Added .NET5 target and DnsSuffix to NameServer

Added DnsSuffix property to NameServer (will be populated if available)
Added DnsString concat
Changed NameServer.ValidateNameServers call to be done only once for fixed name server configuration. No need to do that with every query.
Added an example to MiniDig to use the DnsSuffix in case the query is just a HostName

samples/MiniDig/DigCommand.cs

@@ -34,7 +34,8 @@ public static string Version
 
         public CommandOption ReversArg { get; }
 
-        public DigCommand(CommandLineApplication app, string[] originalArgs) : base(app, originalArgs)
+        public DigCommand(CommandLineApplication app, string[] originalArgs) 
+            : base(app, originalArgs)
         {
             DomainArg = app.Argument("domain", "domain name", false);
             QTypeArg = app.Argument("q-type", "QType", false);
@@ -102,6 +103,7 @@ protected override async Task<int> Execute()
                 }
             }
 
+
             try
             {
                 // finally running the command
@@ -111,6 +113,29 @@ protected override async Task<int> Execute()
 
                 Console.WriteLine($"; Servers: {string.Join(", ", lookup.NameServers)}");
 
+
+                var parsedDnsString = DnsString.Parse(useDomain);
+                if (parsedDnsString.NumberOfLabels == 1 && !parsedDnsString.Original.EndsWith("."))
+                {
+                    foreach(var server in lookup.NameServers)
+                    {
+                        if(server.DnsSuffix != null)
+                        {
+                            var newQuery = parsedDnsString + server.DnsSuffix;
+
+                            var serverResult = useQClass == 0 ?
+                                await lookup.QueryServerAsync(new[] { server }, newQuery, useQType).ConfigureAwait(false) :
+                                await lookup.QueryServerAsync(new[] { server }, newQuery, useQType, useQClass).ConfigureAwait(false);
+
+                            if (!serverResult.HasError)
+                            {
+                                Console.WriteLine(serverResult.AuditTrail);
+                                return 0;
+                            }
+                        }
+                    }
+                }
+
                 var result = useQClass == 0 ?
                     await lookup.QueryAsync(useDomain, useQType).ConfigureAwait(false) :
                     await lookup.QueryAsync(useDomain, useQType, useQClass).ConfigureAwait(false);

samples/MiniDig/DnsCommand.cs

@@ -146,6 +146,7 @@ public bool GetUseCache()
 
         protected virtual void Configure()
         {
+            App.HelpOption("-? | -h | --help | --helpme");
             ServerArg = App.Option(
                 "-s | --server",
                 "The DNS server <name|ip>#<port> (multiple)",
@@ -193,8 +194,6 @@ protected virtual void Configure()
                 "--dnssec",
                 "Request DNS SEC records (do flag).",
                 CommandOptionType.NoValue);
-
-            App.HelpOption("-? | -h | --help | --helpme");
         }
 
         protected abstract Task<int> Execute();

samples/MiniDig/MiniDig.csproj

@@ -1,11 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net45;net471;netcoreapp3.1;</TargetFrameworks>
+    <TargetFramework>net50</TargetFramework>
     <AssemblyName>MiniDig</AssemblyName>
     <OutputType>Exe</OutputType>
     <PackageId>MiniDig</PackageId>
-    <LangVersion>7.2</LangVersion>
+    <LangVersion>latest</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>

samples/MiniDig/Program.cs

@@ -7,26 +7,40 @@ namespace DigApp
 {
     public class Program
     {
-        public static async Task Main(string[] args)
+        public static async Task<int> Main(string[] args)
         {
             DnsClient.Tracing.Source.Switch.Level = SourceLevels.Information;
             DnsClient.Tracing.Source.Listeners.Add(new ConsoleTraceListener());
 
             var app = new CommandLineApplication(throwOnUnexpectedArg: true);
 
-            app.Command("perf", (perfApp) => new PerfCommand(perfApp, args), throwOnUnexpectedArg: true);
-            app.Command("random", (randApp) => new RandomCommand(randApp, args), throwOnUnexpectedArg: true);
+            try
+            {
+                app.Command("perf", (perfApp) => new PerfCommand(perfApp, args), throwOnUnexpectedArg: true);
+                app.Command("random", (randApp) => new RandomCommand(randApp, args), throwOnUnexpectedArg: true);
 
-            var defaultCommand = new DigCommand(app, args);
+                app.Command("dig", (digApp) => new DigCommand(digApp, args), throwOnUnexpectedArg: true);
 
-            try
+                var defaultCommand = new DigCommand(app, args);
+                return await app.ExecuteAsync(args).ConfigureAwait(false);
+            }
+            catch (UnrecognizedCommandParsingException ex)
             {
-                await app.ExecuteAsync(args).ConfigureAwait(false);
+                Console.WriteLine(ex.Message);
+                app.ShowHelp();
+            }
+            catch (CommandParsingException ex)
+            {
+                Console.WriteLine(ex.Message);
+                app.ShowHelp();
             }
             catch (Exception ex)
             {
                 Console.WriteLine(ex);
+                return 500;
             }
+
+            return -1;
         }
     }
 

samples/MiniDig/Properties/launchSettings.json

@@ -2,7 +2,7 @@
   "profiles": {
     "MiniDig": {
       "commandName": "Project",
-      "commandLineArgs": "mx3.mailbox.org spf --time -1"
+      "commandLineArgs": "google.com"
     }
   }
 }

src/DnsClient/DnsClient.csproj

@@ -1,15 +1,15 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <VersionPrefix>1.4.0</VersionPrefix>
+    <VersionPrefix>1.5.0</VersionPrefix>
     <VersionSuffix Condition="'$(VersionSuffix)'!='' AND '$(BuildNumber)' != ''">$(VersionSuffix)-$(BuildNumber)</VersionSuffix>
 
-    <TargetFrameworks>netstandard1.3;netstandard2.0;netstandard2.1;net45;net471</TargetFrameworks>
+    <TargetFrameworks>netstandard1.3;netstandard2.0;netstandard2.1;net50;net45;net471</TargetFrameworks>
     <DebugType>full</DebugType>
 
     <Product>DnsClient.NET</Product>
     <Description>DnsClient.NET is a simple yet very powerful and high performance open source library for the .NET Framework to do DNS lookups</Description>
 
-    <Copyright>Copyright (c) 2020 MichaConrad</Copyright>
+    <Copyright>Copyright (c) 2021 Michael Conrad</Copyright>
     <Authors>MichaCo</Authors>
     <AssemblyName>DnsClient</AssemblyName>
 
@@ -28,7 +28,7 @@
     <RepositoryUrl>https://github.com/MichaCo/DnsClient.NET</RepositoryUrl>
 
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
-    <LangVersion>7.2</LangVersion>
+    <LangVersion>latest</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>

src/DnsClient/DnsString.cs

@@ -1,7 +1,5 @@
 using System;
-using System.Collections.Generic;
 using System.Globalization;
-using System.Linq;
 
 namespace DnsClient
 {
@@ -45,10 +43,17 @@ public class DnsString
         /// </summary>
         public string Value { get; }
 
-        internal DnsString(string original, string value)
+        /// <summary>
+        /// Gets the number of labels of this <see cref="DnsString"/> or null if not applicable.
+        /// This property is only set if the <see cref="Parse(string)"/> method was used to create this instance.
+        /// </summary>
+        public int? NumberOfLabels { get; }
+
+        internal DnsString(string original, string value, int? numLabels = null)
         {
             Original = original;
             Value = value;
+            NumberOfLabels = numLabels;
         }
 
         /// <summary>
@@ -60,6 +65,52 @@ internal DnsString(string original, string value)
         /// </returns>
         public static implicit operator string(DnsString name) => name?.Value;
 
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="a"></param>
+        /// <param name="b"></param>
+        /// <returns></returns>
+        public static DnsString operator +(DnsString a, DnsString b)
+        {
+            if (a is null)
+            {
+                throw new ArgumentNullException(nameof(a));
+            }
+
+            if (b is null)
+            {
+                throw new ArgumentNullException(nameof(b));
+            }
+
+            var result = a.Value + (b.Value.Length > 1 ? b.Value : string.Empty);
+            return new DnsString(result, result);
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="a"></param>
+        /// <param name="b"></param>
+        /// <returns></returns>
+        public static DnsString operator +(DnsString a, string b)
+        {
+            if (a is null)
+            {
+                throw new ArgumentNullException(nameof(a));
+            }
+
+            if (string.IsNullOrWhiteSpace(b))
+            {
+                throw new ArgumentException($"'{nameof(b)}' cannot be null or empty.", nameof(b));
+            }
+
+            b = b[0] == Dot ? b.Substring(1) : b;
+
+            var parsed = Parse(b);
+            return a + parsed;
+        }
+
         /// <inheritdoc />
         public override string ToString()
         {
@@ -83,18 +134,6 @@ public override bool Equals(object obj)
             return obj.ToString().Equals(Value);
         }
 
-        // removed as this is actually the wrong label representation (also, doesn't work if there are escaped \. in the value
-        /////// <summary>
-        /////// Returns labels representation of the <see cref="Value"/>.
-        /////// </summary>
-        ////public IReadOnlyList<string> Labels
-        ////{
-        ////    get
-        ////    {
-        ////        return Value.Split('.').Reverse().Select(p => p + DotStr).ToArray();
-        ////    }
-        ////}
-
         /// <summary>
         /// Parses the given <paramref name="query"/> and validates all labels.
         /// </summary>
@@ -155,7 +194,9 @@ public static DnsString Parse(string query)
                                 result += Dot;
                             }
 
-                            return new DnsString(query, result);
+                            var labels = result.Split(new[] { Dot }, StringSplitOptions.RemoveEmptyEntries);
+
+                            return new DnsString(query, result, labels.Length);
                         }
                         catch (Exception ex)
                         {
@@ -185,10 +226,10 @@ public static DnsString Parse(string query)
 
             if (query[query.Length - 1] != Dot)
             {
-                return new DnsString(query, query + Dot);
+                return new DnsString(query, query + Dot, labelsCount);
             }
 
-            return new DnsString(query, query);
+            return new DnsString(query, query, labelsCount);
         }
 
         /// <summary>