Jetty example source code file (ProxyServlet.java)

This example Jetty source code file (ProxyServlet.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Jetty tags/keywords

connection, httpservletresponse, httpservletresponse, httpurlconnection, httpurlconnection, inetsocketaddress, inputstream, inputstream, io, ioexception, net, network, request, response, servlet, servletexception, string, string, via, x-forwarded-for

The Jetty ProxyServlet.java source code

// ========================================================================
// $Id: ProxyServlet.java 800 2006-08-20 00:01:46Z gregw $
// Copyright 2004-2004 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// Licensed 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.mortbay.servlet;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.URL;
import java.net.URLConnection;
import java.util.Enumeration;
import java.util.HashSet;

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

import org.mortbay.util.IO;



/**
 * EXPERIMENTAL Proxy servlet.
 * @author gregw
 *
 */
public class ProxyServlet implements Servlet
{
    private int _tunnelTimeoutMs=300000;
    
    protected HashSet _DontProxyHeaders = new HashSet();
    {
        _DontProxyHeaders.add("proxy-connection");
        _DontProxyHeaders.add("connection");
        _DontProxyHeaders.add("keep-alive");
        _DontProxyHeaders.add("transfer-encoding");
        _DontProxyHeaders.add("te");
        _DontProxyHeaders.add("trailer");
        _DontProxyHeaders.add("proxy-authorization");
        _DontProxyHeaders.add("proxy-authenticate");
        _DontProxyHeaders.add("upgrade");
    }
    
    private ServletConfig config;
    private ServletContext context;
    
    /* (non-Javadoc)
     * @see javax.servlet.Servlet#init(javax.servlet.ServletConfig)
     */
    public void init(ServletConfig config) throws ServletException
    {
        this.config=config;
        this.context=config.getServletContext();
    }

    /* (non-Javadoc)
     * @see javax.servlet.Servlet#getServletConfig()
     */
    public ServletConfig getServletConfig()
    {
        return config;
    }

    /* (non-Javadoc)
     * @see javax.servlet.Servlet#service(javax.servlet.ServletRequest, javax.servlet.ServletResponse)
     */
    public void service(ServletRequest req, ServletResponse res) throws ServletException,
            IOException
    {
        HttpServletRequest request = (HttpServletRequest)req;
        HttpServletResponse response = (HttpServletResponse)res;
        if ("CONNECT".equalsIgnoreCase(request.getMethod()))
        {
            handleConnect(request,response);
        }
        else
        {
            String uri=request.getRequestURI();
            if (request.getQueryString()!=null)
                uri+="?"+request.getQueryString();
            URL url = new URL(request.getScheme(),
                    		  request.getServerName(),
                    		  request.getServerPort(),
                    		  uri);
            
            context.log("URL="+url);

            URLConnection connection = url.openConnection();
            connection.setAllowUserInteraction(false);
            
            // Set method
            HttpURLConnection http = null;
            if (connection instanceof HttpURLConnection)
            {
                http = (HttpURLConnection)connection;
                http.setRequestMethod(request.getMethod());
                http.setInstanceFollowRedirects(false);
            }

            // check connection header
            String connectionHdr = request.getHeader("Connection");
            if (connectionHdr!=null)
            {
                connectionHdr=connectionHdr.toLowerCase();
                if (connectionHdr.equals("keep-alive")||
                    connectionHdr.equals("close"))
                    connectionHdr=null;
            }
            
            // copy headers
            boolean xForwardedFor=false;
            boolean hasContent=false;
            Enumeration enm = request.getHeaderNames();
            while (enm.hasMoreElements())
            {
                // TODO could be better than this!
                String hdr=(String)enm.nextElement();
                String lhdr=hdr.toLowerCase();

                if (_DontProxyHeaders.contains(lhdr))
                    continue;
                if (connectionHdr!=null && connectionHdr.indexOf(lhdr)>=0)
                    continue;

                if ("content-type".equals(lhdr))
                    hasContent=true;

                Enumeration vals = request.getHeaders(hdr);
                while (vals.hasMoreElements())
                {
                    String val = (String)vals.nextElement();
                    if (val!=null)
                    {
                        connection.addRequestProperty(hdr,val);
                        context.log("req "+hdr+": "+val);
                        xForwardedFor|="X-Forwarded-For".equalsIgnoreCase(hdr);
                    }
                }
            }

            // Proxy headers
            connection.setRequestProperty("Via","1.1 (jetty)");
            if (!xForwardedFor)
                connection.addRequestProperty("X-Forwarded-For",
                                              request.getRemoteAddr());

            // a little bit of cache control
            String cache_control = request.getHeader("Cache-Control");
            if (cache_control!=null &&
                (cache_control.indexOf("no-cache")>=0 ||
                 cache_control.indexOf("no-store")>=0))
                connection.setUseCaches(false);

            // customize Connection
            
            try
            {    
                connection.setDoInput(true);
                
                // do input thang!
                InputStream in=request.getInputStream();
                if (hasContent)
                {
                    connection.setDoOutput(true);
                    IO.copy(in,connection.getOutputStream());
                }
                
                // Connect                
                connection.connect();    
            }
            catch (Exception e)
            {
                context.log("proxy",e);
            }
            
            InputStream proxy_in = null;

            // handler status codes etc.
            int code=500;
            if (http!=null)
            {
                proxy_in = http.getErrorStream();
                
                code=http.getResponseCode();
                response.setStatus(code, http.getResponseMessage());
                context.log("response = "+http.getResponseCode());
            }
            
            if (proxy_in==null)
            {
                try {proxy_in=connection.getInputStream();}
                catch (Exception e)
                {
                    context.log("stream",e);
                    proxy_in = http.getErrorStream();
                }
            }
            
            // clear response defaults.
            response.setHeader("Date",null);
            response.setHeader("Server",null);
            
            // set response headers
            int h=0;
            String hdr=connection.getHeaderFieldKey(h);
            String val=connection.getHeaderField(h);
            while(hdr!=null || val!=null)
            {
                String lhdr = hdr!=null?hdr.toLowerCase():null;
                if (hdr!=null && val!=null && !_DontProxyHeaders.contains(lhdr))
                    response.addHeader(hdr,val);

                context.log("res "+hdr+": "+val);
                
                h++;
                hdr=connection.getHeaderFieldKey(h);
                val=connection.getHeaderField(h);
            }
            response.addHeader("Via","1.1 (jetty)");

            // Handle
            if (proxy_in!=null)
                IO.copy(proxy_in,response.getOutputStream());
            
        }
    }


    /* ------------------------------------------------------------ */
    public void handleConnect(HttpServletRequest request,
                              HttpServletResponse response)
        throws IOException
    {
        String uri = request.getRequestURI();
        
        context.log("CONNECT: "+uri);
        
        String port = "";
        String host = "";
        
        int c = uri.indexOf(':');
        if (c>=0)
        {
            port = uri.substring(c+1);
            host = uri.substring(0,c);
            if (host.indexOf('/')>0)
                host = host.substring(host.indexOf('/')+1);
        }

        
       

        InetSocketAddress inetAddress = new InetSocketAddress (host, Integer.parseInt(port));
        
        //if (isForbidden(HttpMessage.__SSL_SCHEME,addrPort.getHost(),addrPort.getPort(),false))
        //{
        //    sendForbid(request,response,uri);
        //}
        //else
        {
            InputStream in=request.getInputStream();
            OutputStream out=response.getOutputStream();
            
            Socket socket = new Socket(inetAddress.getAddress(),inetAddress.getPort());
            context.log("Socket: "+socket);
            
            response.setStatus(200);
            response.setHeader("Connection","close");
            response.flushBuffer();
            
            

            context.log("out<-in");
            IO.copyThread(socket.getInputStream(),out);
            context.log("in->out");
            IO.copy(in,socket.getOutputStream());
        }
    }
    
    
    
    
    /* (non-Javadoc)
     * @see javax.servlet.Servlet#getServletInfo()
     */
    public String getServletInfo()
    {
        return "Proxy Servlet";
    }

    /* (non-Javadoc)
     * @see javax.servlet.Servlet#destroy()
     */
    public void destroy()
    {

    }
}