package com.monkeyk.sos.web;

import org.apache.commons.lang.StringUtils;

import javax.servlet.http.HttpServletRequest;

/**
 * @author Shengzhao Li
 */
public abstract class WebUtils {


    //private
    private WebUtils() {
    }


    /**
     * Retrieve client ip address
     *
     * @param request HttpServletRequest
     * @return IP
     */
    public static String retrieveClientIp(HttpServletRequest request) {
        String ip = request.getHeader("x-forwarded-for");
        if (isUnAvailableIp(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (isUnAvailableIp(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (isUnAvailableIp(ip)) {
            ip = request.getRemoteAddr();
        }
        return ip;
    }

    private static boolean isUnAvailableIp(String ip) {
        return (StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip));
    }

}