using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Web;

namespace HuizhongLibrary
{
    public class LocalIpAddress
    {
        public static string GetIPAddress
        {
            get
            {
                string result = String.Empty;
                result = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"]; if (result != null && result != String.Empty)
                {
                    //可能有代理   
                    if (result.IndexOf(".") == -1)     //没有“.”肯定是非IPv4格式               
                        result = null;
                    else
                    {
                        if (result.IndexOf(",") != -1)
                        {
                            //有“,”，估计多个代理。取第一个不是内网的IP。               
                            result = result.Replace(" ", "").Replace("'", "");
                            string[] temparyip = result.Split(",;".ToCharArray());
                            for (int i = 0; i < temparyip.Length; i++)
                            {
                                if (IsIPAddress(temparyip[i]) && temparyip[i].Substring(0, 3) != "10." && temparyip[i].Substring(0, 7) != "192.168" && temparyip[i].Substring(0, 7) != "172.16.")
                                {
                                    return temparyip[i];     //找到不是内网的地址
                                }
                            }
                        }
                        else if (IsIPAddress(result)) //代理即是IP格式  
                            return result;
                        else
                            result = null;     //代理中的内容 非IP，取IP       
                    }
                }
                string IpAddress = (HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != null && HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != String.Empty) ? HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] : HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
                if (null == result || result == String.Empty)
                    result = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
                if (result == null || result == String.Empty)
                    result = HttpContext.Current.Request.UserHostAddress;
                return result;
            }
        }


        #region bool IsIPAddress(str1) 判断是否是IP格式 
        /**//// <summary>
            /// 判断是否是IP地址格式 0.0.0.0
            /// </summary>
            /// <param name="str1">待判断的IP地址</param>
            /// <returns>true or false</returns>
        public static bool IsIPAddress(string str1)
        {
            if (str1 == null || str1 == string.Empty || str1.Length < 7 || str1.Length > 15) return false;
            string regformat = @"^\d{1,3}[\.]\d{1,3}[\.]\d{1,3}[\.]\d{1,3}$";
            Regex regex = new Regex(regformat, RegexOptions.IgnoreCase);
            return regex.IsMatch(str1);
        }
        #endregion
    }
}