WWW2014 Overview of W3C Linked Data Platform 20140410

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Update on the upcoming W3C Linked Data Platform Recommendation.

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WWW2014 Overview of W3C Linked Data Platform 20140410

  1. 1. © 2014 IBM Corporation W3C Linked Data Platform Arnaud J Le Hors, IBM Linked Data Standards Lead lehors@us.ibm.com Linked Data Platform 10 April 2014
  2. 2. © 2014 IBM Corporation2 Linked Data Platform Agenda ➢ Linked Data ■ Using Linked Data for Application Integration ■ Challenges of using Linked Data for Application Integration ■ W3C Linked Data Platform ■ Related Projects
  3. 3. © 2014 IBM Corporation Linked Data Platform Linked Data – Defined by Tim Berners-Lee 1. Use URIs as names for things 2. Use HTTP URIs so that people can look up those names. 3. When someone looks up a URI, provide useful information, using the standards (RDF*, SPARQL) 4. Include links to other URIs. so that they can discover more things. He concludes this with: “Simple.” Reference: “Linked Data”, Tim Berners-Lee, 2006-07-27
  4. 4. © 2014 IBM Corporation4 April 10, 2014 Linked Data Platform Linked Data and the Web  Linked Data is a natural extension of the web of documents: Web of Documents Linked Data Standard Global Identifier+Locator Pages are identified by a URL which can also be used to locate the page Pieces of data are identified by a URL which can also be used to locate the data Standard Access Protocol Pages are accessed via HTTP Data is accessed via HTTP Standard Representation Pages are served in a standard format: HTML Data is served in a standard representation: RDF Standard way of linking related items Related pages are linked to one another using their URLs Related pieces of data are linked to one another using their URLs
  5. 5. © 2014 IBM Corporation Linked Data Platform Not All Linked Data needs to be Linked Open Data (LOD) ★ Available on the web (whatever format) but with an open licence, to be Open Data ★★ Available as machine-readable structured data (e.g. excel instead of image scan of a table) ★★★ As (2) plus non-proprietary format (e.g. CSV instead of excel) ★★★★ All the above plus, Use open standards from W3C (RDF and SPARQL) to identify things, so that people can point at your stuff ★★★★★ All the above, plus: Link your data to other people’s data to provide context  This does NOT mean all Linked Data must be freely available.  Just like not all web pages are publicly available not all Linked Data needs to be. Added in 2010 by Tim Berners-Lee: “in order to encourage people, especially government data owners, along the road to good linked data, I have developed this star rating system”
  6. 6. © 2014 IBM Corporation6 Linked Data Platform Agenda ■ Linked Data ➢ Using Linked Data for Application Integration ■ Challenges of using Linked Data for Application Integration ■ W3C Linked Data Platform ■ Related Projects
  7. 7. © 2014 IBM Corporation Linked Data Platform Software Configuration Management Software Configuration Management Work-item & defect tracking (aka Change Management) Work-item & defect tracking (aka Change Management) Build automation & management Build automation & management Test automation & management Test automation & management Requirements management Requirements management IBM Rational's use of Linked Data for Application Integration 7 Integrate with data & open protocols instead of glue code “If the entire Web can connect like this, why wouldn't the same idea work for ALM?”  Applying Linked Data to the ALM Integration Challenge:  Artifacts such as defects, change requests, and tests become resources exposed as RDF that can be linked to each other  Tools simply access the resources via HTTP following the Linked Data principles
  8. 8. © 2014 IBM Corporation Linked Data Platform Applying Linked Data to ALM – A development tools example TestCase 14 is blocked by Issue 973 http://srv/qm/tc/14 qm:blockedBy http://apache.org/jira/HTTPCLIENT-973
  9. 9. © 2014 IBM Corporation Linked Data Platform Applying Linked Data to ALM – A development tools example TestCase 14 is blocked by Issue 973 http://srv/qm/tc/14 qm:blockedBy http://apache.org/jira/HTTPCLIENT-973 Issue 973 depends on Bug 318 http://apache.org/jira/HTTPCLIENT-973 cm:dependsOn http://bugs.sun.com/? id=7172318 Issue 973 is owned by Joe http://apache.org/jira/HTTPCLIENT-973 dc:contributor http://joecoder.me
  10. 10. © 2014 IBM Corporation Linked Data Platform Applying Linked Data to ALM – A development tools example TestCase 14 is blocked by Issue 973 http://srv/qm/tc/14 qm:blockedBy http://apache.org/jira/HTTPCLIENT-973 Issue 973 depends on Bug 318 http://apache.org/jira/HTTPCLIENT-973 cm:dependsOn http://bugs.sun.com/? id=7172318 Issue 973 is owned by Joe http://apache.org/jira/HTTPCLIENT-973 dc:contributor http://joecoder.me Joe is a committer for Apache http://joecoder.me doap:committer http://apache.org
  11. 11. © 2014 IBM Corporation11 Linked Data Platform Agenda ■ Linked Data ■ Using Linked Data for Application Integration ➢ Challenges of using Linked Data for Application Integration ■ W3C Linked Data Platform ■ Related Projects
  12. 12. © 2014 IBM Corporation12 Linked Data Platform Challenges of using Linked Data for Application Integration ■ No formal definition ■ State of the art is primarily about publishing read-only data on the web, downloaded and updated as large dumps or via a SPARQL entry point ■ Tim Berners-Lee's four principles are a terrific foundation but don’t go far enough. ■ Developers are left with many unanswered questions: – How do I create a resource? • It seems obvious that you use POST to create, but what do you POST to? – Where can I get the list of resources that already exist? – Which vocabulary do I use? – Which media types do I use? – When resources get big, how do I split the information into pages? – How do I specify ordering?
  13. 13. © 2014 IBM Corporation13 Linked Data Platform Agenda ■ Linked Data ■ Using Linked Data for Application Integration ■ Challenges of using Linked Data for Application Integration ➢ W3C Linked Data Platform ■ Related Projects
  14. 14. © 2014 IBM Corporation Linked Data Platform W3C Linked Data Platform (LDP) Working Group  Workgroup membership spans 50 participants from 30 organizations  Chair: Arnaud J Le Hors (IBM)  Working towards defining a clear definition of “Linked Data”, in the form of a W3C Recommendation – Based on Tim Berners-Lee four principles of Linked Data  Chartered to produce a “Linked Data Platform” specification that: – HTTP-based (RESTful) application integration patterns using read/write Linked Data – Will complement SPARQL and will be compatible with standards for publishing Linked Data, bringing the data integration features of RDF to RESTful, data-oriented software development.  Chartered to deliver a W3C Recommendation in 1H2014 Details @ http://www.w3.org/2012/ldp
  15. 15. © 2014 IBM Corporation15 Linked Data Platform Linked Data Platform (LDP) ■ A set of rules that clarify and extends Tim Berners-Lee's four basic rules focusing on the following two concepts: – LDP Resources (LDPR) – HTTP and RDF techniques to use to read and write linked data – LDP Containers (LDPC) – An LDPR to which you POST to create new things, GET to find existing things – Similar to what AtomPub does for XML
  16. 16. © 2014 IBM Corporation Linked Data Platform Linked Data Platform Resource (LDPR) Different types: Some general rules: 1. LDPRs are HTTP resources that can be created, modified, deleted and read using standard HTTP methods (i.e., POST, PUT/PATCH, DELETE, GET). 2. LDPRs use RDF to define their states. 3. You can request a Turtle representation of a LDPR and possibly other reps (e.g., XML/RDF) 4. LDP clients use Optimistic Collision Detection on update (etags). This is little more than what HTTP already defines.
  17. 17. © 2014 IBM Corporation Linked Data Platform Linked Data Platform Container (LDPC) Different types: Some general rules: 1. LDPCs are LDPRs 2. Clients can retrieve the list of resource members of an LDPC using GET 3. New resources are created by POSTing to an LDPC 4. Any resource can be POSTed to an LDPC – not just LDPRs (i.e., LDP-NR and LDPCs) 5. After POSTing a new resource to an LDPC, the new resource will appear as a member until it is deleted. 6. Clients can retrieve information about an LDPC without retrieving a full representation of its content, including its members. 7. On deleting an LDPC the server MAY delete member resources.
  18. 18. © 2014 IBM Corporation Linked Data Platform http://example.org LDP BasicContainer – GET lists existing resources Removed HTTP headers to save some space @prefix dcterms: <http://purl.org/dc/terms/>. @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>. @prefix ldp: <http://www.w3.org/ns/ldp#>. <http://example.org/container1>   a ldp:BasicContainer;   dcterms:title "A very simple container";   ldp:contains <http://example.org/container1/member1>, <http://example.org/container1/member2>, <http://example.org/container1/member3>. GET /container1 HTTP/1.1 Host: example.org Accept: text/turtle RequestResponse container1 member1 member2 member3
  19. 19. © 2014 IBM Corporation Linked Data Platform LDP BasicContainer – POST creates a new resource HTTP/1.1 201 CREATED Content-Location: http://example.org/container1/member4 POST /container1 HTTP/1.1 Host: example.org Content-type: text/turtle Content-length: 324 @prefix dcterms: <http://purl.org/dc/terms/>. @prefix o: <http://example.org/ontology/>. <> a o:Stock; dcterms:title “ACME Co.”; o:value 100.00. RequestResponse http://example.org container1 member1 member2 member3 +member4
  20. 20. © 2014 IBM Corporation Linked Data Platform LDP BasicContainer – GET returns updated list Removed HTTP headers to save some space @prefix dcterms: <http://purl.org/dc/terms/>. @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>. @prefix ldp: <http://www.w3.org/ns/ldp#>. <http://example.org/container1>   a ldp:BasicContainer;   dcterms:title "A very simple container";   ldp:contains <http://example.org/container1/member1>, <http://example.org/container1/member2>, <http://example.org/container1/member3>, <http://example.org/container1/member4>. GET /container1 HTTP/1.1 Host: example.org Accept: text/turtle RequestResponse http://example.org container1 member1 member2 member3 member4
  21. 21. © 2014 IBM Corporation Linked Data Platform LDP DirectContainer – Slightly more complex example <http://example.org/netWorth/nw1> a o:NetWorth; o:asset <http://example.org/netWorth/nw1/assetContainer/a1>, <http://example.org/netWorth/nw1/assetContainer/a2>.   • Members are associated with a resource other than the container • Membership predicate is domain specific • Relationship can take two different forms: • <membershipResource> <ldp:hasMemberRelation> <member> • <member> <ldp:isMemberOfRelation> <membershipResource> <http://example.org/netWorth/nw1/assetContainer> a ldp:DirectContainer; dcterms:title "The assets of JohnZSmith"; ldp:membershipResource <http://example.org/netWorth/nw1>; ldp:hasMemberRelation o:asset.
  22. 22. © 2014 IBM Corporation Linked Data Platform LDP DirectContainer (continue) <http://example.org/netWorth/nw1> a o:NetWorth; o:asset <http://example.org/netWorth/nw1/assetContainer/a1>, <http://example.org/netWorth/nw1/assetContainer/a2>,   o:liability <http://example.org/netWorth/nw1/liabilityContainer/l1>. • Several containers can be defined around the same resource (e.g., assets, liabilities) <http://example.org/netWorth/nw1/assetContainer> a ldp:DirectContainer; dcterms:title "The assets of JohnZSmith"; ldp:membershipResource <http://example.org/netWorth/nw1>; ldp:hasMemberRelation o:asset. <http://example.org/netWorth/nw1/liabilityContainer> a ldp:DirectContainer; dcterms:title "The liabilities of JohnZSmith"; ldp:membershipResource <http://example.org/netWorth/nw1>; ldp:hasMemberRelation o:liability.
  23. 23. © 2014 IBM Corporation Linked Data Platform LDP IndirectContainer – More complex example <http://example.org/netWorth/nw1> a o:NetWorth; o:advisor <advisorContainer/bob#me>, <advisorContainer/marsha#me>. • Supports listing non-information resource as members <http://example.org/advisors/> a ldp:IndirectContainer; dcterms:title "The asset advisors of JohnZSmith"; ldp:membershipResource <http://example.org/netWorth/nw1>; ldp:hasMemberRelation o:advisor; ldp:insertedContentRelation foaf:primaryTopic; ldp:contains <advisorContainer/bob>, <advisorContainer/marsha>. <http://example.org/advisorContainer/bob> foaf:primaryTopic #me. #me a foaf:Person, foaf:name "Bob Marlow".
  24. 24. © 2014 IBM Corporation Linked Data Platform LDP Non-RDF Sources a.k.a “Binary Resources” HTTP/1.1 201 CREATED Content-Location: http://example.org/attachments/myimage Link: <http://example.org/mycontainer/myimage-info>; rel=describedby POST /attachments/ HTTP/1.1 Host: example.org Content-type: image/png Content-length: 1048 Slug: myimage [binary content not displayed] RequestResponse  Created by POSTing to a Container  As a result the server may create two resources: – An LDP Non-RDF Source that is added as a member – An LDP RDF Source that describes the LDP-NR http://example.org attachments member1 member2 member3 +myimage
  25. 25. © 2014 IBM Corporation Linked Data Platform LDP Status update  Published First Last Call Working Draft on 30 July 2013  Received several comments that required changes: – Did not provide enough interoperability, especially for “vanilla clients” • Too many SHOULDs, not enough MUSTs • Silent failure is a big NO NO: e.g., servers may discard triples sent by client – Paging mechanism to be moved to HTTP layer  Published Second Last Call Working Draft on 11 March 2014 – A lot more MUSTs – Three types of containers – Differentiates containment from membership – Moved paging and ordering out – Replaced non-member properties with use of Prefer header – Added support for interaction models  Review period ended on April 2 with a few minor comments  Candidate Recommendation expected by the end of the April  Proposed Recommendation in June
  26. 26. © 2014 IBM Corporation Linked Data Platform LDP Status update (continue)  Other deliverables in the works: – Use Cases & Requirements (WG Note – updated on 13 March 2014) – Paging & Ordering (Working Draft) – Primer (WG Note) – Best Practices & Guidelines (WG Note) – Access Control Use cases & requirements (WG Note)
  27. 27. © 2014 IBM Corporation Linked Data Platform Looking Forward Linked Data has the potential of becoming an important application integration model in the enterprise but several necessary and desirable features are not in scope for LDP 1.0: ■ Security – Authentication, Access control – WG is chartered to identify requirements and use cases – Several technologies can already be used: OAuth, WebId, etc.  Validation/Constraints – RDFS and OWL are for inference not validation – There is currently no standard technology to perform validation • Discussions to launch a new effort at W3C are underway.  Deployment challenges – URL changes – Server cloning – Cross-server query
  28. 28. © 2014 IBM Corporation28 Linked Data Platform Agenda ■ Linked Data ■ Using Linked Data for Application Integration ■ Challenges of using Linked Data for Application Integration ■ W3C Linked Data Platform ➢ Related Projects
  29. 29. © 2014 IBM Corporation Linked Data Platform LDP Implementations SDK and supporting tools to help the community to adopt OSLC specifications and build compliant tools Implementation of LDP that can be extended and deployed easily by organizations who want to publish data or build custom applications Marmotta For a more complete list see: http://www.w3.org/wiki/LDP_Implementations Several implementations are already available:
  30. 30. © 2014 IBM Corporation Linked Data Platform Automation Monitoring  Community driven and governed  400+ registered community members  Workgroup members from 34+ organizations  Wide range of interests, expertise, & participation  Open specifications for numerous disciplines  Defined by scenarios – solution oriented  Implementations from IBM, BPs, and Others  Based on Linked Data Open Services for Lifecycle Collaboration Lifecycle integration inspired by the web Inspired by the web Proven Free to use and share Open Changing the industry Innovative Open Services for Lifecycle Collaboration (OSLC) Working to improve the way software lifecycle tools share data open-services.net For more info see: http://open-services.net
  31. 31. © 2014 IBM Corporation Linked Data Platform

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