React Native

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.

React Native

import { AuthAws, Crypt2, Rest, Stream } from '@chilkat/react-native'

async 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.
  const crypt = new Crypt2();
  // ----------------------------------------------------
  // Important: Wasabi requires a lowercase hex format.
  // ----------------------------------------------------
  crypt.encodingMode = 'hex-lower';
  crypt.hashAlgorithm = 'sha-256';
  const fileToUploadPath = 'qa_data/xml/hamlet.xml';
  const hashStr = await crypt.hashFileENCAsync(fileToUploadPath);

  const rest = new Rest();

  // Connect to the Amazon AWS REST server.
  const bTls = true;
  const port = 443;
  const bAutoReconnect = true;
  // This example will demonstrate uploading to a bucket in the eu-west-2 region
  await rest.connectAsync('s3.eu-west-2.wasabisys.com', port, bTls, bAutoReconnect);

  // Provide AWS credentials for the REST call.
  const authAws = new AuthAws();
  authAws.accessKey = 'access-key';
  authAws.secretKey = 'secret-key';
  authAws.serviceName = 's3';
  // Provide the pre-computed SHA-256 here:
  authAws.precomputedSha256 = hashStr;

  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';

  const fileStream = new 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.
  let responseStr: string;
  try {
    responseStr = await rest.fullRequestStreamAsync('PUT', '/hamlet.xml', fileStream);
  } catch {
    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}`);
  }
}