Suprisingly, there is no connection between the entity IRIs and the wikipage URLs. If one was given the IRI of an entity from Wikidata, and had no further information about how Wikidata works, they would not be able to retrieve HTML content about the entity.
If you require the "text/html" MIME type, you are going to be redirected to the HTML content. For example, you could try to go to https://www.wikidata.org/entity/Q42 using your favorite browser or execute:
curl --header 'Accept: text/html' https://www.wikidata.org/wiki/Special:EntityData/Q42 -v
Cheers,
Thomas
Le 1 mai 2018 à 10:03, Antoine Zimmermann antoine.zimmermann@emse.fr a écrit :
On 01/05/2018 03:25, Peter F. Patel-Schneider wrote:
As far as I can tell real IRIs for Wikidata are https URIs. The http IRIs redirect to https IRIs.
That's right.
As far as I can tell no content negotiation is done.
No, you're mistaken. Your tried the URL of a wikipage in your curl command. Those are for human consumption, thus not available in turtle.
The "real IRIs" of Wikidata entities are like this: https://www.wikidata.org/entity/Q%7BNUMBER%7D
However, they 303 redirect to https://www.wikidata.org/wiki/Special:EntityData/Q%7BNUMBER%7D
which is the identifier of a schema:Dataset. Then, if you HTTP GET these URIs, you can content negotiate them to JSON (https://www.wikidata.org/wiki/Special:EntityData/Q%7BNUMBER%7D.json) or to turtle (https://www.wikidata.org/wiki/Special:EntityData/Q%7BNUMBER%7D.ttl).
Suprisingly, there is no connection between the entity IRIs and the wikipage URLs. If one was given the IRI of an entity from Wikidata, and had no further information about how Wikidata works, they would not be able to retrieve HTML content about the entity.
BTW, I'm not sure the implementation of content negotiation in Wikidata is correct because the server does not tell me the format of the resource to which it redirects (as opposed to what DBpedia does, for instance).
--AZ
peter idefix merging> curl -I http://www.wikidata.org/wiki/Q52000000 HTTP/1.1 301 TLS Redirect Date: Tue, 01 May 2018 01:13:09 GMT Server: Varnish X-Varnish: 227838359 X-Cache: cp1068 int X-Cache-Status: int-front Set-Cookie: WMF-Last-Access=01-May-2018;Path=/;HttpOnly;secure;Expires=Sat, 02 Jun 2018 00:00:00 GMT Set-Cookie: WMF-Last-Access-Global=01-May-2018;Path=/;Domain=.wikidata.org;HttpOnly;secure;Expires=Sat, 02 Jun 2018 00:00:00 GMT X-Client-IP: 199.4.160.88 Location: https://www.wikidata.org/wiki/Q52000000 Content-Length: 0 Connection: keep-alive idefix merging> curl -I https://www.wikidata.org/wiki/Q52000000 HTTP/2 200 date: Tue, 01 May 2018 01:14:58 GMT content-type: text/html; charset=UTF-8 server: mw1252.eqiad.wmnet x-content-type-options: nosniff p3p: CP="This is not a P3P policy! See https://www.wikidata.org/wiki/Special:CentralAutoLogin/P3P for more info." x-powered-by: HHVM/3.18.6-dev content-language: en link: </static/images/project-logos/wikidatawiki.png>;rel=preload;as=image vary: Accept-Encoding,Cookie,Authorization x-ua-compatible: IE=Edge backend-timing: D=75094 t=1525107829593021 x-varnish: 754403290 624210434, 194797954 924438274 via: 1.1 varnish (Varnish/5.1), 1.1 varnish (Varnish/5.1) age: 29467 x-cache: cp1067 hit/8, cp1068 hit/9 x-cache-status: hit-front set-cookie: CP=H2; Path=/; secure strict-transport-security: max-age=106384710; includeSubDomains; preload set-cookie: WMF-Last-Access=01-May-2018;Path=/;HttpOnly;secure;Expires=Sat, 02 Jun 2018 00:00:00 GMT set-cookie: WMF-Last-Access-Global=01-May-2018;Path=/;Domain=.wikidata.org;HttpOnly;secure;Expires=Sat, 02 Jun 2018 00:00:00 GMT x-analytics: ns=0;page_id=52899665;https=1;nocookies=1 x-client-ip: 199.4.160.88 cache-control: private, s-maxage=0, max-age=0, must-revalidate set-cookie: GeoIP=US:MA:Woburn:42.49:-71.16:v4; Path=/; secure; Domain=.wikidata.org accept-ranges: bytes idefix merging> curl -I -H "Accept: text/turtle" https://www.wikidata.org/wiki/Q52000000 HTTP/2 200 date: Tue, 01 May 2018 01:15:52 GMT content-type: text/html; charset=UTF-8 server: mw1252.eqiad.wmnet x-content-type-options: nosniff p3p: CP="This is not a P3P policy! See https://www.wikidata.org/wiki/Special:CentralAutoLogin/P3P for more info." x-powered-by: HHVM/3.18.6-dev content-language: en link: </static/images/project-logos/wikidatawiki.png>;rel=preload;as=image vary: Accept-Encoding,Cookie,Authorization x-ua-compatible: IE=Edge backend-timing: D=75094 t=1525107829593021 x-varnish: 754403290 624210434, 160015159 924438274 via: 1.1 varnish (Varnish/5.1), 1.1 varnish (Varnish/5.1) age: 29522 x-cache: cp1067 hit/8, cp1068 hit/10 x-cache-status: hit-front set-cookie: CP=H2; Path=/; secure strict-transport-security: max-age=106384710; includeSubDomains; preload set-cookie: WMF-Last-Access=01-May-2018;Path=/;HttpOnly;secure;Expires=Sat, 02 Jun 2018 00:00:00 GMT set-cookie: WMF-Last-Access-Global=01-May-2018;Path=/;Domain=.wikidata.org;HttpOnly;secure;Expires=Sat, 02 Jun 2018 00:00:00 GMT x-analytics: ns=0;page_id=52899665;https=1;nocookies=1 x-client-ip: 199.4.160.88 cache-control: private, s-maxage=0, max-age=0, must-revalidate set-cookie: GeoIP=US:MA:Woburn:42.49:-71.16:v4; Path=/; secure; Domain=.wikidata.org accept-ranges: bytes On 04/30/2018 02:53 PM, Lucas Werkmeister wrote:
The real URI (without scare quotes :) ) is not https://www.wikidata.org/wiki/Q52000000 but http://www.wikidata.org/entity/Q52000000 – and depending on your Accept header, that will redirect you to the wiki page, JSON dump, or RDF data (in XML or Turtle formats). Since the LOD Cloud criteria explicitly mentions content negotiation, I think we’re good :)
Cheers, Lucas
On 30.04.2018 23:08, Peter F. Patel-Schneider wrote:
Does it? The point is not just that Wikidata has real pointers to external resources.
Wikidata needs to serve RDF (e.g., in Turtle) in an accepted fashion. Is having https://www.wikidata.org/wiki/Special:EntityData/Q52000000.ttl available and linked to with an alternate link count when the "real" URI is https://www.wikidata.org/wiki/Q52000000? I don't know enough about this corner of web standards to know.
peter
On 04/30/2018 01:45 PM, Federico Leva (Nemo) wrote:
Peter F. Patel-Schneider, 30/04/2018 23:32:
Does the way that Wikidata serves RDF (https://www.wikidata.org/wiki/Special:EntityData/Q52000000.rdf) satisfy this requirement?
I think that part was already settled with: https://lists.wikimedia.org/pipermail/wikidata/2017-October/011314.html
More information: https://phabricator.wikimedia.org/T85444
Federico
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