decryptFile method

@override FutureOr<File> decryptFile({ required File file, required String writeToDirectory, String moduleKey = defaultModuleKey, })

Implementation

@override
FutureOr<File> decryptFile({required File file, required String writeToDirectory, String moduleKey = defaultModuleKey}) async {
  bool isFileExist = await file.exists();
  if(!isFileExist){throw NUICryptoException(cause: NUICryptoError.FILE_TO_ENCRYPT_NOT_FOUND);}

  // file/path/to/image.jpg.encrypted -> image.jpg.encrypted
  String baseFilename = file.path.split('/').last;
  // image.jpg.encrypted -> "encrypted"
  String extension = baseFilename.split('.').last;

  // image.jpg.encrypted -> ["image","jpg","encrypted"]
  List<String> extensions = baseFilename.split('.');
  // [image","jpg","encrypted"] -> ["image","jpg"]
  extensions.removeLast();
  // ["image","jpg"] -> image.jpg
  String filename = extensions.join(".");

  if(extension != 'encrypted'){throw NUICryptoException(cause: NUICryptoError.FILE_TO_ENCRYPT_NOT_FOUND);}
  String writeTo = writeToDirectory + "${writeToDirectory.endsWith('/') ? "" : "/"}" + filename;

  //Info to pass into isolate
  if(!module.containsKey(moduleKey)){
    throw NUICryptoException(cause: NUICryptoError.KEY_NOT_FOUND);
  }

  final sink = File(writeTo).openWrite();

  try{
    final streamData = file.openRead();
    final decryptedStream = await _doDecryptionFile(streamData, module[moduleKey]!);
    await sink.addStream(decryptedStream);

  }on Exception catch(e){
    logNUI("NUICryptography in Flutter Isolate", "Encryption Exception ${e.toString()}");
    rethrow;
  }finally {
    sink.close();
    return File(writeTo);
  }
}