content: /*
   * Copyright (C) 2013 Glyptodon LLC
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  
  package org.glyptodon.guacamole.net.basic.crud.connectiongroups;
  
  import java.io.IOException;
  import java.util.Set;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import javax.xml.stream.XMLOutputFactory;
  import javax.xml.stream.XMLStreamException;
  import javax.xml.stream.XMLStreamWriter;
  import org.glyptodon.guacamole.GuacamoleException;
  import org.glyptodon.guacamole.GuacamoleSecurityException;
  import org.glyptodon.guacamole.GuacamoleServerException;
  import org.glyptodon.guacamole.net.auth.ConnectionGroup;
  import org.glyptodon.guacamole.net.auth.Directory;
  import org.glyptodon.guacamole.net.auth.User;
  import org.glyptodon.guacamole.net.auth.UserContext;
  import org.glyptodon.guacamole.net.auth.permission.ConnectionPermission;
  import org.glyptodon.guacamole.net.auth.permission.ObjectPermission;
  import org.glyptodon.guacamole.net.auth.permission.Permission;
  import org.glyptodon.guacamole.net.auth.permission.SystemPermission;
  import org.glyptodon.guacamole.net.basic.AuthenticatingHttpServlet;
  
  /**
   * Simple HttpServlet which outputs XML containing a list of all authorized
   * connection groups for the current user.
   *
   * @author Michael Jumper
   */
  public class List extends AuthenticatingHttpServlet {
  
      /**
       * System administration permission.
       */
      private static final Permission SYSTEM_PERMISSION = 
                  new SystemPermission(SystemPermission.Type.ADMINISTER);
  
      
      /**
       * Checks whether the given user has permission to perform the given
       * object operation. Security exceptions are handled appropriately - only
       * non-security exceptions pass through.
       *
       * @param user The user whose permissions should be verified.
       * @param type The type of operation to check for permission for.
       * @param identifier The identifier of the connection the operation
       *                   would be performed upon.
       * @return true if permission is granted, false otherwise.
       *
       * @throws GuacamoleException If an error occurs while checking permissions.
       */
      private boolean hasConfigPermission(User user, ObjectPermission.Type type,
              String identifier)
      throws GuacamoleException {
  
          // Build permission
          Permission permission = new ConnectionPermission(
              type,
              identifier
          );
  
          try {
              // Return result of permission check, if possible
              return user.hasPermission(permission);
          }
          catch (GuacamoleSecurityException e) {
              // If cannot check due to security restrictions, no permission
              return false;
          }
  
      }
  
      /**
       * Writes the XML for the given connection group.
       * 
       * @param self The user whose permissions dictate the availability of the
       *             data written.
       * @param xml The XMLStremWriter to use when writing the data.
       * @param group The connection group whose XML representation will be
       *              written.
       * @throws GuacamoleException If an error occurs while reading the
       *                            requested data.
       * @throws XMLStreamException If an error occurs while writing the XML.
       */
      private void writeConnectionGroup(User self, XMLStreamWriter xml,
              ConnectionGroup group) throws GuacamoleException, XMLStreamException {
  
          // Write group 
          xml.writeStartElement("group");
          xml.writeAttribute("id", group.getIdentifier());
          xml.writeAttribute("name", group.getName());
  
          // Write group type
          switch (group.getType()) {
  
              case ORGANIZATIONAL:
                  xml.writeAttribute("type", "organizational");
                  break;
  
              case BALANCING:
                  xml.writeAttribute("type", "balancing");
                  break;
  
          }
  
          // Write contained connection groups
          writeConnectionGroups(self, xml, group.getConnectionGroupDirectory());
  
          // End of group
          xml.writeEndElement();
  
      }
  
      /**
       * Writes the XML for the given directory of connection groups.
       * 
       * @param self The user whose permissions dictate the availability of the
       *             data written.
       * @param xml The XMLStremWriter to use when writing the data.
       * @param directory The directory whose XML representation will be
       *                  written.
       * @throws GuacamoleException If an error occurs while reading the
       *                            requested data.
       * @throws XMLStreamException If an error occurs while writing the XML.
       */
      private void writeConnectionGroups(User self, XMLStreamWriter xml,
              Directory<String, ConnectionGroup> directory)
              throws GuacamoleException, XMLStreamException {
  
          // If no connections, write nothing
          Set<String> identifiers = directory.getIdentifiers();
          if (identifiers.isEmpty())
              return;
          
          // Begin connections
          xml.writeStartElement("groups");
  
          // For each entry, write corresponding connection element
          for (String identifier : identifiers) {
  
              // Write each group
              ConnectionGroup group = directory.get(identifier);
              writeConnectionGroup(self, xml, group);
  
          }
  
          // End connections
          xml.writeEndElement();
  
      }
  
      @Override
      protected void authenticatedService(
              UserContext context,
              HttpServletRequest request, HttpServletResponse response)
      throws GuacamoleException {
  
          // Do not cache
          response.setHeader("Cache-Control", "no-cache");
  
          // Write XML content type
          response.setHeader("Content-Type", "text/xml");
          
          // Set encoding
          response.setCharacterEncoding("UTF-8");
  
          // Get root group
          ConnectionGroup root = context.getRootConnectionGroup();
  
          // Write actual XML
          try {
  
              // Get self
              User self = context.self();
  
              XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
              XMLStreamWriter xml = outputFactory.createXMLStreamWriter(response.getWriter());
  
              // Write content of root group
              xml.writeStartDocument();
              writeConnectionGroup(self, xml, root);
              xml.writeEndDocument();
  
          }
          catch (XMLStreamException e) {
              throw new GuacamoleServerException(
                      "Unable to write connection group list XML.", e);
          }
          catch (IOException e) {
              throw new GuacamoleServerException(
                      "I/O error writing connection group list XML.", e);
          }
  
      }
  
  }
  
  