How do I pass a buffer as a piped input to a node script?

Question

I want to send a buffer as a piped input to a node script on the terminal. Thus I created a script ping.js with the following code:

#!/usr/local/bin/node

function bufferDemo() {
  var objBuffer = new Buffer(29);
  objBuffer.writeUInt32LE(29,0);
  objBuffer.write('{message:"pingfrompingjs"}',4);

  return objBuffer;
}

bufferDemo();

Then I ran the following command on the command line:

 ./ping.js | ./index.js

I also tried:

 ./ping.js > out.json

out.json is empty so obviously the ping.js is not passing the buffer. How do I achieve this? I am relatively new to node.

so as colleagues suggested use something like `console.log(buffer.toString('utf8'));` because `|` works with unix based `stdin` and `stdout`. so you want to pass data via that channel first. — Eugene Hauptmann, Feb 06 '16 at 22:18

score 2 · Answer 1 · answered Feb 06 '16 at 22:15

2

returning from the function is no effect whatsoever. If you want your command to output something, you have to write to stdout (or stderr):

process.stdout.write(objBuffer);

answered Feb 06 '16 at 22:15

Felix Kling

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score 2 · Accepted Answer · answered Feb 06 '16 at 22:15

2

You're not actually outputting anything by returning the value in your function. You should be writing to process.stdout:

process.stdout.write(objBuffer)

answered Feb 06 '16 at 22:15

Wex

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How do I pass a buffer as a piped input to a node script?

2 Answers2