This book describes a set of methods, architectures, and tools to extend the data pipeline at the disposal of developers when they need to publish and consume data from Knowledge Graphs (graph-structured knowledge bases that describe the entities and relations within a domain in a semantically meaningful way) using SPARQL, Web APIs, and JSON. To do so, it focuses on the paradigmatic cases of two middleware software packages, grlc and SPARQL Transformer, which automatically build and run SPARQL-based REST APIs and allow the specification of JSON schema results, respectively.
The authors highlight the underlying principles behind these technologies--query management, declarative languages, new levels of indirection, abstraction layers, and separation of concerns--, explain their practical usage, and describe their penetration in research projects and industry.
The book, therefore, serves a double purpose: to provide a sound and technical description of tools and methods at the disposal of publishers and developers to quickly deploy and consume Web Data APIs on top of Knowledge Graphs; and to propose an extensible and heterogeneous Knowledge Graph access infrastructure that accommodates a growing ecosystem of querying paradigms.
Author(s): Albert Meroño-Peñuela, Pasquale Lisena, Carlos Martínez-Ortiz
Series: Synthesis Lectures on Data, Semantics, and Knowledge
Edition: 1
Publisher: Morgan & Claypool
Year: 2021
Language: English
Commentary: Vector PDF
Pages: 118
City: San Rafael, CA
Tags: JSON; Queries; GraphQL; Semantic Web; Resource Description Framework; Knowledge Graph; REST API; SPARQL
Foreword by Tobias Kuhn
Preface
Acknowledgments
Knowledge Graphs of Linked Data
Knowledge Graphs and Linked Data
RDF: Resource Description Framework
SPARQL: SPARQL Protocol and RDF Query Language
GraphQL: Web API Made Easy
Accessing Knowledge Graphs Programmatically
Querying Knowledge Graphs
HTTP Requests
SPARQL Libraries
Manipulating SPARQL's Output
Web Data APIs Over SPARQL
REST APIs
The OpenAPI Specification
Writing Web APIs
Writing Knowledge Graph APIs
Limitations of Knowledge Graph APIs
Repetitive Work
Query Management
Controlling Results
grlc: API Automation by Query Sharing
Overview
Architecture
Working with grlc
Features
Query Documentation
Query Variables
Query Execution
Query Result Manipulation
Exercises
Shaping JSON Results: SPARQL Transformer
SPARQL Results JSON Format: The Curse of the Bindings
Data Reshape with SPARQL Transformer
A Single JSON Object as Query and Template
Architecture
Features and Syntax
Merging Around an Anchor
Overview of $-Modifiers
Dealing with Languages
A Complete Example
grlc and SPARQL Transformer
Exercises
Applications
grlc
Linked Data Platform for Genetics Research
Nanopublications
CLARIAH and Social History Research
TNO: FoodCube
NewGen Chennai: Conference Proceedings
EU RISIS: Science, Technology, and Innovation
SPARQL Transformer
KG Explorer
FADE
grlc and Transformer
Demos/Links
Conclusion and Future Challenges
Solutions
Chapter 4
Chapter 5
Bibliography
Authors' Biographies
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