前言

1.什么是工作流

工作流是OA系统比较重要的功能之一，主要在于企业流程协同审批，有效进行流程管理。

流程管理起源于生产组织和办公自动化领域，是针对日常工作中具有固定程序的活动提出的一个概念。目的是通过将工作分解成定义良好的任务、角色，按照一定的规则和过程来执行这些任务并对它们进行监控，达到提高办事效率、降低生产成本、提高企业生产经营管理水平和企业竞争力的目标。

现代计算机技术实现了工作流，是支持企业经营过程高效执行并监控其执行过程的计算机软件系统。工作流软件类似电脑桌面操作系统，操作系统驱动电脑各部件协同运转，工作流软件则驱动业务过程自动有序进行。

Workflow-Core地址：https://github.com/danielgerlag/workflow-core

一、Workflow-Core轻量级工作流引擎

1.安装包

Install-Package WorkflowCore
Microsoft.Extensions.Logging
Microsoft.Extensions.Logging.Debug

2.数据流转

模型类

public class MyDataClass
{
    public int Value1 { get; set; }

    public int Value2 { get; set; }

    public int Value3 { get; set; }

}

2.1 定义步骤

1、步骤一

public class AddNumbers : StepBodyAsync
{
    public int Input1 { get; set; }

    public int Input2 { get; set; }

    public int Output { get; set; }


    public override async Task<ExecutionResult> RunAsync(IStepExecutionContext context)
    {
        Output = (Input1 + Input2);
        return ExecutionResult.Next();
    }
}

2、步骤二

public class CustomMessage : StepBody
{
    
    public string Message { get; set; }

    public override ExecutionResult Run(IStepExecutionContext context)
    {
        Console.WriteLine(Message);
        return ExecutionResult.Next();
    }
}

2.2 定义工作流

1、模型类工作流

public class PassingDataWorkflow : IWorkflow<MyDataClass>
{  
    public void Build(IWorkflowBuilder<MyDataClass> builder)
    {
        builder
            .StartWith(context =>
            {
                Console.WriteLine("Starting workflow...");
                return ExecutionResult.Next();
            })
            .Then<AddNumbers>()
                .Input(step => step.Input1, data => data.Value1)
                .Input(step => step.Input2, data => data.Value2)
                .Output(data => data.Value3, step => step.Output)
            .Then<CustomMessage>()
                .Name("Print custom message")
                .Input(step => step.Message, data => "The answer is " + data.Value3.ToString())
            .Then(context =>
                {
                    Console.WriteLine("Workflow complete");
                    return ExecutionResult.Next();
                });
    }

    public string Id => "PassingDataWorkflow";
        
    public int Version => 1;

}

2、字典工作流

public class PassingDataWorkflow2 : IWorkflow<Dictionary<string, int>>
{
    public void Build(IWorkflowBuilder<Dictionary<string, int>> builder)
    {
        builder
            .StartWith(context =>
            {
                Console.WriteLine("Starting workflow...");
                return ExecutionResult.Next();
            })
            .Then<AddNumbers>()
                .Input(step => step.Input1, data => data["Value1"])
                .Input(step => step.Input2, data => data["Value2"])
                .Output((step, data) => data["Value3"] = step.Output)
            .Then<CustomMessage>()
                .Name("Print custom message")
                .Input(step => step.Message, data => "The answer is " + data["Value3"].ToString())
            .Then(context =>
                {
                    Console.WriteLine("Workflow complete");
                    return ExecutionResult.Next();
                });
    }

    public string Id => "PassingDataWorkflow2";

    public int Version => 1;

}

2.3 启动工作流

using Microsoft.Extensions.DependencyInjection;
using WorkflowCore.Interface;
using WorkflowCore.Sample03;

IServiceProvider serviceProvider = ConfigureServices();

//start the workflow host
var host = serviceProvider.GetService<IWorkflowHost>();
host.RegisterWorkflow<PassingDataWorkflow, MyDataClass>();
host.RegisterWorkflow<PassingDataWorkflow2, Dictionary<string, int>>();
host.Start();

var initialData = new MyDataClass
{
    Value1 = 2,
    Value2 = 3
};

//host.StartWorkflow("PassingDataWorkflow", 1, initialData);


var initialData2 = new Dictionary<string, int>
{
    ["Value1"] = 7,
    ["Value2"] = 2
};

host.StartWorkflow("PassingDataWorkflow2", 1, initialData2);

Console.ReadLine();
host.Stop();

static IServiceProvider ConfigureServices()
{
    //setup dependency injection
    IServiceCollection services = new ServiceCollection();
    services.AddLogging();
    services.AddWorkflow();
    var serviceProvider = services.BuildServiceProvider();

    return serviceProvider;
}

2.4 运行

1、模型类工作流

2、字典工作流

二、Workflow-Core的流程配置

1.代码配置

public class MyWorkflow : IWorkflow
{
    public void Build(IWorkflowBuilder<MyData> builder)
    {    
        builder
           .StartWith<Task1>()
           .Then<Task2>()
           .Then<Task3>();
    }
}

2.JSON配置

{
  "Id": "HelloWorld",
  "Version": 1,
  "Steps": [
    {
      "Id": "Hello",
      "StepType": "MyApp.HelloWorld, MyApp",
      "NextStepId": "Bye"
    },        
    {
      "Id": "Bye",
      "StepType": "MyApp.GoodbyeWorld, MyApp"
    }
  ]
}

3.YAML配置

Id: HelloWorld
Version: 1
Steps:
- Id: Hello
  StepType: MyApp.HelloWorld, MyApp
  NextStepId: Bye
- Id: Bye
  StepType: MyApp.GoodbyeWorld, MyApp