javadev / pt-backend

@Service

class ExerciseImageService {

    private static final String BASE64_PREFIX = ";base64,";

    private static final int BASE64_PREFIX_LENGTH = 8;

    private final ExerciseFileRepository exerciseFileRepository;

    ExerciseImageService(ExerciseFileRepository exerciseFileRepository) {

        this.exerciseFileRepository = exerciseFileRepository;

    }

            throws IOException {

        final ExerciseFile exerciseFile = exerciseFileRepository.findById(id).orElse(null);

        if (exerciseFile == null) {

            throw new ResourceNotFoundException("File with id " + id + " not found");

        }

        dataUrlToOutputStream(exerciseFile.getData_url(), outputStream);

        return new ExerciseImageDTO()

                .setId(exerciseFile.getId())

                .setFileName(exerciseFile.getFile_name())

                .setFileType(exerciseFile.getFile_type());

    }

    void dataUrlToOutputStream(String dataUrl, OutputStream outputStream) throws IOException {

        final String encodedString =

                dataUrl.substring(dataUrl.indexOf(BASE64_PREFIX) + BASE64_PREFIX_LENGTH);

        outputStream.write(Base64.getDecoder().decode(encodedString));