From c3fefdf4d3fa4eeefcc442505b977ac350ecc165 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=99=88=E5=9B=BD=E4=BC=9F?= <366193849@qq.com>
Date: Fri, 16 Jul 2021 16:05:22 +0800
Subject: [PATCH] =?UTF-8?q?=E5=BC=82=E5=B8=B8=E8=BE=93=E5=87=BA?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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---
 .../KestrelServerOptionsExtensions.cs         |  2 +-
 ...everseProxyApplicationBuilderExtensions.cs | 22 +++++++++---
 .../ReverseProxyException.cs                  | 20 +++++++++++
 FastGithub.ReverseProxy/TrustedResolver.cs    | 36 ++++++++++++-------
 4 files changed, 62 insertions(+), 18 deletions(-)
 create mode 100644 FastGithub.ReverseProxy/ReverseProxyException.cs

diff --git a/FastGithub.ReverseProxy/KestrelServerOptionsExtensions.cs b/FastGithub.ReverseProxy/KestrelServerOptionsExtensions.cs
index a2dc252..47d865d 100644
--- a/FastGithub.ReverseProxy/KestrelServerOptionsExtensions.cs
+++ b/FastGithub.ReverseProxy/KestrelServerOptionsExtensions.cs
@@ -77,7 +77,7 @@ namespace FastGithub
                         store.Close();
                     }
                 }
-                catch (Exception  )
+                catch (Exception)
                 {
                     logger.LogError($"安装根证书{caPublicCerPath}失败：请手动安装到“将所有的证书都放入下载存储”\\“受信任的根证书颁发机构”");
                 }
diff --git a/FastGithub.ReverseProxy/ReverseProxyApplicationBuilderExtensions.cs b/FastGithub.ReverseProxy/ReverseProxyApplicationBuilderExtensions.cs
index 9fcc6c8..bfac93d 100644
--- a/FastGithub.ReverseProxy/ReverseProxyApplicationBuilderExtensions.cs
+++ b/FastGithub.ReverseProxy/ReverseProxyApplicationBuilderExtensions.cs
@@ -30,13 +30,25 @@ namespace FastGithub
                 if (options.CurrentValue.IsMatch(host) == false)
                 {
                     await context.Response.WriteAsJsonAsync(new { message = $"不支持以{host}访问" });
+                    return;
                 }
-                else
+
+                var port = context.Request.Host.Port ?? 443;
+                var destinationPrefix = $"https://{host}:{port}/";
+                var httpClient = new HttpMessageInvoker(httpClientHanlder, disposeHandler: false);
+                var error = await httpForwarder.SendAsync(context, destinationPrefix, httpClient);
+
+                if (error != ForwarderError.None)
                 {
-                    var port = context.Request.Host.Port ?? 443;
-                    var destinationPrefix = $"https://{host}:{port}/";
-                    var httpClient = new HttpMessageInvoker(httpClientHanlder, disposeHandler: false);
-                    await httpForwarder.SendAsync(context, destinationPrefix, httpClient);
+                    var errorFeature = context.GetForwarderErrorFeature();
+                    if (errorFeature != null)
+                    {
+                        await context.Response.WriteAsJsonAsync(new
+                        {
+                            error = error.ToString(),
+                            message = errorFeature.Exception?.Message
+                        });
+                    }
                 }
             });
 
diff --git a/FastGithub.ReverseProxy/ReverseProxyException.cs b/FastGithub.ReverseProxy/ReverseProxyException.cs
new file mode 100644
index 0000000..16aa1b7
--- /dev/null
+++ b/FastGithub.ReverseProxy/ReverseProxyException.cs
@@ -0,0 +1,20 @@
+using System;
+
+namespace FastGithub.ReverseProxy
+{
+    /// <summary>
+    /// 反向代理异常
+    /// </summary>
+    sealed class ReverseProxyException : Exception
+    {
+        /// <summary>
+        /// 反向代理异常
+        /// </summary>
+        /// <param name="message"></param>
+        /// <param name="inner"></param>
+        public ReverseProxyException(string message, Exception? inner)
+            : base(message, inner)
+        {
+        }
+    }
+}
diff --git a/FastGithub.ReverseProxy/TrustedResolver.cs b/FastGithub.ReverseProxy/TrustedResolver.cs
index 2f8d721..402786f 100644
--- a/FastGithub.ReverseProxy/TrustedResolver.cs
+++ b/FastGithub.ReverseProxy/TrustedResolver.cs
@@ -5,7 +5,6 @@ using Microsoft.Extensions.Options;
 using System;
 using System.Linq;
 using System.Net;
-using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -44,23 +43,36 @@ namespace FastGithub.ReverseProxy
         {
             // 缓存以避免做不必要的并发查询
             var key = $"domain:{domain}";
-            var address = await this.memoryCache.GetOrCreateAsync(key, async e =>
+            var address = await this.memoryCache.GetOrCreateAsync(key, e =>
             {
                 e.SetAbsoluteExpiration(this.cacheTimeSpan);
-                var dnsClient = new DnsClient(this.options.CurrentValue.TrustedDns.ToIPEndPoint());
-                var addresses = await dnsClient.Lookup(domain, DNS.Protocol.RecordType.A, cancellationToken);
-                return addresses?.FirstOrDefault();
+                return this.LookupAsync(domain, cancellationToken);
             });
 
-            if (address == null)
-            {
-                var message = $"无法解析{domain}的ip";
-                this.logger.LogWarning(message);
-                throw new HttpRequestException(message);
-            }
-
             this.logger.LogInformation($"[{address}->{domain}]");
             return address;
         }
+
+        /// <summary>
+        /// 查找ip
+        /// </summary>
+        /// <param name="domain"></param>
+        /// <param name="cancellationToken"></param>
+        /// <returns></returns>
+        private async Task<IPAddress> LookupAsync(string domain, CancellationToken cancellationToken)
+        {
+            var endpoint = this.options.CurrentValue.TrustedDns.ToIPEndPoint();
+            try
+            {
+                var dnsClient = new DnsClient(endpoint);
+                var addresses = await dnsClient.Lookup(domain, DNS.Protocol.RecordType.A, cancellationToken);
+                var address = addresses?.FirstOrDefault();
+                return address ?? throw new Exception($"解析不到{domain}的ip");
+            }
+            catch (Exception ex)
+            {
+                throw new ReverseProxyException($"dns({endpoint})：{ex.Message}", ex);
+            }
+        }
     }
 }