update torrent info and save .torent file from BEP9 metadata

libi2pd_client/Torrents.cpp

@@ -373,7 +373,6 @@ namespace torrents
 		return len;
 	}
 
-
 	size_t Torrent::ParseInfo (std::string_view buf)
 	{
 		size_t len = ParseDictionary (buf, [this](std::string_view key, std::string_view buf)->size_t
@@ -423,6 +422,12 @@ namespace torrents
 		return len;
 	}
 
+	std::string Torrent::CreateTorrentFileContent () const
+	{
+		if (m_Info.empty ()) return "";
+		return CreateDictionary ( {{ "info", std::string_view ((const char *)m_Info.data (), m_Info.size ()) }} );
+	}
+
 	bool Torrent::IsSafeName (std::string_view name)
 	{
 		if (name.empty () || name == "." || name == "..") return false;
@@ -1279,7 +1284,7 @@ namespace torrents
 
 	void PeerConnection::HandleBitfieldMsg (const uint8_t * buf, size_t len)
 	{
-		if (!m_Torrent) return;
+		if (!m_Torrent || !m_Torrent->GetLength ()) return; // we are magnet and don't have torrent info yet
 		m_IsInterested = false;
 		size_t numPieces = m_Torrent->GetNumPieces ();
 		m_RemoteBitfield.resize (numPieces);
@@ -1640,6 +1645,9 @@ namespace torrents
 					}
 					return 0;
 				});
+			if (!m_Torrent->GetLength () && m_RemoteMetadataSize) // torrent is magnet and peer supports BEP9
+				// request first piece of info
+				SendExtendedMsg (EXTENSION_MSGID_UT_METADATA, CreateDictionary ({{ "msg_type", CreateInteger (0) }, { "piece", CreateInteger (0) }}));
 		}
 		else
 		{
@@ -1748,11 +1756,10 @@ namespace torrents
 							uint8_t digest[SHA_DIGEST_LENGTH];
 							SHA1 (m_RemoteMetadata.data (), m_RemoteMetadata.size (), digest);
 							if (memcmp (m_Torrent->GetInfoHash ().data (), digest, SHA_DIGEST_LENGTH))
+								GetTorrentsTunnel ()->UpdateTorrentInfo (m_Torrent, std::string_view ((const char *)m_RemoteMetadata.data (), m_RemoteMetadata.size ()));
+							else
 								LogPrint (eLogError, "Torrents: ut_metadata info doesn't match infoHash");
-							// TODO: update torrent
-							// cleanup
-							std::vector<uint8_t> tmp;
-							m_RemoteMetadata.swap (tmp);
+							Close (); // we need to reconnect to receive bitfield
 						}
 					}
 					break;

libi2pd_client/Torrents.h

@@ -162,6 +162,8 @@ namespace torrents
 
 			Torrent (std::string_view buf);
 			Torrent (const InfoHash& infoHash);
+			size_t ParseInfo (std::string_view buf);
+			std::string CreateTorrentFileContent () const;
 			void ParseTrackerResponse (size_t trackerID, std::string_view buf);
 			void HandleDatagramTrackerResponse (size_t trackerID, uint32_t interval,
 				const uint8_t * hashes, size_t hashesLen, int numSeeders, int numLeechers);
@@ -230,7 +232,6 @@ namespace torrents
 
 			Torrent ();
 			size_t ParsePieces (std::string_view buf);
-			size_t ParseInfo (std::string_view buf);
 			size_t ParsePeers (size_t trackerID, std::string_view buf);
 			size_t ParseFiles (std::string_view buf);
 			static bool IsSafeName (std::string_view name); // a name from a torrent file before it becomes a path

libi2pd_client/TorrentsTunnel.cpp

@@ -134,6 +134,20 @@ namespace torrents
 		}
 	}
 
+	void TorrentsTunnel::SaveTorrentFile (std::shared_ptr<Torrent> torrent)
+	{
+		if (!torrent) return;
+		auto torrentFilePath = torrent->GetFullPath (); torrentFilePath += ".torrent";
+		std::ofstream f(torrentFilePath, std::ofstream::binary);
+		if (f)
+		{
+			auto content = torrent->CreateTorrentFileContent ();
+			f.write (content.data (), content.size ());
+		}
+		else
+			LogPrint (eLogError, "TorrentsTunnel: Can't open ", torrentFilePath);
+	}
+
 	void TorrentsTunnel::InitTorrentFiles (std::shared_ptr<Torrent> torrent)
 	{
 		if (!torrent) return;
@@ -315,15 +329,20 @@ namespace torrents
 		if (m_Torrents.find (torrent->GetInfoHash ()) == m_Torrents.end ())
 		{
 			torrent->SetFullPath (m_TorrentsDir/std::filesystem::path (torrent->GetName ()));
-			{
-				auto torrentFilePath = torrent->GetFullPath ();  torrentFilePath += ".torrent";
-				std::ofstream f(torrentFilePath, std::ofstream::binary);
-				if (f)
-					f.write (torrentFileContent.data (), torrentFileContent.size ());
-				else
-					return { torrent, 0 };
-			}
-			InitTorrentFiles (torrent);
+			std::string content (torrentFileContent);
+			boost::asio::post (GetDiskIOService (), [this, torrent, content]()
+				{
+					auto torrentFilePath = torrent->GetFullPath ();  torrentFilePath += ".torrent";
+					{
+						// TODO: replace by SaveTorrentFile
+						std::ofstream f(torrentFilePath, std::ofstream::binary);
+						if (f)
+							f.write (content.data (), content.size ());
+						else
+							LogPrint (eLogError, "TorrentsTunnel: Can't open ", torrentFilePath);
+					}
+					InitTorrentFiles (torrent);
+				});
 			return { torrent, InsertTorrent (torrent) };
 		}
 		return { torrent, 0 };
@@ -502,6 +521,18 @@ namespace torrents
 		return true;
 	}
 
+	void TorrentsTunnel::UpdateTorrentInfo (std::shared_ptr<Torrent> torrent, std::string_view info)
+	{
+		if (!torrent) return;
+		torrent->ParseInfo (info);
+		torrent->SetFullPath (m_TorrentsDir/std::filesystem::path (torrent->GetName ()));
+		boost::asio::post (GetDiskIOService (), [this, torrent]()
+			{
+				SaveTorrentFile (torrent);
+				InitTorrentFiles (torrent);
+			});
+	}
+
 	void TorrentsTunnel::Accept ()
 	{
 		auto localDestination = GetLocalDestination ();

libi2pd_client/TorrentsTunnel.h

@@ -100,6 +100,7 @@ namespace torrents
 			std::vector<int> GetTorrentIDs () const;
 			std::pair<std::shared_ptr<Torrent>, int> AddTorrent (std::string_view torrentFileContent); // retrun (torrent, id)
 			std::pair<std::shared_ptr<Torrent>, int> AddMagnet (std::string_view magnet); // return (torrent, id)
+			void UpdateTorrentInfo (std::shared_ptr<Torrent> torrent, std::string_view info); // magnet
 			bool RemoveTorrent (int id, bool deleteFiles);
 			bool StopTorrent (int id);
 			bool StartTorrent (int id);
@@ -112,6 +113,7 @@ namespace torrents
 
 			void Accept ();
 			void ReadTorrentFile (const std::filesystem::path& torrentFilePath);
+			void SaveTorrentFile (std::shared_ptr<Torrent> torrent);
 			void InitTorrentFiles (std::shared_ptr<Torrent> torrent);
 			int InsertTorrent (std::shared_ptr<Torrent> torrent); // returns id > 0 if success and 0 if failed
 			void RemoveTorrent (std::shared_ptr<Torrent> torrent, bool deleteFiles);