AsyncAPI–ASP.NET Core integration

AsyncAPI is an open source initiative with as goal to document event-driven architectures in a similar that OpenAPI documents REST APIs. If you want to get a good introduction chec k out my previous posts about AsyncAPI:

• AsyncApi–Share your message contracts in a language agnostic manner - Part 1
• AsyncApi–Share your message contracts in a language agnostic manner - Part 2

Today I want to talk about that allows you to integrate an AsyncAPI more easily into your ASP.NET Core application; Neuroglia AsyncAPI.

Let me walk you through a small example I created.

• First add the following nuget package to your ASP.NET Core project:
• Neuroglia.AsyncApi.AspNetCore.UI
• Now we can register the necessary configuration:

	builder.Services.AddAsyncApiUI();
	builder.Services.AddAsyncApiGeneration(builder =>
	builder.WithMarkupType<OrdersController>()
	.UseDefaultConfiguration(asyncApi =>
	{
	}));

view raw Program.cs hosted with ❤ by GitHub
• Notice in the code above that I’m referring to an OrdersController class. This ASP.NET core controller publishes an event to create a new order:

	[AsyncApi("Order API", "1.0.0")]
	[Route("api/[controller]")]
	[ApiController]
	public class OrdersController : ControllerBase
	{
	private readonly IPublishEndpoint _publishEndpoint;
	public OrdersController(IPublishEndpoint publishEndpoint)
	{
	_publishEndpoint = publishEndpoint;
	}
	// POST api/createorder
	[Channel("order/create"), PublishOperation(OperationId = "PlaceOrder", Summary = "Place a new order")]
	[HttpPost]
	[ProducesResponseType(StatusCodes.Status200OK)]
	[ProducesResponseType(StatusCodes.Status400BadRequest)]
	public async Task<ActionResult> CreateOrder(OrderProductCommand command)
	{
	await _publishEndpoint.Publish(new PlaceOrderMessage { OrderId = command.ProductId });
	return Ok();
	}
	}

view raw OrdersController.cs hosted with ❤ by GitHub
• The library scans the provided class to find specific attributes to build up the AsyncAPI schema. We also need to register the necessary middleware:
• If we now run the application and browse to the asyncapi endpoint, you can see the AsyncAPI information:

	//Adds the middleware used to serve AsyncAPI documents
	app.UseAsyncApiGeneration();

view raw Program.cs hosted with ❤ by GitHub

Remark: Be aware that to make this work you need to enable RazorPages (which is not mentioned in the documentation):

	//Required for AsyncAPI
	builder.Services.AddRazorPages();

view raw Program.cs hosted with ❤ by GitHub