Feature: RDAP improvements

Source/NETworkManager.Converters/RDAPQueryTypeToWatermarkConverter.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Globalization;
+using System.Windows.Data;
+using NETworkManager.Localization.Resources;
+using NETworkManager.Models.RDAP;
+
+namespace NETworkManager.Converters;
+
+/// <summary>
+///     Convert <see cref="RDAPQueryType" /> to an example input (watermark).
+/// </summary>
+public sealed class RDAPQueryTypeToWatermarkConverter : IValueConverter
+{
+    /// <summary>
+    ///     Convert <see cref="RDAPQueryType" /> to an example input (watermark).
+    /// </summary>
+    /// <param name="value">Object from type <see cref="RDAPQueryType" />.</param>
+    /// <param name="targetType"></param>
+    /// <param name="parameter"></param>
+    /// <param name="culture"></param>
+    /// <returns>Example input for the <see cref="RDAPQueryType" />.</returns>
+    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+    {
+        return value switch
+        {
+            RDAPQueryType.Nameserver => StaticStrings.ExampleRDAPNameserver,
+            RDAPQueryType.TLD => StaticStrings.ExampleTLD,
+            RDAPQueryType.IPAddress => StaticStrings.ExampleIPAddressOrCIDR,
+            RDAPQueryType.ASN => StaticStrings.ExampleASN,
+            RDAPQueryType.Entity => StaticStrings.ExampleRDAPEntityHandle,
+            _ => StaticStrings.ExampleDomain
+        };
+    }
+
+    /// <summary>
+    ///     !!! Method not implemented !!!
+    /// </summary>
+    /// <param name="value"></param>
+    /// <param name="targetType"></param>
+    /// <param name="parameter"></param>
+    /// <param name="culture"></param>
+    /// <returns></returns>
+    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+    {
+        throw new NotImplementedException();
+    }
+}

Source/NETworkManager.Localization/Resources/StaticStrings.resx

@@ -372,4 +372,7 @@
   <data name="ExampleRDAPEntityHandle" xml:space="preserve">
     <value>ORG-RIEN1-RIPE</value>
   </data>
+  <data name="ExampleRDAPNameserver" xml:space="preserve">
+    <value>a.iana-servers.net</value>
+  </data>
 </root>

Source/NETworkManager.Localization/Resources/Strings.resx

@@ -4809,4 +4809,28 @@ Cloudflare may log your IP address and network information. See Cloudflare's pri
   <data name="DeleteRulesX" xml:space="preserve">
     <value>Delete rules ({0})</value>
   </data>
+  <data name="RDAPQueryType_Auto" xml:space="preserve">
+    <value>Auto</value>
+  </data>
+  <data name="EnterValidRDAPQuery" xml:space="preserve">
+    <value>Enter a valid domain, IP address, AS number or entity handle!</value>
+  </data>
+  <data name="RDAPTimeoutAfterXSeconds" xml:space="preserve">
+    <value>The RDAP server did not respond within {0} seconds.</value>
+  </data>
+  <data name="RDAPQueryType_Nameserver" xml:space="preserve">
+    <value>Nameserver</value>
+  </data>
+  <data name="EnterValidNameserver" xml:space="preserve">
+    <value>Enter a valid nameserver (e.g., "ns1.example.com")!</value>
+  </data>
+  <data name="ASNumbers" xml:space="preserve">
+    <value>AS numbers</value>
+  </data>
+  <data name="RDAPDots" xml:space="preserve">
+    <value>RDAP...</value>
+  </data>
+  <data name="RDAPNoRecordForXShowingY" xml:space="preserve">
+    <value>No RDAP record found for "{0}", showing the registration data of "{1}".</value>
+  </data>
 </root>

Source/NETworkManager.Models/RDAP/RDAPBootstrapService.cs

@@ -173,7 +173,8 @@ public List<string> GetBaseUrls(RDAPQuery query)
         var urls = query.Type switch
         {
             RDAPQueryType.TLD => [IANARootZoneUrl],
-            RDAPQueryType.Domain => FindDomain(query.DomainName),
+            // A nameserver is served by the registry of its TLD (RFC 9224 4).
+            RDAPQueryType.Domain or RDAPQueryType.Nameserver => FindDomain(query.DomainName),
             RDAPQueryType.IPAddress => FindIPAddress(query.IPAddress, query.PrefixLength),
             RDAPQueryType.ASN => FindASN(query.ASN),
             RDAPQueryType.Entity => FindEntity(query.Handle),
@@ -319,14 +320,22 @@ private async Task UpdateAsync(string cacheDirectory, bool force, CancellationTo
 
             Directory.CreateDirectory(_cacheDirectory);
 
+            // Load the cached files first, so a file that can't be parsed is downloaded again in this update (see
+            // ReadServices).
+            if (_dns == null)
+                LoadRegistries();
+
             var attempted = false;
             var contentChanged = false;
             Exception networkError = null;
 
             foreach (var info in _cacheInfos)
             {
-                // "Expires" is the time of the next check, after a successful update as well as after a failure.
-                if (!force && info.Expires > DateTime.Now)
+                var path = Path.Combine(_cacheDirectory, info.FileName);
+
+                // "Expires" is the time of the next check, after a successful update as well as after a failure. A
+                // missing file is tried with every query, since the query type can't be used without it.
+                if (!force && info.Expires > DateTime.Now && File.Exists(path))
                     continue;
 
                 attempted = true;
@@ -340,8 +349,6 @@ private async Task UpdateAsync(string cacheDirectory, bool force, CancellationTo
                     continue;
                 }
 
-                var path = Path.Combine(_cacheDirectory, info.FileName);
-
                 try
                 {
                     contentChanged |= await DownloadAsync(info, path, File.Exists(path), cancellationToken)
@@ -382,7 +389,7 @@ private async Task UpdateAsync(string cacheDirectory, bool force, CancellationTo
     /// <summary>
     ///     Records a failed update. A cached file is retried after <see cref="RetryInterval" />, at most
     ///     <see cref="MaxFailedAttempts" /> times, then after the regular <see cref="RefreshInterval" />. A missing file
-    ///     is retried after <see cref="RetryInterval" />, since the query type cannot be used without it.
+    ///     is tried again with the next query (see <see cref="UpdateAsync" />).
     /// </summary>
     private void RecordFailure(RDAPBootstrapCacheInfo info, Exception ex)
     {
@@ -680,6 +687,16 @@ private void LoadRegistries()
         catch (Exception ex)
         {
             Log.Error($"Could not parse RDAP bootstrap file {path}.", ex);
+
+            // Download the file again with the next query. Without ETag and Last-Modified, the request is not
+            // conditional, so the server can't answer with "304 Not Modified" and the file is replaced.
+            var info = _cacheInfos.First(x => x.Type == type);
+
+            info.ETag = null;
+            info.LastModified = null;
+            info.Expires = null;
+            info.LastError = ex.Message;
+
             return null;
         }
     }