Unleashing Swagger: Displaying Output Type when using IEndpointRouteBuilder.MapGet and Results.Ok

Are you tired of scratching your head, trying to figure out how to display the output type when using IEndpointRouteBuilder.MapGet and Results.Ok in your ASP.NET Core application? Well, buckle up, friend, because today we’re going to take a deep dive into the world of Swagger and learn how to make it work like a charm!

What is Swagger?

Before we dive into the nitty-gritty, let’s quickly cover what Swagger is. Swagger is an open-source framework that allows you to generate interactive documentation for your API. It’s like having a personal assistant that helps you understand and use your API, without having to write a single line of code.

Why do we need to display output type?

When building an API, it’s essential to provide clear documentation for your endpoints. This includes information about the request and response formats, including the output type. Without this information, it can be challenging for consumers to understand how to use your API correctly.

The Problem: IEndpointRouteBuilder.MapGet and Results.Ok

When using IEndpointRouteBuilder.MapGet and Results.Ok, the output type is not displayed by default in Swagger. This can be frustrating, especially when you’ve spent hours crafting the perfect API.

app.UseEndpoints(endpoints =>
{
    endpoints.MapGet("/api/values", async context =>
    {
        var values = await _valueService.GetValues();
        return Results.Ok(values);
    });
});

Solving the Problem: Adding Swagger Configuration

So, how do we solve this problem? The answer lies in configuring Swagger correctly. Let’s take a look at an example:

services.AddSwaggerGen(c =>
{
    c.SwaggerDoc("v1", new OpenApiInfo { Title = "My API", Version = "v1" });
    c.DocInclusionPredicate((docName, apiDesc) =>
    {
        var actionAttrs = apiDesc.ActionDescriptor.EndpointMetadata.OfType<ApiResponseAttribute>();
        if (!actionAttrs.Any())
        {
            return true;
        }

        foreach (var attr in actionAttrs)
        {
            if (attr.StatusCode.ToString() == docName)
            {
                return true;
            }
        }

        return false;
    });
});

In the above code, we’re adding Swagger configuration to our ASP.NET Core application. We’re specifying the Swagger document name and version, as well as configuring the DocInclusionPredicate.

What is DocInclusionPredicate?

The DocInclusionPredicate is a callback that determines whether an action should be included in the Swagger document. In our case, we’re using it to include actions that have an ApiResponseAttribute.

Adding ApiResponseAttribute

Now that we’ve configured Swagger, it’s time to add the ApiResponseAttribute to our actions:

[ApiController]
[Route("api/[controller]")]
public class ValuesController : ControllerBase
{
    [HttpGet]
    [ProducesResponseType(StatusCodes.Status200OK, Type = typeof(List<Value>))]
    public async Task<IActionResult> GetValues()
    {
        var values = await _valueService.GetValues();
        return Results.Ok(values);
    }
}

In the above code, we’re adding the ApiResponseAttribute to the GetValues action. We’re specifying a HTTP status code of 200 OK and indicating that the response type is a List of Value objects.

Displaying Output Type in Swagger

Finally, let’s take a look at our Swagger documentation:

Endpoint	HTTP Method	Response
/api/values	GET	200 OK application/json { type: array items: $ref: ‘#/components/schemas/Value’ }

Voilà! Our Swagger documentation now displays the output type for our GetValues endpoint.

Conclusion

In this article, we’ve covered how to display the output type when using IEndpointRouteBuilder.MapGet and Results.Ok in ASP.NET Core. By configuring Swagger correctly and adding ApiResponseAttribute to our actions, we can provide clear documentation for our API consumers.

So, the next time you’re building an API, remember to add Swagger and configure it correctly. Your consumers (and your future self) will thank you!

Bonus: Swagger Configuration Options

Swagger provides a range of configuration options to customize your API documentation. Here are a few more options you might find useful:

• c.SwaggerDoc(“v1”, new OpenApiInfo { Title = “My API”, Version = “v1”, Description = “My API description” }); – Adds a description to your Swagger document.
• c.OrderActionsBy(apiDesc => apiDesc.RelativePath); – Orders actions by relative path.
• c.TagActionsBy(apiDesc => apiDesc.RelativePath); – Tags actions by relative path.
• c.DocInclusionPredicate((docName, apiDesc) => true); – Includes all actions in the Swagger document.

By leveraging these configuration options, you can customize your Swagger documentation to meet your API’s specific needs.

Common Pitfalls

When working with Swagger, it’s easy to overlook a few common pitfalls. Here are some mistakes to watch out for:

1. Forgetting to add the Swagger middleware to the pipeline.
2. Not configuring the Swagger document correctly.
3. Not adding ApiResponseAttribute to actions.
4. Not specifying the response type correctly.

By being aware of these common pitfalls, you can avoid frustration and ensure that your Swagger documentation is accurate and up-to-date.

Conclusion (Again!)

That’s it! With these instructions, you should now be able to display the output type when using IEndpointRouteBuilder.MapGet and Results.Ok in your ASP.NET Core application. Remember to configure Swagger correctly, add ApiResponseAttribute to your actions, and watch out for common pitfalls.

HAPPY CODING!

Frequently Asked Question

Let’s dive into the world of Swagger and IEndpointRouteBuilder, where displaying output types can be a real challenge. Don’t worry, we’ve got you covered!