(Node.js) Transfer a File using Sockets (TLS or non-TLS)

Demonstrates how to two programs, one a socket writer and the other a socket reader, can transfer a file. The connection can be TLS or a regular non-encrypted TCP connection.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

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

    // On the sending side, we'll load the file into a BinData object and send.
    // On the receiving side, we'll read from the socket connection into a BinData, and save to a file.
    // This example assumes the file is not crazy-large, and that the entire contents
    // can fit into memory.  
    // (If the file is too large for memory, there are other ways to send. It just involves streaming or 
    // sending the file chunk-by-chunk..)

    // This section of code is for the sender.
    var bdToSend = new chilkat.BinData();
    var success = bdToSend.LoadFile("somePath/someFile.dat");
    // Assume success for the example...

    var sndSock = new chilkat.Socket();
    var bUseTls = true;
    var port = 5555;
    var maxWaitMs = 5000;
    success = sndSock.Connect("some_domain_or_ip.com",port,bUseTls,maxWaitMs);
    // Assume success for the example...

    // Tell the receiver how many bytes are coming.
    var numBytes = bdToSend.NumBytes;
    var bBigEndian = true;
    success = sndSock.SendInt32(numBytes,bBigEndian);

    // Send the file data (sends the entire contents of bdToSend).
    success = sndSock.SendBd(bdToSend,0,0);

    // Get an acknowledgement.
    success = sndSock.ReceiveInt32(bBigEndian);
    if (success !== true) {
        console.log(sndSock.LastErrorText);
        return;
    }

    // Did the receiver get the correct number of bytes?
    if (sndSock.ReceivedInt !== numBytes) {
        console.log("The receiver did not acknowledge with the correct number of bytes.");
        return;
    }

    console.log("File sent!");

    // ------------------------------------------------------------------------------------
    // The code below is for the receiving side (running on some other computer..)

    var listenSock = new chilkat.Socket();

    success = listenSock.BindAndListen(5555,25);
    if (success !== true) {
        console.log(listenSock.LastErrorText);
        return;
    }

    // Get the next incoming connection
    // Wait a maximum of 20 seconds (20000 millisec)
    // rcvSock: Socket
    var rcvSock;
    rcvSock = listenSock.AcceptNextConnection(20000);
    if (listenSock.LastMethodSuccess == false) {
        console.log(listenSock.LastErrorText);
        return;
    }

    // The sender will first send the big-endian integer for the number of bytes
    // that are forthcoming..
    success = rcvSock.ReceiveInt32(bBigEndian);
    if (success !== true) {
        console.log(rcvSock.LastErrorText);

        return;
    }

    var numBytesComing = rcvSock.ReceivedInt;

    // Receive that many bytes..
    var bdReceived = new chilkat.BinData();
    success = rcvSock.ReceiveBdN(numBytesComing,bdReceived);
    if (success !== true) {
        console.log(rcvSock.LastErrorText);

        return;
    }

    // Acknowledge the sender by sending back the number of bytes we received.
    success = rcvSock.SendInt32(bdReceived.NumBytes,bBigEndian);

    // Close the connection.
    var maxWaitMs = 20;
    rcvSock.Close(maxWaitMs);

    // Save the received data to a file.
    success = bdReceived.WriteFile("somePath/someFile.dat");
    // Assume success for the example...

    console.log("File received!");

}

chilkatExample();