We don't need to store full User in session file anymore

README.md

@@ -7,7 +7,7 @@
 
 ## _Telegram Client API library written 100% in C# and .NET Standard_
 
-## How to use
+# How to use
 
 ⚠️ This library relies on asynchronous C# programming (`async/await`) so make sure you are familiar with this before proceeding.
 
@@ -166,6 +166,8 @@ This library can be used for any Telegram scenarios including:
 
 Secret chats (end-to-end encryption, PFS) and connection to CDN DCs have not been tested yet.
 
+Please don't use this library for Spam or Scam. Respect Telegram [Terms of Service](https://telegram.org/tos) or you might get banned from Telegram servers.
+
 Developers feedbacks are welcome in the Telegram channel [@WTelegramClient](https://t.me/WTelegramClient)
 
 If you like this library, please [consider a donation](http://wizou.fr/donate.html). ❤ This will help the project keep going.

src/Client.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Buffers.Binary;
 using System.Collections.Generic;
-using System.Diagnostics;
 using System.Globalization;
 using System.IO;
 using System.Linq;
@@ -164,7 +163,7 @@ namespace WTelegram
 					}
 			}
 			if (resetUser)
-				_session.User = null;
+				_session.UserId = 0;
 		}
 
 		/// <summary>Establish connection to Telegram servers</summary>
@@ -310,7 +309,7 @@ namespace WTelegram
 				try
 				{
 					Auth_ExportedAuthorization exported = null;
-					if (_session.User != null && IsMainDC && altSession.UserId != _session.User.id)
+					if (_session.UserId != 0 && IsMainDC && altSession.UserId != _session.UserId)
 						exported = await this.Auth_ExportAuthorization(dcId);
 					await altSession.Client.ConnectAsync();
 					if (exported != null)
@@ -318,7 +317,6 @@ namespace WTelegram
 						var authorization = await altSession.Client.Auth_ImportAuthorization(exported.id, exported.bytes);
 						if (authorization is not Auth_Authorization { user: User user })
 							throw new ApplicationException("Failed to get Authorization: " + authorization.GetType().Name);
-						_session.User = user;
 						altSession.UserId = user.id;
 					}
 				}
@@ -419,6 +417,7 @@ namespace WTelegram
 								_pendingRequests.Clear();
 								_bareRequest = 0;
 							}
+							// TODO: implement an Updates gaps handling system? https://core.telegram.org/api/updates
 							var udpatesState = await this.Updates_GetState(); // this call reenables incoming Updates
 							OnUpdate(udpatesState);
 						}
@@ -785,7 +784,7 @@ namespace WTelegram
 					}
 					else if (rpcError.error_code == 500 && rpcError.error_message == "AUTH_RESTART")
 					{
-						_session.User = null; // force a full login authorization flow, next time
+						_session.UserId = 0; // force a full login authorization flow, next time
 						_session.Save();
 					}
 					throw new RpcException(rpcError.error_code, rpcError.error_message);
@@ -927,33 +926,30 @@ namespace WTelegram
 		{
 			await ConnectAsync();
 			string botToken = Config("bot_token");
-			var prevUser = _session.User;
+			if (_session.UserId != 0) // a user is already logged-in
-			if (prevUser != null)
 			{
 				try
 				{
-					if (prevUser.id == int.Parse(botToken.Split(':')[0]))
+					var users = await this.Users_GetUsers(new[] { InputUser.Self }); // this calls also reenable incoming Updates
+					var self = users[0] as User;
+					if (self.id == long.Parse(botToken.Split(':')[0]))
 					{
-						// Update our info about the user, and reenable incoming Updates
+						_session.UserId = _dcSession.UserId = self.id;
-						var users = await this.Users_GetUsers(new[] { InputUser.Self });
+						return self;
-						if (users.Length > 0 && users[0] is User self)
-							_session.User = prevUser = self;
-						return prevUser;
 					}
-					Helpers.Log(3, $"Current logged user {prevUser.id} mismatched bot_token. Logging out and in...");
+					Helpers.Log(3, $"Current logged user {self.id} mismatched bot_token. Logging out and in...");
 				}
 				catch (Exception ex)
 				{
 					Helpers.Log(4, $"Error while verifying current bot! ({ex.Message}) Proceeding to login...");
 				}
 				await this.Auth_LogOut();
-				_dcSession.UserId = 0;
+				_session.UserId = _dcSession.UserId = 0;
 			}
 			var authorization = await this.Auth_ImportBotAuthorization(0, _apiId, _apiHash, botToken);
 			if (authorization is not Auth_Authorization { user: User user })
 				throw new ApplicationException("Failed to get Authorization: " + authorization.GetType().Name);
-			_session.User = user;
+			_session.UserId = _dcSession.UserId = user.id;
-			_dcSession.UserId = user.id;
 			_session.Save();
 			return user;
 		}
@@ -968,36 +964,27 @@ namespace WTelegram
 		{
 			await ConnectAsync();
 			string phone_number = null;
-			var prevUser = _session.User;
+			if (_session.UserId != 0) // a user is already logged-in
-			if (prevUser != null)
 			{
 				try
 				{
-					bool sameUser = true;
+					var users = await this.Users_GetUsers(new[] { InputUser.Self }); // this calls also reenable incoming Updates
-					var userId = _config("user_id"); // if config prefers to validate current user by its id, use it
+					var self = users[0] as User;
-					if (userId == null || !int.TryParse(userId, out int id) || id != -1 && prevUser.id != id)
+					// check user_id or phone_number match currently logged-in user
+					if ((int.TryParse(_config("user_id"), out int id) && (id == -1 || self.id == id)) ||
+						self.phone == string.Concat((phone_number = Config("phone_number")).Where(char.IsDigit)))
 					{
-						phone_number = Config("phone_number"); // otherwise, validation is done by the phone number
+						_session.UserId = _dcSession.UserId = self.id;
-						if (prevUser.phone != string.Concat(phone_number.Where(char.IsDigit)))
+						return self;
-							sameUser = false;
 					}
-					if (sameUser)
+					Helpers.Log(3, $"Current logged user {self.id} mismatched user_id or phone_number. Logging out and in...");
-					{
-						// TODO: implement a more complete Updates gaps handling system? https://core.telegram.org/api/updates
-						// Update our info about the user, and reenable incoming Updates
-						var users = await this.Users_GetUsers(new[] { InputUser.Self });
-						if (users.Length > 0 && users[0] is User self)
-							_session.User = prevUser = self;
-						return prevUser;
-					}
-					Helpers.Log(3, $"Current logged user {prevUser.id} mismatched user_id or phone_number. Logging out and in...");
 				}
 				catch (Exception ex)
 				{
 					Helpers.Log(4, $"Error while verifying current user! ({ex.Message}) Proceeding to login...");
 				}
 				await this.Auth_LogOut();
-				_dcSession.UserId = 0;
+				_session.UserId = _dcSession.UserId = 0;
 			}
 			phone_number ??= Config("phone_number");
 			Auth_SentCode sentCode;
@@ -1043,8 +1030,7 @@ namespace WTelegram
 			}
 			if (authorization is not Auth_Authorization { user: User user })
 				throw new ApplicationException("Failed to get Authorization: " + authorization.GetType().Name);
-			_session.User = user;
+			_session.UserId = _dcSession.UserId = user.id;
-			_dcSession.UserId = user.id;
 			_session.Save();
 			return user;
 		}

src/Helpers.cs

@@ -26,41 +26,6 @@ namespace WTelegram
 			Console.ResetColor();
 		}
 
-		internal class PolymorphicConverter<T> : JsonConverter<T> where T : class
-		{
-			public override bool HandleNull => true;
-
-			public override void Write(Utf8JsonWriter writer, T value, JsonSerializerOptions options)
-			{
-				if (value == null)
-					writer.WriteNullValue();
-				else
-				{
-					writer.WriteStartObject();
-					writer.WritePropertyName(value.GetType().FullName);
-					JsonSerializer.Serialize(writer, value, value.GetType(), JsonOptions);
-					writer.WriteEndObject();
-				}
-			}
-
-			public override T Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
-			{
-				if (reader.TokenType == JsonTokenType.Null)
-					return null;
-				else if (reader.TokenType == JsonTokenType.StartObject)
-				{
-					if (!reader.Read() || reader.TokenType != JsonTokenType.PropertyName) throw new JsonException();
-					var returnType = typeToConvert.Assembly.GetType(reader.GetString());
-					if (!typeToConvert.IsAssignableFrom(returnType)) throw new JsonException();
-					var result = (T)JsonSerializer.Deserialize(ref reader, returnType, JsonOptions);
-					if (!reader.Read() || reader.TokenType != JsonTokenType.EndObject) throw new JsonException();
-					return result;
-				}
-				else
-					throw new JsonException();
-			}
-		}
-
 		/// <summary>Get a cryptographic random 64-bit value</summary>
 		public static long RandomLong()
 		{

src/Session.cs

@@ -5,17 +5,19 @@ using System.Linq;
 using System.Net;
 using System.Security.Cryptography;
 using System.Text.Json;
-using System.Threading;
 
 namespace WTelegram
 {
 	internal class Session
 	{
-		public TL.User User;
+		public long UserId;
 		public int MainDC;
 		public Dictionary<int, DCSession> DCSessions = new();
 		public TL.DcOption[] DcOptions;
 
+		public UserShim User; // obsolete, to be removed
+		public class UserShim { public long id; } // to be removed
+
 		public class DCSession
 		{
 			public long Id;
@@ -39,14 +41,6 @@ namespace WTelegram
 		private string _pathname;
 		private byte[] _apiHash;	// used as AES key for encryption of session file
 
-		private static readonly JsonSerializerOptions JsonOptions = new(Helpers.JsonOptions)
-		{
-			Converters = {
-				new Helpers.PolymorphicConverter<TL.UserProfilePhoto>(),
-				new Helpers.PolymorphicConverter<TL.UserStatus>()
-			}
-		};
-
 		internal static Session LoadOrCreate(string pathname, byte[] apiHash)
 		{
 			if (File.Exists(pathname))
@@ -54,6 +48,7 @@ namespace WTelegram
 				try
 				{
 					var session = Load(pathname, apiHash);
+					if (session.User != null) { session.UserId = session.User.id; session.User.id = 0; session.User = null; }
 					session._pathname = pathname;
 					session._apiHash = apiHash;
 					Helpers.Log(2, "Loaded previous session");
@@ -76,12 +71,12 @@ namespace WTelegram
 			var utf8Json = decryptor.TransformFinalBlock(input, 16, input.Length - 16);
 			if (!sha256.ComputeHash(utf8Json, 32, utf8Json.Length - 32).SequenceEqual(utf8Json[0..32]))
 				throw new ApplicationException("Integrity check failed in session loading");
-			return JsonSerializer.Deserialize<Session>(utf8Json.AsSpan(32), JsonOptions);
+			return JsonSerializer.Deserialize<Session>(utf8Json.AsSpan(32), Helpers.JsonOptions);
 		}
 
 		internal void Save()
 		{
-			var utf8Json = JsonSerializer.SerializeToUtf8Bytes(this, JsonOptions);
+			var utf8Json = JsonSerializer.SerializeToUtf8Bytes(this, Helpers.JsonOptions);
 			var finalBlock = new byte[16];
 			var output = new byte[(16 + 32 + utf8Json.Length + 16) & ~15];
 			Encryption.RNG.GetBytes(output, 0, 16);