SDK: Flow Steps (Basic)

Updated on 15 Feb 2023
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Overview

Developers can easily create custom Flow and Rule steps by methods in a Class Library (.NET Core) project. This article will show users how to accomplish this. For more examples

Prerequisites

Knowledge of the desired integrated development environment (IDE) for development
Understanding of SDK in Decisions. To learn more, visit SDK Overview and SDK Basics.
Custom steps will be located and stored at C:\Program Files\Decisions\Decisions Server\modules\Decisions.Local\CoreServiceDlls

Basic Flow Step

The below code example will create a Flow step that checks if a string is 5 digits long. For more examples, check the Public GitHub Repository for Decisions.

This code uses the AutoRegisterMethodsOnClass attribute, which will allow the code to show as a Flow step in the Steps panel. This attribute and others are further explained in the AutoRegister Attribute Glossary article.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using DecisionsFramework.Design.Flow;

namespace ShippingExtensions
{
    [AutoRegisterMethodsOnClass(true, "SDK/ZipCode")]
    public class ZipCodeManagement
    {
        public bool IsZipCodeValid(string zipCode) {
            if (zipCode.Length ==5) {
                foreach (char eachChar in zipCode.ToCharArray()) {
                    if (Char.IsDigit(eachChar) == false) {
                        return false;
                    }
                }
                return true;
            }
            return false;
        }
    }
}

Code Snippet	What it does
using DecisionsFramework.Design.Flow	Decisions reference
[AutoRegisterMethodsOnClass(true, "SDK/ZipCode")]	This attribute will allow the code to show as a Flow step in the Steps panel. "SDK/ZipCode" will be the categories that this step is nested in within.
IsZipCodeValid(string zipCode)	This will be the name of the step and (string zipCode) will be the input.
return true	The output of this step
return false	The output of this step

Using the Method in Decisions

After writing the method to build the project, add it to Decisions by following the steps in Software Development Kit (SDK) Overview.

Custom code needs to be saved here: C:\Program Files\Decisions\Decisions Server\modules\Decisions.Local\CoreServicesDlls

Create a new Flow.
In the Steps panel, navigate to SDK > ZipCode.
Drag and drop the custom Is Zip Code Valid step onto the workspace.
This step displays as a Rule step with a True and False outcome as stated in the method written. The step also has the Zip Code input that is expecting a string.
Click Unknown and select Constant as the mapping type, and type in a 5-digit zip code.
Click Save to save changes to the Flow.