Data Access

The client core package provides several data services to allow you to access FHIR and custom data easily.

FHIR Service#

Kailona has FHIR API Gateway which allows client components to access the FHIR server in a secure way using Nextcloud security mechanism.

The client components use FHIRService class from @kailona/core package. For example, you can read a specific Observation resource from the FHIR service using the following source code:

import { FHIRService } from '@kailona/core';
const fhirService = new FHIRService('Observation');
const observation = await fhirService.read('some-observation-id');

The constructor of BaseResourceService class gets resource type as a parameter. It implements the following methods as defined in FHIR standard:

  • transaction: Update, create or delete a set of resources in a single interaction with the FHIR server
  • create: Create a new resource with a server assigned id in the FHIR server
  • read: Read the current state of the resource in the FHIR server
  • vread: Read the state of a specific version of the resource in the FHIR server
  • update: Update an existing resource by its id in the FHIR server
  • patch: Update an existing resource by posting a set of changes to it in the FHIR server
  • delete: Delete a resource in the FHIR server
  • history: Retrieve the change history for a particular resource in the FHIR server
  • search: Search the resource type based on some filter criteria in the FHIR server
danger

FHIR API Gateway automatically sets patient id parameter in all search queries to prevent unauthorized access in a shared FHIR server! You can setup FHIR server in a tenant infrastructure and use individual tenant for each Nextcloud user to completely isolate health data.

We would like to accept any contributions and security checks in this area.

caution

FHIR API Gateway automatically replaces URLs in the FHIR responses to allow client components call them directly.

Base Resource Service#

BaseResourceService class is a base class which should be overridden before it is used. It is useful for quick data access of a group of FHIR resources. For example, you can implement a class to manage data with custom mappers using the following source code:

import { BaseResourceService } from '@kailona/core';
export default class MyDataService extends BaseResourceService {
constructor() {
super('Observation');
}
async fetchData(params) {
const data = await super.fetchData(params);
// TODO: Map data
return data;
}
async fetchNextData() {
const data = await super.fetchNextData();
// TODO: Map data
return data;
}
async upsertData(data) {
// TODO: Map data
return await super.upsertData(data);
}
}

The constructor of BaseResourceService class gets resource type as a parameter. It implements the following methods:

  • hasNextData: Check whether there is more data to retrieve from the FHIR server, useful for pagination
  • fetchData: Retrieve data from the FHIR server
  • fetchNextData: Retrieve next data from the FHIR server, useful for pagination
  • upsertData: Update the existing data or create if it is new in the FHIR server
  • removeData: Remove the data in the FHIR server

Mail Service#

MailService class is used to send email based on some workflow such as data request. It implements the following method:

  • sendRequestData: Sends an email to request health data via Nextcloud

Settings Service#

SettingsService class is used to retrieve and store application and user settings. It implements the following methods:

  • retrieveAdminSettings: Retrieve admin settings in Nextcloud
  • saveAdminSettings: Store admin settings in Nextcloud
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