content: /*
   * 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_BASE_PATH = "basePath";
      public static final String PARAM_TRUSTED_PROXIES = "trustedProxies";
  
      private String basePath;
      private Pattern trustedProxies;
  
      @Override
      public void init(FilterConfig filterConfig) throws ServletException {
          basePath = filterConfig.getInitParameter(PARAM_BASE_PATH);
  
          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);
              }
          }
      }
  
      @Override
      public void doFilter(ServletRequest request, ServletResponse response, final 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, basePath);
          }
  
          // call next
          chain.doFilter(request, response);
      }
  
      @Override
      public void destroy() {
      }
  }
  