.Net core Routing URLEncoded URL not working - asp.net

Question

I have a .Net core 2.2 WebAPI that works perfectly fine with "normal" style URLs e.g. /api/controller/action/param etc. I have a 3rd party service that does a POST to this API with a URL encoded path and the Asp.Net routing fails to route this request correctly.
The controller is at: .../api/file/uploadFile/{filename}
The POST from the 3rd party is:
".../api%2Ffile%2FuploadFile%2FMaintenanceReport_2019_08_05_17_11_10.html.gz".
Replacing the %2F in the path appears to work as expected:
".../api/file/uploadFile/MaintenanceReport_2019_08_05_17_11_10.html.gz"
The filename is: "MaintenanceReport_2019_08_05_17_11_10.html.gz"
Placing a Route Attribute with %2F instead of "/" sort of works, but looks very messy.
The filename passed into the path is also not resolving correctly as a parameters. I suspect this is due to the file extension being included.
I've searched the net and did not find anything related jumping out at me. Any suggestions/ideas?
[Route("api/[controller]/[action]")]
[Route("api%2F[controller]%2F[action]")]
public class FileController : Controller
{
...
}
I would have thought that the .Net core routing engine would detect the path

Answer 1

The default path separator in the url generated by the route is / .The issue seems that the separator before the parameter which is as part of the path value is not recognized or missing .
If you request the url like .../api%2Ffile%2FuploadFile%2FMaintenanceReport_2019_08_05_17_11_10.html.gz , you could try to use URL Rewriting Middleware like below :
In Configure
app.UseRewriter(new RewriteOptions()
.Add(RewriteRouteRules.ReWriteRequests)
);
2.Custom a class containing ReWriteRequests
public class RewriteRouteRules
{
public static void ReWriteRequests(RewriteContext context)
{
var request = context.HttpContext.Request;
if (request.Path.Value.Contains("%2F", StringComparison.OrdinalIgnoreCase))
{
context.HttpContext.Request.Path = context.HttpContext.Request.Path.Value.Replace("%2F", "/");
}
}
}
Reference: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/url-rewriting?view=aspnetcore-2.1&tabs=aspnetcore2x