WebAPI request throws 404 error ... on same request

Question

I have done some looking around and not stumbled onto anything resembling the issue I am experiencing so I thought I would throw it up here and see what, if anything sticks.

I have a controller and method set up.

public class BoothAPIController : ITApiControllerBase
{
    [HttpGet]
    public HttpResponseMessage GetActiveAssetNumbersLike([FromUri] String id)
    {
        HttpResponseMessage ret;

        // ... do some processing

        return ret;
    }
}

The routes are set up in Global.asax

protected void Application_Start(object sender, EventArgs e)
{

    GlobalConfiguration.Configuration.Routes.MapHttpRoute(
            name: "CustomApi",
            routeTemplate: "api/{controller}/{action}/{id}",
            defaults: new { id = RouteParameter.Optional });


    GlobalConfiguration.Configuration.Routes.MapHttpRoute(
            name: "BoothWithDateAPI",
            routeTemplate: "api/{controller}/{boothID}/{year}/{month}/{day}");

    GlobalConfiguration.Configuration.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional });

}

And these two requests execute flawlessly ...

http://localhost:52211/api/BoothAPI/GetActiveAssetNumbersLike/PR
http://localhost:52211/api/BoothAPI/GetActiveAssetNumbersLike/PRN0

This one however ... returns a 404 error ...

http://localhost:52211/api/BoothAPI/GetActiveAssetNumbersLike/PRN

The Header for the failed request looks like ...

Cache-Control →private
Content-Length →2879
Content-Type →text/html; charset=utf-8
Date →Mon, 29 Aug 2016 12:53:08 GMT
Server →Microsoft-IIS/8.0
X-AspNet-Version →4.0.30319
X-Powered-By →ASP.NET
X-SourceFiles →= [string]

While the successful requests look like

Cache-Control →no-cache
Content-Length →7731
Content-Type →application/json; charset=utf-8
Date →Mon, 29 Aug 2016 13:13:43 GMT
Expires →-1
Pragma →no-cache
Server →Microsoft-IIS/8.0
X-AspNet-Version →4.0.30319
X-Powered-By →ASP.NET
X-SourceFiles → [string]

(Shrugs) I dunno ... I am at a complete loss why the one change in the parameter makes a difference.

Answer 1

I did a little digging on this and was surprised myself. Turn out that the parameter you are trying to send PRN is a reserved word in MS-DOS Device Driver

Below is a list of default device driver names.

PRN System list device, usually a parallel port

This question has an answer to the problem: IIS gives 404 when MS-DOS reserved names are used in parameters values

But you should be aware of the potentials pitfalls in setting RelaxedUrlToFileSystemMapping to true. See this article by Scott Hanselman: Experiments in Wackiness: Allowing percents, angle-brackets, and other naughty things in the ASP.NET/IIS Request URL