Flowable for Developers

This lecture demonstrates how to use a Flowable Script Task to add lightweight functions within a workflow.

The creator shows how to:

• Create a new process model and add a "Human Task" to ask for a department. (0:20, 1:06)

• Drag and drop a "Script Task" into the workflow, connecting it after the "Ask Department" task. (1:12)

• Write a JavaScript inside the script task to set an email variable based on the department input (e.g., if department is "sales," set email to "sales@gmail.com"; otherwise, "general@gmail.com"). (2:41, 3:00)

• Validate the script task and then end the process. (1:30)

• Deploy and run the workflow, demonstrating how the script task processes the department input and assigns the correct email. (5:01, 8:42)

The lecture also highlights that script tasks are meant for minimal operations and not complex logic, suggesting service tasks or APIs for more intricate functions. (1:40, 1:52)

This lecture explains and demonstrates the use of Flowable Service Tasks (0:09). This lecture highlights that service tasks are suitable for complex business logic, offering more capabilities compared to script tasks (0:15-0:27).

The demonstration covers:

• Creating a Service Task process model in Flowable (0:31-1:58).

• Implementing a Java delegate class (2:38), which is the core of the service task, to handle business logic such as identifying an email based on department input (4:18-5:49).

• Connecting the Java delegate to the service task in the Flowable model (6:51-7:28).

• Demonstrating the workflow execution where a department is provided, and the service task identifies the corresponding email (8:13-10:04).

In this lecture, we will see that service tasks can execute complex operations like database calls or API calls, making them the suggested approach for robust workflow automation (5:58-6:34, 10:44-10:55).

This lecture demonstrates how to use the Flowable HTTP Task to integrate external API calls into a workflow. The lecture shows how to:

• Design a workflow using Flowable Modeler, adding an HTTP Task to call an API (like a public movie database API). (0:29)

• Configure the HTTP Task properties, including the request method (GET, POST, etc.), request URL, headers, body, timeout, and how to store the API response in a variable. (2:24)

• Deploy the designed workflow model into the Flowable engine. (6:28)

• Initiate a workflow instance from the Flowable dashboard and observe the API call's execution and the stored response variables, including the HTTP status code. (8:40)

The lecture concludes by showing how to validate that the API call was successful and how the response data is captured within the workflow. (9:31)

This lecture demonstrates how to use a Flowable DMN (Decision Model and Notation) Task to integrate decision-making into a workflow.

The creator walks through the following steps:

• Creating a process that includes an input task, a decision task, and a manual task to validate the decision's output (1:04).

• Defining a decision table for the DMN task, specifying input variables (like 'age' and 'gender') and an output variable ('isAllowed') (2:17).

• Setting up rules within the decision table based on combinations of input values (3:31).

• Deploying the process and DMN table to the Flowable engine (7:14).

• Demonstrating the DMN task's execution by providing different inputs (age and gender) and showing how the decision rules determine the 'isAllowed' output (8:56).

• Illustrating what happens when no rules are hit by the provided input, and how to configure the DMN task to throw an error in such cases (12:30).

The lecture highlights how DMN tasks can automate decision-making within a business process based on defined rules.

This lecture demonstrates how to implement error handling for HTTP tasks in Flowable.

The video first shows a scenario where an HTTP task calls a non-existent API endpoint, resulting in a 404 error that isn't handled, causing the process to get stuck (3:34).

It then explains how to add a boundary error event to the HTTP task in the Flowable model (4:06). You can specify which HTTP status codes (e.g., 500, 400, 404) should trigger this error event using the "Handle status codes" property (5:09). When an error occurs, the process flow is diverted to the connected error handling path, which in the demo is a "Manual task" (4:23).

Finally, the video shows that when the URL is corrected and a 200 OK status is returned, the process bypasses the error handling path and continues to the next successful task (7:49). The video emphasizes anticipating potential errors and defining how the workflow should respond (8:12).

This lecture demonstrates how to use a Postman collection to interact with Flowable's REST APIs.

The main steps covered are:

• Downloading the Swagger YAML file: The video shows how to find and download the BPMN Swagger YAML file from the official Flowable documentation (0:21-1:54).

• Importing into Postman: It then guides on importing this YAML file into Postman to create a collection (1:57-2:29).

• Exploring the Collection: The video highlights different sections of the imported collection, such as forms, history, management, queries, and repository APIs, explaining what each can be used for (2:45-5:15).

• Configuring the Base URL: It explains how to correct the "invalid URL" error by setting the base URL environment variable in Postman to your Flowable server's address (5:41-7:07).

• Making API Calls: Finally, it shows examples of making calls to list process definitions, deployments, and process instances, demonstrating how to include process variables in the response (7:08-9:10).