Change WorkflowCore.DSL to support External Mapper (for example User Task)

[aprilesalvatore]

Hi,

I change the DSL to support a UserTask (package WorkflowCore.Users) on my solution and I wish to share with you my solution. With there changes you will be able to implement a workflow definition using json or yaml

First of all adding this class:

using System;
using System.Collections.Generic;
using System.Text;
using WorkflowCore.Models;
using WorkflowCore.Models.DefinitionStorage.v1;

namespace WorkflowCore.DSL.Models
{
    public class ExternalMapper
    {
        public StepSourceV1 Source { get; set; }
        public Type DataType { get; set; }
        public Type StepType { get; set; }

        public WorkflowStep Step { get; set; }
    }
}

Then change the object StepSourceV1 adding Option property

public Dictionary<string, string> Options { get; set; } = new Dictionary<string, string>();

Change IDefinitionLoader adding an overload of LoadDefinition method

 WorkflowDefinition LoadDefinition(string source, Func<string, DefinitionSourceV1> deserializer, Action<ExternalMapper> externalMapper);

Last changes on DefinitionLoader

private Action<ExternalMapper> _externalMapping;

 public WorkflowDefinition LoadDefinition(string source, Func<string, DefinitionSourceV1> deserializer, Action<ExternalMapper> externalMapper)
        {
            _externalMapping = externalMapper;
         ...
       }

and from the row 107

targetStep.ExternalId = $"{nextStep.Id}";
targetStep.ProceedOnCancel = nextStep.ProceedOnCancel;

if (_externalMapping != null)
    _externalMapping(new ExternalMapper() { DataType = dataType, Source = nextStep, Step = targetStep, StepType = stepType });

AttachInputs(nextStep, dataType, stepType, targetStep);
AttachOutputs(nextStep, dataType, stepType, targetStep);

How to use ?

this is an example:

 _definitionLoader.LoadDefinition(json, Deserializers.Json, (mapper) =>
 {
     if (mapper.Source.Options != null && mapper.Step.GetType().ContainsProperty("Options"))
     {
         mapper.Step.SetProperty("Options", mapper.Source.Options);
     }
 });

//where ContainsProperty and SetProperty are 2 extension methods 

 public static bool ContainsProperty(this Type targetType, string propertyName)
 {
     if (targetType == null || String.IsNullOrEmpty(propertyName))
         return false;

     var prop = targetType.GetProperty(propertyName);
     return prop != null;
 }

 public static void SetProperty(this WorkflowStep step, string propertyName, object obj)
 {
     if (step == null || String.IsNullOrEmpty(propertyName) || obj == null)
         return;

     var prop = step.GetType().GetProperty(propertyName);

     if (prop != null)
         prop.SetValue(step, obj, null);
 }

this is a Json example :

{
  "Id": "ApprovedWorkflow",
  "Version": 1,
  "DataType": "TestApp.Model.Release, TestApp",
  "Steps": [
    {
      "Id": "CheckReleaseStatusEditing",
      "StepType": "WorkflowCore.Primitives.If, WorkflowCore",
      "Inputs": {
        "Condition": "data.State.Status ==  ReleaseStatus.Editing"
      },
      "NextStepId": "CheckReleaseStatusCompleted",
      "Do": [
        [
          {
            "Id": "UserTaskCompleteRelease",
            "StepType": "WorkflowCore.Users.Primitives.UserTaskStep, WorkflowCore.Users",
            "NextStepId": "setCompletedOutput",
            "Inputs": {
              "Prompt": "\"Completare la release?\"",
              "AssignedPrincipal": "data.CompletedByUser"
            },
            "Options": {
              "Completed": "\"Completa\"",
              "Cancel": "\"Annulla\""
            }
          },
          {
            "Id": "setCompletedOutput",
            "StepType": "TestApp.Steps.SetOutputStep, TestApp",
            "Outputs": {
              "State.Status": "Utils.SetStatus(UserAction)",
              "State.Name": "Utils.SetName(UserAction)"
            }
          }
        ]
      ]
    },
    {
      "Id": "CheckReleaseStatusCompleted",
      "StepType": "WorkflowCore.Primitives.If, WorkflowCore",
      "Inputs": {
        "Condition": "data.State.Status ==  ReleaseStatus.Completed && Utils.CompareUser(data.CompletedByUser, context)"
      },
      "Do": [
        [
          {
            "Id": "UserTaskApproveRelease",
            "StepType": "WorkflowCore.Users.Primitives.UserTaskStep, WorkflowCore.Users",
            "NextStepId": "setApprovedOutput",
            "Inputs": {
              "Prompt": "\"Approvare la release?\"",
              "AssignedPrincipal": "data.CompletedByUser"
            },
            "Options": {
              "Approved": "\"Approvate\"",
              "Declined": "\"Declina\"",
              "Cancel": "\"Annulla\""
            }
          },
          {
            "Id": "setApprovedOutput",
            "StepType": "TestApp.Steps.SetOutputStep, TestApp",
            "Outputs": {
              "State.Status": "Utils.SetStatus(UserAction)",
              "State.Name": "Utils.SetName(UserAction)"
            }
          }
        ]
      ]
    }
  ]
}