Building FHIR Bundles

FHIR Bundles are used to bundle multiple resources into a single request. This guide explains how to build FHIR Bundles in WSO2 Healthcare solution. The WSO2 Healthcare solution provides a set of built-in capabilities to construct FHIR Bundles.

Note

WSO2 Healthcare Solution offers two distinct solutions (Ballerina and Micro Integrator) each tailored to different architectural preferences. For systems that favor the Enterprise Service Bus (ESB) pattern, the Micro Integrator, enhanced with FHIR accelerators, can be utilized.
On the other hand, Ballerina, a programming language specifically designed for integrations, is ideal for implementing FHIR integrations structured as microservices.

BallerinaMicro Integrator

The following example demonstrates how to build a FHIR Bundle using Ballerina.

Step 1: Set Up Ballerina

Before you begin, ensure you have Ballerina installed on your system. Follow the instructions in the Installation Steps to install Ballerina and set up the development environment.

Step 2: Implement the logic to build the FHIR Bundle

1. Create a Ballerina project using the following command. It will create the Ballerina project and the main.bal file can be used to implement the logic.

   $ bal new fhir_bundle_sample
   

2. Import the required modules to the Ballerina program. In this sample, we are using the FHIR R4 module to build the FHIR Bundle. Therefore, we need to import the ballerinax/health.fhir.r4 package.

   import ballerinax/health.fhir.r4.international401;
   import ballerinax/health.fhir.r4;
   import ballerina/io;
   

3. Implement the logic to initialize FHIR bundle and add FHIR resources to the bundle. In this sample, we are building a FHIR Bundle with a Patient and Observation resources.

   import ballerinax/health.fhir.r4.international401;
   import ballerinax/health.fhir.r4;
   import ballerina/io;
   
   public function main2() returns error? {
       // Initialize a bundle with desired type
       r4:Bundle bundle = { resourceType: "Bundle", 'type: "searchset"};
       r4:BundleEntry[] entries = []; 
       // Sample patient data
       international401:Patient patient = { resourceType: "Patient", id: "pat1", active: true };
       entries.push({ 'resource: patient });
       // Sample observation data
       international401:Observation observation = { resourceType: "Observation", id: "obx1", status: "final" ,code: { coding: [{ system: "http://loinc.org", code: "8480-6", display: "Systolic blood pressure"}]}};
       entries.push({ 'resource: observation });
       // Add the entries to the bundle
       bundle.entry = entries;
       io:println(bundle.toString());
   }            
   

Step 3: Run the Ballerina Program

Run the Ballerina program using the following command:

```bash
$ bal run
```

The following example demonstrates how to build a FHIR Bundle using the WSO2 Micro Integrator.

Step 1: Set Up WSO2 Micro Integrator

Before you begin, download the WSO2 Micro Integrator and install by following the Installation Steps.

Step 2: Implement the logic to build the FHIR Bundle

1. Create a MI project using the MI VSCode plugin by following the guide on Creating a New Integration Project.

2. Create a REST API.

3. Add fhirbase connector to the project.

4. Implement the logic to build the FHIR Bundle. The createBundle operation can be used to create a FHIR Bundle and addBundleEntry operation can be used to add FHIR resources to the Bundle.

   

   <?xml version="1.0" encoding="UTF-8"?>
   <api context="/r4" name="PatientAPI" xmlns="http://ws.apache.org/ns/synapse">
       <resource methods="GET" uri-template="/Patient">
           <inSequence>
               <fhirbase.createBundle>
                   <type>searchset</type>
               </fhirbase.createBundle>
               <payloadFactory media-type="json" template-type="default">
                   <format>{ resourceType: "Patient", id: "pat1", active:
                       true }</format>
                   <args>
                   </args>
               </payloadFactory>
               <fhirbase.parse />
               <!-- Add the parsed resource to the bundle -->
               <fhirbase.addBundleEntry />
               <!-- Serialize the bundle -->
               <fhirbase.serialize />
               <respond />
           </inSequence>
           <faultSequence>
           </faultSequence>
       </resource>
   </api>
   

Step 3: Deploy and Test the Integration Project

Deploy the integration project to the MI runtime by following the guide on Deploying the Integration Project and test the API using a REST client.