001    //$HeadURL: svn+ssh://jwilden@svn.wald.intevation.org/deegree/base/branches/2.5_testing/src/org/deegree/enterprise/servlet/RedirectServlet.java $
002    /*----------------------------------------------------------------------------
003     This file is part of deegree, http://deegree.org/
004     Copyright (C) 2001-2009 by:
005       Department of Geography, University of Bonn
006     and
007       lat/lon GmbH
008    
009     This library is free software; you can redistribute it and/or modify it under
010     the terms of the GNU Lesser General Public License as published by the Free
011     Software Foundation; either version 2.1 of the License, or (at your option)
012     any later version.
013     This library is distributed in the hope that it will be useful, but WITHOUT
014     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
015     FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
016     details.
017     You should have received a copy of the GNU Lesser General Public License
018     along with this library; if not, write to the Free Software Foundation, Inc.,
019     59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
020    
021     Contact information:
022    
023     lat/lon GmbH
024     Aennchenstr. 19, 53177 Bonn
025     Germany
026     http://lat-lon.de/
027    
028     Department of Geography, University of Bonn
029     Prof. Dr. Klaus Greve
030     Postfach 1147, 53001 Bonn
031     Germany
032     http://www.geographie.uni-bonn.de/deegree/
033    
034     e-mail: info@deegree.org
035    ----------------------------------------------------------------------------*/
036    
037    package org.deegree.enterprise.servlet;
038    
039    import static org.deegree.framework.log.LoggerFactory.getLogger;
040    
041    import java.io.IOException;
042    import java.util.Enumeration;
043    import java.util.TreeMap;
044    
045    import javax.servlet.ServletConfig;
046    import javax.servlet.ServletException;
047    import javax.servlet.ServletRequest;
048    import javax.servlet.ServletResponse;
049    import javax.servlet.http.HttpServlet;
050    import javax.servlet.http.HttpServletRequest;
051    import javax.servlet.http.HttpServletResponse;
052    
053    import org.deegree.framework.log.ILogger;
054    
055    /**
056     * To configure the <code>RedirectServlet</code>, have the tomcat match everything (/*) for this
057     * servlet. Add the following init parameters:
058     *
059     * <ul>
060     * <li>defaultLocation: set it to the location to be used if no rule matches</li>
061     * <li>rule&lt;xxx&gt: set the value to a String to match, followed by ",", followed by
062     * the String to replace it with</li>
063     * </ul>
064     *
065     * Using a log4j logging level of debug will output all redirections that take place.
066     *
067     * @author <a href="mailto:schmitz@lat-lon.de">Andreas Schmitz</a>
068     * @author last edited by: $Author: mschneider $
069     *
070     * @version $Revision: 18195 $, $Date: 2009-06-18 17:55:39 +0200 (Do, 18 Jun 2009) $
071     */
072    public class RedirectServlet extends HttpServlet {
073    
074        private static final long serialVersionUID = -8507813259962496365L;
075    
076        private static final ILogger LOG = getLogger( RedirectServlet.class );
077    
078        private ServletConfig config;
079    
080        private TreeMap<String, String> redirections;
081    
082        private TreeMap<String, String> redirectionOrder;
083    
084        private String defaultLocation;
085    
086        @Override
087        public void destroy() {
088            config = null;
089        }
090    
091        @Override
092        public ServletConfig getServletConfig() {
093            return config;
094        }
095    
096        @Override
097        public String getServletInfo() {
098            return "Simple redirection servlet";
099        }
100    
101        @Override
102        public void init( ServletConfig config )
103                                throws ServletException {
104            this.config = config;
105            redirections = new TreeMap<String, String>();
106            redirectionOrder = new TreeMap<String, String>();
107    
108            Enumeration<?> enumer = config.getInitParameterNames();
109            while ( enumer.hasMoreElements() ) {
110                String name = (String) enumer.nextElement();
111                if ( name.equalsIgnoreCase( "defaultlocation" ) ) {
112                    defaultLocation = config.getInitParameter( name );
113                }
114    
115                if ( name.toLowerCase().startsWith( "rule" ) ) {
116                    String[] r = config.getInitParameter( name ).split( "," );
117                    redirections.put( r[0], r[1] );
118                    redirectionOrder.put( name.toLowerCase(), r[0] );
119                    if ( LOG.isDebug() ) {
120                        LOG.logDebug( "Adding rule " + r[0] + " -> " + r[1] );
121                    }
122                }
123            }
124    
125            if ( defaultLocation == null ) {
126                LOG.logWarning( "No default location given. I hope your rules match all possible URLs." );
127            }
128        }
129    
130        @Override
131        public void service( ServletRequest request, ServletResponse response )
132                                throws ServletException, IOException {
133            HttpServletRequest r = (HttpServletRequest) request;
134    
135            String req = r.getRequestURL().toString() + ( r.getQueryString() == null ? "" : ( "?" + r.getQueryString() ) );
136    
137            String location = defaultLocation;
138    
139            // use the first match
140            for ( String rule : redirectionOrder.keySet() ) {
141                String p = redirectionOrder.get( rule );
142                if ( req.indexOf( p ) != -1 ) {
143                    LOG.logDebug( "Rule with key " + p + " matches." );
144                    location = req.replace( p, redirections.get( p ) );
145                    break;
146                }
147            }
148    
149            if ( LOG.isDebug() ) {
150                LOG.logDebug( "Redirecting " + req + " to " + location );
151            }
152    
153            // do the redirect
154            HttpServletResponse httpResponse = ( (HttpServletResponse) response );
155            httpResponse.setHeader( "Location", location );
156            httpResponse.setStatus( 302 );
157        }
158    
159    }