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 Open Healthcare. The WSO2 Open Healthcare provides a set of built-in capabilities to construct FHIR Bundles.

:::note These guides use Ballerina, a language designed for integration and network services, to build healthcare integrations as microservices. :::

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
```