Fixed duplicate insertions into the filtered database.

Models/Handler/DbHandler.cs

@@ -25,6 +25,7 @@ public class DbHandler
     private const string ReadUnfilteredIdsStatement = "SELECT Id FROM Unfiltered WHERE Id != 0 ORDER BY Id DESC LIMIT 1;";
     private const string ReadFilteredStatement = "SELECT Title2, Url2 FROM Filtered WHERE (Url2 NOT NULL AND Url2 != '') AND (Title2 NOT NULL AND Title2 != '') ORDER BY Url2 DESC;";
     private const string ReadFilteredIdsStatement = "SELECT Id FROM Filtered WHERE Id != 0 ORDER BY Id DESC LIMIT 1;";
+    private const string ReadFilteredIpStatement = "SELECT Ip FROM Filtered WHERE Ip == @ip ORDER BY Ip DESC LIMIT 1;";
     private const string ReadDiscardedSeqIdsStatement = "SELECT seq FROM sqlite_sequence;";
     private const string ReadAndDeleteResumeStatement = "SELECT * FROM Resume WHERE ThreadNumber == @threadNumber; DELETE FROM RESUME WHERE ThreadNumber == @threadNumber;";
     
@@ -365,7 +366,27 @@ public class DbHandler
 
     public bool GetFilteredIp(string ip)
     {
-        return true;
+        using SqliteConnection connection = new(_filteredConnectionString);
+        connection.Open();
+        
+        using SqliteCommand command = new(ReadFilteredIpStatement, connection);
+        command.Parameters.AddWithValue("@ip", ip);
+        
+        using SqliteDataReader reader = command.ExecuteReader();
+        
+        if (!reader.HasRows)
+        {
+            return false;
+        }
+        
+        string ipAddress = "";
+        
+        while (reader.Read())
+        {
+            ipAddress = reader.GetString(0);
+        }
+        
+        return ipAddress == ip;
     }
     
     public List<SearchResult?> GetSearchResults()