HttpListener ignores port on some windows platform(s)

Hello,

we distribute a cross-plaform (Windows, Mac, Linux) application that opens a port to accept incoming web requests in order to receive OAuth auth browser callback.s. The code does something like:

listener = new HttpListener();

listener.Prefixes.Add("http://127.0.0.1:12345"); // hardcoded uri for the example.

listener.Start();

Unfortunately on at least one server, the port number specified in the uri appears to be ignored and the effective opened port seems random. See the difference between the log file and the netstat output on the right.



The affectetd server runs Windows Server 2012 R2.

We tried DotNet 3.5 or 4.6, x86 or 64 targets. Using Unity 2017.4.29f1.

To me this sounds like a bug in Mono. I had a quick look at the HttpListener mono code and it looks rather straightforward. So we've filled a bug report yesterday.

We're considering adding custom code to detect the effective port number.

Has anyone encountered something similar? Any idea for a work-around?

Update: sample available here https://github.com/DragonBox/unity_httplistenerport_bug

Thanks

 

@Tautvydas-Zilys if you mean the 4.6 equivalent present in Unity 2017.4.29f1, we tried and it still fails. (That's what I tried saying when I wrote "We tried DotNet 3.5 or 4.6, x86 or 64 targets. Using Unity 2017.4.29f1.")

If you want me to try to test something else, let us know. In the mean time we wrote an open port detection work-around... The case is #1178646

 

Hello @Tautvydas-Zilys, we got told in our bug report that the HttpListener is not part of Unity and our issue was closed.

As far as we understand, the Windows binary ships with a Mono System.dll containing the HttpListener implementation.

Could we get the issue resolution re-evaluated? Thanks