Hosting multiple protocols

Reference the protocol package for every generated server protocol alongside NSmithy.Server.AspNetCore; see Server packages.

A service can declare more than one protocol trait. When it does, codegen emits a Map{Service} extension with a generated {Service}Protocols flags enum. Each selected protocol resolves the registered operation handlers. Their method signatures use the same model types across protocols.

Program.cs

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddWeatherServiceHandler<WeatherHandler>();   // one handler

var app = builder.Build();
app.MapWeatherService(
    WeatherServiceProtocols.RestJson1 | WeatherServiceProtocols.RpcV2Cbor);
app.Run();

The client must select the matching protocol as well as the endpoint.

Server runtime registration

Endpoints resolve SmithyServerRuntime from request services, and use a default runtime when none is registered. Add{Service}Handler<THandler>() registers it through AddSmithyServer(); an existing application registration takes precedence.

To implement operations separately, register each operation handler. The runtime needs no registration of its own:

builder.Services.AddScoped<IGetWeatherHandler, GetWeatherHandler>();
builder.Services.AddScoped<IGetForecastHandler, GetForecastHandler>();

The runtime currently has no configurable lifecycle options. DI establishes its ownership and lifetime; it does not add interceptors or telemetry by itself.

What can share a port

Endpoints are port-agnostic — ports are a deployment concern, so the generated Map extension never binds one. Whether two protocols can share a listener depends on their routes and transport:

• Protocols can share a listener when their routes do not conflict. REST paths are model-defined, so check them against RPC or gRPC dispatch paths.
• Conflicting routes need separate host or port constraints; the generated router does not distinguish protocols by Content-Type.
• gRPC requires HTTP/2. Use a dedicated HTTP/2 listener for cleartext development. With TLS, HTTP/1.1 and HTTP/2 can share a listener through ALPN negotiation.

Pinning a protocol to a port

Use ASP.NET Core’s RequireHost to scope a protocol’s endpoints to a specific port, and configure Kestrel to listen there:

builder.WebHost.ConfigureKestrel(options =>
{
    options.ListenLocalhost(5000);                                   // HTTP/1.1 — REST
    options.ListenLocalhost(5001, o => o.Protocols = HttpProtocols.Http2); // gRPC
});

var app = builder.Build();
app.MapGroup("")
    .RequireHost("*:5000")
    .MapWeatherService(WeatherServiceProtocols.RestJson1);
app.MapGroup("")
    .RequireHost("*:5001")
    .MapWeatherService(WeatherServiceProtocols.Grpc);
app.Run();

See gRPC for the full gRPC hosting example.