Java tutorial
/* * This library is part of OpenCms - * the Open Source Content Management System * * Copyright (c) Alkacon Software GmbH (http://www.alkacon.com) * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * For further information about Alkacon Software GmbH, please see the * company website: http://www.alkacon.com * * For further information about OpenCms, please see the * project website: http://www.opencms.org * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package org.opencms.file.history; import org.opencms.file.CmsObject; import org.opencms.file.CmsResource; import org.opencms.file.CmsResourceFilter; import org.opencms.file.Messages; import org.opencms.main.CmsException; import org.opencms.main.CmsLog; import org.opencms.main.CmsResourceInitException; import org.opencms.main.I_CmsResourceInit; import org.opencms.util.CmsRequestUtil; import java.util.Map; import javax.servlet.ServletRequest; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.logging.Log; /** * Resource init handler that loads historical versions of resources.<p> * * @since 6.9.1 */ public class CmsHistoryResourceHandler implements I_CmsResourceInit { /** Constant for the historical version request attribute name. */ public static final String ATTRIBUTE_NAME = "org.opencms.file.history.CmsHistoryResourceHandler"; /** The historical version handler path. */ public static final String HISTORY_HANDLER = "/system/shared/showversion"; /** Request parameter name for the version number. */ public static final String PARAM_VERSION = "version"; /** Constant for the offline project version. */ public static final int PROJECT_OFFLINE_VERSION = Integer.MAX_VALUE; /** The static log object for this class. */ private static final Log LOG = CmsLog.getLog(CmsHistoryResourceHandler.class); /** * Returns the historical version of a resource, * if the given request is displaying a history version.<p> * * @param req the request to check * * @return the historical resource if the given request is displaying an historical version */ public static I_CmsHistoryResource getHistoryResource(ServletRequest req) { return (I_CmsHistoryResource) req.getAttribute(ATTRIBUTE_NAME); } /** * Appends the <code>version</code> parameter to the URI if needed.<p> * * @param uri the resource URI * @param req the current request * * @return the same URI, with additional parameters in case of a historical request */ public static String getHistoryResourceURI(String uri, ServletRequest req) { String histUri = uri; if (CmsHistoryResourceHandler.isHistoryRequest(req)) { String version = req.getParameter(CmsHistoryResourceHandler.PARAM_VERSION); histUri = CmsRequestUtil.appendParameter(uri, CmsHistoryResourceHandler.PARAM_VERSION, version); } return histUri; } /** * Returns the correct resource for the given URI, taken into account historical versions * marked by the <code>version</code> parameter.<p> * * @param cms the current CMS context * @param resourceUri the resource URI * * @return the resource, which can be an instance of {@link org.opencms.file.history.I_CmsHistoryResource} * * @throws CmsException if something goes wrong */ public static CmsResource getResourceWithHistory(CmsObject cms, String resourceUri) throws CmsException { CmsResource resource = null; if (resourceUri.contains(CmsRequestUtil.URL_DELIMITER)) { int pos = resourceUri.indexOf(CmsRequestUtil.URL_DELIMITER); Map<String, String[]> params = CmsRequestUtil.createParameterMap(resourceUri.substring(pos)); if (params.containsKey(CmsHistoryResourceHandler.PARAM_VERSION)) { int version = Integer.parseInt(params.get(CmsHistoryResourceHandler.PARAM_VERSION)[0]); String sitemapPath = resourceUri.substring(0, pos); resource = cms.readResource(sitemapPath); resource = (CmsResource) cms.readResource(resource.getStructureId(), version); } } if (resource == null) { resource = cms.readResource(resourceUri); } return resource; } /** * Returns <code>true</code> if the given request is displaying an historical version.<p> * * @param req the request to check * * @return <code>true</code> if the given request is displaying a historical version */ public static boolean isHistoryRequest(ServletRequest req) { return (null != req.getAttribute(ATTRIBUTE_NAME)); } /** * @see org.opencms.main.I_CmsResourceInit#initResource(org.opencms.file.CmsResource, org.opencms.file.CmsObject, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) */ public CmsResource initResource(CmsResource resource, CmsObject cms, HttpServletRequest req, HttpServletResponse res) throws CmsResourceInitException { // we only have to check for history resources if the handler was called // during a real request and NOT during a dummy-request while doing // a static export if (req != null) { String uri = cms.getRequestContext().getUri(); // check if the resource starts with the HISTORY_HANDLER if (uri.startsWith(HISTORY_HANDLER)) { String version = req.getParameter(PARAM_VERSION); // only do something if the resource was not found and there was a "versionid" parameter included if ((resource == null) && (version != null)) { // test if the current user is allowed to read historical versions of resources // this can be done by trying to read the history handler resource if (cms.existsResource(HISTORY_HANDLER)) { String storedSiteRoot = cms.getRequestContext().getSiteRoot(); try { // we now must switch to the root site to read the history resource cms.getRequestContext().setSiteRoot("/"); // extract the "real" resourcename uri = uri.substring(HISTORY_HANDLER.length(), uri.length()); int id = new Integer(version).intValue(); if (id == CmsHistoryResourceHandler.PROJECT_OFFLINE_VERSION) { resource = new CmsHistoryFile( cms.readFile(uri, CmsResourceFilter.IGNORE_EXPIRATION)); } else { // get the current resource CmsResource currRes = cms.readResource(uri, CmsResourceFilter.IGNORE_EXPIRATION); // get the historical version of the resource CmsHistoryFile hisRes = (CmsHistoryFile) cms.readResource( cms.readResource(uri, CmsResourceFilter.IGNORE_EXPIRATION).getStructureId(), id); // the resource root path is not changed after the resource is moved or renamed // change the resource root path to current root path, so e.g. properties can be read if necessary if (!currRes.getRootPath().equals(hisRes.getRootPath())) { resource = new CmsHistoryFile(hisRes.getPublishTag(), hisRes.getStructureId(), hisRes.getResourceId(), currRes.getRootPath(), hisRes.getTypeId(), hisRes.getFlags(), hisRes.getProjectLastModified(), hisRes.getState(), hisRes.getDateCreated(), hisRes.getUserCreated(), hisRes.getDateLastModified(), hisRes.getUserLastModified(), hisRes.getDateReleased(), hisRes.getDateExpired(), hisRes.getLength(), hisRes.getDateContent(), hisRes.getVersion(), hisRes.getParentId(), null, hisRes.getResourceVersion(), hisRes.getStructureVersion()); } else { resource = hisRes; } } if (res != null) { // store a request attribute to indicate that this is in fact a historical version req.setAttribute(ATTRIBUTE_NAME, resource); } } catch (CmsException e) { if (LOG.isErrorEnabled()) { LOG.error(Messages.get().getBundle().key(Messages.ERR_HISTORYRESOURCE_2, uri, version)); } throw new CmsResourceInitException( Messages.get().container(Messages.ERR_SHOWVERSION_2, uri, version), e); } finally { // restore the siteroot and modify the uri to the one of the correct resource cms.getRequestContext().setSiteRoot(storedSiteRoot); if (resource != null) { // resource may be null in case of an error cms.getRequestContext().setUri(cms.getSitePath(resource)); } } } } } } return resource; } }