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TJe · ‎2021 Apr 13

In this tutorial, I will share, how you can develop custom script Activities with JavaScript for your API. This is a generic template/pattern you can adopt for APIs of different products.

Main goals are

support the Low-Code/No-Code approach with additional Activities
mainly for Citizen Developers or Business Process Experts, they will use the final package

support the development of custom scripts with a template / design pattern
for Developers, they will develop and maintain the package and can see several concepts for SAP Intelligent RPA and JavaScript in action

The idea is based on the experience of custom script development from other projects (e.g. Use SAP Analytics Cloud REST API or Use SAP BusinessObjects REST API). Even with the a small set of custom scripts, there is duplicated code and adding features would make this even more worse and leads to code which is hard to maintain.

Tutorial Blogs

Overview and Concept (please read this first)
Getting started

Custom script SDK – Design Pattern (this blog)
Overview, Concepts and Step by Step guide

Custom script SDK – Rest API sample
Step by Step guide using the Rest API of SAP Analytics Cloud
provides the template for a JavaScript class using the HTTP request activity from the SAP Intelligent RPA core SDK

Concepts

We will learn the concepts of the design pattern, create the project, implement a sample API, test the SDK, generate and share a package.
The sample API is very simple, the methods init, execute (with parameters) and done will only write messages to the console.

Here the design pattern concept with dependencies and how it can be used for APIs:

JavaScript
Classes seems to be a good idea to implement the SDK in one custom script
Functions in variables can reduce duplications
Define async functions and use await, e.g. useful when using REST APIs and HTTP Request to wait till an asynchronous function is returning a value

SAP Intelligent RPA
Data Types are a good way to make the use of Parameters simpler and more structured (input, output, activity)
Automations are used to get an Activity like usage of the scripts
a naming convention is used to identify content of the SDK (prefix cs_ for Custom Script SDK)

Of course there are always different ways to implement solutions, so feel free to adopt and enhance.

Overview

To test the pattern, we will create demo automations for No-Code and Low-Code

Content List

Area	Name	Description
Data Type	cs_class	instance of the JavaScript class with Activities
	cs_package	package content, currently only activites (cs_class)
	cs_activities_Sample	enum with all activity names of the Sample API
	cs_param_Sample_Execute	example of a parameter definition for the activity execute
Automation	cs_function_Core	custom script, returns a JavaScript function ActivityCore() that can be stored in a variable
	cs_package_Sample	reuse the function ActivityCore(), custom script with the implementation of the API in the class Sample, save the activities in the package variable
	cs_activity_Sample	call the specified activity from the package, activity and parameter are defined as input parameters. Used as activity in your automations.
	Demo_SampleSDK	Demo automation of the SDK for no-code usage
	Demo_SampleSDK_Expert	Demo automation of the SDK for low-code usage

Create a New Project

Use the Project name: Custom Script SDK Sample & Design Pattern

Use the Description:
Content for custom APIs - similar to SAP Intelligent RPA SDKs - reuse the template to develop your custom script ACTIVITIES with JavaScript leveraging your APIs

Create Data Types

Step: Create Data Type

Use the name cs_class

Define the fields of the data type as show in the picture below
– use New Field to add a new row

Select Save

Step: Create Data Type

Use the name cs_package

Define the fields of the data type

Select Save

Step: Create Data Type

Use the name cs_activities_Sample

Define the fields of the data type
for the Enumeration, add the name of the activities: init,execute,done
(the allowed and implemented activities for your API)

Select Save

Step: Create Data Type

Use the name cs_param_Sample_Execute

Define the fields of the data type

– use New Chield to add a new entry for details

Select Save

Automations - Define Design Pattern

Automation - cs_function_Core

Define a Custom script which returns a JavaScript function ActivityCore() that can be stored in a variable.

Step: Create Automation

Use the name cs_function_Core

Select I/O to define an Output parameter
The automation will return a JavaScript function and we will use the function in other automations as input parameter
name: cs_function_ActivitiesCore, select type Any from the list

Save your automation – select Save

Step: Add Custom Script

Select Tools and add the activity Custom Script to your automation

Select the activity Custom script in the flow diagram

Use Step name Define Activities Core

Select Edit Script

Select Add new output parameter

Enter Output parameter name functionDef, select type Any

Copy the following script code to line 1

return function ActivityCore(name) {

    this._name = name;

    this._activity = '';



    this.call = async function(caller, activity, parameter) {

        this._activity = activity;

        // if you specify a String in JSON format --> JSONObject

        if (typeof parameter === 'string' || parameter instanceof String) {

           if (parameter.length > 0) parameter = JSON.parse(parameter);

       } 

       try {

            delete parameter.$_jsonSchemaCons; // IRPA data types, not needed as parameter value

       } catch (e) {

       }

        this._parameter = parameter;

        await caller[activity](parameter);

    };



    this.log = function() {

        irpa_core.core.log(this._name + '.' + this._activity + (this._parameter ? '(' + JSON.stringify(this._parameter) + ')' : ''));

    };

};

Close the Script View (X Icon on top right corner next to Save, or just click an empty area in the canvas)

Select Define Activities Core in the flow diagram
Output Parameters should contain the name functionDef

Step: Set Automation Output Parameters

Select End in the flow diagram
now we will assign the value for the output parameter of the automation, we have defined under I/O. Select functionDef from the list (n the custom script we have returned the function in this variable)

Save your automation

Automation - cs_package_Sample

Reuse the function ActivityCore(), define a custom script with the implementation of the API in the JavaScript class Sample and save the activities definition in the package variable

Step: Create Automation

Use the name cs_package_Sample

Select I/O to define an Output parameter
The automation will return the package definition, we will use in other automations as input parameter
name: cs_SamplePackage, select type cs_package from the list

Save the automation

Step: Add Automation

Add the automation cs_function_Core to your flow

Select the step and use name Define Function ActivitiesCore

Add the activity Custom Script to your automation

Select the activity Custom script in the flow diagram

Use Step name Define Activities Class

Select Edit Script

Select Add new input parameter

Select Add new output parameter

Enter Input parameter name fnActivityCore, select type Any

Enter Output parameter name activities, select type cs_class

Copy the following script code to line 1 (only sample code to show the concept)

/**

* @description enter the description for your Sample SDK, which API is used, ...

*/

class Sample {



    constructor() {

        this._fnActivityCore = new fnActivityCore('Sample');

    }



    async call(value, parameter) {

       await this._fnActivityCore.call(this, value.activity, parameter);

    }



	/**

	* @activity init - Sample

	* @note description of your activity 

	*/

    async init() {

        this._fnActivityCore.log();

    }



	/**

	* @activity init - Sample

	* @note description of your activity 

    * @param description of parameter

	*/

    async execute(parameter) {

        this._fnActivityCore.log();

    }

    

	/**

	* @activity init - Sample

	* @note description of your activity 

	*/

    async done() {

        this._fnActivityCore.log();

    }



}



return new Sample();

Close the Script View (X Icon on top right corner next to Save, or just click an empty area in the canvas)

The red marker is an indicator, that the parameters are missing
Select the step in the flow
for parameter fnActivityCore, select cs_function_ActivityCore from the list (output from the previous step)
Output Parameters should contain the name activities

Step: Create Variable

Add the activity to set the package parameters to your automation
– select from Data – Data Types cs_package and drop to the flow diagram

Select the activity Create cs_package variable in the flow diagram

Use step name Create Package
Use Output Parameters name cs_package

Select Edit Activity
For the parameter instance select activities from the list

For Output Parameters set name cs_Package

Step: Set Automation Output Parameters

Select End in the flow diagram
now we will assign the value for the output parameter of the automation, we have defined under I/O. Select cs_package from the list (output parameter from previous step)

Save your automation

Automation - cs_activity_Sample

Call an activity from the package, The Activity name and parameter values will be specified as input parameters when the automation is re-used in your automations (no-code).

Step: Create Automation

Use the name cs_activity_Sample

Select I/O to define the three Input parameters
name: cs_package_Sample, select type cs_package from the list
name: cs_activity_Sample, select type cs_activities_Sample from the list
name: parameter, select type Any from the list

Save your automation – select Save

Step: Add Custom Script

Select Tools and add the activity Custom Script to your automation
Select the activity Custom script in the flow diagram

Use Step name Call Activity

Select Edit Script

Select Add new input parameter
3 times, we will pass all automation parameters to the script
name: activities, select type cs_class from the list
name: activity, select type cs_activities_Sample from the list
name: parameter, select type Any from the list

Copy the following script code to line 1

await activities.instance.call(activity, parameter);

Close the Script View (X Icon on top right corner next to Save, or just click an empty area in the canvas)

The red marker is an indicator, that the parameters are missing
select the step in the flow

Save your automation

For parameter activities, enter cs and select cs_package_Sample.activities from the list
(the list will not show the entry without typing 'cs')

For activity select cs_activities_Sample from the list

For parameter select parameter from the list

Save the automation

Automations - Test Design Pattern

We are using the activities init, execute and done of our sample API in automations using

custom scripts (low-code)

reuse an automation (no-code)

You can try to build the automations of your own or follow the step by step instructions.

Test input parameter

You can select the activity as input parameter from the list:

Test output

The console should show the same execution logs, cause both are calling the activities of the sample API

Automation Low-Code - use Custom scripts

To reduce the definition effort, we will create copies of the Custom Script activity in our flow.

Step: Create Automation

Use the name Demo_SampleSDK_LC

Select I/O to define an Input parameter
The automation will allow to select an activity as input parameter
name: activity, select type cs_activities_Sample from the list

Step: Add Automation

Select Tools and add automation cs_package_Sample
Select the activity in the flow diagram
Use step name: Define Package - Samples

Step: Add Custom Script

Add the activity Custom Script to your automation
Select the activity Custom script in the flow diagram
Use Step name Activity
Select Edit Script

Select Add new input parameter
2 times, we will pass all automation parameters to the script
name: activities, select type cs_class from the list
name: activity, select type cs_activities_Sample from the list

Copy the following script code to line 1

await activities.instance.call(activity);

Save the automation

Close the Script View (X Icon on top right corner next to Save, or just click an empty area in the canvas)

Select Activity in the flow

For parameter activities, enter cs and select cs_SamplePackage.activities from the list
(the list will not show the entry without typing 'cs')

Step: Duplicate Custom Script

Duplicate the activity 3 times (Context menu - Duplicate or Ctrl+D)
Set the step names, you should have
Activity - InputParameter
Activity - init
Activity - execute
Activity - done

Select step Activity - InputParameter
Input Parameters - activity: select activity from the list

Select step Activity - init
Input Parameters - activity: select Create Custom Data, enter activity value: init

Select step Activity - done
Input Parameters - activity: select Create Custom Data, enter activity value: done

Step: Create parameters variable

select from Data – Data Types cs_param_Sample_Execute and drop to the flow diagram (before Activity - Execute)
use Step name; Set param - execute
select Edit Activity
set values for name, code and description (myExpert, 1111, myDescription)
change the Output parameters name to paramExecute

Save the automation

Select the step Activity - execute
Input Parameters - activity: select Create Custom Data, enter activity value: execute

select Edit Script
select Add new input parameter
name: parameter, select type cs_param_Sample_Execute from the list

change the script code to

await activities.instance.call(activity, parameter);

Close the Script View (X Icon on top right corner next to Save, or just click an empty area in the canvas)

Save the automation

Select Activity - Execute in the flow

Input Parameters - parameter: select paramExecute from the list

Save your automation

Test

Select Test

Select environment and Input Parameters - activity from the list

Console should show

Automation - No-Code: reuse automation

We will use a copy of the low-code automation to reduce the definition effort.
In the current version it is not possible to copy an automation activity in a flow (standard activities can be copied).

Step: Duplication Automation

From Automations - Select Demo_SampleSDK_LC

Open the context menu (right click) - Select Duplicate
use the name Demo_SampleSDK_NC
select duplicate

Step: delete activities

Delete the custom script activities from the flow
Activity - InputParameter
Activity - init
Activity - execute
Activity - done

you should have / keep the steps
Define Packages - Samples
Set param - execute

Step: Add Automation

add the Automation cs_activity_Sample to your flow (after Define Package - Samples)
select the step in the flow, use name Activity - InputParameter
Input Parameters - cs_package_sample: select cs_SamplePackage from the list
Input Parameters - cs_activity_sample: select activity
Input Parameters - parameter: select Empty Text from the list

add Automation cs_activity_Sample (after Activity - InputParameter)
use name Activity - init
Input Parameters - cs_package_sample: select cs_SamplePackage
Input Parameters - cs_activity_sample: select Create Custom Data, enter activity value init
Input Parameters - parameter: select Empty Text from the list

add Automation cs_activity_Sample (after Set param - execute)
use name Activity - execute
Input Parameters - cs_package_sample: select cs_SamplePackage
Input Parameters - cs_activity_sample: select Create Custom Data, enter activity value execute
Input Parameters - parameter: select paramExecute

add Automation cs_activity_Sample (after Activity - execute)
use name Activity - done
Input Parameters - cs_package_sample: select cs_SamplePackage
Input Parameters - cs_activity_sample: select Create Custom Data, enter activity value done
Input Parameters - parameter: select Empty Text

Save the automation

Test

Select Test

Select environment and Input Parameters - activity from the list

Console should show

Generate and Share the Package

Last part is now to generate and share our package, so it can be reused on other projects.

Step 1 - Generate

Select Overview on your project

Select Generate Package

Use the name: Custom script SDK Sample & Design Pattern

Use the Description:
Content for custom APIs - similar to SAP Intelligent RPA SDKs - reuse the template to develop your custom script ACTIVITIES with JavaScript leveraging your APIs

Select Generate Package

Step 2 - Share

In the Factory - Select Packages

On the package select More Options and Share

On Share Package set Share with: Anyone and Authorization: Read, click on Share

Your Package is now shared and can be used in Projects

Test the shared Package