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import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.filter.OncePerRequestFilter;
/**
* This is a very Spring opinionated HTTPFilter used for intercepting all requests and decorate the thread name with additional contextual
* information. We have extenced the filter from {@link OncePerRequestFilter} class provided by Spring Framework to ensure that the filter is absolutely
* executd only once per request.
*
* The following information will be added:
* <ul>
* <li>Old Thread name: to ensure that we are not losing any original context with thread names;</li>
* <li>Time when the request was intercepted;</li>
* <li>The RequestURI that proviced information on what RestFUL endpoint was accessed as part of this request;</li>
* <li>A Token that was received in the header. This token is encrypted and does not exposes any confidential information. Also, this token provides
* context which helps during debugging;</li>
* <li>The Payload from the token. This information will be very helpful when we have to debug for issues that may be happening with a call request
* as this holds all the information sent from the called.</li>
* </ul>
*
* This filter will also reset the ThreadName back to it's original name once the processing is complete.
*
* @author Kapil Viren Ahuja
*
*/
public class DecorateThreadNameFilter extends OncePerRequestFilter {
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
throws ServletException, IOException {
final Logger LOGGER = LoggerFactory.getLogger(DecorateThreadNameFilter.class);
final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
Thread thread = Thread.currentThread();
String threadOriginalName = thread.getName();
String uri = request.getRequestURI();
String time = dateFormat.format(new Date());
String token = request.getHeader("authorization");
try {
thread.setName(String.format("%s StartTime \"%s\" RequestURI \"%s\" Token \"%s\"", threadOriginalName, time, uri, token));
} catch (Exception ex) {
LOGGER.error("Failed to set the thread name.", ex);
// this is an internal filter and an error here should not impact
// the request processing, hence eat the exception
}
try {
filterChain.doFilter(request, response);
} finally {
try {
thread.setName(threadOriginalName);
} catch (Exception ex) {
LOGGER.error("Failed to reset the thread name.", ex);
// this is an internal filter and an error here should not
// impact the request processing, hence eat the exception
}
}
}
}
/**
* Generic filter for intercepting all requests and perform the following generic tasks:
*
* <ul>
* <li>Intercepts the request and then pushed the user domain into the session if one exists.</li>
* <li> Pushes a uniquely generated request identifier to the LOG4J NDC context. This identifier will then be prepended
* to all log messages generated using LOG4J. This allows tracing all log messages generated as part of the same
* request; </li>
* <li> Pushes the HTTP session identifier to the LOG4J NDC context. This identifier will then be prepended to all log
* messages generated using LOG4J. This allows tracing all log messages generated as part of the same HTTP session;
* </li>
* <li> Pushes the IP address of the client to the LOG4J NDC context. The IP address will then be prepended to all log
* messages generated using LOG4J. This allows tying back multiple user sessions initiated with the same logon name to
* be correctly tied back to their actual origins. </li>
* </ul>
*/
public class RequestInterceptorFilter implements Filter
{
/**
* <p>
* <ul>
* <li>Initializes the LOG4J NDC context before executing an HTTP requests.</li>
* <li>Pushes the domain into the session</li>
* </ul>
* </p>
*/
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException
{
HttpServletRequest httpRequest = (HttpServletRequest) request;
if (httpRequest.isRequestedSessionIdFromCookie() && !httpRequest.isRequestedSessionIdValid())
{
// TODO: Need to define an session expiration page and redirect the application to that page
// As of now this is a non-issue as we are handling session expirations on Flex (Front-end) and hence
// no request will come to server in case the session timeout occurs
// HttpServletResponse httpServletResponse = (HttpServletResponse) response;
// httpServletResponse.sendRedirect(httpRequest.getContextPath() + "?expired");
}
else
{
// Create an NDC context string that will be prepended to all log messages written to files.
org.apache.log4j.NDC.push(getContextualInformation(httpRequest));
// Process the chain of filters
chain.doFilter(request, response);
// Clear the NDC context string so that if the thread is reused for another request, a new context string is
// used.
org.apache.log4j.NDC.remove();
}
}
public void init(FilterConfig arg0) throws ServletException
{
}
public void destroy()
{
}
/**
* <p>
* Generates the Contextual information to be put in the log4j's context. This information helps in tracing requests
* </p>
*
* @param httpRequest
* @return
*/
private String getContextualInformation(HttpServletRequest httpRequest)
{
String httpRequestIdentifier = UUID.randomUUID().toString();
String httpSessionIdentifier = httpRequest.getSession().getId();
String clientAddress = httpRequest.getRemoteAddr();
StringBuffer logNDC = new StringBuffer(httpRequestIdentifier + " | " + httpSessionIdentifier + " | " + clientAddress);
String userName = (String)httpRequest.getSession().getAttribute(WebConstants.USERNAME);
if (userName != null)
{
logNDC.append(" | " + userName);
}
String domain = (String)httpRequest.getSession().getAttribute(WebConstants.DOMAIN);
if (domain != null)
{
logNDC.append(" | " + domain);
}
// Create an NDC context string that will be prepended to all log messages written to files.
return logNDC.toString();
}
}
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