/*!
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This program 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 Lesser General Public License for more details.
*
* Copyright (c) 2002-2013 Pentaho Corporation.. All rights reserved.
*/
package org.pentaho.platform.web.servlet;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.pentaho.platform.api.engine.IPluginManager;
import org.pentaho.platform.api.engine.IPluginManagerListener;
import org.pentaho.platform.engine.core.system.PentahoSystem;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.ListableBeanFactory;
import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
/**
* Dispatches requests to Servlets provided by BIServer plugins. To define a Servlet in a plugin, simply add a bean
* element for the Servlet class in the plugin.spring.xml file in your plugin root directory.
*
* @author Aaron Phillips
*/
public class PluginDispatchServlet implements Servlet {
private static final Log logger = LogFactory.getLog( PluginDispatchServlet.class );
private ServletConfig servletConfig;
private boolean initialized = false;
private IPluginManager pluginManager = PentahoSystem.get( IPluginManager.class );
private Map<String, Servlet> pluginServletMap = new HashMap<String, Servlet>();
public PluginDispatchServlet() {
super();
}
public void destroy() {
for ( Map.Entry<String, Servlet> pluginServlet : pluginServletMap.entrySet() ) {
pluginServlet.getValue().destroy();
}
}
public void service( final ServletRequest req, final ServletResponse res ) throws ServletException, IOException {
if ( !initialized ) {
doInit();
}
if ( !( req instanceof HttpServletRequest ) ) {
throw new IllegalArgumentException( PluginDispatchServlet.class.getSimpleName()
+ " cannot handle non HTTP requests" ); //$NON-NLS-1$
}
HttpServletRequest request = (HttpServletRequest) req;
HttpServletResponse response = (HttpServletResponse) res;
Servlet pluginServlet = getTargetServlet( request, response );
if ( pluginServlet == null ) {
response.setStatus( 404 );
// FIXME: log more detail here for debugging
return;
}
pluginServlet.service( req, res );
}
protected Servlet getTargetServlet( HttpServletRequest request, HttpServletResponse response )
throws ServletException {
String dispatchKey = getDispatchKey( request );
if ( StringUtils.isEmpty( dispatchKey ) ) {
if ( logger.isDebugEnabled() ) {
logger
.debug( "dispatcher servlet is invoked but there is nothing telling it where to dispatch to" ); //$NON-NLS-1$
}
return null;
}
Servlet targetServlet = null;
String checkPath = dispatchKey;
do {
logger.debug(
"checking for servlet registered to service request for \"" + checkPath + "\"" ); //$NON-NLS-1$//$NON-NLS-2$
targetServlet = pluginServletMap.get( checkPath );
if ( targetServlet != null ) {
logger.debug( "servlet " + targetServlet.getClass().getName() + " will service request for \"" + dispatchKey
//$NON-NLS-1$//$NON-NLS-2$
+ "\"" ); //$NON-NLS-1$
return targetServlet;
}
if ( checkPath.contains( "/" ) ) { //$NON-NLS-1$
checkPath = checkPath.substring( 0, checkPath.lastIndexOf( "/" ) ); //$NON-NLS-1$
} else {
checkPath = null;
}
} while ( checkPath != null );
if ( targetServlet == null ) {
logger
.debug( "no servlet registered to service request for \"" + dispatchKey + "\"" ); //$NON-NLS-1$ //$NON-NLS-2$
}
return targetServlet;
}
/**
* Returns the dispatch key for this request. This name is the part of the request path beyond the servlet base path.
* I.e. if the PluginDispatchServlet is mapped to the "/plugin" context in web.xml, then this method will return
* "myPlugin/myServlet" given a request to "http://localhost:8080/pentaho/plugin/myPlugin/myServlet".
*
* @return the part of the request url used to dispatch the request
*/
public String getDispatchKey( HttpServletRequest request ) {
// path info will give us what we want with
String requestPathInfo = request.getPathInfo();
if ( requestPathInfo.startsWith( "/" ) ) { //$NON-NLS-1$
requestPathInfo = requestPathInfo.substring( 1 );
}
if ( requestPathInfo.endsWith( "/" ) ) { //$NON-NLS-1$
requestPathInfo = requestPathInfo.substring( requestPathInfo.length() );
}
return requestPathInfo;
}
public void init( final ServletConfig config ) throws ServletException {
this.servletConfig = config;
pluginManager.addPluginManagerListener( new IPluginManagerListener() {
@Override public void onReload() {
try {
initialized = false;
doInit();
} catch ( ServletException e ) {
logger.error( e );
}
}
} );
doInit();
}
@SuppressWarnings( "unchecked" )
/** Restore the caching once the Plugin Type Tracking system is in place, for now we'll look-up every time **/
private synchronized void doInit() throws ServletException {
if ( logger.isDebugEnabled() ) {
logger.debug( "PluginDispatchServlet.init" ); //$NON-NLS-1$
}
if ( initialized ) {
return;
}
pluginServletMap.clear();
Map<String, ListableBeanFactory> pluginBeanFactoryMap = getPluginBeanFactories();
for ( Map.Entry<String, ListableBeanFactory> pluginBeanFactoryEntry : pluginBeanFactoryMap.entrySet() ) {
Map<String, Servlet> beans =
BeanFactoryUtils.beansOfTypeIncludingAncestors( pluginBeanFactoryEntry.getValue(),
Servlet.class, true, true );
if ( logger.isDebugEnabled() ) {
logger.debug(
"found " + beans.size() + " servlets in " + pluginBeanFactoryEntry.getKey() ); //$NON-NLS-1$//$NON-NLS-2$
}
for ( Map.Entry<String, Servlet> beanEntry : beans.entrySet() ) {
Servlet pluginServlet = (Servlet) beanEntry.getValue();
String servletId = beanEntry.getKey();
String pluginId = pluginBeanFactoryEntry.getKey();
String context = pluginId + "/" + servletId; //$NON-NLS-1$
pluginServletMap.put( context, pluginServlet );
if ( logger.isDebugEnabled() ) {
logger
.debug( "calling init on servlet " + pluginServlet.getClass().getName() + " serving context "
+ context ); //$NON-NLS-1$//$NON-NLS-2$
}
try {
pluginServlet.init( servletConfig );
} catch ( Throwable t ) {
logger.error( "Could not load servlet '" + context + "'", t ); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
}
}
}
// Set initialized to true at the end of the synchronized method, so
// that invocations of service() before this method has completed will not
// cause NullPointerException
initialized = true;
}
public ServletConfig getServletConfig() {
return servletConfig;
}
public String getServletInfo() {
return "A servlet to dispatch requests to Servlets defined in BIServer plugins"; //$NON-NLS-1$
}
protected Map<String, ListableBeanFactory> getPluginBeanFactories() {
Collection<String> pluginIds = pluginManager.getRegisteredPlugins();
Map<String, ListableBeanFactory> pluginBeanFactoryMap = new HashMap<String, ListableBeanFactory>();
for ( String pluginId : pluginIds ) {
ListableBeanFactory beanFactory = pluginManager.getBeanFactory( pluginId );
if ( beanFactory != null ) {
pluginBeanFactoryMap.put( pluginId, beanFactory );
}
}
return pluginBeanFactoryMap;
}
}