Node.js tls.connect() Method

The tls.connect() method is an inbuilt application programming interface of class TLS within tls module which is used to create a tls.TLSSocket object.

Syntax:

const tls.connect(port[, host][, options][, callback])

Parameters: This method accept four parameters as mentioned above and described below:

• port: It is the port number.
• host: It is the name of the host.
• options: These options can be enableTrace, host, port, path, socket, allowHalfOpen, etc.
• callback: It is the callback function for further operation.

Return Value: This method returns the object of tls.TLSSocket.

How to generate Private key and Public certificate?

• Private key: Open notepad and copy paste the following key:

  -----BEGIN RSA PRIVATE KEY-----
  MIICXQIBAAKBgQC38R9wXcUbhOd44FavgmE5R3K4JeYOHLnI7dUq1B8/Gv7l3SOg
  JKef/m9gM1KvUx951mapXGtcWgwB08J3vUE2YOZ4tWJArrVZES0BI/RmFAyhQFP5
  HcWl3LSM9LRihP98F33oIkKaCxA5LxOrkgpV4HrUzIKTABDYah7RPex1WQIDAQAB
  AoGBAIXR71xxa9gUfc5L7+TqBs+EMmrUb6Vusp8CoGXzQvRHMJCMrMFySV0131Nu
  o0YYRDsAh1nJefYLMNcXd1BjqI+qY8IeRsxaY+9CB2KKGVVDO2uLdurdC2ZdlWXT
  Vwr3dDoyR0trnXJMmH2ijTeO6bush8HuXxvxJBjvEllM5QYxAkEA3jwny9JP+RFu
  0rkqPBe/wi5pXpPl7PUtdNAGrh6S5958wUoR4f9bvwmTBv1nQzExKWu4EIp+7vjJ
  fBeRZhnBvQJBANPjjge8418PS9zAFyKlITq6cxmM4gOWeveQZwXVNvav0NH+OKdQ
  sZnnDiG26JWmnD/B8Audu97LcxjxcWI8Jc0CQEYA5PhLU229lA9EzI0JXhoozIBC
  TlcKFDuLm88VSmlHqDyqvF9YNOpEdc/p2rFLuZS2ndB4D+vu6mjwc5iZ3HECQCxy
  GBHRclQ3Ti9w76lpv+2kvI4IekRMZWDWnnWfwta+DGxwCgw2pfpleBZkWqdBepb5
  JFQbcxQJ0wvRYXo8qaUCQQCgTvWswBj6OTP7LTvBlU1teAN2Lnrk/N5AYHZIXW6m
  nUG9lYvH7DztWDTioXMrruPF7bdXfZOVJD8t0I4OUzvC
  -----END RSA PRIVATE KEY-----
  

  Now save the filename as private-key.pem

• Public certificate: Open notepad and copy paste the following key:

  -----BEGIN CERTIFICATE-----
  MIICfzCCAegCCQDxxeXw914Y2DANBgkqhkiG9w0BAQsFADCBgzELMAkGA1UEBhMC
  SU4xEzARBgNVBAgMCldlc3RiZW5nYWwxEDAOBgNVBAcMB0tvbGthdGExFDASBgNV
  BAoMC1BhbmNvLCBJbmMuMRUwEwYDVQQDDAxSb2hpdCBQcmFzYWQxIDAeBgkqhkiG
  9w0BCQEWEXJvZm9mb2ZAZ21haWwuY29tMB4XDTIwMDkwOTA1NTExN1oXDTIwMTAw
  OTA1NTExN1owgYMxCzAJBgNVBAYTAklOMRMwEQYDVQQIDApXZXN0YmVuZ2FsMRAw
  DgYDVQQHDAdLb2xrYXRhMRQwEgYDVQQKDAtQYW5jbywgSW5jLjEVMBMGA1UEAwwM
  Um9oaXQgUHJhc2FkMSAwHgYJKoZIhvcNAQkBFhFyb2ZvZm9mQGdtYWlsLmNvbTCB
  nzANBgkqhkiG9w0BAQEFAAOBjQAwgYkCgYEAt/EfcF3FG4TneOBWr4JhOUdyuCXm
  Dhy5yO3VKtQfPxr+5d0joCSnn/5vYDNSr1MfedZmqVxrXFoMAdPCd71BNmDmeLVi
  QK61WREtASP0ZhQMoUBT+R3Fpdy0jPS0YoT/fBd96CJCmgsQOS8Tq5IKVeB61MyC
  kwAQ2Goe0T3sdVkCAwEAATANBgkqhkiG9w0BAQsFAAOBgQATe6ixdAjoV7BSHgRX
  bXM2+IZLq8kq3s7ck0EZrRVhsivutcaZwDXRCCinB+OlPedbzXwNZGvVX0nwPYHG
  BfiXwdiuZeVJ88ni6Fm6RhoPtu2QF1UExfBvSXuMBgR+evp+e3QadNpGx6Ppl1aC
  hWF6W2H9+MAlU7yvtmCQQuZmfQ==
  -----END CERTIFICATE-----
  

  Now save the filename as public-cert.pem

Example 1: Filename: index.js

// Node.js program to demonstrate the
// tls.connect() method
var tls = require('tls'),
    fs = require('fs'),

// Port and host address for server
PORT = 1337,
HOST = '127.0.0.1',
value = null;

// Private key and public certificate for access
var options = {
  key: fs.readFileSync('private-key.pem'),
  cert: fs.readFileSync('public-cert.pem'),
  rejectUnauthorized: false
};

// Creating and initializing server
var server = tls.createServer(options, function(socket) {

  // Print the data that we received
  socket.on('data', function(data) {
     console.log('\nReceived: %s ',
     data.toString().replace(/(\n)/gm, ""));
  });

  // Stopping the server
  // by using the close() method
  server.close(() => {
    console.log("Server closed successfully");
  });
});

// Start listening on a specific port and address
// by using listen() method
server.listen(PORT, HOST, function() {
  console.log("I'm listening at %s, on port %s", HOST, PORT);
});

// Creating and initializing client
// by using tls.connect() method
var client = tls.connect(PORT, HOST, options, function() {

  // Setting maximum send fragment limit
  // by using tlsSocket.setMaxSendFragment() method
  value = client.setMaxSendFragment(16384);

  if(value)
     client.write("tls fragment is set");
  else
     client.write("tls fragment is not set")

  client.end(() => {
     console.log("Client closed successfully");
  });

});

Run the index.js file using the following command:

node index.js

Output:

I'm listening at 127.0.0.1, on port 1337
Client closed successfully

Received: tls fragment is set
Server closed successfully

Example 2: Filename: index.js

// Node.js program to demonstrate the
// tls.connect() method
var tls = require('tls'),
    fs = require('fs'),

// Port and host address for server
PORT = 1337,
HOST = '127.0.0.1';

// Private key and public certificate for access
var options = {
  key: fs.readFileSync('private-key.pem'),
  cert: fs.readFileSync('public-cert.pem'),
  rejectUnauthorized: false
};

// Creating and initializing server
var server = tls.createServer(options, function(socket) {

  // Setting maximum send fragment limit
  // by using tlsSocket.setMaxSendFragment() method
  value = socket.setMaxSendFragment(16384);

  if(value)
    socket.write("tls fragment is set");
  else
    socket.write("tls fragment is not set")

  // Stopping the server
  // by using the close() method
  server.close(() => {
     console.log("Server closed successfully")
  });
});

// Start listening on a specific port and address
// by using listen() method
server.listen(PORT, HOST, function() {
  console.log("I'm listening at %s, on port %s", HOST, PORT);
});

// Creating and initializing client
// by using tls.connect() method
var client = tls.connect(PORT, HOST, options, function() {
   console.log("client is connected");
});

client.on("data", function(data) {

  console.log('Received: %s',
  data.toString().replace(/(\n)/gm, ""));

  // Close the connection after receiving the message
  client.end(() => {
     console.log("client closed successfully")
  });

});

Run the index.js file using the following command:

node index.js

Output:

I'm listening at 127.0.0.1, on port 1337
client is connected
Received: tls fragment is set
client closed successfully
Server closed successfully

Reference: https://nodejs.org/dist/latest-v12.x/docs/api/tls.html#tls_tls_connect_port_host_options_callback