FreeMASTERのトピックRe: FreeMASTER JSON-RPC Connection Not Successful

FreeMASTER JSON-RPC Connection Not Successful

arun07 — Fri, 25 Jun 2021 22:39:19 GMT

Hello Everyone,

I am trying to play with FreeMASTER, first I tried with ActiveX and it works fine for me, and now I am trying JSON-RPC, and here I am facing a problem with the initial connection, which means with the following line.

pcm = new PCM("localhost:41000", on_connected, on_error, on_error);

The below screenshot is from the debugging session.

Any idea's what can go wrong.

Thanks in Advance

I am using FreeMASTER 3.1.2 (the latest version as of now), and while checking this my FreeMASTER Desktop application is open and running.

Re: FreeMASTER JSON-RPC Connection Not Successful

MichalH — Mon, 28 Jun 2021 06:59:03 GMT

Dear Arun,

I'm not sure what can be wrong here. The port 41000 is open as soon as the FreeMASTER desktop application starts. Perhaps it is blocked by a firewall or some other security settings of your computer.

The easiest way to test if a port is reachable is to use "telnet localhost 41000" The terminal will appear to be empty, so just type two characters: {} which is a shortest-possible (invalid) JSON-RPC command. You should get an answer:

{"jsonrpc":"2.0","id":"","error":{"code":-32600,"message":"Unknown error"}}

The communication should be also possible to be captured by a Wireshark.

Regards,
Michal

Re: FreeMASTER JSON-RPC Connection Not Successful

arun07 — Mon, 28 Jun 2021 08:48:01 GMT

Dear @MichalH

Thanks for your response. Yes, you are right, it looks like that the port is blocked.

I checked the same thing on my personal laptop and it works fine, so this is the problem with my office laptop. Can I do something else to make it work?

Re: FreeMASTER JSON-RPC Connection Not Successful

MichalH — Mon, 28 Jun 2021 14:46:52 GMT

Dear Arun,

I think you will need to talk to your IT administrator to add an exception to a firewall settings. You can also change a TCP port by using a command line argument /rpcs N when launching the FreeMASTER executable (pcmaster.exe). The default N is 41000, but it may be changed this way.

Best regards,
Michal