/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
    *
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v1.0 as published by
    * the Eclipse Foundation
    *
    *   or (per the licensee's choosing)
   *
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package ch.qos.logback.classic.helpers;
  
  import java.io.IOException;
  
  import jakarta.servlet.Filter;
  import jakarta.servlet.FilterChain;
  import jakarta.servlet.FilterConfig;
  import jakarta.servlet.ServletException;
  import jakarta.servlet.ServletRequest;
  import jakarta.servlet.ServletResponse;
  import jakarta.servlet.http.HttpServletRequest;
  
  import org.slf4j.MDC;
  
  import ch.qos.logback.classic.ClassicConstants;
  
  /**
   * A servlet filter that inserts various values retrieved from the incoming http
   * request into the MDC.
   * <p/>
   * <p/>
   * The values are removed after the request is processed.
   *
   * @author Ceki G&uuml;lc&uuml;
   */
  public class MDCInsertingServletFilter implements Filter {
  
      public void destroy() {
          // do nothing
      }
  
      public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
              throws IOException, ServletException {
  
          insertIntoMDC(request);
          try {
              chain.doFilter(request, response);
          } finally {
              clearMDC();
          }
      }
  
      void insertIntoMDC(ServletRequest request) {
  
          MDC.put(ClassicConstants.REQUEST_REMOTE_HOST_MDC_KEY, request.getRemoteHost());
  
          if (request instanceof HttpServletRequest) {
              HttpServletRequest httpServletRequest = (HttpServletRequest) request;
              MDC.put(ClassicConstants.REQUEST_REQUEST_URI, httpServletRequest.getRequestURI());
              StringBuffer requestURL = httpServletRequest.getRequestURL();
              if (requestURL != null) {
                  MDC.put(ClassicConstants.REQUEST_REQUEST_URL, requestURL.toString());
              }
              MDC.put(ClassicConstants.REQUEST_METHOD, httpServletRequest.getMethod());
              MDC.put(ClassicConstants.REQUEST_QUERY_STRING, httpServletRequest.getQueryString());
              MDC.put(ClassicConstants.REQUEST_USER_AGENT_MDC_KEY, httpServletRequest.getHeader("User-Agent"));
              MDC.put(ClassicConstants.REQUEST_X_FORWARDED_FOR, httpServletRequest.getHeader("X-Forwarded-For"));
          }
  
      }
  
      void clearMDC() {
          MDC.remove(ClassicConstants.REQUEST_REMOTE_HOST_MDC_KEY);
          MDC.remove(ClassicConstants.REQUEST_REQUEST_URI);
          MDC.remove(ClassicConstants.REQUEST_QUERY_STRING);
          // removing possibly nonexistent item is OK
          MDC.remove(ClassicConstants.REQUEST_REQUEST_URL);
          MDC.remove(ClassicConstants.REQUEST_METHOD);
          MDC.remove(ClassicConstants.REQUEST_USER_AGENT_MDC_KEY);
          MDC.remove(ClassicConstants.REQUEST_X_FORWARDED_FOR);
      }
  
      public void init(FilterConfig arg0) throws ServletException {
          // do nothing
      }
  }