Message between bash and javascript via named pipes

Question

Message between bash and javascript via named pipes

I have a javascript application who need to start a linux application. Since I did not found any way to start the application and get when it end, I made a bash script wich launch the application, and send a message via a named pipe when the app close.

Until here, all 's good, but I can t find a way to catch this message in the javascript.

Did someone know how to get the message in the javascript?

I did search, but I only found how to do this in C# and C++.

Sample from the javascript:

var test = spawn('sh', ['home/pi/play.sh', data.video_id]);

Just spawn a bash command wich start the script with the name of the video

Sample from the bash:

mkfifo btjpipe
if pgrep omxplayer
then
    echo "AR">btjpipe
else
    clear
    omxplayer $1 > dev/null
    echo "VE">btjpipe

Created the pipe, seeking if the player is already running, then either send AR ("Already Running") or start the player and send VE ("Video End").

javascript
node.js
bash
named-pipes
raspbian

Answer 1

use child_process module and child.stdout to pipe the output where you want

var spawn = require('child_process').spawn;
var test = spawn('sh', ['home/pi/play.sh', data.video_id]);


test.stdin.pipe(process.stdin);
test.stdout.pipe(process.stdout);
test.stderr.pipe(process.stderr);

on this case to the current process

Maybe you can also trying using "exec" instead of spawn, you will get the output in the callback function.