Dart

Get Object MetaData from Google Cloud Storage

See more Google Cloud Storage Examples

Demonstrates how to download a Google Cloud Storage object's metadata. 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 GET equivalent to this curl command.

  // curl -X GET \
  //     -H "Authorization: Bearer [OAUTH2_TOKEN]" \
  //     -o "[SAVE_TO_LOCATION]" \
  //     "https://www.googleapis.com/storage/v1/b/[BUCKET_NAME]/o/[OBJECT_NAME]?projection=full"

  final http = CkHttp();

  http.authToken = sbToken.getAsString();

  // Construct a URL to download the metadata for the object named "starfish.jpg" located in the "chilkat-ocean" bucket.
  http.setUrlVar('bucket_name', 'chilkat-ocean');
  http.setUrlVar('object_name', 'starfish.jpg');
  final url = 'https://www.googleapis.com/storage/v1/b/{\$bucket_name}/o/{\$object_name}?projection=full';

  // If there is an error response, then we didn't actually download the metadata,
  // but instead we downloaded an error response..
  final sbMetaData = CkStringBuilder();
  try {
    http.downloadSb(url, 'utf-8', sbMetaData);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  final responseCode = http.lastStatus;
  if (responseCode == 401) {
    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.');
  }

  if (responseCode != 200) {
    print('Error response code = $responseCode');
    print('Error:');
    print(sbMetaData.getAsString());
    return;
  }

  print(sbMetaData.getAsString());
  print('Success.');

  // Sample output:

  // {
  //  "kind": "storage#object",
  //  "id": "chilkat-ocean/starfish.jpg/1502670320090292",
  //  "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg",
  //  "name": "starfish.jpg",
  //  "bucket": "chilkat-ocean",
  //  "generation": "1502670320090292",
  //  "metageneration": "1",
  //  "contentType": "image/jpeg",
  //  "timeCreated": "2017-08-14T00:25:20.040Z",
  //  "updated": "2017-08-14T00:25:20.040Z",
  //  "storageClass": "MULTI_REGIONAL",
  //  "timeStorageClassUpdated": "2017-08-14T00:25:20.040Z",
  //  "size": "6229",
  //  "md5Hash": "LpxZ2/JmI2fcl9/dqF2gSA==",
  //  "mediaLink": "https://www.googleapis.com/download/storage/v1/b/chilkat-ocean/o/starfish.jpg?generation=1502670320090292&alt=media",
  //  "acl": [
  //   {
  //    "kind": "storage#objectAccessControl",
  //    "id": "chilkat-ocean/starfish.jpg/1502670320090292/project-owners-933037264567",
  //    "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg/acl/project-owners-933037264567",
  //    "bucket": "chilkat-ocean",
  //    "object": "starfish.jpg",
  //    "generation": "1502670320090292",
  //    "entity": "project-owners-933037264567",
  //    "role": "OWNER",
  //    "projectTeam": {
  //     "projectNumber": "933037264567",
  //     "team": "owners"
  //    },
  //    "etag": "CLT5kpW71dUCEAE="
  //   },
  //   {
  //    "kind": "storage#objectAccessControl",
  //    "id": "chilkat-ocean/starfish.jpg/1502670320090292/project-editors-933037264567",
  //    "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg/acl/project-editors-933037264567",
  //    "bucket": "chilkat-ocean",
  //    "object": "starfish.jpg",
  //    "generation": "1502670320090292",
  //    "entity": "project-editors-933037264567",
  //    "role": "OWNER",
  //    "projectTeam": {
  //     "projectNumber": "933037264567",
  //     "team": "editors"
  //    },
  //    "etag": "CLT5kpW71dUCEAE="
  //   },
  //   {
  //    "kind": "storage#objectAccessControl",
  //    "id": "chilkat-ocean/starfish.jpg/1502670320090292/project-viewers-933037264567",
  //    "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg/acl/project-viewers-933037264567",
  //    "bucket": "chilkat-ocean",
  //    "object": "starfish.jpg",
  //    "generation": "1502670320090292",
  //    "entity": "project-viewers-933037264567",
  //    "role": "READER",
  //    "projectTeam": {
  //     "projectNumber": "933037264567",
  //     "team": "viewers"
  //    },
  //    "etag": "CLT5kpW71dUCEAE="
  //   },
  //   {
  //    "kind": "storage#objectAccessControl",
  //    "id": "chilkat-ocean/starfish.jpg/1502670320090292/user-starfish@chilkat-176611.iam.gserviceaccount.com",
  //    "selfLink": "https://www.googleapis.com/storage/v1/b/chilkat-ocean/o/starfish.jpg/acl/user-starfish@chilkat-176611.iam.gserviceaccount.com",
  //    "bucket": "chilkat-ocean",
  //    "object": "starfish.jpg",
  //    "generation": "1502670320090292",
  //    "entity": "user-starfish@chilkat-176611.iam.gserviceaccount.com",
  //    "role": "OWNER",
  //    "email": "starfish@chilkat-176611.iam.gserviceaccount.com",
  //    "etag": "CLT5kpW71dUCEAE="
  //   }
  //  ],
  //  "owner": {
  //   "entity": "user-starfish@chilkat-176611.iam.gserviceaccount.com"
  //  },
  //  "crc32c": "9RjgwQ==",
  //  "etag": "CLT5kpW71dUCEAE="
  // }
  // 
}