/*
    * 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.chemistry.opencmis.server.filter;
  
  import java.io.IOException;
  
  import java.util.regex.Pattern;
  
  import javax.servlet.Filter;
  import javax.servlet.FilterChain;
  import javax.servlet.FilterConfig;
  import javax.servlet.ServletException;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  import javax.servlet.http.HttpServletRequest;
  
  
  /**
   * A filter that corrects server name, server port and scheme if OpenCMIS is
   * running behind a proxy or load balancer.
   */
  public class ProxyFilter implements Filter
  {
      public static final String PARAM_TRUSTED_PROXIES = "trustedProxies";
      private Pattern trustedProxies;
  
      public void init( FilterConfig filterConfig ) throws ServletException
      {
          trustedProxies = null;
  
          String trustedProxiesString = filterConfig.getInitParameter( PARAM_TRUSTED_PROXIES );
  
          if ( trustedProxiesString != null )
          {
              try
              {
                  trustedProxies = Pattern.compile( trustedProxiesString );
              }
              catch ( Exception e )
              {
                  throw new ServletException( "Could not compile trustedProxies parameter: " + e, e );
              }
          }
      }
  
      public void doFilter( ServletRequest request, ServletResponse response, FilterChain chain )
          throws IOException, ServletException
      {
          // check for trusted proxy
          if ( ( trustedProxies != null ) && ( request instanceof HttpServletRequest ) &&
                  trustedProxies.matcher( request.getRemoteAddr(  ) ).matches(  ) )
          {
              request = new ProxyHttpServletRequestWrapper( (HttpServletRequest) request );
          }
  
          // call next
          chain.doFilter( request, response );
      }
  
      public void destroy(  )
      {
      }
  }