Uno Platform Extensions Services

Patterns for the Uno.Extensions service layer: hosting, DI, authentication, HTTP, configuration, logging, and storage.

Critical Rules

Hosting and Dependency Injection

• •Always start with .UseConfiguration() before other extensions - Configuration is a dependency of most other extensions
• •Use TryAddSingleton / TryAddTransient - Allows downstream code to override registrations
• •Constructor injection is the primary resolution pattern - Inject IServiceProvider only as a last resort
• •Named services use AddNamedSingleton<TService, TImpl>("name") and resolve with GetRequiredNamedService<TService>("name")

// App.xaml.cs - host builder setup
var builder = this.CreateBuilder(args)
    .Configure(host => host
        .UseConfiguration()
        .UseLogging()
        .UseSerilog()
        .UseAuthentication()
        .UseHttp()
        .ConfigureServices((ctx, services) =>
        {
            services.TryAddSingleton<IMyService, MyService>();
        })
    );

UnoFeatures Required

<UnoFeatures>
    Hosting;
    Configuration;
    Logging;
    LoggingSerilog;
    Http;
    HttpKiota;      <!-- or HttpRefit -->
    Authentication;
    AuthenticationMsal; <!-- or AuthenticationOidc -->
    Storage;
</UnoFeatures>

Authentication

• •MSAL for Microsoft identity (Azure AD, Azure AD B2C)
• •OIDC for any OpenID Connect provider (IdentityServer, Auth0, Okta)
• •Add AuthenticationMsal or AuthenticationOidc to UnoFeatures
• •MSAL 5.2+: AddMsal() requires a Window parameter

.UseAuthentication(auth =>
    auth.AddMsal(msal =>
        msal
            .Builder(b => b.WithAuthority("https://login.microsoftonline.com/{tenantId}"))
            .Scopes(new[] { "User.Read" })
    )
)

// OIDC
.UseAuthentication(auth =>
    auth.AddOidc(oidc =>
        oidc
            .Authority("https://your-identity-server.com")
            .ClientId("your-client-id")
            .Scopes(new[] { "openid", "profile" })
    )
)

Common Mistakes:

• •Forgetting the Window parameter for MSAL on 5.2+
• •Not registering redirect URIs per platform (Android needs intent filter, iOS needs URL scheme)
• •Using Authentication UnoFeature alone without AuthenticationMsal or AuthenticationOidc

HTTP Clients

• •Kiota (preferred): Generate strongly-typed clients from OpenAPI specs
• •Refit: Interface-based HTTP clients with attribute routing
• •Configure endpoints in appsettings.json, not hardcoded URLs

// Kiota setup
.UseHttp(http =>
    http.AddClient<MyApiClient>(ctx =>
        new MyApiClient(
            new HttpClientRequestAdapter(
                new AnonymousAuthenticationProvider(),
                httpClient: ctx.HttpClient)))
)

// Refit setup
.UseHttp(http =>
    http.AddRefitClient<IMyApi>(ctx =>
        new RefitSettings())
)

// appsettings.json
{
  "MyApi": {
    "Url": "https://api.example.com",
    "UseNativeHandler": true
  }
}

Common Mistakes:

• •Hardcoding base URLs instead of using configuration
• •Not using UseNativeHandler: true for platform-optimized networking
• •Creating HttpClient instances manually instead of through DI

Configuration

• •Embed appsettings.json as EmbeddedResource in the project
• •Use IOptions<T> for read-only, IWriteableOptions<T> for runtime changes
• •Environment-specific overrides: appsettings.development.json

.UseConfiguration(config =>
    config
        .EmbeddedSource<App>()
        .Section<MySettings>()
)

// Consuming in a ViewModel
public class MyViewModel
{
    public MyViewModel(IOptions<MySettings> settings)
    {
        var baseUrl = settings.Value.BaseUrl;
    }
}

Logging

• •UseLogging() registers ILogger<T> in DI
• •UseSerilog() adds Serilog with structured logging and configurable sinks
• •Add LoggingSerilog to UnoFeatures for Serilog support

.UseLogging(configure: logBuilder =>
    logBuilder
        .SetMinimumLevel(LogLevel.Information)
        .AddFilter("Uno", LogLevel.Warning)
)
.UseSerilog()

Detailed References

• •references/01-hosting-di.md - Read when setting up host builder, registering services, or using named services
• •references/02-authentication.md - Read when adding MSAL, OIDC, or custom auth providers
• •references/03-http-clients.md - Read when configuring Kiota, Refit, or custom HTTP handlers
• •references/04-configuration-logging.md - Read when setting up appsettings, IOptions, ILogger, or Serilog