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![Linked Data Notifications (LDN): W3C Working Draft
• A Working Draft by the W3C Social Web Working Group
• Specialized use of Linked Data Platform (LDP)
• https://www.w3.org/TR/2016/WD-ldn-20160824/ [Capadisli and Guy, 2016]
Linked Data Notifications is a protocol to facilitate exchanging messages
between applications which serve as senders, receivers and/or consumers of
RDF data.
(Sarven Capadisli and Amy Guy: Linked Data Notifications)
3 / 18](https://image.slidesharecdn.com/main-160902145214/75/Linked-Data-Notifications-Distributed-Update-Notification-and-Propagation-on-the-Web-of-Data-6-2048.jpg)
![Other Approaches
• The DSSN Stack [Tramp et al., 2012] with PubSubHubbub and Semantic
Pingback
• Applications in Structured Feedback [Arndt et al., 2016] and Publish and
Subscribe for RDF in Enterprise Value Networks [Frommhold et al., 2016]
11 / 18](https://image.slidesharecdn.com/main-160902145214/75/Linked-Data-Notifications-Distributed-Update-Notification-and-Propagation-on-the-Web-of-Data-15-2048.jpg)
![Linked Data Notifications (LDN): W3C Working Draft
• A Working Draft by the W3C Social Web Working Group
• Specialized use of Linked Data Platform (LDP)
• https://www.w3.org/TR/2016/WD-ldn-20160824/ [Capadisli and Guy, 2016]
Linked Data Notifications is a protocol to facilitate exchanging messages
between applications which serve as senders, receivers and/or consumers of
RDF data.
(Sarven Capadisli and Amy Guy: Linked Data Notifications)
3 / 18](https://crownmelresort.com/image.slidesharecdn.com/main-160902145214/75/Linked-Data-Notifications-Distributed-Update-Notification-and-Propagation-on-the-Web-of-Data-6-2048.jpg)
![Other Approaches
• The DSSN Stack [Tramp et al., 2012] with PubSubHubbub and Semantic
Pingback
• Applications in Structured Feedback [Arndt et al., 2016] and Publish and
Subscribe for RDF in Enterprise Value Networks [Frommhold et al., 2016]
11 / 18](https://crownmelresort.com/image.slidesharecdn.com/main-160902145214/75/Linked-Data-Notifications-Distributed-Update-Notification-and-Propagation-on-the-Web-of-Data-15-2048.jpg)
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Linked Data Notifications Distributed Update Notification and Propagation on the Web of Data
The document discusses Linked Data Notifications (LDN), a W3C working draft that outlines a protocol for exchanging messages between applications using RDF data. It emphasizes the need for active communication in the web of data for social interaction, collaboration, and enterprise use cases, while detailing the roles of senders, receivers, and consumers in the LDN protocol. The draft also highlights security, privacy considerations, and compares LDN with other approaches like pubsubhubbub and semantic pingback.
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Similar to Linked Data Notifications Distributed Update Notification and Propagation on the Web of Data
Linked Data Notifications Distributed Update Notification and Propagation on the Web of Data
- 1. Linked Data Notifications DistributedUpdate Notification and Propagation on the Web of Data Natanael Arndt August 29, 2016 (modified September 2, 2016) AKSW Colloquium
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- 3. Motivation and Problem CC-BY-SA:Linking Open Data cloud diagram 2014, by Max Schmachtenberg, Christian Bizer, Anja Jentzsch and Richard Cyganiak. http://lod-cloud.net/ • The Web of Data is a highly interlinked Data Cloud • This enables us to … • retrieve structured data about things • discover links among datasets • answer questions involving multiple datasets 1 / 18
- 4. Motivation and Problem CC-BY-SA:Linking Open Data cloud diagram 2014, by Max Schmachtenberg, Christian Bizer, Anja Jentzsch and Richard Cyganiak. http://lod-cloud.net/ • But currently there is no established way for active communication • This is needed for … • social interaction: messages, status update, friending; DSSN) • subscription to updates of datasets; graph synchronization • distributed collaboration on structured data • enterprise use cases, such as distributed supply chain management 2 / 18
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- 6. Linked Data Notifications(LDN): W3C Working Draft • A Working Draft by the W3C Social Web Working Group • Specialized use of Linked Data Platform (LDP) • https://www.w3.org/TR/2016/WD-ldn-20160824/ [Capadisli and Guy, 2016] Linked Data Notifications is a protocol to facilitate exchanging messages between applications which serve as senders, receivers and/or consumers of RDF data. (Sarven Capadisli and Amy Guy: Linked Data Notifications) 3 / 18
- 7. Linked Data Notifications(LDN): Introduction • Decoupling between applications and data storage • A notification has its own URI which can be retrieved and reused • The specification does not define the vocabulary of the notification contents • Authentication and verification of notifications is encouraged 4 / 18
- 8. Linked Data Notifications(LDN): Summary Sender • Creates the notification body • Sends the notification as POST to the Inbox URL Consumer • Retrieves the contents of the Inbox URL via GET Receiver • Responds to GET requests to the Inbox URL • Accepts POST requests at the Inbox URL to create notifications • Optionally enforces constraints on notifications Sender Consumer Receiver Inbox (LDP Container) POST GET 5 / 18
- 9. Linked Data Notifications(LDN): Protocol – Discovery • An Inbox can be discovered from any resource • The starting point for discovery is the target • The sender MUST make a request for a ldp:inbox relation (HEAD-Link and Linked Data) Sender Receiver Inbox (LDP Container) HEAD/GET target ldp:inbox ldp:inbox ldp:inbox 6 / 18
- 10. Linked Data Notifications(LDN): Protocol – Sending and Receiving • Senders MUST deliver notifications in a POST request to the Inbox URL • The Receiver can delay processing of the notification: 202 Accepted • Or immediately answer with 201 Created or the appropriate 4xx • Payload defaults to JSON-LD, but can be negotiated • “The sender MUST NOT assume that the receiver can fetch or infer anything additional from the payload, and thus MUST include everything they want the receiver to know.” Sender Receiver Inbox (LDP Container) POST 2xx/4xx 7 / 18
- 11. Linked Data Notifications(LDN): Protocol – Consuming • The Receiver responds to GET requests on the Inbox URL • Notifications must be discoverable through ldp:contains • Payload defaults to JSON-LD, but can be negotiated Consumer Receiver Inbox (LDP Container) GET ldp:contains 8 / 18
- 12. Linked Data Notifications(LDN): Protocol – Security, Privacy and Content Considerations • Inbox URLs can announce shape constraints • consumers may want to take precautions when consuming notifications • Receivers SHOULD ensure or verify the sender • whitelist for write access • require authentication • retrieve a copy of the notification from the sender’s domain to verify its origin • checking a digital signature which accompanies the notification 9 / 18
- 13. Linked Data Notifications(LDN): Summary Sender Consumer Receiver Inbox (LDP Container) POST HEAD/GET target ldp:inbox ldp:inbox ldp:inbox 2xx/4xx GET retrieve (verification) Original Comment Resource 10 / 18
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- 15. Other Approaches • TheDSSN Stack [Tramp et al., 2012] with PubSubHubbub and Semantic Pingback • Applications in Structured Feedback [Arndt et al., 2016] and Publish and Subscribe for RDF in Enterprise Value Networks [Frommhold et al., 2016] 11 / 18
- 16. Other Approaches: Publishand Subscribe for RDF in Enterprise Value Net- works 12 / 18
- 17. Other Approaches: SemanticPingback and Structured Feedback RPC Layer Resource Layer Linking Resource (Source) Linked Resource (Target)(typed) linking observes announces RPC request autodiscovery fetches 1 2 3 4 5 (updates) 6 Publisher Link Reveiver Pingback Server Link Publisher Pingback Client (Link Propagator) (notifies) 7 13 / 18
- 18. Other Approaches: SemanticPingback and Structured Feedback Sender Subscriber (aka. Consumer) Recource Hosting Service Some Graph Semantic Pingback Service PubSubHubbub Hub Comment Container 1. create/store 3. ping/notify 4. retrieve (verification) sioc:container_of 5. update 6. notify 8. notify 0. subscribes 7. retrieve GET 2. HEAD/GET target pingback:to • In contrast to LDN the roll of the Receiver is distributed among the Semantic Pingback Service and the PubSubHubbub Hub • The roll of the Inbox is done by the Comment Container, while it doesn’t necessarily be a LDP, but any Linked Data RDF • The Actual notification resource stays at its origin and doesn’t need to be copied and transfered for the protocol 14 / 18
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- 20. Discussion • This WorkingDraft is a good starting point for active communication on Linked Data • A W3C standard can help us to actually use RDF for communication and create meaningful communication • Less polling, more pushing 15 / 18
- 21. Discussion • Why usingexactly JSON-LD as default and not any other RDF serialization? • Why do all participants MUST support JSON-LD? • Why should the payload replicate and contain the complete notification resource and the references information? Why not build links and reference it? • “Decoupling between applications and data storage“ (4). Maybe also the tasks of the services and the different kinds of data storages can be decoupled. • Why restrict the protocol to LDP and not also allow the resources to e. g. be managed by a SPARQL 1.1 endpoint? 16 / 18
- 22. References I Arndt, N.,Junghanns, K., Meissner, R., Frischmuth, P., Radtke, N., Frommhold, M., and Martin, M. (2016). Structured feedback: A distributed protocol for feedback and patches on the web of data. In Proceedings of the Workshop on Linked Data on the Web co-located with the 25th International World Wide Web Conference (WWW 2016), volume 1593 of CEUR Workshop Proceedings, Montréal, Canada. http://ceur-ws.org/Vol-1593/article-02.pdf. Capadisli, S. and Guy, A. (2016). Linked data notifications. https://www.w3.org/TR/2016/WD-ldn-20160824/. work in progress. 17 / 18
- 23. References II Frommhold, M.,Arndt, N., Tramp, S., and Petersen, N. (2016). Publish and Subscribe for RDF in Enterprise Value Networks. In Proceedings of the Workshop on Linked Data on the Web co-located with the 25th International World Wide Web Conference (WWW 2016), CEUR Workshop Proceedings, Montréal, Canada. http://ceur-ws.org/Vol-1593/article-09.pdf. Tramp, S., Frischmuth, P., Ermilov, T., Shekarpour, S., and Auer, S. (2012). An Architecture of a Distributed Semantic Social Network. Semantic Web Journal, Special Issue on The Personal and Social Semantic Web. http://www.semantic-web-journal.net/sites/default/files/swj201_4.pdf. 18 / 18