From 87deb0c5cbb84919a649b6ead99689064fbe722f Mon Sep 17 00:00:00 2001
From: xljiulang <366193849@qq.com>
Date: Sun, 20 Jun 2021 15:23:15 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BD=BF=E7=94=A8=E6=89=AB=E6=8F=8F=E7=BB=93?=
 =?UTF-8?q?=E6=9E=9C=E6=90=9C=E7=B4=A2=E6=9B=BF=E4=BB=A3dns=E8=A7=A3?=
 =?UTF-8?q?=E6=9E=90?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 ...HttpHandler.cs => GithubDnsHttpHandler.cs} | 40 ++++++-------------
 .../ScannerServiceCollectionExtensions.cs     |  2 +-
 2 files changed, 13 insertions(+), 29 deletions(-)
 rename FastGithub.Scanner/{LoopbackDnsHttpHandler.cs => GithubDnsHttpHandler.cs} (53%)

diff --git a/FastGithub.Scanner/LoopbackDnsHttpHandler.cs b/FastGithub.Scanner/GithubDnsHttpHandler.cs
similarity index 53%
rename from FastGithub.Scanner/LoopbackDnsHttpHandler.cs
rename to FastGithub.Scanner/GithubDnsHttpHandler.cs
index 529d390..abb498b 100644
--- a/FastGithub.Scanner/LoopbackDnsHttpHandler.cs
+++ b/FastGithub.Scanner/GithubDnsHttpHandler.cs
@@ -1,8 +1,5 @@
-using DNS.Client;
-using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection;
 using System;
-using System.Linq;
-using System.Net;
 using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
@@ -10,15 +7,21 @@ using System.Threading.Tasks;
 namespace FastGithub.Scanner
 {
     /// <summary>
-    /// 由本程序提值的dns的httpHandler
+    /// Github的dns解析的httpHandler
+    /// 使扫描索结果作为github的https请求的域名解析
     /// </summary>
     [Service(ServiceLifetime.Transient)]
-    sealed class LoopbackDnsHttpHandler : DelegatingHandler
+    sealed class GithubDnsHttpHandler : DelegatingHandler
     {
+        private readonly GithubContextCollection scanResults;
+
         /// <summary>
-        /// 本程序的dns
+        /// Github的dns解析的httpHandler
         /// </summary>
-        private static readonly DnsClient dnsClient = new(IPAddress.Loopback);
+        public GithubDnsHttpHandler(GithubContextCollection scanResults)
+        {
+            this.scanResults = scanResults;
+        }
 
         /// <summary>
         /// 发送消息
@@ -31,7 +34,7 @@ namespace FastGithub.Scanner
             var uri = request.RequestUri;
             if (uri != null && uri.HostNameType == UriHostNameType.Dns)
             {
-                var address = await LookupAsync(uri.Host);
+                var address = this.scanResults.FindBestAddress(uri.Host);
                 if (address != null)
                 {
                     var builder = new UriBuilder(uri)
@@ -45,24 +48,5 @@ namespace FastGithub.Scanner
 
             return await base.SendAsync(request, cancellationToken);
         }
-
-        /// <summary>
-        /// dns解析ip
-        /// </summary>
-        /// <param name="host"></param>
-        /// <returns></returns>
-        private static async Task<IPAddress?> LookupAsync(string host)
-        {
-            try
-            {
-                using var cancellationTokenSource = new CancellationTokenSource(TimeSpan.FromMilliseconds(500d));
-                var addresses = await dnsClient.Lookup(host, cancellationToken: cancellationTokenSource.Token);
-                return addresses.FirstOrDefault();
-            }
-            catch (Exception)
-            {
-                return default;
-            }
-        }
     }
 }
diff --git a/FastGithub.Scanner/ScannerServiceCollectionExtensions.cs b/FastGithub.Scanner/ScannerServiceCollectionExtensions.cs
index f5cda97..ca46c4d 100644
--- a/FastGithub.Scanner/ScannerServiceCollectionExtensions.cs
+++ b/FastGithub.Scanner/ScannerServiceCollectionExtensions.cs
@@ -37,7 +37,7 @@ namespace FastGithub
                     UseProxy = false,
                     AllowAutoRedirect = false
                 })
-                .AddHttpMessageHandler<LoopbackDnsHttpHandler>();
+                .AddHttpMessageHandler<GithubDnsHttpHandler>();
 
             return services
                 .AddMemoryCache()