Node.js TCP echo server example issue with `socket.pipe()`

Question

Node.js TCP echo server example issue with `socket.pipe()`

I have this example from https://nodejs.org that echoes back the input.

var net = require('net');

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

server.listen(1338, 'localhost');

I used this ruby script to send a data:

require 'socket'
a = TCPSocket.new('localhost', 1338) # could replace 127.0.0.1 with your "real" IP if desired.
a.write "hi server!"
puts "got back:" + a.recv(1024)
a.close

However, I got this error

events.js:85
      throw er; // Unhandled 'error' event
            ^
Error: read ECONNRESET
    at exports._errnoException (util.js:746:11)
    at TCP.onread (net.js:550:26)

What might be wrong? When I just use socket.end(), it just works fine.

var net = require('net');
var server = net.createServer(function (socket) {
    console.log("Connection from " + socket.remoteAddress);
    socket.end("Hello World\n");

});
server.listen(1338, "localhost");

ADDED

I needed to modify the ruby code not to cause an error with nodejs.

require 'socket'
a = TCPSocket.new('localhost', 1338) # could replace 127.0.0.1 with your "real" IP if desired.
a.write "hi server!"
puts "got back:" + a.recv(1024)
puts "got back:" + a.recv(1024)
a.close

node.js
tcp

Answer 1

Your Ruby script is closing the connection prematurely (before reading all the data).

Your Node.js code should anticipate this possibility and handle it:

var server = net.createServer(function (socket) {
  socket.on('error', function(err) {
    console.error('SOCKET ERROR:', err);
  });
  socket.write('Echo server\r\n');
  socket.pipe(socket);
});

Here we’re doing nothing but logging the error, although you could do something else with it.