Linked Data Notifications

SCTA, Basel, 2018-06-29, #LinkedResearch #SocialWeb #LinkedData

Sarven Capadisli http://csarven.ca/#i @csarven

Organisations: TIB Leibniz Information Centre for Science and Technology

Principles

Data on the Web should not be locked in to particular systems or be only readable by the applications which created it. Users should be free to switch between applications and share data between them.

W3C Linked Data Notifications

W3C Linked Data Notifications design principles

Applications generate notifications about activities, interactions, and new information, which may be presented to the user or processed further.

Autonomy; any resource can have an Inbox anywhere
Identifiable unit; notifications have URIs
Reusable; a notification can contain any data; use any vocabulary
Separation of concerns; sender, consumer, receiver

W3C Linked Data Notifications overview

Summary

A target resource advertises its inbox in the HTTP header or the body in RDF.

Sender: discover inbox, POST payload;
Receiver: respond to GET requests made to inbox and notifications, accept POST requests to inbox;
Consumer: discover inbox, GET inbox and notifications.

All must at least speak JSON-LD, but can optionally negotiate for alternative RDF serializations.

HEAD /article HTTP/1.1
Host: example.org
Accept: application/ld+json
 
HTTP/1.1 200 OK
Link: <http://example.org/inbox/>;
       rel="http://www.w3.org/ns/ldp#inbox"

Request and response when discovering an Inbox with a HEAD request, and receiving a Link header

GET /article HTTP/1.1
Host: example.org
Accept: text/html, application/ld+json
HTTP/1.1 200 OK
Content-Type: text/html;charset=utf-8

<section about="#results" id="results"
  property="http://www.w3.org/ns/ldp#inbox" resource="/inbox/">
  <p>The results of this study are as follows..</p>
</section>

Discovering an Inbox with a GET request to retrieve HTML.

POST /inbox/ HTTP/1.1
Host: example.org
Content-Type: application/ld+json;
              profile="https://www.w3.org/ns/activitystreams"
Content-Language: en

Sending example request (headers)

...

{
  "@context": "https://www.w3.org/ns/activitystreams",
  "@id": "",
  "@type": "Announce",
  "actor": "https://rhiaro.co.uk/#me",
  "object": "http://example.net/note",
  "target": "http://example.org/article",
  "updated": "2016-06-28T19:56:20.114Z"
}

Sending example request (payload)

HTTP/1.1 201 Created
Location: http://example.org/inbox/92d72f00

Response for created resource

GET /inbox/ HTTP/1.1
Host: example.org
Accept: application/ld+json
HTTP/1.1 200 OK
Content-Type: application/ld+json
{ "@context": "http://www.w3.org/ns/ldp",
  "@id": "http://example.org/inbox/",
  "contains": [ "http://example.org/inbox/5c6ca040",
    "http://example.org/inbox/92d72f00" ] }

Receiver responds to request on Inbox.