src/java/org/eclipse/jetty/servlets/BalancerServlet.java - platform/external/jetty - Git at Google

 //
 //  ========================================================================
 //  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
 //  ------------------------------------------------------------------------
 //  All rights reserved. This program and the accompanying materials
 //  are made available under the terms of the Eclipse Public License v1.0
 //  and Apache License v2.0 which accompanies this distribution.
 //
 //      The Eclipse Public License is available at
 //      http://www.eclipse.org/legal/epl-v10.html
 //
 //      The Apache License v2.0 is available at
 //      http://www.opensource.org/licenses/apache2.0.php
 //
 //  You may elect to redistribute this code under either of these licenses.
 //  ========================================================================
 //

 package org.eclipse.jetty.servlets;

 import java.net.MalformedURLException;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicInteger;

 import javax.servlet.ServletConfig;
 import javax.servlet.ServletException;
 import javax.servlet.UnavailableException;
 import javax.servlet.http.Cookie;
 import javax.servlet.http.HttpServletRequest;

 import org.eclipse.jetty.http.HttpURI;
 import org.eclipse.jetty.server.Request;

 /**
  * 6
  */
 public class BalancerServlet extends ProxyServlet
 {

     private static final class BalancerMember
     {

         private String _name;

         private String _proxyTo;

         private HttpURI _backendURI;

         public BalancerMember(String name, String proxyTo)
         {
             super();
             _name = name;
             _proxyTo = proxyTo;
             _backendURI = new HttpURI(_proxyTo);
         }

         public String getProxyTo()
         {
             return _proxyTo;
         }

         public HttpURI getBackendURI()
         {
             return _backendURI;
         }

         @Override
         public String toString()
         {
             return "BalancerMember [_name=" + _name + ", _proxyTo=" + _proxyTo + "]";
         }

         @Override
         public int hashCode()
         {
             final int prime = 31;
             int result = 1;
             result = prime * result + ((_name == null)?0:_name.hashCode());
             return result;
         }

         @Override
         public boolean equals(Object obj)
         {
             if (this == obj)
                 return true;
             if (obj == null)
                 return false;
             if (getClass() != obj.getClass())
                 return false;
             BalancerMember other = (BalancerMember)obj;
             if (_name == null)
             {
                 if (other._name != null)
                     return false;
             }
             else if (!_name.equals(other._name))
                 return false;
             return true;
         }

     }

     private static final class RoundRobinIterator implements Iterator<BalancerMember>
     {

         private BalancerMember[] _balancerMembers;

         private AtomicInteger _index;

         public RoundRobinIterator(Collection<BalancerMember> balancerMembers)
         {
             _balancerMembers = (BalancerMember[])balancerMembers.toArray(new BalancerMember[balancerMembers.size()]);
             _index = new AtomicInteger(-1);
         }

         public boolean hasNext()
         {
             return true;
         }

         public BalancerMember next()
         {
             BalancerMember balancerMember = null;
             while (balancerMember == null)
             {
                 int currentIndex = _index.get();
                 int nextIndex = (currentIndex + 1) % _balancerMembers.length;
                 if (_index.compareAndSet(currentIndex,nextIndex))
                 {
                     balancerMember = _balancerMembers[nextIndex];
                 }
             }
             return balancerMember;
         }

         public void remove()
         {
             throw new UnsupportedOperationException();
         }

     }

     private static final String BALANCER_MEMBER_PREFIX = "BalancerMember.";

     private static final List<String> FORBIDDEN_CONFIG_PARAMETERS;
     static
     {
         List<String> params = new LinkedList<String>();
         params.add("HostHeader");
         params.add("whiteList");
         params.add("blackList");
         FORBIDDEN_CONFIG_PARAMETERS = Collections.unmodifiableList(params);
     }

     private static final List<String> REVERSE_PROXY_HEADERS;
     static
     {
         List<String> params = new LinkedList<String>();
         params.add("Location");
         params.add("Content-Location");
         params.add("URI");
         REVERSE_PROXY_HEADERS = Collections.unmodifiableList(params);
     }

     private static final String JSESSIONID = "jsessionid";

     private static final String JSESSIONID_URL_PREFIX = JSESSIONID + "=";

     private boolean _stickySessions;

     private Set<BalancerMember> _balancerMembers = new HashSet<BalancerMember>();

     private boolean _proxyPassReverse;

     private RoundRobinIterator _roundRobinIterator;

     @Override
     public void init(ServletConfig config) throws ServletException
     {
         validateConfig(config);
         super.init(config);
         initStickySessions(config);
         initBalancers(config);
         initProxyPassReverse(config);
         postInit();
     }

     private void validateConfig(ServletConfig config) throws ServletException
     {
         @SuppressWarnings("unchecked")
         List<String> initParameterNames = Collections.list(config.getInitParameterNames());
         for (String initParameterName : initParameterNames)
         {
             if (FORBIDDEN_CONFIG_PARAMETERS.contains(initParameterName))
             {
                 throw new UnavailableException(initParameterName + " not supported in " + getClass().getName());
             }
         }
     }

     private void initStickySessions(ServletConfig config) throws ServletException
     {
         _stickySessions = "true".equalsIgnoreCase(config.getInitParameter("StickySessions"));
     }

     private void initBalancers(ServletConfig config) throws ServletException
     {
         Set<String> balancerNames = getBalancerNames(config);
         for (String balancerName : balancerNames)
         {
             String memberProxyToParam = BALANCER_MEMBER_PREFIX + balancerName + ".ProxyTo";
             String proxyTo = config.getInitParameter(memberProxyToParam);
             if (proxyTo == null || proxyTo.trim().length() == 0)
             {
                 throw new UnavailableException(memberProxyToParam + " parameter is empty.");
             }
             _balancerMembers.add(new BalancerMember(balancerName,proxyTo));
         }
     }

     private void initProxyPassReverse(ServletConfig config)
     {
         _proxyPassReverse = "true".equalsIgnoreCase(config.getInitParameter("ProxyPassReverse"));
     }

     private void postInit()
     {
         _roundRobinIterator = new RoundRobinIterator(_balancerMembers);
     }

     private Set<String> getBalancerNames(ServletConfig config) throws ServletException
     {
         Set<String> names = new HashSet<String>();
         @SuppressWarnings("unchecked")
         List<String> initParameterNames = Collections.list(config.getInitParameterNames());
         for (String initParameterName : initParameterNames)
         {
             if (!initParameterName.startsWith(BALANCER_MEMBER_PREFIX))
             {
                 continue;
             }
             int endOfNameIndex = initParameterName.lastIndexOf(".");
             if (endOfNameIndex <= BALANCER_MEMBER_PREFIX.length())
             {
                 throw new UnavailableException(initParameterName + " parameter does not provide a balancer member name");
             }
             names.add(initParameterName.substring(BALANCER_MEMBER_PREFIX.length(),endOfNameIndex));
         }
         return names;
     }

     @Override
     protected HttpURI proxyHttpURI(HttpServletRequest request, String uri) throws MalformedURLException
     {
         BalancerMember balancerMember = selectBalancerMember(request);
         try
         {
             URI dstUri = new URI(balancerMember.getProxyTo() + "/" + uri).normalize();
             return new HttpURI(dstUri.toString());
         }
         catch (URISyntaxException e)
         {
             throw new MalformedURLException(e.getMessage());
         }
     }

     private BalancerMember selectBalancerMember(HttpServletRequest request)
     {
         BalancerMember balancerMember = null;
         if (_stickySessions)
         {
             String name = getBalancerMemberNameFromSessionId(request);
             if (name != null)
             {
                 balancerMember = findBalancerMemberByName(name);
                 if (balancerMember != null)
                 {
                     return balancerMember;
                 }
             }
         }
         return _roundRobinIterator.next();
     }

     private BalancerMember findBalancerMemberByName(String name)
     {
         BalancerMember example = new BalancerMember(name,"");
         for (BalancerMember balancerMember : _balancerMembers)
         {
             if (balancerMember.equals(example))
             {
                 return balancerMember;
             }
         }
         return null;
     }

     private String getBalancerMemberNameFromSessionId(HttpServletRequest request)
     {
         String name = getBalancerMemberNameFromSessionCookie(request);
         if (name == null)
         {
             name = getBalancerMemberNameFromURL(request);
         }
         return name;
     }

     private String getBalancerMemberNameFromSessionCookie(HttpServletRequest request)
     {
         Cookie[] cookies = request.getCookies();
         String name = null;
         for (Cookie cookie : cookies)
         {
             if (JSESSIONID.equalsIgnoreCase(cookie.getName()))
             {
                 name = extractBalancerMemberNameFromSessionId(cookie.getValue());
                 break;
             }
         }
         return name;
     }

     private String getBalancerMemberNameFromURL(HttpServletRequest request)
     {
         String name = null;
         String requestURI = request.getRequestURI();
         int idx = requestURI.lastIndexOf(";");
         if (idx != -1)
         {
             String requestURISuffix = requestURI.substring(idx);
             if (requestURISuffix.startsWith(JSESSIONID_URL_PREFIX))
             {
                 name = extractBalancerMemberNameFromSessionId(requestURISuffix.substring(JSESSIONID_URL_PREFIX.length()));
             }
         }
         return name;
     }

     private String extractBalancerMemberNameFromSessionId(String sessionId)
     {
         String name = null;
         int idx = sessionId.lastIndexOf(".");
         if (idx != -1)
         {
             String sessionIdSuffix = sessionId.substring(idx + 1);
             name = (sessionIdSuffix.length() > 0)?sessionIdSuffix:null;
         }
         return name;
     }

     @Override
     protected String filterResponseHeaderValue(String headerName, String headerValue, HttpServletRequest request)
     {
         if (_proxyPassReverse && REVERSE_PROXY_HEADERS.contains(headerName))
         {
             HttpURI locationURI = new HttpURI(headerValue);
             if (isAbsoluteLocation(locationURI) && isBackendLocation(locationURI))
             {
                 Request jettyRequest = (Request)request;
                 URI reverseUri;
                 try
                 {
                     reverseUri = new URI(jettyRequest.getRootURL().append(locationURI.getCompletePath()).toString()).normalize();
                     return reverseUri.toURL().toString();
                 }
                 catch (Exception e)
                 {
                     _log.warn("Not filtering header response",e);
                     return headerValue;
                 }
             }
         }
         return headerValue;
     }

     private boolean isBackendLocation(HttpURI locationURI)
     {
         for (BalancerMember balancerMember : _balancerMembers)
         {
             HttpURI backendURI = balancerMember.getBackendURI();
             if (backendURI.getHost().equals(locationURI.getHost()) && backendURI.getScheme().equals(locationURI.getScheme())
                     && backendURI.getPort() == locationURI.getPort())
             {
                 return true;
             }
         }
         return false;
     }

     private boolean isAbsoluteLocation(HttpURI locationURI)
     {
         return locationURI.getHost() != null;
     }

     @Override
     public String getHostHeader()
     {
         throw new UnsupportedOperationException("HostHeader not supported in " + getClass().getName());
     }

     @Override
     public void setHostHeader(String hostHeader)
     {
         throw new UnsupportedOperationException("HostHeader not supported in " + getClass().getName());
     }

     @Override
     public boolean validateDestination(String host, String path)
     {
         return true;
     }

 }
	//
	// ========================================================================
	// Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
	// ------------------------------------------------------------------------
	// All rights reserved. This program and the accompanying materials
	// are made available under the terms of the Eclipse Public License v1.0
	// and Apache License v2.0 which accompanies this distribution.
	//
	// The Eclipse Public License is available at
	// http://www.eclipse.org/legal/epl-v10.html
	//
	// The Apache License v2.0 is available at
	// http://www.opensource.org/licenses/apache2.0.php
	//
	// You may elect to redistribute this code under either of these licenses.
	// ========================================================================
	//

	package org.eclipse.jetty.servlets;

	import java.net.MalformedURLException;
	import java.net.URI;
	import java.net.URISyntaxException;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.HashSet;
	import java.util.Iterator;
	import java.util.LinkedList;
	import java.util.List;
	import java.util.Set;
	import java.util.concurrent.atomic.AtomicInteger;

	import javax.servlet.ServletConfig;
	import javax.servlet.ServletException;
	import javax.servlet.UnavailableException;
	import javax.servlet.http.Cookie;
	import javax.servlet.http.HttpServletRequest;

	import org.eclipse.jetty.http.HttpURI;
	import org.eclipse.jetty.server.Request;

	/**
	* 6
	*/
	public class BalancerServlet extends ProxyServlet
	{

	private static final class BalancerMember
	{

	private String _name;

	private String _proxyTo;

	private HttpURI _backendURI;

	public BalancerMember(String name, String proxyTo)
	{
	super();
	_name = name;
	_proxyTo = proxyTo;
	_backendURI = new HttpURI(_proxyTo);
	}

	public String getProxyTo()
	{
	return _proxyTo;
	}

	public HttpURI getBackendURI()
	{
	return _backendURI;
	}

	@Override
	public String toString()
	{
	return "BalancerMember [_name=" + _name + ", _proxyTo=" + _proxyTo + "]";
	}

	@Override
	public int hashCode()
	{
	final int prime = 31;
	int result = 1;
	result = prime * result + ((_name == null)?0:_name.hashCode());
	return result;
	}

	@Override
	public boolean equals(Object obj)
	{
	if (this == obj)
	return true;
	if (obj == null)
	return false;
	if (getClass() != obj.getClass())
	return false;
	BalancerMember other = (BalancerMember)obj;
	if (_name == null)
	{
	if (other._name != null)
	return false;
	}
	else if (!_name.equals(other._name))
	return false;
	return true;
	}

	}

	private static final class RoundRobinIterator implements Iterator<BalancerMember>
	{

	private BalancerMember[] _balancerMembers;

	private AtomicInteger _index;

	public RoundRobinIterator(Collection<BalancerMember> balancerMembers)
	{
	_balancerMembers = (BalancerMember[])balancerMembers.toArray(new BalancerMember[balancerMembers.size()]);
	_index = new AtomicInteger(-1);
	}

	public boolean hasNext()
	{
	return true;
	}

	public BalancerMember next()
	{
	BalancerMember balancerMember = null;
	while (balancerMember == null)
	{
	int currentIndex = _index.get();
	int nextIndex = (currentIndex + 1) % _balancerMembers.length;
	if (_index.compareAndSet(currentIndex,nextIndex))
	{
	balancerMember = _balancerMembers[nextIndex];
	}
	}
	return balancerMember;
	}

	public void remove()
	{
	throw new UnsupportedOperationException();
	}

	}

	private static final String BALANCER_MEMBER_PREFIX = "BalancerMember.";

	private static final List<String> FORBIDDEN_CONFIG_PARAMETERS;
	static
	{
	List<String> params = new LinkedList<String>();
	params.add("HostHeader");
	params.add("whiteList");
	params.add("blackList");
	FORBIDDEN_CONFIG_PARAMETERS = Collections.unmodifiableList(params);
	}

	private static final List<String> REVERSE_PROXY_HEADERS;
	static
	{
	List<String> params = new LinkedList<String>();
	params.add("Location");
	params.add("Content-Location");
	params.add("URI");
	REVERSE_PROXY_HEADERS = Collections.unmodifiableList(params);
	}

	private static final String JSESSIONID = "jsessionid";

	private static final String JSESSIONID_URL_PREFIX = JSESSIONID + "=";

	private boolean _stickySessions;

	private Set<BalancerMember> _balancerMembers = new HashSet<BalancerMember>();

	private boolean _proxyPassReverse;

	private RoundRobinIterator _roundRobinIterator;

	@Override
	public void init(ServletConfig config) throws ServletException
	{
	validateConfig(config);
	super.init(config);
	initStickySessions(config);
	initBalancers(config);
	initProxyPassReverse(config);
	postInit();
	}

	private void validateConfig(ServletConfig config) throws ServletException
	{
	@SuppressWarnings("unchecked")
	List<String> initParameterNames = Collections.list(config.getInitParameterNames());
	for (String initParameterName : initParameterNames)
	{
	if (FORBIDDEN_CONFIG_PARAMETERS.contains(initParameterName))
	{
	throw new UnavailableException(initParameterName + " not supported in " + getClass().getName());
	}
	}
	}

	private void initStickySessions(ServletConfig config) throws ServletException
	{
	_stickySessions = "true".equalsIgnoreCase(config.getInitParameter("StickySessions"));
	}

	private void initBalancers(ServletConfig config) throws ServletException
	{
	Set<String> balancerNames = getBalancerNames(config);
	for (String balancerName : balancerNames)
	{
	String memberProxyToParam = BALANCER_MEMBER_PREFIX + balancerName + ".ProxyTo";
	String proxyTo = config.getInitParameter(memberProxyToParam);
	if (proxyTo == null \|\| proxyTo.trim().length() == 0)
	{
	throw new UnavailableException(memberProxyToParam + " parameter is empty.");
	}
	_balancerMembers.add(new BalancerMember(balancerName,proxyTo));
	}
	}

	private void initProxyPassReverse(ServletConfig config)
	{
	_proxyPassReverse = "true".equalsIgnoreCase(config.getInitParameter("ProxyPassReverse"));
	}

	private void postInit()
	{
	_roundRobinIterator = new RoundRobinIterator(_balancerMembers);
	}

	private Set<String> getBalancerNames(ServletConfig config) throws ServletException
	{
	Set<String> names = new HashSet<String>();
	@SuppressWarnings("unchecked")
	List<String> initParameterNames = Collections.list(config.getInitParameterNames());
	for (String initParameterName : initParameterNames)
	{
	if (!initParameterName.startsWith(BALANCER_MEMBER_PREFIX))
	{
	continue;
	}
	int endOfNameIndex = initParameterName.lastIndexOf(".");
	if (endOfNameIndex <= BALANCER_MEMBER_PREFIX.length())
	{
	throw new UnavailableException(initParameterName + " parameter does not provide a balancer member name");
	}
	names.add(initParameterName.substring(BALANCER_MEMBER_PREFIX.length(),endOfNameIndex));
	}
	return names;
	}

	@Override
	protected HttpURI proxyHttpURI(HttpServletRequest request, String uri) throws MalformedURLException
	{
	BalancerMember balancerMember = selectBalancerMember(request);
	try
	{
	URI dstUri = new URI(balancerMember.getProxyTo() + "/" + uri).normalize();
	return new HttpURI(dstUri.toString());
	}
	catch (URISyntaxException e)
	{
	throw new MalformedURLException(e.getMessage());
	}
	}

	private BalancerMember selectBalancerMember(HttpServletRequest request)
	{
	BalancerMember balancerMember = null;
	if (_stickySessions)
	{
	String name = getBalancerMemberNameFromSessionId(request);
	if (name != null)
	{
	balancerMember = findBalancerMemberByName(name);
	if (balancerMember != null)
	{
	return balancerMember;
	}
	}
	}
	return _roundRobinIterator.next();
	}

	private BalancerMember findBalancerMemberByName(String name)
	{
	BalancerMember example = new BalancerMember(name,"");
	for (BalancerMember balancerMember : _balancerMembers)
	{
	if (balancerMember.equals(example))
	{
	return balancerMember;
	}
	}
	return null;
	}

	private String getBalancerMemberNameFromSessionId(HttpServletRequest request)
	{
	String name = getBalancerMemberNameFromSessionCookie(request);
	if (name == null)
	{
	name = getBalancerMemberNameFromURL(request);
	}
	return name;
	}

	private String getBalancerMemberNameFromSessionCookie(HttpServletRequest request)
	{
	Cookie[] cookies = request.getCookies();
	String name = null;
	for (Cookie cookie : cookies)
	{
	if (JSESSIONID.equalsIgnoreCase(cookie.getName()))
	{
	name = extractBalancerMemberNameFromSessionId(cookie.getValue());
	break;
	}
	}
	return name;
	}

	private String getBalancerMemberNameFromURL(HttpServletRequest request)
	{
	String name = null;
	String requestURI = request.getRequestURI();
	int idx = requestURI.lastIndexOf(";");
	if (idx != -1)
	{
	String requestURISuffix = requestURI.substring(idx);
	if (requestURISuffix.startsWith(JSESSIONID_URL_PREFIX))
	{
	name = extractBalancerMemberNameFromSessionId(requestURISuffix.substring(JSESSIONID_URL_PREFIX.length()));
	}
	}
	return name;
	}

	private String extractBalancerMemberNameFromSessionId(String sessionId)
	{
	String name = null;
	int idx = sessionId.lastIndexOf(".");
	if (idx != -1)
	{
	String sessionIdSuffix = sessionId.substring(idx + 1);
	name = (sessionIdSuffix.length() > 0)?sessionIdSuffix:null;
	}
	return name;
	}

	@Override
	protected String filterResponseHeaderValue(String headerName, String headerValue, HttpServletRequest request)
	{
	if (_proxyPassReverse && REVERSE_PROXY_HEADERS.contains(headerName))
	{
	HttpURI locationURI = new HttpURI(headerValue);
	if (isAbsoluteLocation(locationURI) && isBackendLocation(locationURI))
	{
	Request jettyRequest = (Request)request;
	URI reverseUri;
	try
	{
	reverseUri = new URI(jettyRequest.getRootURL().append(locationURI.getCompletePath()).toString()).normalize();
	return reverseUri.toURL().toString();
	}
	catch (Exception e)
	{
	_log.warn("Not filtering header response",e);
	return headerValue;
	}
	}
	}
	return headerValue;
	}

	private boolean isBackendLocation(HttpURI locationURI)
	{
	for (BalancerMember balancerMember : _balancerMembers)
	{
	HttpURI backendURI = balancerMember.getBackendURI();
	if (backendURI.getHost().equals(locationURI.getHost()) && backendURI.getScheme().equals(locationURI.getScheme())
	&& backendURI.getPort() == locationURI.getPort())
	{
	return true;
	}
	}
	return false;
	}

	private boolean isAbsoluteLocation(HttpURI locationURI)
	{
	return locationURI.getHost() != null;
	}

	@Override
	public String getHostHeader()
	{
	throw new UnsupportedOperationException("HostHeader not supported in " + getClass().getName());
	}

	@Override
	public void setHostHeader(String hostHeader)
	{
	throw new UnsupportedOperationException("HostHeader not supported in " + getClass().getName());
	}

	@Override
	public boolean validateDestination(String host, String path)
	{
	return true;
	}

	}