IpHelper 根据客户端IP进行网站分流
public class IpHelper
{
// 核心方法：IP搜索
/// <summary>
/// 查找IP所属地区，确保web.config存在IPData或者BackIpData配置节
/// </summary>
/// <param name="ips">IP</param>
/// <returns></returns>
public static IpLocation GetIpLocation(string ips)
{
string fn =HttpContext.Current.Server.MapPath(ConfigurationManager.AppSettings["IPData"]);
string backData = HttpContext.Current.Server.MapPath(ConfigurationManager.AppSettings["BackIpData"]);
if (!File.Exists(fn))
{
if (!File.Exists(backData))
{
throw new Exception("文件不存在");
}
fn = backData;
}
FileStream fs = new FileStream(fn, FileMode.Open, FileAccess.Read, FileShare.Read);
BinaryReader fp = new BinaryReader(fs);
//读文件头,获取首末记录偏移量
int fo = fp.ReadInt32();
int lo = fp.ReadInt32();
//IP值
uint ipv = IpStringToInt(ips);
// 获取IP索引记录偏移值
int rcOffset = getIndexOffset(fs, fp, fo, lo, ipv);
fs.Seek(rcOffset, System.IO.SeekOrigin.Begin);
IpLocation ipl;
if (rcOffset >= 0)
{
fs.Seek(rcOffset, System.IO.SeekOrigin.Begin);
//读取开头IP值
ipl.IpStart = fp.ReadUInt32();
//转到记录体
fs.Seek(ReadInt24(fp), System.IO.SeekOrigin.Begin);
//读取结尾IP值
ipl.IpEnd = fp.ReadUInt32();
ipl.Country = GetString(fs, fp);
ipl.City = GetString(fs, fp);
}
else
{
//没找到
ipl.IpStart = 0;
ipl.IpEnd = 0;
ipl.Country = "未知国家";
ipl.City = "未知地址";
}
fp.Close();
fs.Close();
return ipl;
}
// 函数功能: 采用“二分法”搜索索引区, 定位IP索引记录位置
private static int getIndexOffset(FileStream fs, BinaryReader fp, int _fo, int _lo, uint ipv)
{
int fo = _fo, lo = _lo;
int mo; //中间偏移量
uint mv; //中间值
uint fv, lv; //边界值
uint llv; //边界末末值
fs.Seek(fo, System.IO.SeekOrigin.Begin);
fv = fp.ReadUInt32();
fs.Seek(lo, System.IO.SeekOrigin.Begin);
lv = fp.ReadUInt32();
//临时作它用,末记录体偏移量
mo = ReadInt24(fp);
fs.Seek(mo, System.IO.SeekOrigin.Begin);
llv = fp.ReadUInt32();
//边界检测处理
if (ipv < fv)
return -1;
else if (ipv > llv)
return -1;
//使用"二分法"确定记录偏移量
do
{
mo = fo + (lo - fo) / 7 / 2 * 7;
fs.Seek(mo, System.IO.SeekOrigin.Begin);
mv = fp.ReadUInt32();
if (ipv >= mv)
fo = mo;
else
lo = mo;
if (lo - fo == 7)
mo = lo = fo;
} while (fo != lo);
return mo;
}
// 字符串数值型判断
public static bool IsNumeric(string s)
{
if (s != null && System.Text.RegularExpressions.Regex.IsMatch(s, @"^-?\d+$"))
return true;
else
return false;
}
// IP字符串->长整型值
public static uint IpStringToInt(string IpString)
{
uint Ipv = 0;
string[] IpStringArray = IpString.Split('.');
int i;
uint Ipi;
for (i = 0; i < 4 && i < IpStringArray.Length; i++)
{
if (IsNumeric(IpStringArray[i]))
{
Ipi = (uint)Math.Abs(Convert.ToInt32(IpStringArray[i]));
if (Ipi > 255) Ipi = 255;
Ipv += Ipi << (3 - i) * 8;
}
}
return Ipv;
}
// 长整型值->IP字符串
public static string IntToIpString(uint Ipv)
{
string IpString = "";
IpString += (Ipv >> 24) + "." + ((Ipv & 0x00FF0000) >> 16) + "." + ((Ipv & 0x0000FF00) >> 8) + "." + (Ipv & 0x000000FF);
return IpString;
}
// 读取字符串
private static string ReadString(BinaryReader fp)
{
byte[] TempByteArray = new byte[128];
int i = 0;
do
{
TempByteArray[i] = fp.ReadByte();
} while (TempByteArray[i++] != '\0' && i < 128);
return System.Text.Encoding.Default.GetString(TempByteArray).TrimEnd('\0');
}
// 读取三字节的整数
private static int ReadInt24(BinaryReader fp)
{
if (fp == null) return -1;
int ret = 0;
ret |= (int)fp.ReadByte();
ret |= (int)fp.ReadByte() << 8 & 0xFF00;
ret |= (int)fp.ReadByte() << 16 & 0xFF0000;
return ret;
}
// 读取IP所在地字符串
private static string GetString(FileStream fs, BinaryReader fp)
{
byte Tag;
int Offset;
Tag = fp.ReadByte();
if (Tag == 0x01) // 重定向模式1: 城市信息随国家信息定向
{
Offset = ReadInt24(fp);
fs.Seek(Offset, System.IO.SeekOrigin.Begin);
return GetString(fs, fp);
}
else if (Tag == 0x02) // 重定向模式2: 城市信息没有随国家信息定向
{
Offset = ReadInt24(fp);
int TmpOffset = (int)fs.Position;
fs.Seek(Offset, System.IO.SeekOrigin.Begin);
string TmpString = GetString(fs, fp);
fs.Seek(TmpOffset, System.IO.SeekOrigin.Begin);
return TmpString;
}
else // 无重定向: 最简单模式
{
fs.Seek(-1, System.IO.SeekOrigin.Current);
return ReadString(fp);
}
}
}
// IP查询结果结构
public struct IpLocation
{
public uint IpStart;
public uint IpEnd;
/// <summary>
/// 国家或城市
/// </summary>
public string Country;
/// <summary>
/// 城市或详细地址
/// </summary>
public string City;
}
