package com.ccic.cas.utils;

import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;

public class ServletUtils {

private static String IP_UNKNOW = "unknown";
private static String[] POSSIBLE_HEADERS = new String[] { "x-forwarded-for", "Proxy-Client-IP",
"WL-Proxy-Client-IP" };

/**
* Get the remote IP address of the client
*/
public static String getRemoteAddr(ServletRequest req) {
if (req instanceof HttpServletRequest) {
HttpServletRequest request = (HttpServletRequest) req;
String ip = null;
for (int i = 0; i < POSSIBLE_HEADERS.length && isInvalidIP(ip); i++) {
ip = request.getHeader(POSSIBLE_HEADERS[i]);
}
if (isInvalidIP(ip)) {
ip = request.getRemoteAddr();
}
return ip;
} else {
return req.getRemoteAddr();
}
}

private static boolean isInvalidIP(String ip) {
return ip == null || ip.trim().length() == 0 || IP_UNKNOW.equalsIgnoreCase(ip);
}
}