Node.js

Wasabi File Streaming Upload

See more Wasabi Examples

Demonstrates how to do a streaming upload from a file to the Wasabi 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.

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.

    // 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();
    // ----------------------------------------------------
    // Important: Wasabi requires a lowercase hex format.
    // ----------------------------------------------------
    crypt.EncodingMode = "hex-lower";
    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;
    // This example will demonstrate uploading to a bucket in the eu-west-2 region
    success = rest.Connect("s3.eu-west-2.wasabisys.com",port,bTls,bAutoReconnect);

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

    success = rest.SetAuthAws(authAws);

    rest.AddHeader("Expect","100-continue");
    rest.AddHeader("Content-Type","application/xml");

    // Set the bucket name via the HOST header.
    // In this case, the bucket name is "chilkat100".
    rest.Host = "chilkat100.s3.eu-west-2.wasabisys.com";

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

    // Upload to the Wasabi 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 Wasabi 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();