@RequiredArgsConstructor
public class CategoryImageViewerServlet extends HttpServlet {

	private final ManagedCrudService categoryImageDao;

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		Long imageId = Long.valueOf(request.getPathInfo().substring(1));
		categoryImageDao.inTransaction(session -> {
			//TODO: cache
			session.createSelectionQuery("from CategoryDetailEntity c where c.id = :cid", CategoryDetailEntity.class)
				.setParameter("cid", imageId)
				.setCacheable(true)
				.uniqueResultOptional()
				.ifPresent(categoryDetail -> {
					response.setContentType("image/jpg");
					response.setHeader("Content-disposition", String.format("inline; filename=\"%s.jpg\"", imageId));
					try (OutputStream os = response.getOutputStream(); InputStream is = categoryDetail.getImage().getBinaryStream()) {
						IOUtil.fastCopy(is, os);
					} catch (SQLException e) {
						throw new RuntimeException(e);
					} catch (IOException e) {
						throw new RuntimeException(e);
					}
				});
		});
	}
}