Reprise 1.1.0

Reprise

Reprise is a micro-framework that brings the REPR (Request-Endpoint-Response) pattern and vertical slice architecture into ASP.NET Core 6 Minimal APIs. It aims to be unopioniated towards the API behavior and to provide a thin layer of abstractions that encourages the creation of convention-based and modular codebases.

Getting Started

1. Create a new ASP.NET Core 6 empty project.

2. Install the Reprise NuGet package.

3. Modify your Program.cs to use Reprise.

var builder = WebApplication.CreateBuilder();
builder.ConfigureServices();
var app = builder.Build();
app.MapEndpoints();
app.Run();

4. Create an endpoint Endpoints/GetHelloEndpoint.cs.

[Endpoint]
public class GetHelloEndpoint
{
    [Get("/")]
    public static string Handle() => "Hello, world!";
}

5. Run the application.

Endpoints

An endpoint is a public class that is decorated with the EndpointAttribute. It should contain a public static Handle method which should be decorated with one of the HTTP method and route attributes. These are:

• GetAttribute
• PostAttribute
• PutAttribute
• PatchAttribute
• DeleteAttribute
• MapAttribute - for other/multiple HTTP methods

The Handle method can be synchronous as well as asynchronous and can have any signature and any return type.

[Endpoint]
public class UpdateUserEndpoint
{
    [Authorize]
    [Put("/users/{id}")]
    public static IResult Handle(int id, UserDto userDto, DataContext context)
    {
        // ...
    }
}

In the example id comes from the route, userDto - from the body, and context - from the DI container. Check the Minimal APIs documentation for more information on the topic.

On application startup, app.MapEndpoints() and app.MapEndpoints(assembly) perform an assembly scan and map all endpoints. Reprise will throw an InvalidOperationExcaption when:

• An endpoint has no Handle method
• An endpoint has multiple Handle methods
• A Handle method has no HTTP method and route attribute
• A Handle method has multiple HTTP method and route attributes
• A Handle method has an empty route
• A Handle method has an empty HTTP method
• An HTTP method and route combination is handled by more than one endpoint

Services

Any class (including an endpoint) that has a public parameterless constructor and implements IServiceConfgurator can configure services.

[Endpoint]
public class GetWeather : IServiceConfigurator
{
    public void ConfigureServices(WebApplicationBuilder builder)
    {
        builder.Services.AddWeatherService();
    }

    [Get("/weather")]
    public static async Task<WeatherForecast[]> Handle(IWeatherService weatherService)
    {
        return await weatherService.GetForecast();
    }
}

On application startup, builder.ConfigureServices() and builder.ConfigureServices(assembly) perform an assembly scan and invoke all ConfigureServices(WebApplicationBuilder builder) implementations. Reprise will throw an InvalidOperationException if a service configurator has no public paramereterless constructor.

Configuration

Reprise makes it possible to bind a strongly typed hierarchical configuration. A simple example would look like this:

[Endpoint]
public class GetGreetings
{
    [Get("/greetings")]
    public static IEnumerable<string> Handle(GreetingConfiguration configuration)
    {
        return configuration.Names.Select(name => string.Format(configuration.Message, name));
    }
}

[Configuration("Greeting")]
public class GreetingConfiguration
{
    public string Message { get; set; } = null!;

    public List<string> Names { get; set; } = null!;
}

The GreetingConfiguration is added to the DI container with a singleton lifetime and is bound to the following section in appsettings.json:

{
    "Greeting": {
        "Message": "Hello, {0}!",
        "Names": [ "Alice", "John", "Skylar" ]
    }
}

Deeper nested sub-sections could as well be bound using a key like "Foo:Bar".

On application startup, builder.ConfigureServices() and builder.ConfigureServices(assembly) perform an assembly scan and add all configurations with a singleton lifetime. Reprise will throw an InvalidOperationException if a configuration model could not be bound or when a sub-section is bound to multiple types.

OpenAPI

In order to group endpoints in the Swagger UI, Reprise extracts a tag from the route of every endpoint. The first segment that is not "api" (case insensitive) or a parameter is capitalized and set as a tag. "/" is used when no match is found.

Performance

Besides the assembly scans at application startup when configuring the DI container and mapping endpoints, Reprise doesn't add any performance overhead when handling requests.

Support

If you spot any problems and/or have improvement ideas, please share them via the issue tracker.