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ASP.NET Core 9 integration

dotnet add package Scalar.AspNetCore

Program.cs

builder.Services.AddOpenApi();

if (app.Environment.IsDevelopment())
{
    app.MapOpenApi();
    // add the following lines
    app.MapScalarApiReference(options =>
    {
        options
            .WithTitle("MyApp API Reference")
            .WithTheme(ScalarTheme.Solarized)
            .WithClientButton(false);
            //.WithDefaultOpenAllTags(true)
    });
}

URL: http://localhost:5000/scalar

Properties/launchSettings.json

{
  "profiles": {
    "http": {
      "launchBrowser": true,
      "launchUrl": "http://localhost:5000/scalar",
      "applicationUrl": "http://localhost:5000"
    }
  }
}

OAuth 2 authentication

OpenApiConfiguration.cs

public static class OpenApiConfiguration
{
    private const string oAuth2Scheme = "oauth2";

    public static IMvcBuilder ConfigureOpenApi(this IMvcBuilder builder, AzureAdConfiguration configuration)
    {
        builder.Services.AddOpenApi(options =>
        {
            options.AddDocumentTransformer((document, context, cancellationToken) =>
            {
                document.Components ??= new OpenApiComponents();
                document.Components.SecuritySchemes.Add(oAuth2Scheme, new OpenApiSecurityScheme
                {
                    Type = SecuritySchemeType.OAuth2,
                    Flows = new OpenApiOAuthFlows
                    {
                        AuthorizationCode = new OpenApiOAuthFlow
                        {
                            AuthorizationUrl = new Uri($"https://login.microsoftonline.com/{configuration.TenantId}/oauth2/v2.0/authorize"),
                            TokenUrl = new Uri($"https://login.microsoftonline.com/{configuration.TenantId}/oauth2/v2.0/token"),
                            Scopes = new Dictionary<string, string>
                            {
                                { $"{configuration.ClientId}/contributor offline_access", "API access" }
                            }
                        }
                    }
                });

                return Task.CompletedTask;
            });
        });

        return builder;
    }

    public static void ConfigureOAuthAuthenticationForScalar(this WebApplication app, AzureAdConfiguration configuration)
    {
        if (app.Environment.IsDevelopment())
        {
            app.MapScalarApiReference(options =>
            {
                options
                    .WithTitle("Maia API Reference")
                    .WithTheme(ScalarTheme.Solarized)
                    .WithClientButton(false)
                    .WithPreferredScheme(oAuth2Scheme)
                    .WithOAuth2Authentication(oauth =>
                    {
                        oauth.ClientId = configuration.SwaggerClientId;
                        oauth.Scopes = [$"{configuration.ClientId}/contributor offline_access"];
                    });
            });
        }
    }
}