Working with REST Tasks

BPMN REST tasks allow you to invoke REST endpoints within your BPMN processes. You can achieve this by adding a REST Task and handling the REST invocation part in a process implementation. This tutorial simulates a scenario, in which you access a REST endpoint of a Health Care Service via a REST Task to retrieve information of a patient appointment, and approve it based on the date as an administrator.

Starting the back-end service

Download and start the back-end service:

1. Download the JAR file of the back-end service.

2. Open a terminal and 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

The Healthcare service is now active and you can start sending requests to the service.

Sending the request to the backend service

Follow the steps below to send the request to the backend service. This creates the appointment of the patient.

1. Send a request to the Backend service by entering the below details using a REST Client (e.g., Postman).

   Open

   

Creating the BPMN artifacts

Follow the steps below to create the BPMN artifacts including the REST Task,

1. Create a new BPMN project named RestTaskBPMN. For instructions, see Creating a BPMN Project.

2. Create a BPMN Diagram named RestTask.bpmn. For instructions, see Creating the BPMN Diagram.

3. Click anywhere on the canvas, go to the Properties tab, and fill in the following details:
   Id               : restTask
   Name         : REST Task Process
   Namespace:  http://wso2.org/bpmn/rest Task

4. To implement the order approval process, drag and drop a Start Event element, a REST Task element, a User Task element and an End Event element to the canvas. 

   Open

   

Configuring the Start Event

Select the  Properties  tab of the Start Event, click  Form ,   click  New ,   update the following and click  OK.

Open

You view both fields added to the form as shown below.

Open

Configuring the REST Task

1. Select the  Properties  tab of the REST Task, click  General  and enter the  Name  as  Get Appointment. 

2. In the Properties tab of the REST Task, click Main config and update the following: 
   

   Open

   

Configuring the User Task

1. Select the Properties tab of the User Task, click General and enter the Name as Confirm Appointment. 

2. Click  Properties , click  Main config    and give admin as the Assignee.  
   

3. In the  Properties  tab click  Form , click  New  and add the following.

   Click New next to Form values and add the following:

   Open

   

4. In the Properties tab click Form, click New and add the following.

   You view the fields added to the Form of the User Task as shown below.

   Open

   

5. Press Ctrl+S to save all your artifacts.

Deploying the artifacts

1. For instructions on creating the deployable artifacts, see Creating the deployable archive.

2. For instructions on deploying them, see Deploying BPMN artifacts.

Testing the output

1. Log in to the BPMN-explorer at https://localhost:9445/bpmn-explorer  using  admin  for both the username and password.

2. Click PROCESSES in the top menu, and click the Start option of the REST Task Process.

3. Enter a value for the Name of the Patient and Appointment Number and click Start. This creates a Claimable Task.

   Open

   

4. Click TASKS in the top menu, and then click Claimable Tasks. 

5. Click on the new  Claimable Task .

   Open

   
   
   You view the Appointment Number you entered before and the Number of Days retrieved as 1, which means you can approve it since it is one day ahead from today.

6. Click Complete Task, to approve the appointment.

7. Click  TASKS  →  COMPLETED TASKS  to view the completed task.