(Node.js) AWS S3 File Streaming Upload

Demonstrates how to do a streaming upload from a file to the AWS S3 storage service. The AWS authorization presents some difficulties when the REST request body is to be streamed from a file (or from some other source). The issue is that the SHA-256 hash of the file data must be calculated. There are only two possible ways to do this: (1) stream the file into memory in its entirety and calculate the SHA-256 hash prior to uploading, or (2) pre-calculate the SHA-256 in a streaming fashion, and then provide it to the AWS authentication object.

If the application does NOT pre-compute the SHA-256, then Chilkat (internally) is forced to stream into memory, calculate the SHA-256, and then upload from the in-memory copy of the file.

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.

    // This first part is optional.  AWS authentication requires
    // the SHA-256 hash of the request body (i.e. the contents of the file
    // to be uploaded).  We can choose to pre-calculate the SHA-256 in a streaming fashion
    // and then provide it to the authenticator object.  This way, if the file is
    // extremely large, it never needs to completely reside in memory.
    var crypt = new chilkat.Crypt2();
    crypt.EncodingMode = "hex";
    crypt.HashAlgorithm = "sha-256";
    var fileToUploadPath = "qa_data/xml/hamlet.xml";
    var hashStr = crypt.HashFileENC(fileToUploadPath);

    var rest = new chilkat.Rest();

    // Connect to the Amazon AWS REST server.
    var bTls = true;
    var port = 443;
    var bAutoReconnect = true;
    var success = rest.Connect("s3.amazonaws.com",port,bTls,bAutoReconnect);

    // ----------------------------------------------------------------------------
    // Important: For buckets created in regions outside us-east-1,
    // there are three important changes that need to be made.
    // See Working with S3 Buckets in Non-us-east-1 Regions for the details.
    // ----------------------------------------------------------------------------

    // Provide AWS credentials for the REST call.
    var authAws = new chilkat.AuthAws();
    authAws.AccessKey = "AWS_ACCESS_KEY";
    authAws.SecretKey = "AWS_SECRET_KEY";
    authAws.ServiceName = "s3";
    // Provide the pre-computed SHA-256 here:
    authAws.PrecomputedSha256 = hashStr;

    success = rest.SetAuthAws(authAws);

    // Set the bucket name via the HOST header.
    // In this case, the bucket name is "chilkat100".
    rest.Host = "chilkat100.s3.amazonaws.com";

    var fileStream = new chilkat.Stream();
    fileStream.SourceFile = fileToUploadPath;

    // Upload to the S3 Storage service.
    // If the application provided the SHA-256 hash of the file contents (as shown above)
    // then file is streamed and never has to completely reside in memory.
    // If the application did NOT provide the SHA-256, then Chilkat will (internally) 
    // load the entire file into memory, calculate the SHA-256, and then upload.
    var responseStr = rest.FullRequestStream("PUT","/hamlet.xml",fileStream);
    if (rest.LastMethodSuccess !== true) {
        console.log(rest.LastErrorText);
        return;
    }

    // When successful, the S3 Storage service will respond with a 200 response code,
    // with an XML body.  
    if (rest.ResponseStatusCode == 200) {
        console.log(responseStr);
        console.log("File uploaded.");
    }
    else {
        // Examine the request/response to see what happened.
        console.log("response status code = " + rest.ResponseStatusCode);
        console.log("response status text = " + rest.ResponseStatusText);
        console.log("response header: " + rest.ResponseHeader);
        console.log("response body: " + responseStr);
        console.log("---");
        console.log("LastRequestStartLine: " + rest.LastRequestStartLine);
        console.log("LastRequestHeader: " + rest.LastRequestHeader);
    }


}

chilkatExample();