Elsa 工作流引擎 Hello World

Elsa 简介

Elsa 是一个基于MIT协议的.Net的开源工作流引擎，也就是你可以基于它修改源码及进行商业化。与其他工作流产品的区别是首先它可以很轻量级的嵌入到你的应用里，为你的应用提供流程化的能力; 其次它有设计器、API可以可视化的进行流程设计; 再次，它提供性能或功能的扩展能力，扩展性强。

配置Elsa工作流引擎

简单配置Elsa 的Hello World应用程序使用Http请求作为触发条件和Http Response作为输出。

创建一个项目 dotnet new web -n "ElsaQuickstarts.Server.DashboardAndServer"
进入该项目目录
cd ElsaQuickstarts.Server.DashboardAndServer
添加项目包引用
dotnet add package Elsa dotnet add package Elsa.Activities.Http dotnet add package Elsa.Activities.Temporal.Quartz dotnet add package Elsa.Persistence.EntityFramework.Sqlite dotnet add package Elsa.Server.Api dotnet add package Elsa.Designer.Components.Web
使用Visual Studio修改Setup文件，使用如下内容替换原有内容。
using Elsa; using Elsa.Persistence.EntityFramework.Core.Extensions; using Elsa.Persistence.EntityFramework.Sqlite; using Microsoft.AspNetCore.Builder; using Microsoft.AspNetCore.Hosting; using Microsoft.Extensions.Configuration; using Microsoft.Extensions.DependencyInjection; using Microsoft.Extensions.Hosting; namespace ElsaQuickstarts.Server.DashboardAndServer { public class Startup { public Startup(IWebHostEnvironment environment, IConfiguration configuration) { Environment = environment; Configuration = configuration; } private IWebHostEnvironment Environment { get; } private IConfiguration Configuration { get; } public void ConfigureServices(IServiceCollection services) { var elsaSection = Configuration.GetSection("Elsa"); // Elsa services. services .AddElsa(elsa => elsa .UseEntityFrameworkPersistence(ef => ef.UseSqlite()) .AddConsoleActivities() .AddHttpActivities(elsaSection.GetSection("Server").Bind) .AddQuartzTemporalActivities() .AddWorkflowsFrom<Startup>() ); // Elsa API endpoints. services.AddElsaApiEndpoints(); // For Dashboard. services.AddRazorPages(); } public void Configure(IApplicationBuilder app) { if (Environment.IsDevelopment()) { app.UseDeveloperExceptionPage(); } app .UseStaticFiles() // For Dashboard. .UseHttpActivities() .UseRouting() .UseEndpoints(endpoints => { // Elsa API Endpoints are implemented as regular ASP.NET Core API controllers. endpoints.MapControllers(); // For Dashboard. endpoints.MapFallbackToPage("/_Host"); }); } } }
创建Pages文件夹，并建立_Host.cshtml文件，使用如下内容替换原文件。
@page "/" @{ var serverUrl = $"{Request.Scheme}://{Request.Host}"; } <!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"/> <meta name="viewport" content="width=device-width, initial-scale=1.0"/> <title>Elsa Workflows</title> <link rel="icon" type="image/png" sizes="32x32" href="/_content/Elsa.Designer.Components.Web/elsa-workflows-studio/assets/images/favicon-32x32.png"> <link rel="icon" type="image/png" sizes="16x16" href="/_content/Elsa.Designer.Components.Web/elsa-workflows-studio/assets/images/favicon-16x16.png"> <link rel="stylesheet" href="/_content/Elsa.Designer.Components.Web/elsa-workflows-studio/assets/fonts/inter/inter.css"> <link rel="stylesheet" href="/_content/Elsa.Designer.Components.Web/elsa-workflows-studio/elsa-workflows-studio.css"> <script src="/_content/Elsa.Designer.Components.Web/monaco-editor/min/vs/loader.js"></script> <script type="module" src="/_content/Elsa.Designer.Components.Web/elsa-workflows-studio/elsa-workflows-studio.esm.js"></script> </head> <body> <elsa-studio-root server-url="@serverUrl" monaco-lib-path="_content/Elsa.Designer.Components.Web/monaco-editor/min"> <elsa-studio-dashboard></elsa-studio-dashboard> </elsa-studio-root> </body> </html>
项目解决方案如下图
在Visual Studio中启动该服务