com.thinkberg.webdav.LockHandler.java Source code

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Here is the source code for com.thinkberg.webdav.LockHandler.java

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/*
 * Copyright 2007 Matthias L. Jugel.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.thinkberg.webdav;

import com.thinkberg.webdav.lock.Lock;
import com.thinkberg.webdav.lock.LockConflictException;
import com.thinkberg.webdav.lock.LockManager;
import com.thinkberg.webdav.vfs.VFSBackend;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.vfs.FileObject;
import org.dom4j.*;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.net.URL;
import java.text.ParseException;
import java.util.Iterator;
import java.util.List;

/**
 * Handle WebDAV LOCK requests.
 *
 * @author Matthias L. Jugel
 * @version $Id$
 */
public class LockHandler extends WebdavHandler {
    private static final Log LOG = LogFactory.getLog(LockHandler.class);

    private static final String TAG_LOCKSCOPE = "lockscope";
    private static final String TAG_LOCKTYPE = "locktype";
    private static final String TAG_OWNER = "owner";
    private static final String TAG_HREF = "href";
    private static final String TAG_PROP = "prop";
    private static final String TAG_LOCKDISCOVERY = "lockdiscovery";

    private static final String HEADER_LOCK_TOKEN = "Lock-Token";

    public void service(HttpServletRequest request, HttpServletResponse response) throws IOException {
        FileObject object = VFSBackend.resolveFile(request.getPathInfo());

        try {
            final LockManager manager = LockManager.getInstance();
            final LockManager.EvaluationResult evaluation = manager.evaluateCondition(object, getIf(request));
            if (!evaluation.result) {
                response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED);
                return;
            } else {
                if (!evaluation.locks.isEmpty()) {
                    LOG.debug(String.format("discovered locks: %s", evaluation.locks));
                    sendLockAcquiredResponse(response, evaluation.locks.get(0));
                    return;
                }
            }
        } catch (LockConflictException e) {
            List<Lock> locks = e.getLocks();
            for (Lock lock : locks) {
                if (Lock.EXCLUSIVE.equals(lock.getType())) {
                    response.sendError(SC_LOCKED);
                    return;
                }
            }
        } catch (ParseException e) {
            response.sendError(HttpServletResponse.SC_PRECONDITION_FAILED);
            return;
        }

        try {
            SAXReader saxReader = new SAXReader();
            Document lockInfo = saxReader.read(request.getInputStream());
            //log(lockInfo);

            Element rootEl = lockInfo.getRootElement();
            String lockScope = null, lockType = null;
            Object owner = null;
            Iterator elIt = rootEl.elementIterator();
            while (elIt.hasNext()) {
                Element el = (Element) elIt.next();
                if (TAG_LOCKSCOPE.equals(el.getName())) {
                    lockScope = el.selectSingleNode("*").getName();
                } else if (TAG_LOCKTYPE.equals(el.getName())) {
                    lockType = el.selectSingleNode("*").getName();
                } else if (TAG_OWNER.equals(el.getName())) {
                    // TODO correctly handle owner
                    Node subEl = el.selectSingleNode("*");
                    if (subEl != null && TAG_HREF.equals(subEl.getName())) {
                        owner = new URL(el.selectSingleNode("*").getText());
                    } else {
                        owner = el.getText();
                    }
                }
            }

            LOG.debug("LOCK(" + lockType + ", " + lockScope + ", " + owner + ")");

            Lock requestedLock = new Lock(object, lockType, lockScope, owner, getDepth(request),
                    getTimeout(request));
            try {
                LockManager.getInstance().acquireLock(requestedLock);
                sendLockAcquiredResponse(response, requestedLock);
            } catch (LockConflictException e) {
                response.sendError(SC_LOCKED);
            } catch (IllegalArgumentException e) {
                response.sendError(HttpServletResponse.SC_BAD_REQUEST);
            }
        } catch (DocumentException e) {
            e.printStackTrace();
            response.sendError(HttpServletResponse.SC_BAD_REQUEST);
        }
    }

    private void sendLockAcquiredResponse(HttpServletResponse response, Lock lock) throws IOException {
        if (!lock.getObject().exists()) {
            response.setStatus(SC_CREATED);
        }
        response.setContentType("text/xml");
        response.setCharacterEncoding("UTF-8");
        response.setHeader(HEADER_LOCK_TOKEN, "<" + lock.getToken() + ">");

        Document propDoc = DocumentHelper.createDocument();
        Element propEl = propDoc.addElement(TAG_PROP, "DAV:");
        Element lockdiscoveryEl = propEl.addElement(TAG_LOCKDISCOVERY);

        lock.serializeToXml(lockdiscoveryEl);

        XMLWriter xmlWriter = new XMLWriter(response.getWriter());
        xmlWriter.write(propDoc);

        logXml(propDoc);
    }

    protected void logXml(Node element) {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        try {
            XMLWriter xmlWriter = new XMLWriter(bos, OutputFormat.createPrettyPrint());
            xmlWriter.write(element);
            LOG.debug(bos.toString());
        } catch (IOException e) {
            LOG.debug("ERROR writing XML log: " + e.getMessage());
        }
    }
}