GlobalMapperRegistry.java

/**
* 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.  
* <p>
*/ 

package org.olat.core.dispatcher.mapper;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.olat.core.dispatcher.Dispatcher;
import org.olat.core.dispatcher.DispatcherModule;
import org.olat.core.gui.media.MediaResource;
import org.olat.core.gui.media.NotFoundMediaResource;
import org.olat.core.gui.media.ServletUtil;
import org.olat.core.helpers.Settings;
import org.olat.core.logging.AssertException;
import org.olat.core.logging.OLATSecurityException;
import org.olat.core.util.WebappHelper;

/**
 * Description:<br>
 * Allows to register so called mappers. Here you can create urls which are valid for all users and will be dispatched to the given mapper.
 * If you need urls that are only accessible for one user, use MapperRegistry.java
 * <P>
 * Initial Date:  10.06.2005 <br>
 *
 * @author Felix Jost
 */
public class GlobalMapperRegistry implements Dispatcher {
	private static final MediaResource NOTFOUND = new NotFoundMediaResource("not found");
	private static final GlobalMapperRegistry INSTANCE = new GlobalMapperRegistry();
	
	// The global mapper hash map contains mappers:
	// keys: String objects representing the mapped path (derived from class name).
	// values: the mapper
	private Map<String, Mapper> pathToMapper = new HashMap<String, Mapper>();

	/**
	 * 
	 */
	private GlobalMapperRegistry() {
		// nothing to do
	}

	/**
	 * @return MapperRegistry
	 */
	public static GlobalMapperRegistry getInstance() {
		return INSTANCE;
	}

	/**
	 * Register a named global mapper. This mapper is registered at
	 * /g/globalname/
	 * @param globalNameClass class for the name of the mapper. the name of the mapper is the name of the class (including the package)
	 * @param mapper
	 * @return the path under which this mapper will be called, without / at the end, e.g. /olat/g/521org.olat.demo.tabledemo.MyController (the 521 here is the versionId to guarantee the uniqueness across releases to trick out buggy css browser caches)
	 */
	public String register(Class<?> globalNameClass, Mapper mapper) {
		String globalName = Settings.getBuildIdentifier()+globalNameClass.getName();
		if (pathToMapper.containsKey(globalName)) {
			throw new AssertException("Could not register global named mapper, name already used::" + globalName);
		}
		pathToMapper.put(globalName, mapper);
		return WebappHelper.getServletContextPath() + DispatcherModule.PATH_GLOBAL_MAPPED + globalName ;			
	}
	
	public String register(String relPath, Mapper mapper) {
		pathToMapper.put(relPath, mapper);
		return WebappHelper.getServletContextPath() + DispatcherModule.PATH_GLOBAL_MAPPED + relPath ;			
	}


	/**
	 * @param hreq
	 * @param hres
	 */
	@Override
	public void execute(HttpServletRequest hreq, HttpServletResponse hres) throws IOException {
		String pathInfo = DispatcherModule.subtractContextPath(hreq);
		// e.g. 23423/bla/blu.html
		String subInfo = pathInfo.substring(DispatcherModule.PATH_GLOBAL_MAPPED.length());
		int slashPos = subInfo.indexOf('/');
		if (slashPos == -1) {
			DispatcherModule.sendNotFound("not found", hres);
			return;
		}
		
		// smappath e.g. org.olat.demo.DemoController
		String smappath = subInfo.substring(0, slashPos);
		Mapper m = pathToMapper.get(smappath);

		MediaResource mr;
		if (m == null) { // not mapped
			mr = NOTFOUND;
		} else {
			String mod = subInfo.substring(slashPos);
			// brasato:: can this happen at all, or does tomcat filter out - till now never reached - needs some little cpu cycles
			if (mod.indexOf("..") != -1) throw new OLATSecurityException("mapper path contained '..' : " + mod);
			// /bla/blu.html
			mr = m.handle(mod, hreq);
		}
		ServletUtil.serveResource(hreq, hres, mr);
	}

	/**
	 * remove a registered mapper if it is no longer needed.
	 * @param mapper
	 */
	public void deregister(Mapper mapper) {
		boolean removed = pathToMapper.values().remove(mapper);
		if (!removed) throw new AssertException("trying to remove a mapper that was never registered");
	}

}