. Now this doesn't put Windows at 
fault since the whole issue seems to have arisen from a spec typo!

Action Items: for use, we'll just add an additional re-write rule for # 
URIs that cross the wire :-)


Kingsley

>
> Henry's site does not issue an error, for a GET on the wire that bears 
> a fragment.
>
> Is it important to the relative naming resolution (of sparql) that the 
> site support GET requests with fragments (on the wire)?
>
> In the analogous openid world, it is NOT important when those agents 
> obtained (XRD) metadata. Validating agents MUST normalize the URI, to 
> remove the fragment from the wire-form of the URI - thus emulating a 
> browser.
>
> By default, a bog standard wizard-driven website built on windows does 
> what I show. One can trivally amend the document so doctypes have the 
> right DTD and the HTML gets RDFa markup. But, IS THIS ENOUGH for 
> semantic web compliance?
>
> Perhaps this is the core issue.
>
>
>
> > Date: Wed, 28 Dec 2011 09:44:10 +0100
> > From: j.jakobitsch@semantic-web.at
> > To: home_pw@msn.com
> > CC: kidehen@openlinksw.com; public-xg-webid@w3.org
> > Subject: Re: neither FCNS nor FOAFSSL can read a new foaf card 
> (hosted in Azure). RDFa validators at W3C and RDFachecker say its fine...
> >
> > hi,
> >
> > you should use http://www.w3.org/2007/08/pyRdfa/ to check your rdfa.
> >
> > paste
> >
> > 1. 
> http://b3d0c8f68475422784748b65f76b1642.cloudapp.net:8080/Aboutrel.aspx => 
> rdf
> > 2. 
> http://b3d0c8f68475422784748b65f76b1642.cloudapp.net:8080/Aboutrel.aspx#me 
> => empty rdf
> >
> > in the "distill by URI" tab.
> >
> > wkr http://www.turnguard.com/turnguard
> >
> > ----- Original Message -----
> > From: "Peter Williams" <home_pw@msn.com>
> > To: kidehen@openlinksw.com, public-xg-webid@w3.org
> > Sent: Wednesday, December 28, 2011 8:08:19 AM
> > Subject: RE: neither FCNS nor FOAFSSL can read a new foaf card 
> (hosted in Azure). RDFa validators at W3C and RDFachecker say its fine...
> >
> >
> >
> > Your tester fails against 
> http://b3d0c8f68475422784748b65f76b1642.cloudapp.net:8080/Aboutrel.aspx#me 
>
> >
> > The stream is literally the RDFa card from the spec (with the 
> modulus changed).
> >
> > (The endpoint will provide an error response, should the GET bear a 
> fragment in the URI request arg.)
> >
> > While the "snippet" of that spec card works fine in blogger with all 
> test sites, none of the 3 testing sites work with what is actually 
> given. This suggests the spec needs to change its example.
> >
> > One notes how the Turtle example is absolutely anchored (unlike the 
> RDfa example). Advise that the spec have identical triples (in 
> different representations)
> >
> >
> > > From: home_pw@msn.com
> > > To: kidehen@openlinksw.com; public-xg-webid@w3.org
> > > Date: Tue, 27 Dec 2011 21:37:48 -0800
> > > Subject: RE: neither FCNS nor FOAFSSL can read a new foaf card 
> (hosted in Azure). RDFa validators at W3C and RDFachecker say its fine...
> > >
> > >
> > > I have spent a few hours getting really to grips with both ODS and 
> linkburner.
> > >
> > > Certain things are VERY straightforward.
> > >
> > >
> > >
> > > I logon with a password, and then map a cert to the account (just 
> like in windows). And, I can use the ODS builtin CA, to mint a second 
> cert with a variety of browser plugins/keygentags. The net result is I 
> can do https client auhn to ODS, replacing the password challenge. 
> Technically, a cert-based login to ODS may even count as an act of 
> webid validation (rather than mere https client authn based on 
> fingerprint matching).
> > >
> > >
> > >
> > > Next, the account gives me a profile page. For any n certs 
> registered (with logon privileges, or not), the profile publishes 
> cert:key. Well done. From cert, infer cert:key. For a third party 
> cert, I can now reissue it (same pubkey) adding the ODS profile URI.
> > >
> > >
> > >
> > > Then I got a real feel for sponging an html/rdfa resource. The 
> proxy prpofile/URI is essentially a new profile, borrowing bits from 
> the "data source" that it screen scrapes. It has nothing to do with 
> the accounts' own profile page. The resultant profile has a proxy URI, 
> and one can put this in the SAN URI set of the cert whose pubkey was 
> in the the original data source (and now in the proxy profile).
> > >
> > >
> > >
> > > I altered by http://yorkporc2.blogspot.com/ template/page. It now 
> as a webid.cert relation/link. Its a data URI, of type cert... with 
> base64 blog content. Ideally, sponger would now infer cert:key from 
> that link (but not any webid/foaf material), much like ODS profile 
> inferred cert:key from its store of mapped certs/accounts. It would 
> sponge the rest of the foaf card as normal.
> > >
> > >
> > >
> > > I was able to use the ODS webid validator to validate against my 
> cloud/azure hosted TTL card.
> > >
> > >
> > >
> > > I was able to run sparql queries on my yorkporc HTML and TTL 
> resources. I now understand (finally, after 2 years) why the sparql 
> query for HTML gives the proxy name for the subject (with cert:key) 
> rather than the data sources URI. Im really doing sparql against the 
> proxy profile (not the data source), despite the FROM clause in the 
> sparql identifying the data source. When one uses a non sponged 
> resouce (TTL), the sparql result is more insituitive as to subject names.
> > >
> > >
> > >
> > > i went through all the product documentation.
> > >
> > >
> > >
> > > I learned that you are using the foaf:account as a mapping 
> mechanism (not merely a publication device). If one uses facebook 
> websso to authenticate, it maps to an ODS account whose foaf profile 
> publishes said foacebook account name in a foaf:account property.
> > >
> > >
> > >
> > > I suspect (but could not confirm) that the foaf:openid similarly 
> enables an openid identifier presented in openid websso to mapto a ODS 
> profile, on login authentication. O failed at any UI to get the system 
> to act as an openid relying party, talking to my 
> http://yorkporc.wordpress.com's openid server.
> > >
> > >
> > >
> > > The built in openid server (that uses a webid challenge) is 
> confusing. I dont know if the webids and profiles that it vouches for 
> are limited to those in an ODS profile, in a proxy profile, or are for 
> any other public webid (for which a proxy profile is immediately 
> created).
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
> > --
> > | Jürgen Jakobitsch,
> > | Software Developer
> > | Semantic Web Company GmbH
> > | Mariahilfer Straße 70 / Neubaugasse 1, Top 8
> > | A - 1070 Wien, Austria
> > | Mob +43 676 62 12 710 | Fax +43.1.402 12 35 - 22
> >
> > COMPANY INFORMATION
> > | http://www.semantic-web.at/
> >
> > PERSONAL INFORMATION
> > | web : http://www.turnguard.com
> > | foaf : http://www.turnguard.com/turnguard
> > | skype : jakobitsch-punkt
> >


-- 

Regards,

Kingsley Idehen	
Founder&  CEO
OpenLink Software
Company Web: http://www.openlinksw.com
Personal Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca handle: @kidehen
Google+ Profile: https://plus.google.com/112399767740508618350/about
LinkedIn Profile: http://www.linkedin.com/in/kidehen








Received on Wednesday, 28 December 2011 18:53:47 GMT

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