/**
* 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;
import org.apache.hadoop.gateway.audit.api.Action;
import org.apache.hadoop.gateway.audit.api.ActionOutcome;
import org.apache.hadoop.gateway.audit.api.AuditServiceFactory;
import org.apache.hadoop.gateway.audit.api.Auditor;
import org.apache.hadoop.gateway.audit.api.ResourceType;
import org.apache.hadoop.gateway.audit.log4j.audit.AuditConstants;
import org.apache.hadoop.gateway.descriptor.GatewayDescriptor;
import org.apache.hadoop.gateway.descriptor.GatewayDescriptorFactory;
import org.apache.hadoop.gateway.filter.AbstractGatewayFilter;
import org.apache.hadoop.gateway.i18n.messages.MessagesFactory;
import org.apache.hadoop.gateway.i18n.resources.ResourcesFactory;
import org.apache.hadoop.gateway.services.GatewayServices;
import javax.servlet.Filter;
import javax.servlet.FilterConfig;
import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URISyntaxException;
import java.util.Enumeration;
public class GatewayServlet implements Servlet {
public static final String GATEWAY_DESCRIPTOR_LOCATION_DEFAULT = "gateway.xml";
public static final String GATEWAY_DESCRIPTOR_LOCATION_PARAM = "gatewayDescriptorLocation";
private static final GatewayResources res = ResourcesFactory.get( GatewayResources.class );
private static final GatewayMessages LOG = MessagesFactory.get( GatewayMessages.class );
private static Auditor auditor = AuditServiceFactory.getAuditService()
.getAuditor( AuditConstants.DEFAULT_AUDITOR_NAME,
AuditConstants.KNOX_SERVICE_NAME, AuditConstants.KNOX_COMPONENT_NAME );
private FilterConfigAdapter filterConfig;
private volatile GatewayFilter filter;
public GatewayServlet( GatewayFilter filter ) {
this.filterConfig = null;
this.filter = filter;
}
public GatewayServlet() {
this( null );
}
public synchronized GatewayFilter getFilter() {
return filter;
}
public synchronized void setFilter( GatewayFilter filter ) throws ServletException {
Filter prev = filter;
if( filterConfig != null ) {
filter.init( filterConfig );
}
this.filter = filter;
if( prev != null && filterConfig != null ) {
prev.destroy();
}
}
@Override
public synchronized void init( ServletConfig servletConfig ) throws ServletException {
try {
if( filter == null ) {
filter = createFilter( servletConfig );
}
filterConfig = new FilterConfigAdapter( servletConfig );
if( filter != null ) {
filter.init( filterConfig );
}
} catch( ServletException e ) {
LOG.failedToInitializeServletInstace( e );
throw e;
} catch( RuntimeException e ) {
LOG.failedToInitializeServletInstace( e );
throw e;
}
}
@Override
public ServletConfig getServletConfig() {
return filterConfig.getServletConfig();
}
@Override
public void service( ServletRequest servletRequest, ServletResponse servletResponse ) throws ServletException, IOException {
GatewayFilter f = filter;
if( f != null ) {
try {
f.doFilter( servletRequest, servletResponse );
} catch( IOException e ) {
LOG.failedToExecuteFilter( e );
throw e;
} catch( ServletException e ) {
LOG.failedToExecuteFilter( e );
throw e;
}
} else {
((HttpServletResponse)servletResponse).setStatus( HttpServletResponse.SC_SERVICE_UNAVAILABLE );
}
String requestUri = (String)servletRequest.getAttribute( AbstractGatewayFilter.SOURCE_REQUEST_CONTEXT_URL_ATTRIBUTE_NAME );
int status = ((HttpServletResponse)servletResponse).getStatus();
auditor.audit( Action.ACCESS, requestUri, ResourceType.URI, ActionOutcome.SUCCESS, res.responseStatus( status ) );
}
@Override
public String getServletInfo() {
return res.gatewayServletInfo();
}
@Override
public synchronized void destroy() {
if( filter != null ) {
filter.destroy();
}
filter = null;
}
private static GatewayFilter createFilter( ServletConfig servletConfig ) throws ServletException {
GatewayFilter filter = null;
try {
InputStream stream = null;
String location = servletConfig.getInitParameter( GATEWAY_DESCRIPTOR_LOCATION_PARAM );
if( location != null ) {
stream = servletConfig.getServletContext().getResourceAsStream( location );
if( stream == null ) {
stream = servletConfig.getServletContext().getResourceAsStream( "/WEB-INF/" + location );
}
} else {
stream = servletConfig.getServletContext().getResourceAsStream( GATEWAY_DESCRIPTOR_LOCATION_DEFAULT );
}
if( stream != null ) {
try {
GatewayDescriptor descriptor = GatewayDescriptorFactory.load( "xml", new InputStreamReader( stream ) );
filter = GatewayFactory.create( descriptor );
} finally {
stream.close();
}
}
} catch( IOException e ) {
throw new ServletException( e );
} catch( URISyntaxException e ) {
throw new ServletException( e );
}
return filter;
}
private class FilterConfigAdapter implements FilterConfig {
private ServletConfig config;
private FilterConfigAdapter( ServletConfig config ) {
this.config = config;
}
private ServletConfig getServletConfig() {
return config;
}
@Override
public String getFilterName() {
return config.getServletName();
}
@Override
public ServletContext getServletContext() {
return config.getServletContext();
}
@Override
public String getInitParameter( String name ) {
return config.getInitParameter( name );
}
@Override
public Enumeration<String> getInitParameterNames() {
return config.getInitParameterNames();
}
}
}