Failed to load API definition

Question

I have a simple ASP.NET Core API where I have a controller which was supposed to work with an input parameter of HttpRequestMessage. I tried the standard formatters and they did not work:

  services.AddMvc(options =>
        {

             options.RespectBrowserAcceptHeader = true;

             options.InputFormatters.Add(new XmlSerializerInputFormatter());
             options.OutputFormatters.Add(new XmlSerializerOutputFormatter());

        }

Also tried this formatter:

XmlDataContractSerializerOutputFormatter

And it did not work neither. So as result, I end up with a custom formatter:

public class RawInputFormatter : InputFormatter
{
    public override Boolean CanRead(InputFormatterContext context)
    {
        return true;
    }

    public override async Task<InputFormatterResult> ReadRequestBodyAsync(InputFormatterContext context)
    {
        if (context == null)
            throw new ArgumentNullException(nameof(context));

        var request = context.HttpContext.Request;
        using (var reader = new StreamReader(request.Body))
        {
            try
            {
                var content = await reader.ReadToEndAsync();
                return await InputFormatterResult.SuccessAsync(content);
            }
            catch
            {
                return await InputFormatterResult.FailureAsync();
            }
        }
    }
}

And consequently had to change the input parameter type from HttpRequestMessage to [FromBody]string

And I am being able to read the input xml after this change.

BUT

Now when I start the API (and I use Swagger), the Swagger's screen contains the error message: Failed to load API definition

And it's for all the controllers in the API I have.

I googled but did not find anything valuable. Please advise.

Answer 1

It would be more easy to address this problem if you would have shared your swagger configuration.

Try adding this to your swagger configuration:

options.ResolveConflictingActions(apiDescriptions => apiDescriptions.First());