Swashbuckle Swagger - How to annotate content types?

Question

How do I annotate my ASP.NET WebAPI actions so that the swagger metadata includes the content-types that my resources support?

Specifically, I want the documentation

Answer 1

Following on OzBob's answer. Since Swashbuckle 4.0.x, you may need to update the operation filter code slightly:

ResponseContentTypeOperationFilter.cs

using Swashbuckle.AspNetCore.Swagger;
using Swashbuckle.AspNetCore.SwaggerGen;
using System.Linq;

public class ResponseContentTypeOperationFilter : IOperationFilter
{
    public void Apply(Operation operation, OperationFilterContext context)
    {
        if (!context.ApiDescription.TryGetMethodInfo(out var methodInfo))
        {
            return;
        }
        var requestAttributes = methodInfo.GetCustomAttributes(true).OfType().FirstOrDefault();

        if (requestAttributes != null)
        {
            if (requestAttributes.Exclusive)
                operation.Produces.Clear();

            operation.Produces.Add(requestAttributes.ResponseType);
        }
    }
}