Nick Parsons Nick Parsons - 6 months ago 140
Javascript Question

Using pipe() in Node.js net

I'm having trouble wrapping my head around the

pipe
function shown in several Node.js examples for the net module.

var net = require('net');

var server = net.createServer(function (socket) {
socket.write('Echo server\r\n');
socket.pipe(socket);
});


Can anyone offer an explanation on how this works and why it's required?

Answer

The pipe() function reads data from a readable stream as it becomes available and writes it to a destination writable stream.

The example in the documentation is an echo server, which is a server that sends what it receives. The socket object implements both the readable and writable stream interface, so it is therefore writing any data it receives back to the socket.

This is the equivalent of using the pipe() method using event listeners:

var net = require('net');
net.createServer(function (socket) {
  socket.write('Echo server\r\n');
  socket.on('data', function(chunk) {
    socket.write(chunk);
  });
  socket.on('end', socket.end);
});
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