Authorization solution for full stack FHIR HAPI access

The Health Level Seven's (HL7) Fast Healthcare Interoperability Resources (FHIR) standard enables the standardized access to the health related data stored in different Electronic Health Record (EHR) backends. A popular open source implementation of FHIR is the Java-based HAPI. It provides generic FHIR-compatible Representational State Transfer (REST) interfaces for data access. One weak point of this solution is the lack of client side support. It supports only Java-based client environments. This is useful in the case of Android-based native client, but for the JavaScript or TypeScript-based full stack environments a JavaScript-based environment is needed. Here, we present our solution which integrates HAPI into a JavaScript-based full stack environment. Another novelty of our solution is that it extends the FHIR's access control model so that it has the best aspects of Role-Based Access Control (RBAC) and Attribute-Based Access Control (ABAC) access control approaches.