chapters.mdc.UserServletFilter Maven / Gradle / Ivy
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* 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 chapters.mdc;
import java.io.IOException;
import java.security.Principal;
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;
/**
* A simple servlet filter that puts the username
* found either in the Principal.
*
* The value is removed from the MDC once the request has been
* fully processed.
*
* @author Sébastien Pennec
*/
public class UserServletFilter implements Filter {
private final String USER_KEY = "username";
public void destroy() {
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
boolean successfulRegistration = false;
HttpServletRequest req = (HttpServletRequest) request;
Principal principal = req.getUserPrincipal();
// Please note that we also could have used a cookie to
// retrieve the user name
if (principal != null) {
String username = principal.getName();
successfulRegistration = registerUsername(username);
}
try {
chain.doFilter(request, response);
} finally {
if (successfulRegistration) {
MDC.remove(USER_KEY);
}
}
}
public void init(FilterConfig arg0) throws ServletException {
}
/**
* Register the user in the MDC under USER_KEY.
*
* @param username
* @return true id the user can be successfully registered
*/
private boolean registerUsername(String username) {
if (username != null && username.trim().length() > 0) {
MDC.put(USER_KEY, username);
return true;
}
return false;
}
}