From 2bc292483bbe2b5e42b9b4403e10b3c6f17402bb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=80=81=E4=B9=9D?= <366193849@qq.com>
Date: Fri, 19 Nov 2021 23:39:23 +0800
Subject: [PATCH] =?UTF-8?q?=E5=AE=8C=E5=96=84IP=E6=B5=8B=E9=80=9F=E7=BC=93?=
 =?UTF-8?q?=E5=AD=98?=
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---
 FastGithub.DomainResolve/DomainResolver.cs    |  8 +--
 .../IPAddressStatusService.cs                 | 53 ++++++++++---------
 2 files changed, 29 insertions(+), 32 deletions(-)

diff --git a/FastGithub.DomainResolve/DomainResolver.cs b/FastGithub.DomainResolve/DomainResolver.cs
index 9d245e2..816d0b1 100644
--- a/FastGithub.DomainResolve/DomainResolver.cs
+++ b/FastGithub.DomainResolve/DomainResolver.cs
@@ -109,13 +109,7 @@ namespace FastGithub.DomainResolve
                     hashSet.Add(address);
                 }
 
-                var statusArray = await this.statusService.GetParallelAsync(hashSet, dnsEndPoint.Port, cancellationToken);
-                var newAddresses = statusArray
-                    .Where(item => item.Elapsed < TimeSpan.MaxValue)
-                    .OrderBy(item => item.Elapsed)
-                    .Select(item => item.Address)
-                    .ToArray();
-
+                var newAddresses = await this.statusService.GetAvailableAddressesAsync(hashSet, dnsEndPoint.Port, cancellationToken);
                 if (oldAddresses.SequenceEqual(newAddresses) == false)
                 {
                     this.dnsEndPointAddress[dnsEndPoint] = newAddresses;
diff --git a/FastGithub.DomainResolve/IPAddressStatusService.cs b/FastGithub.DomainResolve/IPAddressStatusService.cs
index 73c62bb..0ebb56f 100644
--- a/FastGithub.DomainResolve/IPAddressStatusService.cs
+++ b/FastGithub.DomainResolve/IPAddressStatusService.cs
@@ -5,6 +5,7 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using System.Net;
+using System.Net.NetworkInformation;
 using System.Net.Sockets;
 using System.Threading;
 using System.Threading.Tasks;
@@ -13,30 +14,40 @@ namespace FastGithub.DomainResolve
 {
     /// <summary>
     /// IP状态服务
-    /// 连接成功的IP缓存5分钟
-    /// 连接失败的IP缓存2分钟
+    /// 状态缓存5分钟
+    /// 连接超时5秒
     /// </summary>
     sealed class IPAddressStatusService
     {
-        private readonly TimeSpan activeTTL = TimeSpan.FromMinutes(5d);
-        private readonly TimeSpan negativeTTL = TimeSpan.FromMinutes(2d);
+        private readonly TimeSpan brokeExpiration = TimeSpan.FromMinutes(1d);
+        private readonly TimeSpan normalExpiration = TimeSpan.FromMinutes(5d);
         private readonly TimeSpan connectTimeout = TimeSpan.FromSeconds(5d);
         private readonly IMemoryCache statusCache = new MemoryCache(Options.Create(new MemoryCacheOptions()));
 
-
         /// <summary>
-        /// 并行获取多个IP的状态
+        /// 并行获取可连接的IP
         /// </summary>
         /// <param name="addresses"></param>
         /// <param name="port"></param>
         /// <param name="cancellationToken"></param>
         /// <returns></returns>
-        public Task<IPAddressStatus[]> GetParallelAsync(IEnumerable<IPAddress> addresses, int port, CancellationToken cancellationToken)
+        public async Task<IPAddress[]> GetAvailableAddressesAsync(IEnumerable<IPAddress> addresses, int port, CancellationToken cancellationToken)
         {
-            var statusTasks = addresses.Select(item => this.GetAsync(item, port, cancellationToken));
-            return Task.WhenAll(statusTasks);
+            if (addresses.Any() == false)
+            {
+                return Array.Empty<IPAddress>();
+            }
+
+            var statusTasks = addresses.Select(item => this.GetStatusAsync(item, port, cancellationToken));
+            var statusArray = await Task.WhenAll(statusTasks);
+            return statusArray
+                .Where(item => item.Elapsed < TimeSpan.MaxValue)
+                .OrderBy(item => item.Elapsed)
+                .Select(item => item.Address)
+                .ToArray();
         }
 
+
         /// <summary>
         /// 获取IP状态
         /// </summary>
@@ -44,7 +55,7 @@ namespace FastGithub.DomainResolve
         /// <param name="port"></param>
         /// <param name="cancellationToken"></param>
         /// <returns></returns>
-        public async Task<IPAddressStatus> GetAsync(IPAddress address, int port, CancellationToken cancellationToken)
+        private async Task<IPAddressStatus> GetStatusAsync(IPAddress address, int port, CancellationToken cancellationToken)
         {
             var endPoint = new IPEndPoint(address, port);
             if (this.statusCache.TryGetValue<IPAddressStatus>(endPoint, out var status))
@@ -52,19 +63,6 @@ namespace FastGithub.DomainResolve
                 return status;
             }
 
-            status = await this.GetAddressStatusAsync(endPoint, cancellationToken);
-            var ttl = status.Elapsed < TimeSpan.MaxValue ? this.activeTTL : this.negativeTTL;
-            return this.statusCache.Set(endPoint, status, ttl);
-        }
-
-        /// <summary>
-        /// 获取IP状态
-        /// </summary>
-        /// <param name="endPoint"></param>
-        /// <param name="cancellationToken"></param>
-        /// <returns></returns>
-        private async Task<IPAddressStatus> GetAddressStatusAsync(IPEndPoint endPoint, CancellationToken cancellationToken)
-        {
             var stopWatch = Stopwatch.StartNew();
             try
             {
@@ -72,12 +70,17 @@ namespace FastGithub.DomainResolve
                 using var linkedTokenSource = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken, timeoutTokenSource.Token);
                 using var socket = new Socket(endPoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
                 await socket.ConnectAsync(endPoint, linkedTokenSource.Token);
-                return new IPAddressStatus(endPoint.Address, stopWatch.Elapsed);
+
+                status = new IPAddressStatus(endPoint.Address, stopWatch.Elapsed);
+                return this.statusCache.Set(endPoint, status, this.normalExpiration);
             }
             catch (Exception)
             {
                 cancellationToken.ThrowIfCancellationRequested();
-                return new IPAddressStatus(endPoint.Address, TimeSpan.MaxValue);
+
+                status = new IPAddressStatus(endPoint.Address, TimeSpan.MaxValue);
+                var expiration = NetworkInterface.GetIsNetworkAvailable() ? this.normalExpiration : this.brokeExpiration;
+                return this.statusCache.Set(endPoint, status, expiration);
             }
             finally
             {