Reconnect net.socket nodejs

Question

Reconnect net.socket nodejs

I am new to node.js and would like to connect to a TCP socket. For this I am using the net module.

My idea was to wrap the connect sequence into a function then on the 'close' event, attempt a reconnection. Not that easy apparently.

function conn() {

    client.connect(HOST_PORT, HOST_IP, function() {
        startSequence();
    })
}

client.on('close', function(e) {
    log('info','Connection closed! -> ' + e)
    client.destroy();
    setTimeout(conn(),1000);
});

So when the remote host is closed, I see my logs comming through, howere what seems to be happening is that as soons as the remote host comes online ALL the previous attempts start to get processed - if that makes sense. If you look at client.connect, there is a function called startSequence that sends some data that "iniates" the connection from the remote server side. When the server goes offline and I start reconnecting all the failed attempts from before seem to have been buffered and are all sent together when the server goes online.

I have tried the code from this Stackoverflow link as well to no avail (Nodejs - getting client socket to try again after 5 sec time out)

client.connect(HOST_PORT, HOST_IP, function() {
    pmsStartSequence();
})


// Add a 'close' event handler for the client socket
client.on('close', function(e) {
    log('debug','connection  closed -> ' + e)
    client.setTimeout(10000, function() {
        log('debug', 'trying to reconnect')
        client.connect(HOST_PORT, HOST_IP, function() {
            pmsStartSequence();
        })
    })
});

Is there any advice on how I can reconnect a socket after failure?

node.js
sockets

Answer 1

My solution:

var parentHOST = '192.168.2.66';
var parentPORT = 9735;

var net = require('net');
var S = require('string');
var parentClient = new net.Socket();
var parentActive = false;

var startParentClient = function () {
    parentClient = new net.Socket();
    parentActive = false;

    parentClient.connect(parentPORT, parentHOST, function() {
      console.log('Connected ' + cluster.worker.id + ' to parent server: ' + parentHOST + ':' + parentPORT);
      parentActive = true;
    });

    parentClient.on('error', function() {
      parentActive = false;
      console.log('Parent connection error');
    });

    parentClient.on('close', function() {
      parentActive = false;
      console.log('parent connection closed');
      setTimeout(startParentClient(), 4000);
    });
  }

If is necessary connect:

  if (!S(parentHOST).isEmpty() && !S(parentPORT).isEmpty()) {
    startParentClient();
  }