Method getObject returns the error 'NoSuchKey null: The specified key does not exist.'

[dthuesen]

I've tried every possible combination of providing required params.

I'm trying to download a previous version of a pdf file, which exists on the server with getObject. I have checked if the version exists and its versionId in the S3 Console on s3.console.aws.amazon.com. I am also able to list the versions in the ui of the app with use of the method listObjectVersions.

In the app and on S3 I use a prefix called teamId (name is an uuid) to structure the files.

When trying to download a version of a file the code looks like this:

Future<Uint8List?> getConsentByFileIdAndVersionId({
    required String fileId,
    required String versionId,
    required String teamId,
  }) async {
    GetObjectOutput? getObjectOutput;

    /// Access to the S3 instance via the singleton
    final s3Singleton = S3Singleton();
    await s3Singleton.initializeS3Client();
    final accessLevel = s3Singleton.defaultAccessLevel;
    final identityId = s3Singleton.identityId;

    final bucket = s3Singleton.bucket;

    /// These are the different attempts to get the 'key' working
    final keyParam = "$fileId";
    // final keyParam = "$teamId/$fileId";
    // final keyParam = "$identityId/$accessLevel/$teamId/$fileId";
    // final keyParam = "$accessLevel/$teamId/$fileId";
    
    log("keyParam: $keyParam", name: "StorageClient");
    if (bucket != null) {
      try {
        getObjectOutput = await s3Singleton.s3?.getObject(
          bucket: bucket,
          key: keyParam,
          versionId: versionId,
        );
        return getObjectOutput?.body;
      } on Exception catch (e, s) {
        log("EXCEPTION in getConsentByFileIdAndVersionId",
            error: e, stackTrace: s, name: "StorageClient");
        return null;
      }
    }
    return null;
  }

Properties mentioned in the code above:

• fileId is provided by the app, it separates files of different teams
• identityId consists of the region and an id given by s3 separated by a colon.
• accessLevel in the case of my app is 'private'
• identityId is taken from the file's list of versions in the ui and have checked it's existence

Following the code for the s3Singleton:

class S3Singleton {
  static final S3Singleton _singleton = S3Singleton._internal();
  S3? s3;
  String? region;
  String? bucket;
  String? defaultAccessLevel;
  String? identityId;

  factory S3Singleton() {
    return _singleton;
  }

  S3Singleton._internal();

  Future<S3?> initializeS3Client() async {
    AWSCredentials? awsCredentials;

    if (s3 == null) {
      awsCredentials = await fetchCognitoAuthSession();

      final Map<String, dynamic> amplifyConfig =
          jsonDecode(amplifyCofiguration.amplifyconfig);

      region =
          amplifyConfig["storage"]?["plugins"]["awsS3StoragePlugin"]["region"];
      bucket =
          amplifyConfig["storage"]?["plugins"]["awsS3StoragePlugin"]["bucket"];

      /// TODO: figure out how to change the default access level on S3.
      ///
      /// Since currently the default access level is configured to 'guest'
      /// and I currently have no clue to change that, it will stay here
      /// as hard coded value.
      defaultAccessLevel = 'private';
      // defaultAccessLevel = amplifyConfig["storage"]?["plugins"]
      //     ["awsS3StoragePlugin"]["defaultAccessLevel"];

      log("region: $region");
      log("awsCredentials: $awsCredentials");

      if (awsCredentials != null && region != null) {
        log("identityId: $identityId");
        final accessKey = awsCredentials.accessKeyId;
        final secretKey = awsCredentials.secretAccessKey;
        final expiration = awsCredentials.expiration;
        final sessionToken = awsCredentials.sessionToken;

        final s3Credentials = AwsClientCredentials(
          accessKey: accessKey,
          secretKey: secretKey,
          expiration: expiration,
          sessionToken: sessionToken,
        );
        s3 = S3(region: region!, credentials: s3Credentials);
        return s3;
      }
    }
    return s3;
  }

  Future<AWSCredentials?> fetchCognitoAuthSession() async {
    try {
      final cognitoPlugin =
          Amplify.Auth.getPlugin(AmplifyAuthCognito.pluginKey);

      final result = await cognitoPlugin.fetchAuthSession();
      identityId = result.identityIdResult.value;

      final AWSCredentials awsCredentials = result.credentialsResult.value;

      return awsCredentials;
    } on SessionExpiredException catch (e, s) {
      log('''
        
        SessionExpiredException in initializeS3Client, 
        recovery:            ${e.recoverySuggestion} 
        
        underlyingException: ${e.underlyingException}
                
        message:             ${e.message}
        ''', error: e, stackTrace: s, name: "StorageClient", level: 400);
      return null;
    } on AuthException catch (e) {
      safePrint('Error retrieving awsCredentials: ${e.message}');
      return null;
    }
  }
}

Since I've spent some days to get it running, I now try it here. Maybe this is an issue of the library.