Java tutorial
/** * Copyright (c) 2016, University of South Africa and/or its affiliates. All * rights reserved. DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE * HEADER. * * This code is free software; you can redistribute it and/or modify it under * the terms of the GNU General Public License version 2 only, as published by * the Free Software Foundation. * * This code 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 General Public License version 2 for more * details (a copy is included in the LICENSE file that accompanied this code). * * You should have received a copy of the GNU General Public License version 2 * along with this work; if not, write to the Free Software Foundation, Inc., 51 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * */ package za.co.eon.econtentsolutions.component.abstractlticomponent; import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.DatabaseMetaData; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.Properties; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.tsugi.Launch; import org.tsugi.Output; import org.tsugi.Tsugi; import org.tsugi.TsugiFactory; import org.tsugi.util.TsugiUtils; /** * AbstractLTIComponentServlet is the abstract base class for all servlet * component contexts. * * @author Quintin De Clercq * @version %I%, %G% * @since 1.0 * */ public class AbstractLTIComponentServlet extends HttpServlet { private Log log = LogFactory.getLog(AbstractLTIComponentServlet.class); private Tsugi tsugi = null; /** * Processes requests for both HTTP <code>GET</code> and <code>POST</code> * methods. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try (PrintWriter out = response.getWriter()) { Launch launch = tsugi.getLaunch(request, response); if (launch.isComplete()) { launch.getOutput().flashSuccess("LTI Launch validated and redirected"); log.info("LTI Launch validated and redirected..."); return; } if (!launch.isValid()) { out.println("<pre>"); out.println("Launch is not valid but nowhere to redirect"); out.println(launch.getErrorMessage()); out.println("Base String:"); out.println(launch.getBaseString()); out.println("</pre>"); out.close(); throw new RuntimeException(launch.getErrorMessage()); } HttpSession session = request.getSession(); Output o = launch.getOutput(); Properties versions = o.header(out); o.bodyStart(out); o.flashMessages(out); // out.println("<pre>"); // Dump out some stuff from the Request Object out.println(""); out.println( "<a href=\"http://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServletRequest.html\" target=\"_blank\">HttpServletRequest</a> data:"); out.println("req.getRequestURL()=" + request.getRequestURL()); out.println("req.getMethod()=" + request.getMethod()); out.println("req.getServletPath()=" + request.getServletPath()); out.println("req.getPathInfo()=" + request.getPathInfo()); out.println("req.getQueryString()=" + request.getQueryString()); out.println(""); out.print("<a href=\""); out.print(launch.getGetUrl(null) + "/zap"); out.println("\">Click here to see if we stay logged in with a GET</a>"); out.println(""); out.println( "Using the <a href=\"http://csev.github.io/tsugi-java/apidocs/index.html\" target=\"_blank\">Tsugi API</a>:"); out.println("Content Title: " + launch.getContext().getTitle()); out.println("Context Settings: " + launch.getContext().getSettings().getSettingsJson()); out.println("User Email: " + launch.getUser().getEmail()); out.println("isInstructor()=" + launch.getUser().isInstructor()); out.println("isTenantAdmin()=" + launch.getUser().isTenantAdmin()); out.println("Link Title: " + launch.getLink().getTitle()); out.println("Link Settings: " + launch.getLink().getSettings().getSettingsJson()); out.println("Sourcedid: " + launch.getResult().getSourceDID()); out.println("Service URL: " + launch.getService().getURL()); out.println(""); out.println("JavaScript library versions:"); out.println(TsugiUtils.dumpProperties(versions)); out.println(""); out.println("Using the provided JDBC connection:"); Connection c = null; try { c = launch.getConnection(); out.println("Connection: " + c); DatabaseMetaData meta = c.getMetaData(); String productName = meta.getDatabaseProductName(); String productVersion = meta.getDatabaseProductVersion(); String URL = meta.getURL(); out.println("Connection product=" + productName + " version=" + productVersion); out.println("Connection URL=" + URL); } catch (Exception ex) { log.error("Unable to get connection metadata", ex); out.println("Unable to get connection metadata:" + ex.getMessage()); } // Do a simple query just to see how it is done if (c != null) { Statement stmt = null; String query = "SELECT plugin_id, plugin_path FROM lms_plugins;"; try { stmt = c.createStatement(); ResultSet rs = stmt.executeQuery(query); int num = 0; while (rs.next()) { String plugin_path = rs.getString("plugin_path"); out.println("plugin_path=" + plugin_path); num++; } out.println("Successfully read " + num + " rows from the database"); } catch (SQLException e) { out.println("Problems reading database"); out.println("INSERT INTO mjjs (name) VALUES ('tsugi');"); e.printStackTrace(); } } // Cheat and look at the internal data Tsugi maintains - this depends on // the JDBC implementation Properties sess_row = (Properties) session.getAttribute("lti_row"); if (sess_row != null) { out.println(""); out.println("Tsugi-managed internal session data (Warning: org.tsugi.impl.jdbc.Tsugi_JDBC only)"); String x = TsugiUtils.dumpProperties(sess_row); out.println(x); } out.println("</pre>"); // Do the Footer o.footerStart(out); out.println("<!-- App footer stuff goes here -->"); o.footerEnd(out); out.close(); } catch (RuntimeException re) { try (PrintWriter out = response.getWriter()) { /* TODO output your page here. You may use following sample code. */ out.println("<!DOCTYPE html>"); out.println("<html>"); out.println("<head>"); out.println("<title>AbstractLTIComponentServlet Error</title>"); out.println("</head>"); out.println("<body>"); out.println("<h1>AbstractLTIComponentServlet</h1>"); out.println("<h3 style=\"color: red;\">Error</h3>"); out.println("<p>Servlet AbstractLTIComponentServlet at " + request.getContextPath() + " threw an exception.</p>"); out.println("<p>Exception: " + re.toString() + "<br />"); out.println("Message: " + re.getMessage() + "<br />"); out.println("Stacktrace:</p>"); out.println("<p>" + re.getStackTrace().toString() + "</p>"); out.println("</body>"); out.println("</html>"); } } } // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code."> /** * Handles the HTTP <code>GET</code> method. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } /** * Handles the HTTP <code>POST</code> method. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } /** * Returns a short description of the servlet. * * @return a String containing servlet description */ @Override public String getServletInfo() { return "Short description"; } /** * Initializes the servlet for use with the Tsugi LTI wrapper. * * @param config servlet configuration * @throws ServletException if a servlet-specific error occurs */ @Override public void init(ServletConfig config) throws ServletException { super.init(config); if (tsugi == null) { tsugi = TsugiFactory.getTsugi(); } System.out.println("Tsugi init=" + tsugi); }// </editor-fold> }