Web API 2 encodes URLs to Google APIs

Question

I am using Web API 2 to create a Google Analytics Reporting API v4 proxy. I am successfully creating the request parameters using the Google.Apis.AnalyticsReporting.v4 library and succesfully authenticating with a service account. However, when running the BatchGet.Execute() method, the request for batch reports fail.

Fiddler shows the request is a 404:

The requested URL /v4/reports%3AbatchGet was not found on this server. That’s all we know.

Using Postman I can see that the if the URL was correct (https://analyticsreporting.googleapis.com/v4/reports:batchGet) the request succeeds. Something on the back-end of Web API or .NET 4.6.1 is encoding the request URL and causing Google to send back a 404.

How can I configure Web API 2 so that it allows the colon within the URL for the Google API request?

public IHttpActionResult Post([FromBody] RequestObject req)
        {
            var resp = new CompleteResponse();
            try
            {
                var service = new AnalyticsReportingService(new BaseClientService.Initializer
                {
                    HttpClientInitializer = Cert,
                    ApplicationName = "GA Test"
                });
                var report = new GetReportsRequest();

                var result = service.Reports.BatchGet(report).Execute();
                resp.Result = result.Reports[0].Data;
            }
            catch (Exception ex)
            {
                resp.Error = ex.ToString();
            }
            return Ok(resp);
        }

Global.asax:

protected void Application_Start()
        {
            GlobalConfiguration.Configure(WebApiConfig.Register);

            GlobalConfiguration.Configuration.Formatters.JsonFormatter.MediaTypeMappings.Add(new System.Net.Http.Formatting.RequestHeaderMapping("Accept",
                "text/html",
                StringComparison.InvariantCultureIgnoreCase,
                true,
                "application/json"));
        }

WebApiConfig.cs

public static void Register(HttpConfiguration config)
        {
            // Web API configuration and services

            // Web API routes
            config.MapHttpAttributeRoutes();

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

Answer 1

There is a known bug that was fixed in 1.31.1. The solution was updating to the latest version.

See https://github.com/google/google-api-dotnet-client/pull/1121