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    1   // ========================================================================
    2   // $Id: ProxyServlet.java 5263 2009-06-26 09:42:21Z gregw $
    3   // Copyright 2004-2004 Mort Bay Consulting Pty. Ltd.
    4   // ------------------------------------------------------------------------
    5   // Licensed under the Apache License, Version 2.0 (the "License");
    6   // you may not use this file except in compliance with the License.
    7   // You may obtain a copy of the License at
    8   // http://www.apache.org/licenses/LICENSE-2.0
    9   // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  // ========================================================================
    15
    16  package org.mortbay.servlet;
    17
    18  import java.io.IOException;
    19  import java.io.InputStream;
    20  import java.io.OutputStream;
    21  import java.net.HttpURLConnection;
    22  import java.net.InetSocketAddress;
    23  import java.net.MalformedURLException;
    24  import java.net.Socket;
    25  import java.net.URL;
    26  import java.net.URLConnection;
    27  import java.util.Enumeration;
    28  import java.util.HashSet;
    29
    30  import javax.servlet.Servlet;
    31  import javax.servlet.ServletConfig;
    32  import javax.servlet.ServletContext;
    33  import javax.servlet.ServletException;
    34  import javax.servlet.ServletRequest;
    35  import javax.servlet.ServletResponse;
    36  import javax.servlet.UnavailableException;
    37  import javax.servlet.http.HttpServletRequest;
    38  import javax.servlet.http.HttpServletResponse;
    39
    40  import org.mortbay.util.IO;
    41
    42
    43
    44  /**
    45   * Proxy Servlet.
    46   * <p>
    47   * Forward requests to another server either as a standard web proxy (as defined by
    48   * RFC2616) or as a transparent proxy.
    49   *
    50   */
    51  public class ProxyServlet implements Servlet
    52  {
    53
    54      protected HashSet _DontProxyHeaders = new HashSet();
    55      {
    56          _DontProxyHeaders.add("proxy-connection");
    57          _DontProxyHeaders.add("connection");
    58          _DontProxyHeaders.add("keep-alive");
    59          _DontProxyHeaders.add("transfer-encoding");
    60          _DontProxyHeaders.add("te");
    61          _DontProxyHeaders.add("trailer");
    62          _DontProxyHeaders.add("proxy-authorization");
    63          _DontProxyHeaders.add("proxy-authenticate");
    64          _DontProxyHeaders.add("upgrade");
    65      }
    66
    67      protected ServletConfig _config;
    68      protected ServletContext _context;
    69
    70      /* (non-Javadoc)
    71       * @see javax.servlet.Servlet#init(javax.servlet.ServletConfig)
    72       */
    73      public void init(ServletConfig config) throws ServletException
    74      {
    75          this._config=config;
    76          this._context=config.getServletContext();
    77      }
    78
    79      /* (non-Javadoc)
    80       * @see javax.servlet.Servlet#getServletConfig()
    81       */
    82      public ServletConfig getServletConfig()
    83      {
    84          return _config;
    85      }
    86
    87      /* (non-Javadoc)
    88       * @see javax.servlet.Servlet#service(javax.servlet.ServletRequest, javax.servlet.ServletResponse)
    89       */
    90      public void service(ServletRequest req, ServletResponse res) throws ServletException,
    91              IOException
    92      {
    93          HttpServletRequest request = (HttpServletRequest)req;
    94          HttpServletResponse response = (HttpServletResponse)res;
    95          if ("CONNECT".equalsIgnoreCase(request.getMethod()))
    96          {
    97              handleConnect(request,response);
    98          }
    99          else
    100         {
    101             String uri=request.getRequestURI();
    102             if (request.getQueryString()!=null)
    103                 uri+="?"+request.getQueryString();
    104
    105             URL url=proxyHttpURL(request.getScheme(),
    106                     request.getServerName(),
    107                     request.getServerPort(),
    108                     uri);
    109
    110
    111             URLConnection connection = url.openConnection();
    112             connection.setAllowUserInteraction(false);
    113
    114             // Set method
    115             HttpURLConnection http = null;
    116             if (connection instanceof HttpURLConnection)
    117             {
    118                 http = (HttpURLConnection)connection;
    119                 http.setRequestMethod(request.getMethod());
    120                 http.setInstanceFollowRedirects(false);
    121             }
    122
    123             // check connection header
    124             String connectionHdr = request.getHeader("Connection");
    125             if (connectionHdr!=null)
    126             {
    127                 connectionHdr=connectionHdr.toLowerCase();
    128                 if (connectionHdr.equals("keep-alive")||
    129                     connectionHdr.equals("close"))
    130                     connectionHdr=null;
    131             }
    132
    133             // copy headers
    134             boolean xForwardedFor=false;
    135             boolean hasContent=false;
    136             Enumeration enm = request.getHeaderNames();
    137             while (enm.hasMoreElements())
    138             {
    139                 // TODO could be better than this!
    140                 String hdr=(String)enm.nextElement();
    141                 String lhdr=hdr.toLowerCase();
    142
    143                 if (_DontProxyHeaders.contains(lhdr))
    144                     continue;
    145                 if (connectionHdr!=null && connectionHdr.indexOf(lhdr)>=0)
    146                     continue;
    147
    148                 if ("content-type".equals(lhdr))
    149                     hasContent=true;
    150
    151                 Enumeration vals = request.getHeaders(hdr);
    152                 while (vals.hasMoreElements())
    153                 {
    154                     String val = (String)vals.nextElement();
    155                     if (val!=null)
    156                     {
    157                         connection.addRequestProperty(hdr,val);
    158                         xForwardedFor|="X-Forwarded-For".equalsIgnoreCase(hdr);
    159                     }
    160                 }
    161             }
    162
    163             // Proxy headers
    164             connection.setRequestProperty("Via","1.1 (jetty)");
    165             if (!xForwardedFor)
    166                 connection.addRequestProperty("X-Forwarded-For",
    167                                               request.getRemoteAddr());
    168
    169             // a little bit of cache control
    170             String cache_control = request.getHeader("Cache-Control");
    171             if (cache_control!=null &&
    172                 (cache_control.indexOf("no-cache")>=0 ||
    173                  cache_control.indexOf("no-store")>=0))
    174                 connection.setUseCaches(false);
    175
    176             // customize Connection
    177
    178             try
    179             {
    180                 connection.setDoInput(true);
    181
    182                 // do input thang!
    183                 InputStream in=request.getInputStream();
    184                 if (hasContent)
    185                 {
    186                     connection.setDoOutput(true);
    187                     IO.copy(in,connection.getOutputStream());
    188                 }
    189
    190                 // Connect
    191                 connection.connect();
    192             }
    193             catch (Exception e)
    194             {
    195                 _context.log("proxy",e);
    196             }
    197
    198             InputStream proxy_in = null;
    199
    200             // handler status codes etc.
    201             int code=500;
    202             if (http!=null)
    203             {
    204                 proxy_in = http.getErrorStream();
    205
    206                 code=http.getResponseCode();
    207                 response.setStatus(code, http.getResponseMessage());
    208             }
    209
    210             if (proxy_in==null)
    211             {
    212                 try {proxy_in=connection.getInputStream();}
    213                 catch (Exception e)
    214                 {
    215                     _context.log("stream",e);
    216                     proxy_in = http.getErrorStream();
    217                 }
    218             }
    219
    220             // clear response defaults.
    221             response.setHeader("Date",null);
    222             response.setHeader("Server",null);
    223
    224             // set response headers
    225             int h=0;
    226             String hdr=connection.getHeaderFieldKey(h);
    227             String val=connection.getHeaderField(h);
    228             while(hdr!=null || val!=null)
    229             {
    230                 String lhdr = hdr!=null?hdr.toLowerCase():null;
    231                 if (hdr!=null && val!=null && !_DontProxyHeaders.contains(lhdr))
    232                     response.addHeader(hdr,val);
    233
    234                 h++;
    235                 hdr=connection.getHeaderFieldKey(h);
    236                 val=connection.getHeaderField(h);
    237             }
    238             response.addHeader("Via","1.1 (jetty)");
    239
    240             // Handle
    241             if (proxy_in!=null)
    242                 IO.copy(proxy_in,response.getOutputStream());
    243
    244         }
    245     }
    246
    247     /* ------------------------------------------------------------ */
    248     /** Resolve requested URL to the Proxied URL
    249      * @param scheme The scheme of the received request.
    250      * @param serverName The server encoded in the received request(which
    251      * may be from an absolute URL in the request line).
    252      * @param serverPort The server port of the received request (which
    253      * may be from an absolute URL in the request line).
    254      * @param uri The URI of the received request.
    255      * @return The URL to which the request should be proxied.
    256      * @throws MalformedURLException
    257      */
    258     protected URL proxyHttpURL(String scheme, String serverName, int serverPort, String uri)
    259         throws MalformedURLException
    260     {
    261         return new URL(scheme,serverName,serverPort,uri);
    262     }
    263
    264     /* ------------------------------------------------------------ */
    265     public void handleConnect(HttpServletRequest request,
    266                               HttpServletResponse response)
    267         throws IOException
    268     {
    269         String uri = request.getRequestURI();
    270
    271         String port = "";
    272         String host = "";
    273
    274         int c = uri.indexOf(':');
    275         if (c>=0)
    276         {
    277             port = uri.substring(c+1);
    278             host = uri.substring(0,c);
    279             if (host.indexOf('/')>0)
    280                 host = host.substring(host.indexOf('/')+1);
    281         }
    282
    283
    284
    285
    286         InetSocketAddress inetAddress = new InetSocketAddress (host, Integer.parseInt(port));
    287
    288         //if (isForbidden(HttpMessage.__SSL_SCHEME,addrPort.getHost(),addrPort.getPort(),false))
    289         //{
    290         //    sendForbid(request,response,uri);
    291         //}
    292         //else
    293         {
    294             InputStream in=request.getInputStream();
    295             OutputStream out=response.getOutputStream();
    296
    297             Socket socket = new Socket(inetAddress.getAddress(),inetAddress.getPort());
    298
    299             response.setStatus(200);
    300             response.setHeader("Connection","close");
    301             response.flushBuffer();
    302
    303             IO.copyThread(socket.getInputStream(),out);
    304             IO.copy(in,socket.getOutputStream());
    305         }
    306     }
    307
    308
    309
    310
    311     /* (non-Javadoc)
    312      * @see javax.servlet.Servlet#getServletInfo()
    313      */
    314     public String getServletInfo()
    315     {
    316         return "Proxy Servlet";
    317     }
    318
    319     /* (non-Javadoc)
    320      * @see javax.servlet.Servlet#destroy()
    321      */
    322     public void destroy()
    323     {
    324
    325     }
    326     /**
    327      * Transparent Proxy.
    328      *
    329      * This convenience extension to AsyncProxyServlet configures the servlet
    330      * as a transparent proxy.   The servlet is configured with init parameter:<ul>
    331      * <li> ProxyTo - a URI like http://host:80/context to which the request is proxied.
    332      * <li> Prefix  - a URI prefix that is striped from the start of the forwarded URI.
    333      * </ul>
    334      * For example, if a request was received at /foo/bar and the ProxyTo was  http://host:80/context
    335      * and the Prefix was /foo, then the request would be proxied to http://host:80/context/bar
    336      *
    337      */
    338     public static class Transparent extends ProxyServlet
    339     {
    340         String _prefix;
    341         String _proxyTo;
    342
    343         public Transparent()
    344         {
    345         }
    346
    347         public Transparent(String prefix,String server, int port)
    348         {
    349             _prefix=prefix;
    350             _proxyTo="http://"+server+":"+port;
    351         }
    352
    353         public void init(ServletConfig config) throws ServletException
    354         {
    355             if (config.getInitParameter("ProxyTo")!=null)
    356                 _proxyTo=config.getInitParameter("ProxyTo");
    357             if (config.getInitParameter("Prefix")!=null)
    358                 _prefix=config.getInitParameter("Prefix");
    359             if (_proxyTo==null)
    360                 throw new UnavailableException("No ProxyTo");
    361             super.init(config);
    362
    363             _context.log("Transparent ProxyServlet @ "+(_prefix==null?"-":_prefix)+ " to "+_proxyTo);
    364
    365         }
    366
    367         protected URL proxyHttpURL(final String scheme, final String serverName, int serverPort, final String uri) throws MalformedURLException
    368         {
    369             if (_prefix!=null && !uri.startsWith(_prefix))
    370                 return null;
    371
    372             if (_prefix!=null)
    373                 return new URL(_proxyTo+uri.substring(_prefix.length()));
    374             return new URL(_proxyTo+uri);
    375         }
    376     }
    377
    378 }