Create ASP.NET Core with Vue.js SPA

Required Tools

• Node
  • Version 14 or higher
• .Net 6.0
  • winget install --id=Microsoft.DotNet.SDK.6 -e

Setup Project

Create Web Application

dotnet new webapi -n MyWebProject

Create Vue Front-end

• Navigate inside your newly created Web Application project and create a new vue application:

npx create-vue@latest
At the time of writing, the current version includes: vue 3.3.4, vite 4.4.9 - it requires node 14.x to run.

• Name the vue project 'ClientApp'

• The directory structure for you ASP.NET application should look like this:

Add Necessary Packages

• Navigate to the Web Application folder and use the add package command:

  dotnet package add Microsoft.AspNetCore.SpaProxy --version 6.0.21

Alternatively, you can add the package reference to your .csproj file and use the 'dotnet restore' or 'dotnet build' commands for immediate access to the namespace:

<PackageReference Include="Microsoft.AspNetCore.SpaProxy" Version="6.0.21" />

Configure Vite

• In your ClientApp directory, open the 'vite.config.js' file, and edit the code to match the following:

import { fileURLToPath, URL } from 'node:url';
import process from 'node:process';

//match the uri your web application is being hosted at
const proxyTarget = process.env.ASPNETCORE_HTTPS_PORT
  ? `https://localhost:${process.env.ASPNETCORE_HTTPS_PORT}`
  : process.env.ASPNETCORE_URLS
  ? process.env.ASPNETCORE_URLS.split(';')[0]
  : 'https://localhost:5001';

// https://vitejs.dev/config/
export default defineConfig({
  plugins: [vue()],
  resolve: {
    alias: {
      '@': fileURLToPath(new URL('./src', import.meta.url)),
    },
  },
  server: {
    port: 3001,
    proxy: {
      '^/weatherforecast': {
        target: proxyTarget,
        secure: false,
      },
      '^/swagger': {
        target: proxyTarget,
        secure: false,
      },
    },
  },
  build: {
    outDir: '../wwwroot',
    emptyOutDir: true,
  },
});

Now your Vue app will be served at http://localhost:3001 and proxy requests to your backend at https://localhost:5001.

NOTE:

You can configure vite and the spa proxy to serve your app over https, but that will be considered for another tutorial.

Configure SPA proxy

• Open your .csproj file and add the following fields in the first property group under <TargetFramework>net6.0</TargetFramework>:

    <SpaRoot>ClientApp\</SpaRoot>
    <DefaultItemExcludes>$(DefaultItemExcludes);$(SpaRoot)node_modules\**</DefaultItemExcludes>
    <SpaProxyServerUrl>http://localhost:3001</SpaProxyServerUrl>
    <SpaProxyLaunchCommand>npm run dev</SpaProxyLaunchCommand>

• Observe that the 'SpaProxyLaunchCommand' is npm run dev instead of npm start.
• The 'SpaProxyServerUrl' must match the uri that your Vue app will be served at, which is set in the 'vite.config.js' file, using the 'port' keyword.
• Add the following fields to your .csproj file for generation of artifacts when publishing:

  <ItemGroup>
    <!-- Don't publish the SPA source files, but do show them in the project files list -->
    <Content Remove="$(SpaRoot)**" />
    <None Remove="$(SpaRoot)**" />
    <None Include="$(SpaRoot)**" Exclude="$(SpaRoot)node_modules\**" />
  </ItemGroup>

  <Target Name="DebugEnsureNodeEnv" BeforeTargets="Build" Condition=" '$(Configuration)' == 'Debug' And !Exists('$(SpaRoot)node_modules') ">
    <!-- Ensure Node.js is installed -->
    <Exec Command="node --version" ContinueOnError="true">
      <Output TaskParameter="ExitCode" PropertyName="ErrorCode" />
    </Exec>
    <Error Condition="'$(ErrorCode)' != '0'" Text="Node.js is required to build and run this project. To continue, please install Node.js from https://nodejs.org/, and then restart your command prompt or IDE." />
    <Message Importance="high" Text="Restoring dependencies using 'npm'. This may take several minutes..." />
    <Exec WorkingDirectory="$(SpaRoot)" Command="npm install" />
  </Target>

  <Target Name="PublishRunWebpack" AfterTargets="ComputeFilesToPublish">
    <!-- As part of publishing, ensure the JS resources are freshly built in production mode -->
    <Exec WorkingDirectory="$(SpaRoot)" Command="npm install" />
    <Exec WorkingDirectory="$(SpaRoot)" Command="npm run build" />

    <!-- Include the newly-built files in the publish output -->
    <ItemGroup>
      <DistFiles Include="$(SpaRoot)build\**" />
      <ResolvedFileToPublish Include="@(DistFiles->'%(FullPath)')" Exclude="@(ResolvedFileToPublish)">
        <RelativePath>wwwroot\%(RecursiveDir)%(FileName)%(Extension)</RelativePath>
        <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
        <ExcludeFromSingleFile>true</ExcludeFromSingleFile>
      </ResolvedFileToPublish>
    </ItemGroup>

Configure launch settings

• Navigate to the launchSettings.json file in your Web Application project:

Properties > launchSettings.json

It should contain the following json content:

      "applicationUrl": "https://localhost:5001",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development",
        "ASPNETCORE_HOSTINGSTARTUPASSEMBLIES": "Microsoft.AspNetCore.SpaProxy"
      }

• Match the 'applicationUrl' with the proxy target in your 'vite.config.json' file.
• Add the 'ASPNETCORE_HOSTINGSTARTUPASSEMBLIES' key with the value specified above.

Modify Program.cs

Modify your 'Program.cs' by adding the following lines before the map methods are called:

app.UseStaticFiles();
app.MapFallbackToFile("index.html");

Finished

Now you're finished creating an ASP.NET Core with Vue.js Application!

• You can run your project in Visual Studio or using the dotnet cli dotnet run command and you should see the SpaProxy loading page until the app content is served. Enjoy!