A new reusable validation service is now available to validate RDF content using SHACL shapes.
The ISA² Interoperability Test Bed enables conformance testing of semantic and technical specifications. A key element in such testing scenarios is the validation of content, either as a standalone validation or as part of complete processes involving numerous message exchange steps. Although the Test Bed's pluggable architecture allows validation of any content by means of custom GITB-compliant validation services, it has always offered additional support for validation of XML-based content to address this, most common need of its users. Validation using XML has allowed syntactic and content validation using XSD and Schematron that can be customised per use case and be online in a matter or minutes. Such validation can be exposed as a standalone service or as a service to be integrated into further GITB TDL test cases.
The increasing adoption of open data principles and the use of RDF vocabularies as a semantic interoperability enabler has created a need to foresee validation for such content. Based on the popularity of its XML validation capabilities, the Test Bed has now brought online a similar service for RDF content validation using business rules expressed as SHACL shapes. This SHACL validator builds upon the features enjoyed by its XML counterpart, allowing a new validation scenario to be brought online within minutes.
The service is highly configurable and allows adaptation to cater to each user's needs. Available features include:
- Pre-configuration of one or more SHACL files (provided locally or loaded remotely) to express fixed constraints.
- Validation of a single or multiple RDF instance documents, provided inline or via remote reference.
- On-the-fly extension of the applied SHACL shapes as part of individual validation requests.
- Support for numerous RDF syntaxes (e.g. RDF/XML, Turtle, JSON-LD).
- Support for multiple versions or profiles that can be managed and brought online in a fully self-service manner.
- Multiple communication channels, including a REST API, a GITB-compliant SOAP API, a web user interface, email and an offline command-line tool.
Once a new validation scenario is configured (matching a specific community's needs), this can be exposed as a standalone service for one-off anonymous content validation, or be leveraged in test cases configured in the ISA² Test Bed as part of a complete conformance testing campaign. Given these possibilities, a user may validate herself individual RDF documents, or, via the Test Bed, engage in test sessions that involve the automated generation and exchange of RDF content that is validated in each step of the process.
First adopters of the new service are the ISA² Catalogue of Services Action and the Semantic Interoperability Community (SEMIC) for the validation, respectively of CPSV-AP and DCAT-AP. To join and use this service for your own needs the process is simple:
- Send an email to DIGIT-ITB@ec.europa.eu with a brief summary of your case.
- Provide the SHACL shapes (or their remote references) to be used for validation.
- The Test Bed team will then, according to your requirements, bring up the new service instance.
- You will receive information on how to manage your service's configuration and trigger its update.
At the time of writing, the SHACL validator offers a rich REST API, fully documented using Swagger/OpenAPI and Hydra (example from DCAT-AP). Work now continues to implement further configuration options and complete the remaining communication channels. Become a member of our community to be notified when new features become available and to stay up-to-date on other Test Bed news.