Dart Requires Chilkat v11.0.0+

Generate an AWS (S3) Pre-Signed URL to Download File

See more Amazon S3 (new) Examples

Demonstrates how to generate a pre-signed URL to download a file from the Amazon S3 service. Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // This example assumes the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  final http = CkHttp();

  http.awsAccessKey = 'AWS_ACCESS_KEY';
  http.awsSecretKey = 'AWS_SECRET_KEY';

  // Make sure to set your AWS region correctly
  http.awsRegion = 'us-east-1';

  final bucketName = 'chilkat100';
  final objectName = 'starfish/starfish.jpg';
  final localFilePath = 'qa_output/starfish.jpg';
  final awsService = 's3';

  // The signed URL will be valid for this number of seconds:
  final numSecondsValid = 86400;

  // Choose between a URL beginning with "http://" or "https://"...
  final bUseHttps = false;

  // Generate the pre-signed URL
  final String preSignedUrl;
  try {
    preSignedUrl = http.s3GenPresignedUrl('GET', bUseHttps, bucketName, objectName, numSecondsValid, awsService);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // The following URL can be copy-and-pasted into a browser..
  print('Pre-Signed AWS S3 URL: $preSignedUrl');

  // Here's an example of a pre-signed URL. 
  // This URL will only work within 1 day (86400 seconds) after the time this example was published.
  // 
  //     http://chilkat100.s3.amazonaws.com/starfish/starfish.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=16QXXDGY83AJJR6RVQ02%2F20170111%2Fus-west-2%2Fs3%2Faws4_request&X-Amz-Date=20170111T161959Z&X-Amz-Expires=86400&X-Amz-SignedHeaders=host&X-Amz-Signature=72bf4fd9a15d7bbcdd313a3318d937a778905f62a3fbff9b789d8dc28acd9232

  // Now try to do an HTTP Download using the signed URL.
  try {
    http.download(preSignedUrl, 'c:/temp/qa_output/starfish.jpg');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Success.');
}