C# Github访问切换Host

主代码

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net.NetworkInformation;
using System.Runtime.InteropServices;

namespace GithubDNS
{
    internal class Program
    {
        static void Main(string[] args)
        {
            var ips = GetAppSettingsValue("ips");
            GetFastIPDomain(ips);

            var globalips = GetAppSettingsValue("gips");
            GetFastIPDomain(globalips, "github.global.ssl.fastly.net");
        }

        public static void GetFastIPDomain(string ips, string domain = "github.com")
        {
            Dictionary<string, long> dic = new Dictionary<string, long>();
            foreach (var ip in ips.Split(','))
            {
                var time = PingIp(ip);
                if (time > 0)
                {
                    dic.Add(ip, time);
                }
            }

            if (dic.Count > 0)
            {
                var result = dic.OrderBy(c => c.Value).First().Key;
                UpdateHost(result, domain);
            }
        }

        public static string GetAppSettingsValue(string key)
        {
            return ConfigurationManager.AppSettings[key] ?? string.Empty;
        }

        /// <summary>
        /// ping ip,测试能否ping通
        /// </summary>
        /// <param name="strIP">IP地址</param>
        /// <returns></returns>
        private static long PingIp(string strIP, int timeOut = 1000)
        {
            long bRet = 0;
            try
            {
                Ping pingSend = new Ping();
                PingReply reply = pingSend.Send(strIP, timeOut);
                if (reply.Status == IPStatus.Success)
                    bRet = reply.RoundtripTime;
            }
            catch (Exception)
            {
                bRet = 0;
            }
            return bRet;
        }

        public static void UpdateHost(string ip, string domain = "github.com")
        {
            var OSInfo = Environment.OSVersion;
            string pathpart = "hosts";
            if (OSInfo.Platform == PlatformID.Win32NT)
            {
                //is windows NT
                pathpart = "system32\\drivers\\etc\\hosts";
            }
            string hostfile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Windows), pathpart);
            string tales = $"{ip}  {domain}";
            string[] lines = File.ReadAllLines(hostfile);

            if (lines.Any(s => s.Contains(domain)))
            {
                for (int i = 0; i < lines.Length; i++)
                {
                    if (lines[i].Contains(domain))
                        lines[i] = tales;
                }
                File.WriteAllLines(hostfile, lines);
            }
            else if (!lines.Contains(tales))
            {
                File.AppendAllLines(hostfile, new String[] { tales });
            }
        }

        [DllImport("Dnsapi.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool DnsFlushResolverCache();

        public static bool Flush()
        {
            if (Environment.OSVersion.Platform != PlatformID.Win32NT)
            {
                return false;
            }
            if (!DnsFlushResolverCache())
            {
                ExecuteInCmd("ipconfig /flushdns");
                return true;
            }
            return false;
        }

        /// <summary>
        /// 执行内部命令（cmd.exe 中的命令）
        /// </summary>
        /// <param name="cmdline">命令行</param>
        /// <returns>执行结果</returns>
        public static string ExecuteInCmd(string cmdline)
        {
            using (var process = new Process())
            {
                process.StartInfo.FileName = "cmd.exe";
                process.StartInfo.UseShellExecute = false;
                process.StartInfo.RedirectStandardInput = true;
                process.StartInfo.RedirectStandardOutput = true;
                process.StartInfo.RedirectStandardError = true;
                process.StartInfo.CreateNoWindow = true;

                process.Start();
                process.StandardInput.AutoFlush = true;
                process.StandardInput.WriteLine(cmdline + "&exit");

                //获取cmd窗口的输出信息  
                string output = process.StandardOutput.ReadToEnd();

                process.WaitForExit();
                process.Close();

                return output;
            }
        }
    }

}

配置

<?xml version="1.0" encoding="utf-8"?>
<configuration>
	<startup>
		<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2" />
	</startup>
	<appSettings>
		<add key="gips" value="124.11.210.175,128.242.245.180,108.160.163.112,31.13.68.169,108.160.169.174,31.13.96.195,202.53.137.209,103.240.182.55,108.160.169.55,93.179.102.140,108.160.165.173,69.171.229.73,108.160.162.109,162.125.1.8,103.252.115.221,74.86.151.162,108.160.166.9,157.240.10.32,182.50.139.56,185.60.218.50,108.160.167.30,211.104.160.39,199.59.148.202,199.59.149.238,66.220.146.94,198.44.185.131,157.240.15.8,151.101.1.194,104.244.46.211,66.220.147.11,31.13.91.33,108.160.169.186,199.232.45.194,146.75.49.194,157.240.11.40,150.107.3.176,151.101.109.194,108.160.172.204" />
		<add key="ips" value="20.205.243.166,52.78.231.108,15.164.81.167,140.82.113.4,52.192.72.89,140.82.112.3,140.82.113.3,13.114.40.48,192.30.255.112,140.82.114.4,140.82.121.3,192.30.255.113" />
	</appSettings>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Runtime.CompilerServices.Unsafe" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-6.0.0.0" newVersion="6.0.0.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>