done

Netch/3rd/DnsClient.NET/Protocol/TxtRecord.cs

@@ -0,0 +1,76 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace DnsClient.Protocol
+{
+    /*
+    * RFC 1464  https://tools.ietf.org/html/rfc1464
+
+    https://tools.ietf.org/html/rfc1035#section-3.3:
+    <character-string> is a single
+    length octet followed by that number of characters.  <character-string>
+    is treated as binary information, and can be up to 256 characters in
+    length (including the length octet).
+
+    https://tools.ietf.org/html/rfc1035#section-3.3.14:
+    TXT RDATA format
+
+        +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+        /                   TXT-DATA                    /
+        +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+
+    where:
+
+    TXT-DATA        One or more <character-string>s.
+
+    TXT RRs are used to hold descriptive text.  The semantics of the text
+    depends on the domain where it is found.
+    */
+
+    /// <summary>
+    /// A <see cref="DnsResourceRecord"/> represending a text resource.
+    /// <para>
+    /// TXT RRs are used to hold descriptive text. The semantics of the text
+    /// depends on the domain where it is found.
+    /// </para>
+    /// </summary>
+    /// <seealso href="https://tools.ietf.org/html/rfc1035#section-3.3">RFC 1035</seealso>
+    /// <seealso href="https://tools.ietf.org/html/rfc1464">RFC 1464</seealso>
+    public class TxtRecord : DnsResourceRecord
+    {
+        /// <summary>
+        /// Gets the list of TXT values of this resource record in escaped form, valid for root file.
+        /// </summary>
+        /// <remarks>
+        /// See https://tools.ietf.org/html/rfc1035#section-5.1 for escape details.
+        /// </remarks>
+        public ICollection<string> EscapedText { get; }
+
+        /// <summary>
+        /// Gets the actual <c>UTF8</c> representation of the text values of this record.
+        /// </summary>
+        public ICollection<string> Text { get; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="TxtRecord"/> class.
+        /// </summary>
+        /// <param name="info">The information.</param>
+        /// <param name="values">The values.</param>
+        /// <param name="utf8Values">The UTF8 values.</param>
+        /// <exception cref="System.ArgumentNullException">
+        /// If <paramref name="info"/> or <paramref name="utf8Values"/> or <paramref name="values"/> is null.
+        /// </exception>
+        public TxtRecord(ResourceRecordInfo info, string[] values, string[] utf8Values)
+            : base(info)
+        {
+            EscapedText = values ?? throw new ArgumentNullException(nameof(values));
+            Text = utf8Values ?? throw new ArgumentNullException(nameof(utf8Values));
+        }
+
+        private protected override string RecordToString()
+        {
+            return string.Join(" ", EscapedText.Select(p => "\"" + p + "\"")).Trim();
+        }
+    }
+}