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Connecting Web APIs/Cloud Services

What you'll build

When you integrate the systems in your organizaion, it is also necessary to integrate with third-party systems and its capabilities to enhance your services. WSO2 Micro Integrator uses Connectors for the purpose of referring the APIs of third-party systems.

In this tutorial, when a client sends an appointment reservation request to the Micro Integrator, the client should receive an email confirming the appointment reservation details. To build this use case, you can add an Email connector to the mediation flow of the REST resource that you defined in the previous tutorial.

Let's get started!

Step 1: Set up the workspace

Set up WSO2 Integration Studio as follows:

  1. Download the relevant WSO2 Integration Studio based on your operating system. The path to the extracted/installed folder is referred to as MI_TOOLING_HOME throughout this tutorial.
  2. If you did not try the asynchronous messaging tutorial yet:
    1. Open WSO2 Integration Studio and go to File -> Import.
    2. Select Existing WSO2 Projects into workspace under the WSO2 category, click Next, and then upload the pre-packaged project.

Step 2: Develop the integration artifacts

Importing the Email Connector into WSO2 Integration Studio

  1. Right click on Sample Services Configs module in the Project Explorer and select Add or Remove Connector/Module.
  2. Select Add Connector/module and click Next. You are now connected to the WSO2 Connector store.
  3. Find Email from the list of connectors and click the Download button (for the Email connector).

  4. Click Finish. The connector is now downloaded to your workspace in WSO2 Integration Studio and the connector operations are available in the Email Connector palette.

Let's use these connector operations in the configuration.

Update the message flow

The connector operations are used in the sequence named PaymentRequestProcessingSequence. Select this sequence and do the following updates:

  1. Add a Property Mediator just before the Call mediator to retrieve and store the patient's email address.

  2. With the Property mediator selected, access the Property tab of the mediator and fill in the information in the following table:

    Property Description
    Property Name Enter New Property... .
    New Property Name Enter email_id.
    Property Action Enter set .
    Value Type Enter EXPRESSION .
    Value Expression

    Follow the steps given below to specify the expression:

    1. Click the text box for the Value Expression field. This opens the Expression Selector dialog box.
    2. Select Expression from the list.
    3. Enter json-eval($ to overwrite the default expression.
    4. Click OK.
    Description Get Email ID

  3. Add another Property mediator just after the Log mediator to retrieve and store the response sent from SettlePaymentEP. This will be used within the body of the email.

  4. With the Property mediator selected, access the Property tab and specify the details given below.

    Property Value
    Property Name Select New Property
    New Property Name payment_response
    Property Action Select Set
    Value Type Select Expression
    Value Expression json-eval($.)
    Description Get Payment Response
  5. Drag and drop the send operation from the Email Connector palette adjoining the Property mediator you added in the previous step.

  6. With the send operation selected, access the Property tab and create a connection by clicking on the '+' icon.

    In the pop up window, following parameters must be provided.

    Property Value
    Connection Name smtpconnection
    Connection Type Select SMTP Secured Connection
    Port 465
    Username Your email address
    Password Your email password


    If you have enabled 2-factor authentication, an app password should be obtained as instructed here.

  7. After the connection is successfully created, select the created connection as 'Connection' from the drop down in the properties window.

  8. Specify the following details in the Properties tab;

    Property Description
    From Enter your email address as the value. This will be account from which the email is sent.
    To Enter $ctx:email_id as the value. This retrieves the patient email address that was stored in the relevant Property mediator.
    Subject Enter Payment Status as the value. This is the subject line in the email that is sent out.
    Content Enter $ctx:payment_response as the value. This retrieves the payment response that was stored in the relevant Property mediator.

    The updated PaymentRequestProcessingSequence should now look like this:

  9. Save the updated sequence configuration.

  10. Right click on SampleServicesConnectorExporter and navigate to New →  Add/Remove Connectors and select Add connector/module and click on Next . Select Workspace to list down the connectors that were added.

  11. Select the Email connector from the list and click OK and then Finish.

Step 3: Package the artifacts

Package the artifacts in your composite exporter module (SampleServicesCompositeExporter), the registry resource project (SampleRegistryResource project), and the Connector project (SampleServicesConnectorExporter) to be able to deploy the artifacts in the server.

  1. Open the pom.xml file in the composite exporter module.
  2. Ensure that the following modules and artifacts are selected in the POM file.

    • SampleServicesConfigs
      • HealthcareAPI
      • ClemencyEP
      • GrandOakEP
      • PineValleyEP
      • ChannelingFeeEP
      • SettlePaymentEP
      • PaymentRequestMessageStore
      • PaymentRequestProcessingSequence
      • PaymentRequestProcessor
      • Smptpsconnection
    • SampleServicesRegistryResources
    • SampleServicesConnectorExporter
  3. Save the file.

Step 4: Build and run the artifacts

To test the artifacts, deploy the packaged artifacts in the embedded Micro Integrator:

  1. Right-click the Composite Exporter module and click Export Project Artifacts and Run.
  2. In the dialog that opens, make sure all the artifacts of the project are selected.
  3. Click Finish. The artifacts will be deployed in the embedded Micro Integrator and the server will start. See the startup log in the Console tab.


Stop the Micro Integrator before proceeding to test. This is because you need to start the broker profile before starting the Micro Integrator.

Step 5: Test the use case

Let's test the use case by sending a simple client request that invokes the service.

Start the back-end service

  1. Download the JAR file of the back-end service from here.
  2. Open a terminal, navigate to the location where your saved the back-end service.
  3. Execute the following command to start the service:

    java -jar Hospital-Service-JDK11-2.0.0.jar

Start the RabbitMQ Broker

Make sure that you have installed and started a RabbitMQ server instance for the Micro-Integrator to communicate with.

See the RabbitMQ documentation for more information on how to install and run the product.

Restart the Micro Integrator

Let's restart the Micro Integrator with the deployed artifacts:

Right-click the composite exporter module and click Export Project Artifacts and Run as shown below.

The artifacts will be deployed in the embedded Micro Integrator and the server will start.

  • See the startup log in the Console tab.
  • See the URLs of the deployed services and APIs in the Runtime Services tab.

Send the client request

Let's send a request to the API resource. You can use the embedded HTTP Client of WSO2 Integration Studio as follows:

  1. Open the HTTP Client of WSO2 Integration Studio.


    If you don't see the HTTP Client pane, go to Window -> Show View - Other and select HTTP Client to enable the client pane.

  2. Enter the request information as given below and click the Send icon ().

    Method POST
    Headers Content-Type=application/json
    URL http://localhost:8290/healthcare/categories/surgery/reserve

    • The URI-Template format that is used in this URL was defined when creating the API resource: http://:/categories/{category}/reserve.
    { "name": "John Doe", "dob": "1940-03-19", "ssn": "234-23-525", "address": "California", "phone": "8770586755", "email": "[email protected]", "doctor": "thomas collins", "hospital": "grand oak community hospital", "cardNo": "7844481124110331", "appointment_date": "2025-04-02" }

    • This JSON payload contains details of the appointment reservation, which includes patient details, doctor, hospital, and data of appointment.

If you want to send the client request from your terminal:

  1. Install and set up cURL as your REST client.

  2. Create a JSON file names request.json with the following request payload. Make sure you provide a valid email address so that you can test the email being sent to the patient.

    "name": "John Doe",
    "dob": "1940-03-19",
    "ssn": "234-23-525",
    "address": "California",
    "phone": "8770586755",
    "email": "[email protected]",
    "doctor": "thomas collins",
    "hospital": "grand oak community hospital",
    "cardNo": "7844481124110331",
    "appointment_date": "2025-04-02"
  3. Open a command line terminal and execute the following command from the location where the request.json file you created is saved:

    curl -v -X POST --data @request.json http://localhost:8290/healthcare/categories/surgery/reserve --header 

Analyze the response

You will see the response as follows:

{"message":"Payment request successfully submitted. Payment confirmation will be sent via email."}

An email will be sent to the provided patient email address with the following details:

Subject: Payment Status
    {"appointmentNo":2,"doctorName":"thomas collins","patient":"John

You have now explored how to import the Email connector to the Micro Integrator and then use the connector operations to send emails.