HelperAwareJsfTool.java

/**********************************************************************************
* $URL:https://source.sakaiproject.org/svn/osp/trunk/common/tool-lib/src/java/org/theospi/portfolio/shared/control/servlet/HelperAwareJsfTool.java $
* $Id:HelperAwareJsfTool.java 9134 2006-05-08 20:28:42Z chmaurer@iupui.edu $
***********************************************************************************
*
 * Copyright (c) 2005, 2006, 2007, 2008 The Sakai Foundation
 *
 * Licensed under the Educational Community 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.opensource.org/licenses/ECL-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 org.sakaiproject.jsf.util;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.sakaiproject.jsf.util.JsfTool;
import org.sakaiproject.tool.api.ActiveTool;
import org.sakaiproject.tool.api.Tool;
import org.sakaiproject.tool.api.ToolException;
import org.sakaiproject.tool.api.ToolSession;
import org.sakaiproject.tool.cover.ActiveToolManager;
import org.sakaiproject.tool.cover.SessionManager;
import org.sakaiproject.util.Web;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Enumeration;

/**
 * Created by IntelliJ IDEA.
 * User: John Ellis
 * Date: Nov 11, 2005
 * Time: 4:17:18 PM
 * To change this template use File | Settings | File Templates.
 */
public class HelperAwareJsfTool extends JsfTool {

  private static Log M_log = LogFactory.getLog(HelperAwareJsfTool.class);

  private static final String HELPER_EXT = ".helper";

  private static final String HELPER_SESSION_PREFIX = "session.";
  
  /** the alternate next view */
  public static final String ALTERNATE_DONE_URL = "altDoneURL";

  /** the set of alternate views */
  public static final String ALTERNATE_DONE_URL_MAP = "altDoneURLSet";

   protected void dispatch(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException
   {
      // NOTE: this is a simple path dispatching, taking the path as the view id = jsp file name for the view,
      //       with default used if no path and a path prefix as configured.
      // TODO: need to allow other sorts of dispatching, such as pulling out drill-down ids and making them
      //       available to the JSF

      // build up the target that will be dispatched to
      String target = req.getPathInfo();

      // see if we have a helper request
    if (sendToHelper(req, res, target)) {
       return;
    }

      // see if we have a resource request - i.e. a path with an extension, and one that is not the JSF_EXT
      if (isResourceRequest(target))
      {
         // get a dispatcher to the path
         RequestDispatcher resourceDispatcher = getServletContext().getRequestDispatcher(target);
         if (resourceDispatcher != null)
         {
            resourceDispatcher.forward(req, res);
            return;
         }
      }

      if ("Title".equals(req.getParameter("panel")))
      {
         // This allows only one Title JSF for each tool
         target = "/title.jsf";
      }

      else
      {
         ToolSession session = SessionManager.getCurrentToolSession();

         if (target == null || "/".equals(target) || target.length() == 0)
         {
            if (!m_defaultToLastView) {
               // make sure tool session is clean
               session.clearAttributes();
            }

            target = computeDefaultTarget();

            // make sure it's a valid path
            if (!target.startsWith("/"))
            {
               target = "/" + target;
            }

            // now that we've messed with the URL, send a redirect to make it official
            res.sendRedirect(Web.returnUrl(req, target));
            return;
         }

         // see if we want to change the specifically requested view
         String newTarget = redirectRequestedTarget(target);

         // make sure it's a valid path
         if (!newTarget.startsWith("/"))
         {
            newTarget = "/" + newTarget;
         }

         if (!newTarget.equals(target))
         {
            // now that we've messed with the URL, send a redirect to make it official
            res.sendRedirect(Web.returnUrl(req, newTarget));
            return;
         }
         target = newTarget;

         // store this
         session.setAttribute(LAST_VIEW_VISITED, target);
      }

      // add the configured folder root and extension (if missing)
      target = m_path + target;

      // add the default JSF extension (if we have no extension)
      int lastSlash = target.lastIndexOf("/");
      int lastDot = target.lastIndexOf(".");
      if (lastDot < 0 || lastDot < lastSlash)
      {
         target += JSF_EXT;
      }

      // set the information that can be removed from return URLs
      req.setAttribute(URL_PATH, m_path);
      req.setAttribute(URL_EXT, JSF_FACELETS_EXT);

      // set the sakai request object wrappers to provide the native, not Sakai set up, URL information
      // - this assures that the FacesServlet can dispatch to the proper view based on the path info
      req.setAttribute(Tool.NATIVE_URL, Tool.NATIVE_URL);

      // TODO: Should setting the HTTP headers be moved up to the portal level as well?
      res.setContentType("text/html; charset=UTF-8");
      res.addDateHeader("Expires", System.currentTimeMillis() - (1000L * 60L * 60L * 24L * 365L));
      res.addDateHeader("Last-Modified", System.currentTimeMillis());
      res.addHeader("Cache-Control", "no-store, no-cache, must-revalidate, max-age=0, post-check=0, pre-check=0");
      res.addHeader("Pragma", "no-cache");

      // dispatch to the target
      M_log.debug("dispatching path: " + req.getPathInfo() + " to: " + target + " context: "
              + getServletContext().getServletContextName());
      RequestDispatcher dispatcher = getServletContext().getRequestDispatcher(target);
      dispatcher.forward(req, res);

      // restore the request object
      req.removeAttribute(Tool.NATIVE_URL);
      req.removeAttribute(URL_PATH);
      req.removeAttribute(URL_EXT);
   }

  protected boolean sendToHelper(HttpServletRequest req, HttpServletResponse res, String target) {
    String path = req.getPathInfo();
    if (path == null) path = "/";

    // 0 parts means the path was just "/", otherwise parts[0] = "", parts[1] = item id, parts[2] if present is "edit"...
    String[] parts = path.split("/");

    if (parts.length < 2) {
       return false;
    }

    if (!parts[1].endsWith(HELPER_EXT)) {
       return false;
    }

    ToolSession toolSession = SessionManager.getCurrentToolSession();

    Enumeration params = req.getParameterNames();
    while (params.hasMoreElements()) {
       String paramName = (String)params.nextElement();
       if (paramName.startsWith(HELPER_SESSION_PREFIX)) {
          String attributeName = paramName.substring(HELPER_SESSION_PREFIX.length());
          toolSession.setAttribute(attributeName, req.getParameter(paramName));
       }
    }

    // calc helper id
    int posEnd = parts[1].lastIndexOf(".");

    String helperId = target.substring(1, posEnd + 1);
    ActiveTool helperTool = ActiveToolManager.getActiveTool(helperId);

    //get the current location (if one doesn't exist) and save it for when we return from the helper
    if (toolSession.getAttribute(helperTool.getId() + Tool.HELPER_DONE_URL) == null && !target.equals("/sakai.filepicker.helper")) {
       toolSession.setAttribute(helperTool.getId() + Tool.HELPER_DONE_URL,
             req.getContextPath() + req.getServletPath() + computeDefaultTarget(true));
    }
    toolSession.setAttribute(helperTool.getId() + "thetoolPath",
          req.getContextPath() + req.getServletPath());

    
    // saves the alternate done url map into a tool specific attribute
    if (toolSession.getAttribute(helperTool.getId() + ALTERNATE_DONE_URL) == null) {
       toolSession.setAttribute(helperTool.getId() + ALTERNATE_DONE_URL,
             toolSession.getAttribute(ALTERNATE_DONE_URL));
       toolSession.setAttribute(helperTool.getId() + ALTERNATE_DONE_URL_MAP,
             toolSession.getAttribute(ALTERNATE_DONE_URL_MAP));
       toolSession.removeAttribute(ALTERNATE_DONE_URL);
       toolSession.removeAttribute(ALTERNATE_DONE_URL_MAP);
    }


/*comment out for using the global parameter rather than tool-by-tool setting
    SessionState state = UsageSessionService.getSessionState(toolSession.getPlacementId());
		boolean show_other_sites = ServerConfigurationService.getBoolean("syllabus.resources.show_all_collections.helper", true);
		state.setAttribute("resources.allow_user_to_see_all_sites", (new Boolean(show_other_sites)).toString());
		state.setAttribute("resources.user_chooses_to_see_other_sites", (new Boolean(show_other_sites)).toString());
*/
    String context = req.getContextPath() + req.getServletPath() + Web.makePath(parts, 1, 2);
    String toolPath = Web.makePath(parts, 2, parts.length);
     try {
        helperTool.help(req, res, context, toolPath);
     }
     catch (ToolException e) {
        throw new RuntimeException(e);
     }

     return true; // was handled as helper call
  }

  protected String computeDefaultTarget(boolean lastVisited)
  {
     // setup for the default view as configured
     String target = "/" + m_default;

     // if we are doing lastVisit and there's a last-visited view, for this tool placement / user, use that
     if (lastVisited)
     {
        ToolSession session = SessionManager.getCurrentToolSession();
        String last = (String) session.getAttribute(LAST_VIEW_VISITED);
        if (last != null)
        {
           target = last;
        }
     }

     return target;
  }
}