Re: [Linphone-users] Calling linphonec from Java - what changed between 3.7.0 and 3.9.1?

[Adam Granger]

I've tracked this down a bit further... Linphonec is receiving commands,
the issue is in the output buffering back to stdout.

When linphonec.exe is run from a console it behaves 'correctly', just not
from when run from inside Java... This has changed from 3.8.2 to 3.9.1

Apparently there is no easy way to fool child processes to thinking
they're in a console, not on win32 at least...

http://stackoverflow.com/questions/11516258/what-is-the-equivalent-of-unbuffer-program-on-windows/11549033#11549033

Regards,

Adam.

> From my recent stackoverflow post
> (http://stackoverflow.com/questions/35014744/unable-to-write-into-a-console-application)
>
> I'm invoking linphonec.exe, an interactive console application for
> controlling Linphone, an open source Skype-like application via Java
> (1.8u11) on Windows 7.
>
> Everything worked fine in Linphone 3.7.0, however after updating to 3.9.1,
> I can no longer invoke commands from Java into the application. Linphonec
> just ignores the commands
>
> Small example to recreate, issuing the help command..
>
> public class CommandTest {
>     private static class Consumer implements Runnable {
>         private InputStream stream;
>         public Consumer(InputStream stream) {
>             this.stream = stream;
>         }
>         @Override
>         public void run() {
>             int c = 0;
>             try {
>                 while ((c = stream.read()) != -1) {
>                     System.out.print((char) c);
>                 }
>                 System.out.println("Stream finish");
>             } catch (IOException e) {
>                 e.printStackTrace();
>             }
>         }
>     }
>
>     public static void main(String[] args) throws Exception {
>         ProcessBuilder builder = new ProcessBuilder(
>                 Arrays.asList("C:\\Program Files
> (x86)\\Linphone\\bin\\linphonec.exe"));
>         builder.redirectInput(Redirect.PIPE);
>         Process process = builder.start();
>         new Thread(new Consumer(process.getInputStream())).start();
>         new Thread(new Consumer(process.getErrorStream())).start();
>         BufferedWriter stdin = new BufferedWriter(new
> OutputStreamWriter(process.getOutputStream(),
> StandardCharsets.US_ASCII));
>         stdin.write("help\n");
>         stdin.flush();
>         process.waitFor();
>     }
> }
>
> Output - with 3.7.0
>
> Ready
> Warning: video is disabled in linphonec, use -V or -C or -D to enable.
> linphonec> Commands are:
> ---------------------------
>       help  Print commands help.
>       call  Call a SIP uri or number
>       ... etc...
>
> Output - with 3.9.1
>
> Ready
> linphonec> linphonec>
>
>     I believe I'm following best practices for consuming all standard out
> and error on separate threads as per the classic JavaWorld article
>     I was using BufferedReader but simplified to input stream
>     Explicitly specified character set - is this correct for a Windows
> command line application?
>     I note that if I write \n to the stream then linphonec simply responds
> with linphonec>, so it definitely getting something...
>     Manually tested the 3.9.1 installation on the command line - works
> fine
>     Tried different combinations of \r, \n etc.
>
> Out of desperation I even tried this, which didn't work in 3.9.1, only
> 3.7.0
>
> for (char c : "help\n".toCharArray()) {
>     stdin.write(c);
>     stdin.flush();
>     Thread.sleep(100);
> }
>
> If you set ProcessBuilder to inherit IO with
> builder.redirectInput(Redirect.INHERIT) then with 3.7.0 you can type into
> the eclipse console and it works as expected, however with 3.9.1 it fails
> in the same way it does as manually calling write() on outputStream
>
> Questions
>
>     Is there some way an application can read from the console which is
> not supported by ProcessBuilder
>     Am I doing something obviously wrong
>     Anyone have any success integrating with Java using this approach and
> recent versions of Linphone Desktop...
>
> Any ideas... I've been looking at the source at
> https://github.com/BelledonneCommunications/linphone/blob/3.9.x/console/linphonec.c,
> however it's pretty complicated....
>
> Can anyone explain whether "readline" is used in Windows build and what
> _WIN32_WCE would be set to in the Windows build?
>
> Thanks,
>
> Adam.
>
>
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