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.
/**
 * 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 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;

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.


The values are removed after the request is processed.
Author:
Ceki Gülcü/**
 * 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 inexistent 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
    }
}