Java tutorial
/** * OLAT - Online Learning and Training<br> * http://www.olat.org * <p> * Licensed under the Apache License, Version 2.0 (the "License"); <br> * you may not use this file except in compliance with the License.<br> * You may obtain a copy of the License at * <p> * http://www.apache.org/licenses/LICENSE-2.0 * <p> * Unless required by applicable law or agreed to in writing,<br> * software distributed under the License is distributed on an "AS IS" BASIS, <br> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. <br> * See the License for the specific language governing permissions and <br> * limitations under the License. * <p> * Copyright (c) since 2004 at Multimedia- & E-Learning Services (MELS),<br> * University of Zurich, Switzerland. * <hr> * <a href="http://www.openolat.org"> * OpenOLAT - Online Learning and Training</a><br> * This file has been modified by the OpenOLAT community. Changes are licensed * under the Apache 2.0 license as the original file. */ package org.olat.commons.servlets; import java.io.Writer; import java.util.Date; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.pdfbox.io.IOUtils; import org.olat.basesecurity.Authentication; import org.olat.basesecurity.BaseSecurityManager; import org.olat.commons.rss.RSSUtil; import org.olat.core.commons.persistence.DBFactory; import org.olat.core.commons.services.notifications.PersonalRSSFeed; import org.olat.core.dispatcher.DispatcherModule; import org.olat.core.id.Identity; import org.olat.core.logging.OLog; import org.olat.core.logging.Tracing; import org.olat.core.util.i18n.I18nManager; import com.sun.syndication.feed.synd.SyndFeed; import com.sun.syndication.io.FeedException; import com.sun.syndication.io.SyndFeedOutput; /** * Description:<BR> * Servlet that produces a personalized RSS feed of the users notifications. * <P> * Initial Date: Jan 11, 2005 2004 * * @author Florian Gngi */ public class RSSServlet extends HttpServlet { private static final long serialVersionUID = -674630331334472714L; private static final OLog log = Tracing.createLoggerFor(RSSServlet.class); public static final String DEFAULT_ENCODING = "UTF-8"; private static int outputBufferSize = 2048; private static int inputBufferSize = 2048; /** * @see javax.servlet.Servlet#init(javax.servlet.ServletConfig) */ public void init(ServletConfig servletConfig) throws ServletException { super.init(servletConfig); log.info("init statics servlet"); try { String bufSize = servletConfig.getInitParameter("input"); inputBufferSize = Integer.parseInt(bufSize); bufSize = servletConfig.getInitParameter("output"); outputBufferSize = Integer.parseInt(bufSize); } catch (Exception e) { log.warn("problem with config parameters for rss servlets:", e); } log.info("input buffer size: " + inputBufferSize); log.info("output buffer size: " + outputBufferSize); } /** * @see javax.servlet.http.HttpServlet#service(javax.servlet.http.HttpServletRequest, * javax.servlet.http.HttpServletResponse) */ protected void service(HttpServletRequest req, HttpServletResponse resp) { Tracing.setUreq(req); I18nManager.attachI18nInfoToThread(req); try { String method = req.getMethod(); if (method.equals("GET")) { doGet(req, resp); } else { super.service(req, resp); } } catch (Exception e) { log.error("Exception while serving RSS feed::" + req.getPathInfo(), e); } finally { I18nManager.remove18nInfoFromThread(); // consume the user request. Tracing.setUreq(null); } } /** * @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest, * javax.servlet.http.HttpServletResponse) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) { SyndFeed feed = null; Writer writer = null; try { String pathInfo = request.getPathInfo(); if ((pathInfo == null) || (pathInfo.equals(""))) { return; // error } // pathInfo is like /personal/username/tokenid.rss if (pathInfo.indexOf(RSSUtil.RSS_PREFIX_PERSONAL) == 0) { feed = getPersonalFeed(pathInfo); if (feed == null) { DispatcherModule.sendNotFound(pathInfo, response); return; } } else { DispatcherModule.sendNotFound(pathInfo, response); return; } // OLAT-5400 and OLAT-5243 related: sending back the reply can take arbitrary long, // considering slow end-user connections for example - or a sudden death of the connection // on the client-side which remains unnoticed (network partitioning) DBFactory.getInstance().intermediateCommit(); response.setBufferSize(outputBufferSize); String encoding = feed.getEncoding(); if (encoding == null) { encoding = DEFAULT_ENCODING; if (log.isDebug()) { log.debug("Feed encoding::" + encoding); } log.warn("No encoding provided by feed::" + feed.getClass().getCanonicalName() + " Using utf-8 as default."); } response.setCharacterEncoding(encoding); response.setContentType("application/rss+xml"); Date pubDate = feed.getPublishedDate(); if (pubDate != null) { response.setDateHeader("Last-Modified", pubDate.getTime()); } // TODO:GW Do we need this? // response.setContentLength(feed.get); writer = response.getWriter(); SyndFeedOutput output = new SyndFeedOutput(); output.output(feed, writer); } catch (FeedException e) { // throw olat exception for nice logging log.warn("Error when generating RSS stream for path::" + request.getPathInfo(), e); DispatcherModule.sendNotFound("none", response); } catch (Exception e) { log.warn("Unknown Exception in rssservlet", e); DispatcherModule.sendNotFound("none", response); } catch (Error e) { log.warn("Unknown Error in rssservlet", e); DispatcherModule.sendNotFound("none", response); } finally { IOUtils.closeQuietly(writer); DBFactory.getInstance(false).commitAndCloseSession(); } } /** * Creates a personal RSS document * * @param pathInfo * @return RssDocument */ private SyndFeed getPersonalFeed(String pathInfo) { // pathInfo is like /personal/username/tokenid/olat.rss int startIdName = RSSUtil.RSS_PREFIX_PERSONAL.length(); int startIdToken = pathInfo.indexOf("/", RSSUtil.RSS_PREFIX_PERSONAL.length()); String idName = pathInfo.substring(startIdName, startIdToken); int startUselessUri = pathInfo.indexOf("/", startIdToken + 1); String idToken = pathInfo.substring(startIdToken + 1, startUselessUri); // ---- check integrity and user authentication ---- if (idName == null || idName.equals("")) { return null; } Identity identity = BaseSecurityManager.getInstance().findIdentityByName(idName); if (identity == null) { // error - abort return null; } // check if this is a valid authentication Authentication auth = BaseSecurityManager.getInstance().findAuthentication(identity, RSSUtil.RSS_AUTH_PROVIDER); if (auth == null) { // error, rss authentication not yet set. user must login first, then the // auth provider will be generated on the fly return null; } if (!auth.getCredential().equals(idToken)) { // error - wrong authentication return null; } // create rss feed for user notifications return new PersonalRSSFeed(identity); } }