LinkedDataHub dataspaces, applications, and services

Dataspaces

The LinkedDataHub URI address space is split into dataspaces. Every dataspace consists of a pair of LDT applications: end-user and administration.

The end-user app will be available on the given base URI; the admin app will be available at that base URI with admin/ appended. The agent that installed the admin dataset will be the application owner.

Applications

All LDT applications have the following properties:

Base URI
Base URI is a URI by which an application can be identified. An application might have multiple base URIs; all request URIs processed by an application are relative to one of its base URIs. For example, the base URI of this Documentation dataspace is https://linkeddatahub.com/linkeddatahub/docs/.
URIs in the application dataset are usually (but not necessarily) relative to one or more of the base URIs.
Service
SPARQL service
Ontology
Ontology defines the terms (classes, properties etc.) of the application domain as well as its LDT templates. It can import other ontologies from within the application as well as from external applications.
Ontologies as managed in the administration application.

Base URI must end with a forward slash (/).

In addition to that, LinkedDataHub applications have one additional property:

Stylesheet
XSLT stylesheet that renders the applications layout

End-user

The base URI of an end-user application is also the base URI of its dataspace.

Every end-user application is related to one administration application.

Administration

Every administration application is related to one end-user application. It cannot exist standalone.

The base URI(s) of an administration application is the base URI(s) of its end-user application with admin/ appended to it. Note that any URIs in the end-user application that are equal or relative to the admin application base URI will not be accessible.

Administration application provides means to control the structure and access control of its end-user application. Only dataspace owners have access to its administration application.

The agent which installs the adminstration application dataset becomes the owner of its dataspace.

Dataspace hierarchy

Contexts

Contexts are special meta-applications that allow creation of dataspaces (that will belong to the context) and also list public dataspaces that belong to them.

The concept can be compared to servlet context (to which multiple servlets can be added) in Java EE architecture. However, LinkedDataHub concepts and dataspaces are purely RDF data structures and not software artifacts.

LinkedDataHub imports the default datasets for each application type into its service. The dataset URIs are rebased to be relative to the base URI of the application.

Services

LDT architecture

A service is a persistent SPARQL 1.1-compatible store from which the application's RDF dataset is accessible over HTTP. LinkedDataHub supports generic services as well as triplestore-specific services which support easier configuration and optimized access. HTTP Basic is suppported as an authentication scheme. Contact us regarding support for vendor-specific authentication such as API keys.

The end-user application service must be able to federate with the administration application service using the SPARQL SERVICE keyword.

Generic services

Generic service has the following properties:

Endpoint
SPARQL 1.1 Protocol endpoint URI
Graph Store
SPARQL 1.1 Graph Store Protocol endpoint URI
Username
HTTP Basic username (optional)
Password
HTTP Basic password (optional)

Dydra services

LinkedDataHub has built-in support for Dydra services (repositories). It has the following properties:

Repository
Dydra repository URI
Username
HTTP Basic username (optional)
Password
HTTP Basic password (optional)

Contact us for a trial of Dydra.

If you are ready to create a dataspace, see our step-by-step tutorial on dataspace management.

Date Created
17 March 2020 20:44
Maker
Martynas Jusevičius
Owner
Martynas Jusevičius