Feature: HostsFileEditor add/edit

Source/NETworkManager.Localization/Resources/Strings.resx

@@ -679,7 +679,7 @@
     <value>Apply</value>
   </data>
   <data name="ApplyWindowsKeyCombinationsLikeAltTab" xml:space="preserve">
-    <value>Apply Windows key combinations (e.g. ALT+TAB):</value>
+    <value>Apply Windows key combinations (e.g., ALT+TAB):</value>
   </data>
   <data name="Auth" xml:space="preserve">
     <value>Auth</value>
@@ -1367,16 +1367,16 @@ Profile files are not affected!</value>
     <value>Enter a valid IPv4 address!</value>
   </data>
   <data name="EnterValidMACAddress" xml:space="preserve">
-    <value>Enter a valid MAC address (like 00:F1:23:AB:F2:35)!</value>
+    <value>Enter a valid MAC address (e.g., 00:F1:23:AB:F2:35)!</value>
   </data>
   <data name="EnterValidPort" xml:space="preserve">
     <value>Enter a valid port (1 - 65535)!</value>
   </data>
   <data name="EnterValidSubnetmask" xml:space="preserve">
-    <value>Enter a valid subnetmask (like 255.255.255.0)!</value>
+    <value>Enter a valid subnetmask (e.g., 255.255.255.0)!</value>
   </data>
   <data name="EnterValidSubnetmaskOrCIDR" xml:space="preserve">
-    <value>Enter a valid subnetmask or CIDR (like 255.255.255.0 or /24)!</value>
+    <value>Enter a valid subnetmask or CIDR (e.g., 255.255.255.0 or /24)!</value>
   </data>
   <data name="FieldCannotBeEmpty" xml:space="preserve">
     <value>Field cannot be empty!</value>
@@ -1448,10 +1448,10 @@ Profile files are not affected!</value>
     <value>Enter a valid port and/or port range (1 - 65535)!</value>
   </data>
   <data name="EnterValidSubnet" xml:space="preserve">
-    <value>Enter a valid subnet (like 192.168.178.133/26)!</value>
+    <value>Enter a valid subnet (e.g., 192.168.178.133/26)!</value>
   </data>
   <data name="EnterValidWebsiteUri" xml:space="preserve">
-    <value>Enter a valid website (like https://example.com/index.html)</value>
+    <value>Enter a valid website (e.g., https://example.com/index.html)</value>
   </data>
   <data name="Green" xml:space="preserve">
     <value>Green</value>
@@ -1742,7 +1742,7 @@ Profile files are not affected!</value>
     <value>Add a tab to query whois...</value>
   </data>
   <data name="EnterValidDomain" xml:space="preserve">
-    <value>Enter a valid domain (like "example.com")!</value>
+    <value>Enter a valid domain (e.g., "example.com")!</value>
   </data>
   <data name="WhoisServerNotFoundForTheDomain" xml:space="preserve">
     <value>Whois server not found for the domain: "{0}"</value>
@@ -2032,7 +2032,7 @@ is disabled!</value>
     <value>Use custom IPv4 address API</value>
   </data>
   <data name="HelpMessage_CustomPublicIPv4AddressAPI" xml:space="preserve">
-    <value>URL to a web service that can be reached via http or https and returns an IPv4 address like "xx.xx.xx.xx" as response.</value>
+    <value>URL to a web service that can be reached via http or https and returns an IPv4 address e.g., "xx.xx.xx.xx" as response.</value>
   </data>
   <data name="CouldNotParsePublicIPAddressFromXXXMessage" xml:space="preserve">
     <value>Could not parse public ip address from "{0}"! Try another service or use the default... </value>
@@ -3192,7 +3192,7 @@ If the option is disabled again, the values are no longer modified. However, the
     <value>SNTP server(s)</value>
   </data>
   <data name="HelpMessage_CustomPublicIPv6AddressAPI" xml:space="preserve">
-    <value>URL to a web service that can be reached via http or https and returns an IPv6 address like "xxxx:xx:xxx::xx" as response.</value>
+    <value>URL to a web service that can be reached via http or https and returns an IPv6 address e.g., "xxxx:xx:xxx::xx" as response.</value>
   </data>
   <data name="IPEndPoint" xml:space="preserve">
     <value>IP endpoint</value>
@@ -3234,7 +3234,7 @@ If the option is disabled again, the values are no longer modified. However, the
     <value>An SNTP server with this name already exists!</value>
   </data>
   <data name="EnterValidHostnameOrIPAddress" xml:space="preserve">
-    <value>Enter a valid hostname (like "server-01" or "example.com") or a valid IP address (like 192.168.178.1)!</value>
+    <value>Enter a valid hostname (e.g., "server-01" or "example.com") or a valid IP address (e.g., 192.168.178.1)!</value>
   </data>
   <data name="Servers" xml:space="preserve">
     <value>Server(s)</value>
@@ -3528,10 +3528,10 @@ Changes to this value will take effect after the application is restarted. Wheth
     <value>The settings on this page contain errors. Correct them to be able to save.</value>
   </data>
   <data name="HelpMessage_PuTTYHostkey" xml:space="preserve">
-    <value>SSH hostkey to use for the connection (like "71:b8:f2:6e..."). Only available if the mode is "SSH".</value>
+    <value>SSH hostkey to use for the connection (e.g., "71:b8:f2:6e..."). Only available if the mode is "SSH".</value>
   </data>
   <data name="HelpMessage_PuTTYPrivateKeyFile" xml:space="preserve">
-    <value>Full path to the private key file (like "C:\Users\BornToBeRoot\SSH\private_key.ppk"). Only available if the mode is "SSH".</value>
+    <value>Full path to the private key file (e.g., "C:\Users\BornToBeRoot\SSH\private_key.ppk"). Only available if the mode is "SSH".</value>
   </data>
   <data name="HelpMessage_PuTTYUsername" xml:space="preserve">
     <value>Username that will be passed into the PuTTY session. Only available if the mode is "SSH", "Telnet" or "Rlogin".</value>
@@ -3938,4 +3938,22 @@ Right-click for more options.</value>
 
 {0} {1} {2}</value>
   </data>
+  <data name="ExampleHostsFileEntryComment" xml:space="preserve">
+    <value>Primary DNS server</value>
+  </data>
+  <data name="EnterValidHostsFileEntryHostname" xml:space="preserve">
+    <value>Enter a valid hostname (e.g., "server-01" or "example.com")! Multiple hostnames can be separated with a space.</value>
+  </data>
+  <data name="HostsFileReadErrorMessage" xml:space="preserve">
+    <value>The "hosts" file could not be read! See log file for more details.</value>
+  </data>
+  <data name="HostsFileWriteErrorMessage" xml:space="preserve">
+    <value>The "hosts" file could not be written to. See log file for more details.</value>
+  </data>
+  <data name="HostsFileEntryNotFoundMessage" xml:space="preserve">
+    <value>The entry was not found in the "hosts" file! Maybe the file has been modified.</value>
+  </data>
+  <data name="HostsFileBackupErrorMessage" xml:space="preserve">
+    <value>A backup of the "hosts" file could not be created! See log file for more details.</value>
+  </data>
 </root>

Source/NETworkManager.Models/HostsFileEditor/HostsFileEditor.cs

@@ -188,8 +188,18 @@ private static HostsFileEntryModifyResult EnableEntry(HostsFileEntry entry)
             return HostsFileEntryModifyResult.BackupError;
         }
 
-        // Replace the entry in the hosts file
-        var hostsFileLines = File.ReadAllLines(HostsFilePath).ToList();
+        // Enable the entry in the hosts file
+        List<string> hostsFileLines;
+
+        try
+        {
+            hostsFileLines = [.. File.ReadAllLines(HostsFilePath)];
+        }
+        catch (Exception ex)
+        {
+            Log.Error($"EnableEntry - Failed to read hosts file: {HostsFilePath}", ex);
+            return HostsFileEntryModifyResult.ReadError;
+        }
 
         bool entryFound = false;
 
@@ -199,7 +209,15 @@ private static HostsFileEntryModifyResult EnableEntry(HostsFileEntry entry)
             {
                 entryFound = true;
 
-                hostsFileLines[i] = entry.Line.TrimStart('#', ' ');
+                hostsFileLines.RemoveAt(i);
+                hostsFileLines.Insert(i, CreateEntryLine(new HostsFileEntry
+                {
+                    IsEnabled = true,
+                    IPAddress = entry.IPAddress,
+                    Hostname = entry.Hostname,
+                    Comment = entry.Comment,
+                    Line = entry.Line
+                }));
 
                 break;
             }
@@ -250,8 +268,18 @@ private static HostsFileEntryModifyResult DisableEntry(HostsFileEntry entry)
             return HostsFileEntryModifyResult.BackupError;
         }
 
-        // Replace the entry in the hosts file
-        var hostsFileLines = File.ReadAllLines(HostsFilePath).ToList();
+        // Disable the entry in the hosts file
+        List<string> hostsFileLines;
+
+        try
+        {
+            hostsFileLines = [.. File.ReadAllLines(HostsFilePath)];
+        }
+        catch (Exception ex)
+        {
+            Log.Error($"DisableEntry - Failed to read hosts file: {HostsFilePath}", ex);
+            return HostsFileEntryModifyResult.ReadError;
+        }
 
         bool entryFound = false;
 
@@ -261,7 +289,15 @@ private static HostsFileEntryModifyResult DisableEntry(HostsFileEntry entry)
             {
                 entryFound = true;
 
-                hostsFileLines[i] = "# " + entry.Line;
+                hostsFileLines.RemoveAt(i);
+                hostsFileLines.Insert(i, CreateEntryLine(new HostsFileEntry
+                {
+                    IsEnabled = false,
+                    IPAddress = entry.IPAddress,
+                    Hostname = entry.Hostname,
+                    Comment = entry.Comment,
+                    Line = entry.Line
+                }));
 
                 break;
             }
@@ -287,6 +323,133 @@ private static HostsFileEntryModifyResult DisableEntry(HostsFileEntry entry)
         return HostsFileEntryModifyResult.Success;
     }
 
+    /// <summary>
+    /// Add a hosts file entry asynchronously.
+    /// </summary>
+    /// <param name="entry">Entry to add.</param>
+    /// <returns><see cref="HostsFileEntryModifyResult.Success"/> if the entry was added successfully, otherwise an error result.</returns>"/>
+    public static Task<HostsFileEntryModifyResult> AddEntryAsync(HostsFileEntry entry)
+    {
+        return Task.Run(() => AddEntry(entry));
+    }
+
+    /// <summary>
+    /// Add a hosts file entry.
+    /// </summary>
+    /// <param name="entry">Entry to add.</param>
+    /// <returns><see cref="HostsFileEntryModifyResult.Success"/> if the entry was added successfully, otherwise an error result.</returns>"/>
+    private static HostsFileEntryModifyResult AddEntry(HostsFileEntry entry)
+    {
+        // Create a backup of the hosts file before making changes
+        if (CreateBackup() == false)
+        {
+            Log.Error("AddEntry - Failed to create backup before adding entry.");
+            return HostsFileEntryModifyResult.BackupError;
+        }
+
+        // Add the entry to the hosts file       
+        List<string> hostsFileLines;
+
+        try
+        {
+            hostsFileLines = [.. File.ReadAllLines(HostsFilePath)];
+        }
+        catch (Exception ex)
+        {
+            Log.Error($"AddEntry - Failed to read hosts file: {HostsFilePath}", ex);
+            return HostsFileEntryModifyResult.ReadError;
+        }
+
+        hostsFileLines.Add(CreateEntryLine(entry));
+
+        try
+        {
+            Log.Debug($"AddEntry - Writing changes to hosts file: {HostsFilePath}");
+            File.WriteAllLines(HostsFilePath, hostsFileLines);
+        }
+        catch (Exception ex)
+        {
+            Log.Error($"AddEntry - Failed to write changes to hosts file: {HostsFilePath}", ex);
+            return HostsFileEntryModifyResult.WriteError;
+        }
+
+        return HostsFileEntryModifyResult.Success;
+    }
+
+    /// <summary>
+    /// Edit a hosts file entry asynchronously.
+    /// </summary>
+    /// <param name="entry">Entry to edit.</param>
+    /// <param name="newEntry">New entry to replace the old one.</param>
+    /// <returns><see cref="HostsFileEntryModifyResult.Success"/> if the entry was edited successfully, otherwise an error result.</returns>"/>
+    public static Task<HostsFileEntryModifyResult> EditEntryAsync(HostsFileEntry entry, HostsFileEntry newEntry)
+    {
+        return Task.Run(() => EditEntry(entry, newEntry));
+    }
+
+    /// <summary>
+    /// Edit a hosts file entry.
+    /// </summary>
+    /// <param name="entry">Entry to edit.</param>
+    /// <param name="newEntry">New entry to replace the old one.</param>
+    /// <returns><see cref="HostsFileEntryModifyResult.Success"/> if the entry was edited successfully, otherwise an error result.</returns>"/>
+    private static HostsFileEntryModifyResult EditEntry(HostsFileEntry entry, HostsFileEntry newEntry)
+    {
+        // Create a backup of the hosts file before making changes
+        if (CreateBackup() == false)
+        {
+            Log.Error("EditEntry - Failed to create backup before editing entry.");
+            return HostsFileEntryModifyResult.BackupError;
+        }
+
+        // Replace the entry from the hosts file
+        List<string> hostsFileLines;
+
+        try
+        {
+            hostsFileLines = [.. File.ReadAllLines(HostsFilePath)];
+        }
+        catch (Exception ex)
+        {
+            Log.Error($"EditEntry - Failed to read hosts file: {HostsFilePath}", ex);
+            return HostsFileEntryModifyResult.ReadError;
+        }
+
+        bool entryFound = false;
+
+        for (var i = 0; i < hostsFileLines.Count; i++)
+        {
+            if (hostsFileLines[i] == entry.Line)
+            {
+                entryFound = true;
+
+                hostsFileLines.RemoveAt(i);
+                hostsFileLines.Insert(i, CreateEntryLine(newEntry));
+
+                break;
+            }
+        }
+
+        if (!entryFound)
+        {
+            Log.Warn($"EditEntry - Entry not found in hosts file: {entry.Line}");
+            return HostsFileEntryModifyResult.NotFound;
+        }
+
+        try
+        {
+            Log.Debug($"EditEntry - Writing changes to hosts file: {HostsFilePath}");
+            File.WriteAllLines(HostsFilePath, hostsFileLines);
+        }
+        catch (Exception ex)
+        {
+            Log.Error($"EditEntry - Failed to write changes to hosts file: {HostsFilePath}", ex);
+            return HostsFileEntryModifyResult.WriteError;
+        }
+
+        return HostsFileEntryModifyResult.Success;
+    }
+
     /// <summary>
     /// Delete a hosts file entry asynchronously.
     /// </summary>
@@ -312,7 +475,17 @@ private static HostsFileEntryModifyResult DeleteEntry(HostsFileEntry entry)
         }
 
         // Remove the entry from the hosts file
-        var hostsFileLines = File.ReadAllLines(HostsFilePath).ToList();
+        List<string> hostsFileLines;
+
+        try
+        {
+            hostsFileLines = [.. File.ReadAllLines(HostsFilePath)];
+        }
+        catch (Exception ex)
+        {
+            Log.Error($"DeleteEntry - Failed to read hosts file: {HostsFilePath}", ex);
+            return HostsFileEntryModifyResult.ReadError;
+        }
 
         bool entryFound = false;
 
@@ -344,10 +517,29 @@ private static HostsFileEntryModifyResult DeleteEntry(HostsFileEntry entry)
             Log.Error($"DeleteEntry - Failed to write changes to hosts file: {HostsFilePath}", ex);
             return HostsFileEntryModifyResult.WriteError;
         }
-        OnHostsFileChanged();
+
         return HostsFileEntryModifyResult.Success;
     }
 
+    /// <summary>
+    /// Create a line for the hosts file entry.
+    /// </summary>
+    /// <param name="entry">Entry to create the line for.</param>
+    /// <returns>Line for the hosts file entry.</returns>
+    private static string CreateEntryLine(HostsFileEntry entry)
+    {
+        var line = entry.IsEnabled ? "" : "# ";
+
+        line += $"{entry.IPAddress}    {entry.Hostname}";
+
+        if (!string.IsNullOrWhiteSpace(entry.Comment))
+        {
+            line += $"        # {entry.Comment}";
+        }
+
+        return line.Trim();
+    }
+
     /// <summary>
     /// Create a "daily" backup of the hosts file (before making a change).
     /// </summary>

Source/NETworkManager.Models/HostsFileEditor/HostsFileEntryModifyResult.cs

@@ -15,6 +15,11 @@ public enum HostsFileEntryModifyResult
         /// </summary>
         NotFound,
 
+        /// <summary>
+        ///     An error occurred while reading the hosts file.
+        /// </summary>
+        ReadError,
+
         /// <summary>
         ///     An error occurred while writing to the hosts file.
         /// </summary>