/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache 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.apache.org/licenses/LICENSE-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.apache.hadoop.gateway.filter.rewrite.api;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import org.apache.hadoop.gateway.filter.rewrite.i18n.UrlRewriteMessages;
import org.apache.hadoop.gateway.i18n.messages.MessagesFactory;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.MalformedURLException;
import java.net.URL;
public class UrlRewriteServletContextListener implements ServletContextListener {
public static final String PROCESSOR_ATTRIBUTE_NAME = UrlRewriteProcessor.class.getName();
public static final String DESCRIPTOR_LOCATION_INIT_PARAM_NAME = "rewriteDescriptorLocation";
public static final String DESCRIPTOR_DEFAULT_FILE_NAME = "rewrite.xml";
public static final String DESCRIPTOR_DEFAULT_LOCATION = "/WEB-INF/" + DESCRIPTOR_DEFAULT_FILE_NAME;
private static final UrlRewriteMessages LOG = MessagesFactory.get( UrlRewriteMessages.class );
@Override
public void contextInitialized( ServletContextEvent event ) {
UrlRewriteRulesDescriptor descriptor = null;
try {
URL url = locateDescriptor( event.getServletContext() );
descriptor = loadDescriptor( url );
} catch( IOException e ) {
throw new IllegalStateException( e );
}
ServletContext context = event.getServletContext();
UrlRewriteEnvironment environment = new UrlRewriteServletEnvironment( context );
UrlRewriteProcessor processor = new UrlRewriteProcessor();
processor.initialize( environment, descriptor );
event.getServletContext().setAttribute( PROCESSOR_ATTRIBUTE_NAME, processor );
}
@Override
public void contextDestroyed( ServletContextEvent event ) {
UrlRewriteProcessor processor =
(UrlRewriteProcessor)event.getServletContext().getAttribute( PROCESSOR_ATTRIBUTE_NAME );
event.getServletContext().removeAttribute( PROCESSOR_ATTRIBUTE_NAME );
if( processor != null ) {
processor.destroy();
}
}
public static UrlRewriter getUrlRewriter( ServletContext context ) {
return ((UrlRewriteProcessor)context.getAttribute( PROCESSOR_ATTRIBUTE_NAME ));
}
private static URL locateDescriptor( ServletContext context ) throws IOException {
String param = context.getInitParameter( DESCRIPTOR_LOCATION_INIT_PARAM_NAME );
if( param == null ) {
param = DESCRIPTOR_DEFAULT_LOCATION;
}
URL url;
try {
url = context.getResource( param );
} catch( MalformedURLException e ) {
// Ignore it and try using the value directly as a URL.
url = null;
}
if( url == null ) {
url = new URL( param );
}
if( url == null ) {
throw new FileNotFoundException( param );
}
return url;
}
private static UrlRewriteRulesDescriptor loadDescriptor( URL url ) throws IOException {
InputStream stream = url.openStream();
Reader reader = new InputStreamReader( stream, "UTF-8" );
UrlRewriteRulesDescriptor descriptor = UrlRewriteRulesDescriptorFactory.load( "xml", reader );
try {
reader.close();
} catch( IOException closeException ) {
LOG.failedToLoadRewriteRulesDescriptor( closeException );
}
return descriptor;
}
}