the story so farServices and Applications over Linked APIs and Data

workshop at the 12th Extended Semantic Web ConferencePortorož, June 1, 2015

semanticson services

Who Am I?

Partner Technology Manager at Redlink GmbH

also…

External Lecturer at Fachhochschule SalzburgMember of the Apache Software Foundation

previously…

Senior Researcher at Salzburg ResearchResearch Engineer at Fundacion CTIC

Sergio Fernández@wikier

http://linkedin.com/in/sergiofernandez

http://www.wikier.org

- 10+ years experience in software engineering;

- participated in 20+ international research projects;

- successfully deployed 50+ industrial solutions;

- co-founded 3 Apache projects.

the team

Redlink GmbH is a Austrian startup, headquartered in Salzburg, that provides cloud services for Content Analysis, Linked Data Publishing and Semantic Search.

@RedlinkGmbH

http://linkedin.com/company/redlink-gmbh

http://redlink.co

Who Are We?

Redlink offers named-entity

recognition and linking, topic

classification, fact extraction and topic classification from textual and media

documents in different languages.

Text Analysis & Entity Linking

Linked Data Publishing

Application development

Enterprise Data Linking

Redlink offers services to build your own applications by combining existing analysis tools and

datasets.

Redlink offers cleaning,

transformation and reconciliation of

legacy enterprise data using open standards

and technologies.

Redlink offers data management and data publication

using open standards Linked Data

technologies.

connect your content with data that matters

semantics on services

what have we achieved?

Service-Oriented Architectures

● Always aimed to enable the development of applications by combining loosely coupled and interoperable services.

● Many technical proposals have came to address the new problems that a connected world requires.

● But beyond the syntax, the semantics has been always the main issue for services' interoperability.

Services _before_ Semantic Web

Semantics is a much bigger field than what Semantic Web actually touches...

Them, of course, common SOA technologies already have some sense of semantics:

● SOAP○ WSDL

● etc...

● RPC○ only on

failures

● CORBA ○ IDL

then back in 1989Tim Berners-Lee proposed the concept of Semantic Web...

and since that everything is

"semantically-enriched"

Semantic Web Services

Semantics Web Services proposals

● WSMO Stack○ WSMO○ WSML○ WSMX○ ...

● WSDL-S

● OWL-S

● SAWSDL

● etc..

REpresentational State Transfer

● REST revolutionized the Web providing an effective mechanism to implement simple Web APIs

● Simple data formats○ XML at the beginning○ JSON has overtook

● No formal protocol, no "official" standard, just a set of conventions over HTTP○ Therefore no formal semantics beyond the basic

operations / verbs○ Simplicity is the key

where is my contract?

Read-Write Linked Data

2007 Linked Data Design Issueshttp://www.w3.org/DesignIssues/LinkedData.html

2009 Read-Write Linked Datahttp://www.w3.org/DesignIssues/ReadWriteLinkedData.html

2010 Linked Media Principleshttp://bitbucket.org/srfgkmt/lmf/wiki/Principles-Linked-Media

2010 SPARQL 1.1 Graph Store HTTP Protocolhttp://www.w3.org/TR/sparql11-http-rdf-update/

2011 Linked Data Basic Profile 1.0http://www.w3.org/Submission/ldbp/

2012 Linked Data Platform 1.0http://www.w3.org/2012/ldp/

a set of best practices and simple approach for a read-write Linked Data architecture, based on HTTP access to web resources that describe their state using the RDF data model

Linked Data Platform

Linked Data Platform 1.0http://www.w3.org/TR/ldp/ W3C Recommendation 26 February 2015

LDP

https://www.flickr.com/photos/rachelpasch/3432013868

https://www.flickr.com/photos/sybrenstuvel/2468506922

HATEOAS● Hypermedia as the Engine of Application

State is a constraint of REST

● Hydra aims to simplify the development of interoperable Web APIs using hypermedia controls○ JSON-LD as pillar

● Some overlap (better resolved?) with LDP○ containers and pagination

● Some good early results○ e.g., Linked Data Fragments

● Still a lot of work to do in the W3C CG...

Glory of REST

What lies ahead...?● Monolithic services do not scale

● Microservice architectures commonly provide a better solution for Web-scale problems○ Services solving small concrete problems ○ Loosely couple○ Low semantics on description○ Stronger on business

● Open your mind○ RDF is not the single data format○ HTTP is not the single protocol

● Make easy for developers to jump in● Test, learn, combine and test again

vision

https://www.flickr.com/photos/jox1989/4764186425/

test yourself!

scientific evaluation is not the way to validate a solution against real world problems

questions / discussion

hvala!

https://www.flickr.com/photos/hanspoldoja/1218526964/