Dart

Bunny Sign URL and then Download using Signed URL

See more Bunny CDN Examples

Shows how to sign a URL for BunnyCDN Token Authentication and then use it to download. 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 mySecurityKey = 'e7ea8d73-8fa0-44ef-a2cc-91526f7df5ed';

  final url = 'https://test.b-cdn.net/sample-pdf-with-images.pdf';

  // Extract the URL components.
  final urlObj = CkUrl();
  urlObj.parseUrl(url);

  var urlScheme = 'https';
  if (!urlObj.ssl) {
    urlScheme = 'http';
  }

  final urlHost = urlObj.host;
  final urlPath = urlObj.path;

  // Calculate an expiration time 1 hour from the current date/time.
  final expTime = CkDateTime();
  expTime.setFromCurrentSystemTime();
  expTime.addSeconds(3600);
  final expires = expTime.getAsUnixTimeStr(false);

  print('Expires = $expires');

  // Create the string to hash
  final sbToHash = CkStringBuilder();
  sbToHash.append(mySecurityKey);
  sbToHash.append(urlPath);
  sbToHash.append(expires);

  // Base64Url encoding is the same as base64, except "-" is used instead of "+",
  // "_" is used instead of "/", and no "=" padding is added.
  final token = sbToHash.getHash('sha256', 'base64Url', 'utf-8');

  final sbSignedUrl = CkStringBuilder();
  sbSignedUrl.append(urlScheme);
  sbSignedUrl.append('://');
  sbSignedUrl.append(urlHost);
  sbSignedUrl.append(urlPath);
  sbSignedUrl.append('?token=');
  sbSignedUrl.append(token);
  sbSignedUrl.append('&expires=');
  sbSignedUrl.append(expires);

  final signedUrl = sbSignedUrl.getAsString();
  print('Signed URL: $signedUrl');

  // Use the signed URL to download the file.
  final http = CkHttp();
  try {
    http.download(signedUrl, 'c:/aaworkarea/sample.pdf');
    print('Success.');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
  }
}