Node.js

Socket Send/Receive 16-bit Integers

Demonstrates sending and receiving 16-bit integers over a socket connection using either big-endian or little-endian byte ordering. Node.js

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

    //  This example requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    var sock = new chilkat.Socket();

    //  --------------------------------------------------------------------
    //  This example uses the public TCP echo service at https://tcpbin.com/
    //  --------------------------------------------------------------------

    var useTls = false;
    var port = 4242;
    var maxWaitMs = 5000;
    success = sock.Connect("tcpbin.com",port,useTls,maxWaitMs);
    if (success == false) {
        console.log(sock.LastErrorText);
        return;
    }

    //  Wait a max of 2 seconds for a response..
    sock.MaxReadIdleMs = 2000;

    //  Send a 16-bit integer using big-endian byte ordering (also called network byte order)
    //  12022 decimal = 2EF6 hex
    var value = 12022;
    var bigEndian = true;
    sock.SendInt16(value,bigEndian);
    //  Send it again, because we'll read it two different ways..
    sock.SendInt16(value,bigEndian);

    //  The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
    sock.SendByte(10);

    //  Let's see hex values of the 2 bytes sent in network byte order (big-endian)
    //  (The echo server sends back exactly the bytes received.)
    var hexStr = sock.ReceiveNBytesENC(2,"hex");

    //  In the big-ending byte order, the byte order is most significant byte to least significant,
    //  therefore we should see the bytes in the order 0x2E 0xF6.
    console.log("Expecting big-endian 2EF6");
    console.log(hexStr);

    //  Let's read directly to an integer..
    success = sock.ReceiveInt16(bigEndian,true);
    console.log("Expecting 12022");
    console.log("Received: " + sock.ReceivedInt);

    //  Consume the LF that gets echoed back..
    sock.ReceiveByte(true);

    //  --------------------------------------------------------------------
    //  Let's do the same thing, but with little-endian byte ordering.

    console.log("----");

    //  12022 decimal = 2EF6 hex, but little-endian byte ordering will send the bytes in the order 0xF6 0x2E
    value = 12022;
    bigEndian = false;
    sock.SendInt16(value,bigEndian);
    sock.SendInt16(value,bigEndian);
    sock.SendByte(10);

    hexStr = sock.ReceiveNBytesENC(2,"hex");

    console.log("Expecting little-endian F62E");
    console.log(hexStr);

    success = sock.ReceiveInt16(bigEndian,true);
    console.log("Expecting 12022");
    console.log("Received: " + sock.ReceivedInt);

    //  Consume the LF that gets echoed back..
    sock.ReceiveByte(true);

    sock.Close(1000);

    //  Output:

    //  Expecting big-endian 2EF6
    //  2EF6
    //  Expecting 12022
    //  Received: 12022
    //  ----
    //  Expecting little-endian F62E
    //  F62E
    //  Expecting 12022
    //  Received: 12022

}

chilkatExample();