feat: Notification update subscription exception status code

Netch/Forms/MainForm.MenuStrip.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Net;
@@ -147,7 +148,17 @@ namespace Netch.Forms
                         if (Global.Settings.UseProxyToUpdateSubscription)
                             request.Proxy = new WebProxy($"http://127.0.0.1:{Global.Settings.HTTPLocalPort}");
 
-                        var servers = ShareLink.ParseText(await WebUtil.DownloadStringAsync(request));
+                        List<Server> servers;
+
+                        var result = WebUtil.DownloadString(request, out var rep);
+                        if (rep.StatusCode == HttpStatusCode.OK)
+                        {
+                            servers = ShareLink.ParseText(result);
+                        }
+                        else
+                        {
+                            throw new Exception($"{item.Remark} Response Status Code: {rep.StatusCode}");
+                        }
 
                         foreach (var server in servers)
                         {

Netch/Utils/WebUtil.cs

@@ -47,6 +47,22 @@ namespace Netch.Utils
             return memoryStream.ToArray();
         }
 
+        /// <summary>
+        ///     异步下载并编码为字符串
+        /// </summary>
+        /// <param name="req"></param>
+        /// <param name="rep"></param>
+        /// <param name="encoding">编码，默认UTF-8</param>
+        /// <returns></returns>
+        public static string DownloadString(HttpWebRequest req, out HttpWebResponse rep, string encoding = "UTF-8")
+        {
+            rep = (HttpWebResponse) req.GetResponse();
+            using var responseStream = rep.GetResponseStream();
+            using var streamReader = new StreamReader(responseStream, Encoding.GetEncoding(encoding));
+
+            return streamReader.ReadToEnd();
+        }
+
         /// <summary>
         ///     异步下载并编码为字符串
         /// </summary>