On Deck tweaks + Bugfixes (#1141)

* Tweaked the On deck to only look for series that have progress in past 30 days. This number is just to test it out, it will be configurable later. Tweaked the layout of the dashboard to remove a redundant section.

* Fixed a bug where archives with __MACOSX/ inside would break the reader during flattening.

* Fixed a bug where confirm service rejection should have resolved as false.

* Fixed an issue with checking if server is accessible with loopback and local ips

API/Services/EmailService.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Linq;
+using System.Net;
 using System.Threading.Tasks;
 using API.Data;
 using API.DTOs.Email;
@@ -40,14 +42,22 @@ public class EmailService : IEmailService
             cli.Settings.HttpClientFactory = new UntrustedCertClientFactory());
     }
 
+    /// <summary>
+    /// Test if this instance is accessible outside the network
+    /// </summary>
+    /// <remarks>This will do some basic filtering to auto return false if the emailUrl is a LAN ip</remarks>
+    /// <param name="emailUrl"></param>
+    /// <returns></returns>
     public async Task<EmailTestResultDto> TestConnectivity(string emailUrl)
     {
-        // FlurlHttp.ConfigureClient(emailUrl, cli =>
-        //     cli.Settings.HttpClientFactory = new UntrustedCertClientFactory());
-
         var result = new EmailTestResultDto();
         try
         {
+            if (IsLocalIpAddress(emailUrl))
+            {
+                result.Successful = false;
+                result.ErrorMessage = "This is a local IP address";
+            }
             result.Successful = await SendEmailWithGet(emailUrl + "/api/email/test");
         }
         catch (KavitaException ex)
@@ -72,6 +82,7 @@ public class EmailService : IEmailService
     public async Task<bool> CheckIfAccessible(string host)
     {
         // This is the only exception for using the default because we need an external service to check if the server is accessible for emails
+        if (IsLocalIpAddress(host)) return false;
         return await SendEmailWithGet(DefaultApiUrl + "/api/email/reachable?host=" + host);
     }
 
@@ -138,4 +149,34 @@ public class EmailService : IEmailService
         return true;
     }
 
+    private static bool IsLocalIpAddress(string url)
+    {
+        var host = url.Split(':')[0];
+        try
+        {
+            // get host IP addresses
+            var hostIPs = Dns.GetHostAddresses(host);
+            // get local IP addresses
+            var localIPs = Dns.GetHostAddresses(Dns.GetHostName());
+
+            // test if any host IP equals to any local IP or to localhost
+            foreach (var hostIp in hostIPs)
+            {
+                // is localhost
+                if (IPAddress.IsLoopback(hostIp)) return true;
+                // is local address
+                if (localIPs.Contains(hostIp))
+                {
+                    return true;
+                }
+            }
+        }
+        catch
+        {
+            // ignored
+        }
+
+        return false;
+    }
+
 }