manager/src/main/java/org/eclipse/app4mc/cloud/manager/storage/FileSystemStorageService.java

/*********************************************************************************
 * Copyright (c) 2020 Robert Bosch GmbH and others.
 *
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     Robert Bosch GmbH - initial API and implementation
 ********************************************************************************
 */
package org.eclipse.app4mc.cloud.manager.storage;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Comparator;
import java.util.stream.Stream;

import org.springframework.core.io.Resource;
import org.springframework.core.io.UrlResource;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

@Service
public class FileSystemStorageService implements StorageService {

	private static final String TEMP_DIR_PREFIX = "app4mc_mgr_";
	
	private final String defaultBaseDir = System.getProperty("java.io.tmpdir");
	private final Path tempLocation = Paths.get(defaultBaseDir);
	
	@Override
	public String store(MultipartFile file) {
		try {
			if (file.isEmpty()) {
				throw new StorageException("Failed to store empty file " + file.getOriginalFilename());
			}
			Path path = Files.createTempDirectory(TEMP_DIR_PREFIX);
			
			// extract uuid from pathname
			String uuid = path.toString().substring(path.toString().lastIndexOf('_') + 1);
			
			Files.copy(file.getInputStream(), path.resolve(file.getOriginalFilename()));
			
			return uuid;
		} catch (IOException e) {
			throw new StorageException("Failed to store file " + file.getOriginalFilename(), e);
		}
	}

	@Override
	public Stream<Path> loadAll() {
		try {
			return Files.walk(this.tempLocation, 1)
					.filter(path -> !path.equals(this.tempLocation))
					.filter(path -> path.getFileName().toString().startsWith(TEMP_DIR_PREFIX))
					.map(path -> this.tempLocation.relativize(path));
		} catch (IOException e) {
			throw new StorageException("Failed to read stored files", e);
		}

	}

	@Override
	public Path load(String uuid, String... path) {
		Path result = this.tempLocation.resolve(TEMP_DIR_PREFIX + uuid);
		for (String p : path) {
			result = result.resolve(p);
		}
		return result;
	}

	@Override
	public Resource loadAsResource(String uuid, String... path) {
		Path file = load(uuid, path);
		try {
			Resource resource = new UrlResource(file.toUri());
			if (resource.exists() || resource.isReadable()) {
				return resource;
			}
			else {
				throw new StorageFileNotFoundException("Could not read file: " + file);
			}
		} catch (MalformedURLException e) {
			throw new StorageFileNotFoundException("Could not read file: " + file, e);
		}
	}

	@Override
	public void delete(String uuid) {
		Path path = load(uuid);
		try {
			Files.walk(path)
				.sorted(Comparator.reverseOrder())
				.map(java.nio.file.Path::toFile)
				.forEach(File::delete);
		} catch (IOException e) {
			throw new StorageFileNotFoundException("Could not delete: " + path);
		}
	}
	
	@Override
	public void deleteAll() {
//		loadAll().forEach(path -> FileSystemUtils.deleteRecursively(path.toFile()));
		loadAll().forEach(System.out::println);
	}
}