Default SPA handler proxies arbitrary requests

[vincent-163]

The default SPA application created from template proxies arbitrary requests.
For example, create a react based SPA application using dotnet new react
Then do curl http://localhost:5000//example.com (note the double slash here; I disabled https redirection for simplicity)
I get HTML code from example.com

This seems to be caused by:
https://github.com/aspnet/JavaScriptServices/blob/15884cbadb94d880c77111017e76e8d37d8d4a72/src/Microsoft.AspNetCore.SpaServices.Extensions/Proxying/SpaProxy.cs#L61-L63
Where new Uri(Uri, string) has the strange behavior where it ignores the URI when the second parameter is absolute

[mkArtakMSFT]

Thank you for your feedback.
We're closing this issue as the behavior discussed is by design.