(Node.js) File Read Blocks

Demonstrates how to read a file in fixed-size blocks (except for the very last block).

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() {

    // Demonstrates how to read a file in blocks,
    // which can be useful when uploading to cloud storage
    // services such as Azure, S3, Google, etc.

    // For this example, we're simply writing the blocks
    // to an output file, and then checking to see if the
    // resulting file contents equals the original file contents.

    var facSrc = new chilkat.FileAccess();
    var facDest = new chilkat.FileAccess();

    var srcPath = "qa_data/xml/hamlet.xml";
    var destPath = "qa_output/hamletOut.xml";

    var success = facSrc.OpenForRead(srcPath);
    success = facDest.OpenForWrite(destPath);
    // Assuming success for the example..

    // How many 1024-byte blocks?  (Including 1 for the last partial block)
    var numBlocks = facSrc.GetNumBlocks(1024);

    var i = 0;
    while ((i < numBlocks)) {
        dataBlock = facSrc.ReadBlock(i,1024);
        if (facSrc.LastMethodSuccess !== true) {
            console.log(facSrc.LastErrorText);
            return;
        }

        success = facDest.FileWrite(dataBlock);
        if (success !== true) {
            console.log(facDest.LastErrorText);
            return;
        }

        i = i+1;
    }

    facSrc.FileClose();
    facDest.FileClose();

    var bEqual = facSrc.FileContentsEqual(srcPath,destPath);
    if (bEqual !== true) {
        console.log("Something went wrong!");
        return;
    }

    console.log("File successfully copied by blocks.");

}

chilkatExample();