Save original info hash when parsing torrent

Author: Krusen

BencodeNET.Tests/Parsing/TorrentParserTests.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Text;
 using BencodeNET.Exceptions;
 using BencodeNET.IO;
@@ -555,5 +554,35 @@ public void MultiFile_Files_MissingPathField_ThrowsInvalidTorrentException()
             action.ShouldThrow<InvalidTorrentException>()
                 .Where(ex => ex.InvalidField == TorrentFilesFields.Path);
         }
+
+        [Fact]
+        public void OriginalInfoHash_IsSet()
+        {
+            // Arrange
+            ParsedData = ValidSingleFileTorrentData;
+            var expectedInfoHash = TorrentUtil.CalculateInfoHash(ParsedData.Get<BDictionary>("info"));
+
+            // Act
+            var parser = new TorrentParser(BencodeParser);
+            var torrent = parser.Parse((BencodeStream) null);
+
+            // Assert
+            torrent.OriginalInfoHash.Should().Be(expectedInfoHash);
+        }
+
+        [Fact]
+        public void OriginalInfoHashBytes_IsSet()
+        {
+            // Arrange
+            ParsedData = ValidSingleFileTorrentData;
+            var expectedInfoHashBytes = TorrentUtil.CalculateInfoHashBytes(ParsedData.Get<BDictionary>("info"));
+
+            // Act
+            var parser = new TorrentParser(BencodeParser);
+            var torrent = parser.Parse((BencodeStream) null);
+
+            // Assert
+            torrent.OriginalInfoHashBytes.Should().Equal(expectedInfoHashBytes);
+        }
     }
 }

BencodeNET/BencodeNET.csproj

@@ -5,7 +5,7 @@
     <NetStandardImplicitPackageVersion Condition=" '$(TargetFramework)' == 'netstandard1.3' ">1.6.0</NetStandardImplicitPackageVersion>
     <GenerateDocumentationFile>True</GenerateDocumentationFile>
     <PackageId>BencodeNET</PackageId>
-    <Version>2.2.2</Version>
+    <Version>2.2.3</Version>
     <Authors>Søren Kruse</Authors>
     <Company />
     <Product>BencodeNET</Product>
@@ -15,7 +15,7 @@
     <PackageIconUrl>https://raw.githubusercontent.com/Krusen/BencodeNET/master/Assets/icon.png</PackageIconUrl>
     <RepositoryUrl>https://github.com/Krusen/BencodeNET</RepositoryUrl>
     <RepositoryType>git</RepositoryType>
-    <PackageReleaseNotes>Now uses the encoding information of a .torrent when parsing the torrent data.</PackageReleaseNotes>
+    <PackageReleaseNotes>Save original info hash of parsed torrents</PackageReleaseNotes>
     <PackageTags>bencode;torrent;torrents</PackageTags>
     <GeneratePackageOnBuild>True</GeneratePackageOnBuild>
     <IncludeSource>True</IncludeSource>

BencodeNET/Parsing/TorrentParser.cs

@@ -60,7 +60,7 @@ protected Torrent CreateTorrent(BDictionary data)
 
             var encoding = ParseEncoding(data.Get<BString>(TorrentFields.Encoding)) ?? BencodeParser.Encoding;
 
-            var torrent = new Torrent
+            var torrent = new Torrent(info)
             {
                 IsPrivate = info.Get<BNumber>(TorrentInfoFields.Private) == 1,
                 PieceSize = info.Get<BNumber>(TorrentInfoFields.PieceLength),

BencodeNET/Torrents/Torrent.cs

@@ -15,6 +15,36 @@ namespace BencodeNET.Torrents
     /// </summary>
     public class Torrent : BObject
     {
+        /// <summary>
+        ///
+        /// </summary>
+        public Torrent()
+        {
+        }
+
+        /// <summary>
+        /// Creates a torrent and populates the <see cref="OriginalInfoHash"/> and <see cref="OriginalInfoHashBytes"/>
+        /// properties from the provided <see cref="BDictionary"/>.
+        /// </summary>
+        /// <param name="originalInfoDictionary"></param>
+        internal Torrent(BDictionary originalInfoDictionary)
+        {
+            OriginalInfoHashBytes = TorrentUtil.CalculateInfoHashBytes(originalInfoDictionary);
+            OriginalInfoHash = TorrentUtil.BytesToHexString(OriginalInfoHashBytes);
+        }
+
+        /// <summary>
+        /// The original info hash value from when the torrent was parsed.
+        /// This will be null if the instance was created manually and not by the parser.
+        /// </summary>
+        public string OriginalInfoHash { get; protected set; }
+
+        /// <summary>
+        /// The original info hash bytes from when the torrent was parsed.
+        /// This will be null if the instance was created manually and not by the parser.
+        /// </summary>
+        public byte[] OriginalInfoHashBytes { get; protected set; }
+
         /// <summary>
         /// Add any custom fields to this <see cref="BDictionary"/> and they will
         /// be merged with the torrent data when encoded.

BencodeNET/Torrents/TorrentUtil.cs

@@ -54,8 +54,7 @@ public static byte[] CalculateInfoHashBytes(Torrent torrent)
         public static string CalculateInfoHash(BDictionary info)
         {
             var hashBytes = CalculateInfoHashBytes(info);
-
-            return BitConverter.ToString(hashBytes).Replace("-", "");
+            return BytesToHexString(hashBytes);
         }
 
         /// <summary>
@@ -79,6 +78,15 @@ public static byte[] CalculateInfoHashBytes(BDictionary info)
             }
         }
 
+        /// <summary>
+        /// Converts the byte array to a hexadecimal string representation without hyphens.
+        /// </summary>
+        /// <param name="bytes"></param>
+        public static string BytesToHexString(byte[] bytes)
+        {
+            return BitConverter.ToString(bytes).Replace("-", "");
+        }
+
         /// <summary>
         /// Creates a Magnet link in the BTIH (BitTorrent Info Hash) format: xt=urn:btih:{info hash}
         /// </summary>