FHIR Connector Example

In this example the connector uses the FHIR REST API to interact with FHIR.

What you'll build

Given below is a sample API that illustrates how you can connect to a FHIR server and invoke operations. It exposes FHIR functionalities as a restful service. Users can invoke the API with HTTP/HTTPs with required information.

  1. /create : creates a new patient at FHIR server
  2. /read : retrieve information about the patient from FHIR server
  3. /readSpecificResourceById: map this to the scenario is it read patient by Id
  4. /update : update patient information from FHIR server.
  5. /delete : remove added patient information from FHIR server.

To know the further information about these operations please refer this link.

Note: If no ID element is provided, or the value is wrong, the server responds with a HTTP 400 error code and provides an operation outcome identifying the issue.

Before you start configuring the FHIR connector, you also need WSO2 MI, and we refer to that location as <PRODUCT_HOME>.

Before starting the product, you need to enable configurations for specific message builders/formatters.

You need to enable transport by adding the following configurations to the /conf/deployment.toml file. You can further refer to the Working with Message Builders and Formatters and Product Configurations documentations.

[[custom_message_builders]]
content_type = "application/fhir+json"
class = "org.wso2.micro.integrator.core.json.JsonStreamBuilder"
[[custom_message_formatters]]
content_type = "application/fhir+json"
class = "org.wso2.micro.integrator.core.json.JsonStreamFormatter"

If you are using EI 6, you can enable this property by doing the following Axis2 configurations in the /repository/conf/axis2/axis2.xml file.

messageFormatters

<messageFormatter contentType="application/fhir+json" 
class="org.wso2.carbon.integrator.core.json.JsonStreamFormatter"/>
messageBuilders 
<messageBuilder contentType="application/fhir+json" 
class="org.wso2.carbon.integrator.core.json.JsonStreamBuilder"/>

The following diagram illustrates all the required functionality of the FHIR API service that you are going to build.

In here FHIR clients can invoke the API with HTTP/HTTPs with required information. The FHIR connector exposes each request to converting to the Health Level Seven International standards and then send to the resources available in the FHIR server.

This server is regularly loaded with a standard set of test data sets and also this server can store any data that related to administrative concepts such as patients, providers, organizations and devices, as well as a variety of clinical concepts including problems, medications, diagnostics, care plans and financial issues, among others.

FHIR Connector

Configure the connector in WSO2 Integration Studio

Follow these steps to set up the Integration Project and the Connector Exporter Project.

{!references/connectors/importing-connector-to-integration-studio.md!}

  1. Right click on the created Integration Project and select New -> Rest API to create the REST API.

  2. Specify the API name as SendisoTestAPI and API context as /resources. You can go to the source view of the XML configuration file of the API and copy the following configuration (source view).

<?xml version="1.0" encoding="UTF-8"?>
<api context="/resources" name="SampleApi" xmlns="http://ws.apache.org/ns/synapse">
    <resource methods="POST" url-mapping="/create">
        <inSequence>
            <property expression="json-eval($.base)" name="base" scope="default" type="STRING"/>
            <property expression="json-eval($.resourceType)" name="type" scope="default" type="STRING"/>
            <property expression="json-eval($.format)" name="format" scope="default" type="STRING"/>
            <log level="custom">
                <property expression="get-property('transport','Content-Type')" name="base"/>
            </log>
            <fhir.init>
                <base>http://hapi.fhir.org/baseR4</base>
            </fhir.init>
            <switch source="get-property('transport','Content-Type')">
                <case regex="application/json">
                    <property name="format" scope="default" type="STRING" value="json"/>
                    <fhir.create>
                        <type>{$ctx:type}</type>
                        <format>{$ctx:format}</format>
                    </fhir.create>
                </case>
                <case regex="application/xml">
                    <property name="format" scope="default" type="STRING" value="xml"/>
                    <fhir.create>
                        <type>{$ctx:type}</type>
                        <format>{$ctx:format}</format>
                    </fhir.create>
                </case>
                <default/>
            </switch>
            <log level="full" separator=","/>
            <send/>
        </inSequence>
        <outSequence/>
        <faultSequence/>
    </resource>
    <resource methods="POST" url-mapping="/read">
        <inSequence>
            <property expression="json-eval($.base)" name="base" scope="default" type="STRING"/>
            <property expression="json-eval($.resourceType)" name="type" scope="default" type="STRING"/>
            <property expression="json-eval($.format)" name="format" scope="default" type="STRING"/>
            <fhir.init>
                <base>http://hapi.fhir.org/baseR4</base>
            </fhir.init>
            <switch source="get-property('transport','Content-Type')">
                <case regex="application/json">
                    <property name="format" scope="default" type="STRING" value="json"/>
                    <fhir.readResource>
                        <type>{$ctx:type}</type>
                        <format>{$ctx:format}</format>
                    </fhir.readResource>
                </case>
                <case regex="application/xml">
                    <property name="format" scope="default" type="STRING" value="xml"/>
                    <fhir.readResource>
                        <type>{$ctx:type}</type>
                        <format>{$ctx:format}</format>
                    </fhir.readResource>
                </case>
                <default/>
            </switch>
            <log level="full" separator=","/>
            <send/>
        </inSequence>
        <outSequence/>
        <faultSequence/>
    </resource>
    <resource methods="POST" url-mapping="/readSpecificResourceById">
        <inSequence>
            <property expression="json-eval($.base)" name="base" scope="default" type="STRING"/>
            <property expression="json-eval($.resourceType)" name="type" scope="default" type="STRING"/>
            <property expression="json-eval($.format)" name="format" scope="default" type="STRING"/>
            <property expression="json-eval($.id)" name="id" scope="default" type="STRING"/>
            <property expression="json-eval($.summary)" name="summary" scope="default" type="STRING"/>
            <fhir.init>
                <base>http://hapi.fhir.org/baseR4</base>
            </fhir.init>
            <switch source="get-property('transport','Content-Type')">
                <case regex="application/json">
                    <property name="format" scope="default" type="STRING" value="json"/>
                    <fhir.readSpecificResourceById>
                        <type>{$ctx:type}</type>
                        <id>{$ctx:id}</id>
                        <format>{$ctx:format}</format>
                        <summary>{$ctx:summary}</summary>
                    </fhir.readSpecificResourceById>
                </case>
                <case regex="application/xml">
                    <property name="format" scope="default" type="STRING" value="xml"/>
                    <fhir.readSpecificResourceById>
                        <type>{$ctx:type}</type>
                        <id>{$ctx:id}</id>
                        <format>{$ctx:format}</format>
                        <summary>{$ctx:summary}</summary>
                    </fhir.readSpecificResourceById>
                </case>
                <default/>
            </switch>
            <log level="full" separator=","/>
            <send/>
        </inSequence>
        <outSequence/>
        <faultSequence/>
    </resource>
    <resource methods="POST" url-mapping="/update">
        <inSequence>
            <property expression="json-eval($.base)" name="base" scope="default" type="STRING"/>
            <property expression="json-eval($.resourceType)" name="type" scope="default" type="STRING"/>
            <property expression="json-eval($.format)" name="format" scope="default" type="STRING"/>
            <property expression="json-eval($.idToUpdate)" name="idToDelete" scope="default" type="STRING"/>
            <fhir.init>
                <base>http://hapi.fhir.org/baseR4</base>
            </fhir.init>
            <switch source="get-property('transport','Content-Type')">
                <case regex="application/json">
                    <property name="format" scope="default" type="STRING" value="json"/>
                    <fhir.update>
                        <type>{$ctx:type}</type>
                        <idToUpdate>{$ctx:idToUpdate}</idToUpdate>
                        <format>{$ctx:format}</format>
                    </fhir.update>
                </case>
                <case regex="application/xml">
                    <property name="format" scope="default" type="STRING" value="xml"/>
                    <fhir.update>
                        <type>{$ctx:type}</type>
                        <idToUpdate>{$ctx:idToUpdate}</idToUpdate>
                        <format>{$ctx:format}</format>
                    </fhir.update>
                </case>
                <default/>
            </switch>
            <log level="full" separator=","/>
            <send/>
        </inSequence>
        <outSequence/>
        <faultSequence/>
    </resource>
    <resource methods="POST" url-mapping="/delete">
        <inSequence>
            <property expression="json-eval($.base)" name="base" scope="default" type="STRING"/>
            <property expression="json-eval($.resourceType)" name="type" scope="default" type="STRING"/>
            <property expression="json-eval($.format)" name="format" scope="default" type="STRING"/>
            <property expression="json-eval($.idToDelete)" name="idToDelete" scope="default" type="STRING"/>
            <fhir.init>
                <base>http://hapi.fhir.org/baseR4</base>
            </fhir.init>
            <switch source="get-property('transport','Content-Type')">
                <case regex="application/json">
                    <property name="format" scope="default" type="STRING" value="json"/>
                    <fhir.delete>
                        <type>{$ctx:type}</type>
                        <idToDelete>{$ctx:idToDelete}</idToDelete>
                    </fhir.delete>
                </case>
                <case regex="application/xml">
                    <property name="format" scope="default" type="STRING" value="xml"/>
                    <fhir.delete>
                        <type>{$ctx:type}</type>
                        <idToDelete>{$ctx:idToDelete}</idToDelete>
                    </fhir.delete>
                </case>
                <default/>
            </switch>
            <log level="full" separator=","/>
            <send/>
        </inSequence>
        <outSequence/>
        <faultSequence/>
    </resource>
</api>
To learn about supported operations and their parameters, please refer to FHIR connector reference.

  1. Now we can export the imported connector and the API into a single CAR application. The CAR application is what we are going to deploy during server runtime.

{!references/connectors/exporting-artifacts.md!}

Get the project

You can download the ZIP file and extract the contents to get the project code.

Download ZIP

Deployment

Follow these steps to deploy the exported CApp in the Enterprise Integrator Runtime.

{!references/connectors/deploy-capp.md!}

Testing

Invoke the API as shown below using the curl command. Curl Application can be downloaded from here.

Add patient information

Sample Request 

curl -v POST -d 
   '  {  "resourceType": "Patient",
           "name": [{"family": "Jhone","given": ["Winney","Rodrigo"]}]
      }' "http://localhost:8290/resources/create" -H "Content-Type:application/json"
Expected Response: 

<jsonObject>
       <resourceType>Patient</resourceType>
       <id>698021</id>
        <meta>
          <versionId>1</versionId>
          <lastUpdated>2020-03-24T07:57:14.506+00:00</lastUpdated>
        </meta>
         <text>
           <status>generated</status>
           <div>&lt;div xmlns="http://www.w3.org/1999/xhtml"&gt;&lt;div class="hapiHeaderText"&gt;Winney Rodrigo &lt;b&gt;JHONE &lt;/b&gt;&lt;/div&gt;&lt;table class="hapiPropertyTable"&gt;&lt;tbody/&gt;&lt;/table&gt;&lt;/div&gt;</div>
         </text>    
         <name>
            <family>Jhone</family>
            <given>Winney</given>
            <given>Rodrigo</given>
        </name>
</jsonObject>

Read patient information

Sample Request 

curl -v POST -d 
   '  {  
        "resourceType": "Patient"
      }' "http://localhost:8290/resources/read" -H "Content-Type:application/json"

Expected Response:

It will retrieve all the existing resources in the FHIR server.

Read specific patient information

Sample Request 

curl -v POST -d 
   '{
       "resourceType":"Patient",
       "id":"698021"
    }' "http://localhost:8290/resources/readSpecificResourceById" -H "Content-Type:application/json"

Expected Response: 

<jsonObject>
    <resourceType>Patient</resourceType>
    <id>698021</id>
    <meta>
        <versionId>1</versionId>
        <lastUpdated>2020-03-24T07:57:14.506+00:00</lastUpdated>
    </meta>
    <text>
        <status>generated</status>
        <div>&lt;div xmlns="http://www.w3.org/1999/xhtml"&gt;&lt;div class="hapiHeaderText"&gt;Winney Rodrigo &lt;b&gt;JHONE &lt;/b&gt;&lt;/div&gt;&lt;table class="hapiPropertyTable"&gt;&lt;tbody/&gt;&lt;/table&gt;&lt;/div&gt;</div>
        </text>
               <name>
                  <family>Jhone</family>
                  <given>Winney</given>
                  <given>Rodrigo</given>
               </name>
</jsonObject>

Update patient information

Sample Request 

curl -v POST -d 
         '{
             "resourceType":"Patient",
             "idToUpdate":"597079",
             "name":[
                {
                   "family":"Marry",
                   "given":[
                      "Samsong",
                      "Perera"
                   ]
                }
             ]
          }' "http://localhost:8290/resources/update" -H "Content-Type:application/json"

Expected Response: 

<jsonObject>
         <resourceType>Patient</resourceType>
         <id>597079</id>
         <meta>
            <versionId>1</versionId>
            <lastUpdated>2020-03-24T07:57:14.506+00:00</lastUpdated>
         </meta>
         <text>
            <status>generated</status>
            <div>&lt;div xmlns="http://www.w3.org/1999/xhtml"&gt;&lt;div class="hapiHeaderText"&gt;Winney Rodrigo &lt;b&gt;JHONE &lt;/b&gt;&lt;/div&gt;&lt;table class="hapiPropertyTable"&gt;&lt;tbody/&gt;&lt;/table&gt;&lt;/div&gt;</div>
         </text>
         <name>
            <family>Marry</family>
            <given>Samsong</given>
            <given>Perera</given>
         </name>
</jsonObject>

Delete patient information

Sample Request 

curl -v POST -d 
   '{
      "resourceType":"Patient",
      "idToDelete":"597079",
    }' "http://localhost:8290/resources/delete" -H "Content-Type:application/json"

Expected Response: 

<jsonObject>
         <resourceType>OperationOutcome</resourceType>
         <text>
            <status>generated</status>
            <div>&lt;div xmlns="http://www.w3.org/1999/xhtml"&gt;&lt;h1&gt;Operation Outcome&lt;/h1&gt;&lt;table border="0"&gt;&lt;tr&gt;&lt;td style="font-weight: bold;"&gt;INFORMATION&lt;/td&gt;&lt;td&gt;[]&lt;/td&gt;&lt;td&gt;&lt;pre&gt;Successfully deleted 1 resource(s) in 46ms&lt;/pre&gt;&lt;/td&gt;


                            &lt;/tr&gt;
                        &lt;/table&gt;
                    &lt;/div&gt;</div>
         </text>
         <issue>
            <severity>information</severity>
            <code>informational</code>
            <diagnostics>Successfully deleted 1 resource(s) in 46ms</diagnostics>
         </issue>
</jsonObject>

This demonstrates how the WSO2 EI FHIR connector works.

What's next

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