React Native

REST Stream Response to File (Streaming Download) (Amazon S3)

See more Amazon S3 (new) Examples

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

import { AuthAws, 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.

  const rest = new Rest();

  // Connect to the Amazon AWS REST server.
  const bTls = true;
  const port = 443;
  const bAutoReconnect = true;
  await rest.connectAsync('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.
  const authAws = new AuthAws();
  authAws.accessKey = 'AWS_ACCESS_KEY';
  authAws.secretKey = 'AWS_SECRET_KEY';
  authAws.serviceName = 's3';
  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.
  try {
    await rest.sendReqNoBodyAsync('GET', '/starfish.jpg');
  } catch {
    console.log(rest.lastErrorText);
    return;
  }

  // Read the response header.
  const responseStatusCode = await rest.readResponseHeaderAsync();
  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) {

    const bodyStream = new 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.
    try {
      await rest.readRespBodyStreamAsync(bodyStream, true);
    } catch {
      console.log(rest.lastErrorText);
      return;
    }

    console.log('Successfully received the JPG file.');
  } else {
    try {
      const errResponse = await rest.readRespBodyStringAsync();
      console.log(errResponse);
    } catch {
      console.log(rest.lastErrorText);
    }
  }
}