(Node.js) REST Stream Response to File (Streaming Download) (Amazon S3)

Demonstrates how to stream the response body directly to a file. (The example shows how to stream a JPG from the Amazon S3 service.)

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.

    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";
    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";

    // Send the request to download the JPG.
    success = rest.SendReqNoBody("GET","/starfish.jpg");
    if (success !== true) {
        console.log(rest.LastErrorText);
        return;
    }

    // Read the response header.
    var responseStatusCode = rest.ReadResponseHeader();
    if (responseStatusCode < 0) {
        console.log(rest.LastErrorText);
        return;
    }

    console.log("Response status code = " + responseStatusCode);

    // We expect a 200 response status if the JPG data is coming.
    // Otherwise, we'll get a string response body with an error message(or no response body).
    if (responseStatusCode == 200) {

        var bodyStream = new chilkat.Stream();

        // The stream's sink will be a file.
        bodyStream.SinkFile = "qa_output/starfish.jpg";

        // Read the response body to the stream.  Given that we've
        // set the stream's sink to a file, it will stream directly
        // to the file.
        success = rest.ReadRespBodyStream(bodyStream,true);
        if (success !== true) {
            console.log(rest.LastErrorText);
            return;
        }

        console.log("Successfully received the JPG file.");

    }
    else {
        var errResponse = rest.ReadRespBodyString();
        if (rest.LastMethodSuccess !== true) {
            console.log(rest.LastErrorText);
        }
        else {
            console.log(errResponse);
        }

    }


}

chilkatExample();