Dart Requires Chilkat v11.0.0+
Upload String to Google Cloud Storage

Demonstrates how to upload an in-memory string to Google Cloud Storage.
Chilkat Dart Downloads

Dart
import 'package:chilkat/chilkat.dart';

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

  // This example uses a previously obtained access token having permission for the 
  // scope "https://www.googleapis.com/auth/cloud-platform"

  // In this example, Get Google Cloud Storage OAuth2 Access Token, 
  // the service account access token was saved to a text file.  This example fetches the access token from the file..
  final sbToken = CkStringBuilder();
  sbToken.loadFile('qa_data/tokens/googleCloudStorageAccessToken.txt', 'utf-8');

  // Send a POST equivalent to this curl command.
  // The content of the file is contained in the request body.

  // curl -X POST --data-binary @[OBJECT] \
  //     -H "Authorization: Bearer [OAUTH2_TOKEN]" \
  //     -H "Content-Type: [OBJECT_CONTENT_TYPE]" \
  //     "https://www.googleapis.com/upload/storage/v1/b/[BUCKET_NAME]/o?uploadType=media&name=[OBJECT_NAME]"

  final http = CkHttp();
  http.authToken = sbToken.getAsString();

  // Create an XML document, and write it to a StringBuilder.
  // We'll be uploading this XML document.
  final xml = CkXml();
  xml.tag = 'note';
  xml.updateChildContent('to', 'Tove');
  xml.updateChildContent('from', 'Jani');
  xml.updateChildContent('heading', 'Reminder');
  xml.updateChildContent('body', 'Don\'t forget me this weekend!');

  // Write the XML to sbXml.
  final sbXml = CkStringBuilder();
  xml.getXmlSb(sbXml);

  // sbXml contains this:

  // <note>
  //     <to>Tove</to>
  //     <from>Jani</from>
  //     <heading>Reminder</heading>
  //     <body>Don't forget me this weekend!</body>
  // </note>

  // Construct a URL to upload to an object named "test.xml" in the "chilkat-ocean" bucket.
  http.setUrlVar('bucket_name', 'chilkat-ocean');
  http.setUrlVar('object_name', 'test.xml');
  final url = 'https://www.googleapis.com/upload/storage/v1/b/{\$bucket_name}/o?uploadType=media&name={\$object_name}';

  final resp = CkHttpResponse();
  try {
    http.httpSb('POST', url, sbXml, 'utf-8', 'application/xml', resp);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final responseCode = resp.statusCode;
  if (responseCode == 401) {
    print(resp.bodyStr);
    print('If invalid credentials, then it is likely the access token expired.');
    print('Your app should automatically fetch a new access token and re-try.');
    return;
  }

  print('Response code: $responseCode');
  print('Response body');
  print(resp.bodyStr);

  // A successful response looks like this:
  // Response code: 200
  // Response body
  // {
  //  "kind": "storage#object",
  //  "id": "chilkat-ocean/test.xml/1502669565429870",
  //  "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/test.xml",
  //  "name": "test.xml",
  //  "bucket": "chilkat-ocean",
  //  "generation": "1502669565429870",
  //  "metageneration": "1",
  //  "contentType": "application/xml",
  //  "timeCreated": "2017-08-14T00:12:45.379Z",
  //  "updated": "2017-08-14T00:12:45.379Z",
  //  "storageClass": "MULTI_REGIONAL",
  //  "timeStorageClassUpdated": "2017-08-14T00:12:45.379Z",
  //  "size": "181",
  //  "md5Hash": "TCR0L7TWsw2TzOvfNvgEfA==",
  //  "mediaLink": "https://www.googleapis.com/download/storage/v1/b/chilkat-ocean/o/test.xml?generation=1502669565429870&alt=media",
  //  "crc32c": "ZFd5sA==",
  //  "etag": "CO6Qpq241dUCEAE="
  // }
}