bff-aspnetcore-vuejs

Implement a secure web application using Vue.js and an ASP.NET Core server

Setup Server

The ASP.NET Core project is setup to run in development and production. In production, it uses the Vue.js production build deployed to the wwwroot. In development, it uses MS YARP reverse proxy to forward requests.

Important

In production, the Vue.js project is built into the wwwroot of the .NET project.

Configure the YARP reverse proxy to match the Vue.js URL. This is only required in development. I always use HTTPS in development and the port needs to match the Vue.js developement env (vite.config.js).

 "UiDevServerUrl": "https://localhost:4201",
  "ReverseProxy": {
    "Routes": {
      "route1": {
        "ClusterId": "cluster1",
        "Match": {
          "Path": "{**catch-all}"
        }
      }
    },
    "Clusters": {
      "cluster1": {
        "HttpClient": {
          "SslProtocols": [
            "Tls12"
          ]
        },
        "Destinations": {
          "cluster1/destination1": {
            "Address": "https://localhost:4201/"
          }
        }
      }
    }
  }

Setup Vue.js Vite project

Add the certificates to the nx project for example in the /certs folder

Update the vite.config.ts file:

import { defineConfig } from 'vite'
import vue from '@vitejs/plugin-vue'
import fs from 'fs';

// https://vitejs.dev/config/
export default defineConfig({
  plugins: [vue()],
  server: {
    https: {
      key: fs.readFileSync('./certs/dev_localhost.key'),
      cert: fs.readFileSync('./certs/dev_localhost.pem'),
	},
    port: 4202,
    strictPort: true, // exit if port is in use
    hmr: {
      clientPort: 4202, // point vite websocket connection to vite directly, circumventing .net proxy
    },
  },
  optimizeDeps: {
    force: true,
  },
  build: {
    outDir: "../server/wwwroot",
    emptyOutDir: true
  },
})

Note

The ASP.NET Core project setup uses port 4202, this needs to match the YARP reverse proxy settings for development.

Setup development

The development environment is setup to use the defualt tools for each of the tech stacks. Vue.js is used like recommended. I use Visual Studio code. A YARP reverse proxy is used to integrate the Vue.js development into the backend application.

Note

Always run in HTTPS, both in development and production

npm start

Azure App Registration setup

The application(s) are deployed as one. This is an OpenID Connect confidential client with a user secret or a certification for client assertion.

Use the Web client type on setup.

The OpenID Connect client is setup using Microsoft.Identity.Web. This implements the Microsoft Entra ID client. I have created downstream APIs using the OBO flow and a Microsoft Graph client. This could be replaced with any OpenID Connect client and requires no changes in the frontend part of the solution.

var scopes = configuration.GetValue<string>("DownstreamApi:Scopes");
string[] initialScopes = scopes!.Split(' ');

services.AddMicrosoftIdentityWebAppAuthentication(configuration, "MicrosoftEntraID")
    .EnableTokenAcquisitionToCallDownstreamApi(initialScopes)
    .AddMicrosoftGraph("https://graph.microsoft.com/v1.0", initialScopes)
    .AddInMemoryTokenCaches();

services.AddControllersWithViews(options =>
    options.Filters.Add(new AutoValidateAntiforgeryTokenAttribute()));

services.AddRazorPages().AddMvcOptions(options =>
{
    //var policy = new AuthorizationPolicyBuilder()
    //    .RequireAuthenticatedUser()
    //    .Build();
    //options.Filters.Add(new AuthorizeFilter(policy));
}).AddMicrosoftIdentityUI();

Add the Azure App registration settings to the appsettings.Development.json and the ClientSecret to the user secrets.

"MicrosoftEntraID": {
    "Instance": "https://login.microsoftonline.com/",
    "Domain": "[Enter the domain of your tenant, e.g. contoso.onmicrosoft.com]",
    "TenantId": "[Enter 'common', or 'organizations' or the Tenant Id (Obtained from the Azure portal. Select 'Endpoints' from the 'App registrations' blade and use the GUID in any of the URLs), e.g. da41245a5-11b3-996c-00a8-4d99re19f292]",
    "ClientId": "[Enter the Client Id (Application ID obtained from the Azure portal), e.g. ba74781c2-53c2-442a-97c2-3d60re42f403]",
    "ClientSecret": "[Copy the client secret added to the app from the Azure portal]",
    "ClientCertificates": [
    ],
    // the following is required to handle Continuous Access Evaluation challenges
    "ClientCapabilities": [ "cp1" ],
    "CallbackPath": "/signin-oidc"
},

App Service (linux plan) configuration

MicrosoftEntraID__Instance               --your-value--
MicrosoftEntraID__Domain                 --your-value--
MicrosoftEntraID__TenantId               --your-value--
MicrosoftEntraID__ClientId               --your-value--
MicrosoftEntraID__CallbackPath           /signin-oidc
MicrosoftEntraID__SignedOutCallbackPath  /signout-callback-oidc

The client secret or client certificate needs to be setup, see Microsoft Entra ID documentation.

Debugging

Start the Vue.js project from the ui folder

npm start

Start the ASP.NET Core project from the server folder

dotnet run

Or just open Visual Studio and run the solution.

github actions build

Github actions is used for the DevOps. The build pipeline builds both the .NET project and the Vue.js project using npm. The two projects are built in the same step because the UI project is built into the wwwroot of the server project.

name: .NET and npm build

on:
  push:
    branches: [ "main" ]
  pull_request:
    branches: [ "main" ]

jobs:
  build:
    runs-on: ubuntu-latest

    steps:

      - uses: actions/checkout@v4
      - name: Setup .NET
        uses: actions/setup-dotnet@v4
        with:
          dotnet-version: 8.0.x

      - name: Restore dependencies
        run: dotnet restore

      - name: npm setup
        working-directory: ui
        run: npm install

      - name: ui-build
        working-directory: ui
        run: npm run build

      - name: Build
        run: dotnet build --no-restore
      - name: Test
        run: dotnet test --no-build --verbosity normal

github actions Azure deployment

The deployment pipeline builds both projects and deployes this to Azure using an Azure App Service. See azure-webapps-dotnet-core.yml

deployment test server: https://bff-vue-aspnetcore.azurewebsites.net/

Credits and used libraries

• NetEscapades.AspNetCore.SecurityHeaders
• Yarp.ReverseProxy
• Microsoft.Identity.Web
• ASP.NET Core
• Vue.js
• Vite

Links

https://vuejs.org/

https://vitejs.dev/

https://github.com/vuejs/create-vue

https://learn.microsoft.com/en-us/aspnet/core/introduction-to-aspnet-core

https://github.com/AzureAD/microsoft-identity-web

https://www.koderhq.com/tutorial/vue/vite/

https://github.com/isolutionsag/aspnet-react-bff-proxy-example

https://github.com/damienbod/bff-aspnetcore-angular

https://github.com/damienbod/bff-auth0-aspnetcore-angular

https://github.com/damienbod/bff-openiddict-aspnetcore-angular

https://github.com/damienbod/bff-azureadb2c-aspnetcore-angular

https://github.com/damienbod/bff-MicrosoftEntraExternalID-aspnetcore-angular