Java tutorial
/** * This file Copyright (c) 2003-2012 Magnolia International * Ltd. (http://www.magnolia-cms.com). All rights reserved. * * * This file is dual-licensed under both the Magnolia * Network Agreement and the GNU General Public License. * You may elect to use one or the other of these licenses. * * This file is distributed in the hope that it will be * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the * implied warranty of MERCHANTABILITY or FITNESS FOR A * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT. * Redistribution, except as permitted by whichever of the GPL * or MNA you select, is prohibited. * * 1. For the GPL license (GPL), you can redistribute and/or * modify this file under the terms of the GNU General * Public License, Version 3, as published by the Free Software * Foundation. You should have received a copy of the GNU * General Public License, Version 3 along with this program; * if not, write to the Free Software Foundation, Inc., 51 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * 2. For the Magnolia Network Agreement (MNA), this file * and the accompanying materials are made available under the * terms of the MNA which accompanies this distribution, and * is available at http://www.magnolia-cms.com/mna.html * * Any modifications to this file must keep this entire header * intact. * */ package info.magnolia.module.files; import info.magnolia.cms.core.Content; import info.magnolia.cms.core.HierarchyManager; import info.magnolia.cms.core.NodeData; import info.magnolia.cms.util.ContentUtil; import info.magnolia.cms.util.NodeDataUtil; import org.apache.commons.codec.binary.Hex; import javax.jcr.RepositoryException; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.security.DigestInputStream; import java.security.DigestOutputStream; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; /** * A FileExtractorOperation which checks extracted files against an MD5 checksum * stored in the repository. If the checksum does not exist or is identical to the * file being extracted, the file is extracted and potentially overwrites the * existing one. If not, which means the file was modified by the user, * the operation is cancelled. * * TODO : what to do with removed files ? should probably be the responsibility of a different Task. * * * @author gjoseph * @version $Revision: $ ($Author: $) */ class MD5CheckingFileExtractorOperation extends BasicFileExtractorOperation { private final FileExtractionLogger log; private final HierarchyManager hm; MD5CheckingFileExtractorOperation(FileExtractionLogger log, HierarchyManager hm, String resourcePath, String absoluteTargetPath) { super(resourcePath, absoluteTargetPath); this.log = log; this.hm = hm; } @Override protected InputStream checkInput() throws IOException { return wrap(super.checkInput()); } // TODO : behaviour: overwrite, log, backup, .. ? @Override protected File checkOutput() throws IOException { final File out = super.checkOutput(); if (out.exists()) { // check md5 of the existing file final InputStream stream = new FileInputStream(out); final String existingFileMD5 = calculateMD5(stream); // check repository md5 final NodeData repoMD5prop = getRepositoryNode().getNodeData("md5"); if (repoMD5prop.isExist()) { final String repoMD5 = repoMD5prop.getString(); if (existingFileMD5.equals(repoMD5)) { // resourcePath was found, with correct md5 in repo : repoMD5 return out; } log.error("Can't extract " + resourcePath + " as this file was probably modified locally: expected MD5 [" + repoMD5 + "] but current MD5 is [" + existingFileMD5 + "]."); return null; } // resourcePath was found, but no md5 found in repo ... } else { // resourcePath does not exist yet, extracting ... } return out; } @Override protected OutputStream openOutput(File outFile) throws IOException { final OutputStream outputStream = super.openOutput(outFile); final MessageDigest md5 = getMessageDigest(); return new DigestOutputStream(outputStream, md5); } @Override protected void copyAndClose(InputStream in, OutputStream out) throws IOException { super.copyAndClose(in, out); final DigestInputStream md5Stream = (DigestInputStream) in; final String newMD5 = retrieveMD5(md5Stream); try { NodeDataUtil.getOrCreate(getRepositoryNode(), "md5").setValue(newMD5); } catch (RepositoryException e) { throw new RuntimeException(e); // TODO } //TODO save .. ? } protected Content getRepositoryNode() { try { final String repoPath = getRepositoryPath(resourcePath); final Content node; if (!hm.isExist(repoPath)) { node = ContentUtil.createPath(hm, repoPath); } else { node = hm.getContent(repoPath); } return node; } catch (RepositoryException e) { throw new RuntimeException(e); // TODO } } /** * Returns the path to the node that has the property with this resource's MD5. * TODO : implement properly + test */ protected String getRepositoryPath(String resourcePath) { return "/server/install" + resourcePath; } /** * Completely reads an InputStream and returns its MD5. * TODO : should we close it? */ protected String calculateMD5(InputStream stream) throws IOException { final DigestInputStream md5Stream = wrap(stream); byte[] buffer = new byte[1024]; while (md5Stream.read(buffer) != -1) { } return retrieveMD5(md5Stream); } protected DigestInputStream wrap(InputStream stream) { final MessageDigest md5 = getMessageDigest(); return new DigestInputStream(stream, md5); } protected String retrieveMD5(DigestInputStream md5Stream) { final byte[] digInBytes = md5Stream.getMessageDigest().digest(); return String.valueOf(Hex.encodeHex(digInBytes)); } protected MessageDigest getMessageDigest() { try { return MessageDigest.getInstance("MD5"); } catch (NoSuchAlgorithmException e) { throw new RuntimeException("Can't check files with md5: " + e.getMessage(), e); } } }