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Elsa 3.0

Installation

Elsa Studio Blazor Server

Introduction

In the previous chapter, we looked at setting up Elsa Studio in a Blazor Webassembly project.

In this chapter, we will create the same application, but this time using Blazor Server.

When to use Blazor Server?

Although the Blazor Webassembly app is a great way to get started with Elsa Studio, it can be challenging when you are writing custom extensions that you need to debug. When running your app using Blazor Server, debugging becomes much easier.

Setup

To setup Elsa Studio, we'll go through the following steps:

  1. Create a new Blazor Server application.
  2. Add the Elsa Studio packages.
  3. Modify the Program.cs. file.
  4. Remove any superfluous files.
  5. Update the appsettings.json file.
  6. Update the Pages/_Host.cshtml file.

Let's delve into each step in detail:

1. Creating a New Blazor Server App

Kickstart your project by generating a new Blazor Server application using the following command:

dotnet new blazorserver-empty -n "ElsaStudioBlazorServer" -f net7.0

2. Adding Elsa Studio Packages

Navigate to the root directory of your project and integrate the following Elsa Studio packages:

cd ElsaStudioBlazorServer
dotnet add package Elsa.Studio
dotnet add package Elsa.Studio.Core.BlazorServer
dotnet add package Elsa.Studio.Login.BlazorServer
dotnet add package Elsa.Api.Client

3. Modifying Program.cs

Open the Program.cs file and replace its existing content with the code provided below:

Program.cs

using Elsa.Studio.Core.BlazorServer.Extensions;
using Elsa.Studio.Dashboard.Extensions;
using Elsa.Studio.Extensions;
using Elsa.Studio.Login.BlazorServer.Extensions;
using Elsa.Studio.Login.HttpMessageHandlers;
using Elsa.Studio.Shell.Extensions;
using Elsa.Studio.Workflows.Extensions;
using Elsa.Studio.Workflows.Designer.Extensions;

// Build the host.
var builder = WebApplication.CreateBuilder(args);
var configuration = builder.Configuration;

// Register Razor services.
builder.Services.AddRazorPages();
builder.Services.AddServerSideBlazor(options =>
{
    // Register the root components.
    options.RootComponents.RegisterCustomElsaStudioElements();
});

// Register shell services and modules.
builder.Services.AddCore();
builder.Services.AddShell(options => configuration.GetSection("Shell").Bind(options));
builder.Services.AddRemoteBackend(
    elsaClient => elsaClient.AuthenticationHandler = typeof(AuthenticatingApiHttpMessageHandler),
    options => configuration.GetSection("Backend").Bind(options));
builder.Services.AddLoginModule();
builder.Services.AddDashboardModule();
builder.Services.AddWorkflowsModule();

// Configure SignalR.
builder.Services.AddSignalR(options =>
{
    // Set MaximumReceiveMessageSize to handle large workflows.
    options.MaximumReceiveMessageSize = 5 * 1024 * 1000; // 5MB
});

// Build the application.
var app = builder.Build();

// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
    app.UseResponseCompression();

    // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();
app.UseAuthorization();
app.MapBlazorHub();
app.MapFallbackToPage("/_Host");

// Run the application.
app.Run();

4. Removing Unnecessary Files

For a cleaner project structure, eliminate the following directories and files:

  • wwwroot/css
  • Pages/Index.razor
  • App.razor
  • MainLayout.razor

5. Updating appsettings.json

Update the appsettings.json file with the following content:

{
  "Backend": {
    "Url": "https://localhost:5001/elsa/api"
  }
}

6. Updating _Host.cshtml

To conclude the setup, open the Pages/_Host.cshtml file and replace its content with the code showcased below:

index.html

@page "/"
@using Elsa.Studio.Shell
@using Microsoft.AspNetCore.Components.Web
@namespace ElsaStudioBlazorServer.Pages
@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8"/>
    <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
    <base href="~/"/>
    <link rel="apple-touch-icon" sizes="180x180" href="_content/Elsa.Studio.Shell/apple-touch-icon.png">
    <link rel="icon" type="image/png" sizes="32x32" href="_content/Elsa.Studio.Shell/favicon-32x32.png">
    <link rel="icon" type="image/png" sizes="16x16" href="_content/Elsa.Studio.Shell/favicon-16x16.png">
    <link rel="manifest" href="_content/Elsa.Studio.Shell/site.webmanifest">
    <link rel="preconnect" href="https://fonts.googleapis.com">
    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
    <link href="https://fonts.googleapis.com/css?family=Roboto:300,400,500,700&display=swap" rel="stylesheet"/>
    <link href="https://fonts.googleapis.com/css2?family=Ubuntu:wght@300;400;500;700&display=swap" rel="stylesheet">
    <link href="https://fonts.googleapis.com/css2?family=Montserrat:wght@400;500;600;700&display=swap" rel="stylesheet">
    <link href="https://fonts.googleapis.com/css2?family=Grandstander:wght@100&display=swap" rel="stylesheet">
    <link href="_content/MudBlazor/MudBlazor.min.css" rel="stylesheet"/>
    <link href="_content/CodeBeam.MudBlazor.Extensions/MudExtensions.min.css" rel="stylesheet"/>
    <link href="_content/Radzen.Blazor/css/material-base.css" rel="stylesheet">
    <link href="_content/Elsa.Studio.Shell/css/shell.css" rel="stylesheet">
    <link href="Elsa.Studio.Host.Server.styles.css" rel="stylesheet">
    <component type="typeof(HeadOutlet)" render-mode="ServerPrerendered"/>
</head>
<body>
<component type="typeof(App)" render-mode="ServerPrerendered" />

<div id="blazor-error-ui">
    <environment include="Staging,Production">
        An error has occurred. This application may no longer respond until reloaded.
    </environment>
    <environment include="Development">
        An unhandled exception has occurred. See browser dev tools for details.
    </environment>
    <a href="" class="reload">Reload</a>
    <a class="dismiss">🗙</a>
</div>
<script src="_content/BlazorMonaco/jsInterop.js"></script>
<script src="_content/BlazorMonaco/lib/monaco-editor/min/vs/loader.js"></script>
<script src="_content/BlazorMonaco/lib/monaco-editor/min/vs/editor/editor.main.js"></script>
<script src="_content/MudBlazor/MudBlazor.min.js"></script>
<script src="_content/CodeBeam.MudBlazor.Extensions/MudExtensions.min.js"></script>
<script src="_content/Radzen.Blazor/Radzen.Blazor.js"></script>
<script src="_framework/blazor.server.js"></script>
</body>
</html>

Launching the Application

To see your application in action, execute the following command:

dotnet run --urls "https://localhost:7001"

Your application should now be accessible at https://localhost:7001. By default, you can log in using:

Username: admin
Password: password

Source code

The source code for this chapter can be found here

What's Next?

In our upcoming chapter, we will explore the customization possibilities of the Elsa Studio application. Stay tuned!

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HTTP workflows