Set the maximum number of player on the server through the config.json (#1001)

* Show server status to three-party game launcher

* Set the maximum number of player on the server through the config.json

* modify the logical order and show the number of maxplayer to API /status/server

* Now even players who have token already cannot bypass the maxPlayer check

src/main/java/emu/grasscutter/auth/DefaultAuthenticators.java

@@ -23,14 +23,16 @@ public final class DefaultAuthenticators {
             
             var requestData = request.getPasswordRequest();
             assert requestData != null; // This should never be null.
+            int playerCount = Grasscutter.getGameServer().getPlayers().size();
 
             boolean successfulLogin = false; 
             String address = request.getRequest().ip();
             String responseMessage = translate("messages.dispatch.account.username_error");
+            String loggerMessage = "";
 
             // Get account from database.
             Account account = DatabaseHelper.getAccountByName(requestData.account);
-            
+            if (ACCOUNT.maxPlayer <= -1 || playerCount < ACCOUNT.maxPlayer) {
                 // Check if account exists.
                 if(account == null && ACCOUNT.autoCreate) {
                     // This account has been created AUTOMATICALLY. There will be no permissions added.
@@ -49,6 +51,14 @@ public final class DefaultAuthenticators {
                     }
                 } else if(account != null)
                     successfulLogin = true;
+                 else
+                    loggerMessage = translate("messages.dispatch.account.account_login_exist_error", address);
+
+            } else {
+                responseMessage = translate("messages.dispatch.account.server_max_player_limit");
+                loggerMessage = translate("messages.dispatch.account.login_max_player_limit", address);
+            }
+
             
             // Set response data.
             if(successfulLogin) {
@@ -57,15 +67,13 @@ public final class DefaultAuthenticators {
                 response.data.account.token = account.generateSessionKey();
                 response.data.account.email = account.getEmail();
 
-                // Log the login.
-                Grasscutter.getLogger().info(translate("messages.dispatch.account.login_success", address, account.getId()));
+                loggerMessage = translate("messages.dispatch.account.login_success", address, account.getId());
             } else {
                 response.retcode = -201;
                 response.message = responseMessage;
 
-                // Log the failure.
-                Grasscutter.getLogger().info(translate("messages.dispatch.account.account_login_exist_error", address));
             }
+            Grasscutter.getLogger().info(loggerMessage);
 
             return response;
         }
@@ -83,10 +91,14 @@ public final class DefaultAuthenticators {
 
             boolean successfulLogin;
             String address = request.getRequest().ip();
+            String loggerMessage;
+            int playerCount = Grasscutter.getGameServer().getPlayers().size();
 
             // Log the attempt.
             Grasscutter.getLogger().info(translate("messages.dispatch.account.login_token_attempt", address));
 
+            if (ACCOUNT.maxPlayer <= -1 || playerCount < ACCOUNT.maxPlayer) {
+
                 // Get account from database.
                 Account account = DatabaseHelper.getAccountById(requestData.uid);
 
@@ -101,15 +113,23 @@ public final class DefaultAuthenticators {
                     response.data.account.email = account.getEmail();
 
                     // Log the login.
-                Grasscutter.getLogger().info(translate("messages.dispatch.account.login_token_success", address, requestData.uid));
+                    loggerMessage = translate("messages.dispatch.account.login_token_success", address, requestData.uid);
                 } else {
                     response.retcode = -201;
                     response.message = translate("messages.dispatch.account.account_cache_error");
 
                     // Log the failure.
-                Grasscutter.getLogger().info(translate("messages.dispatch.account.login_token_error", address));
+                    loggerMessage = translate("messages.dispatch.account.login_token_error", address);
+                }
+
+            } else {
+                response.retcode = -201;
+                response.message = translate("messages.dispatch.account.server_max_player_limit");
+
+                loggerMessage = translate("messages.dispatch.account.login_max_player_limit", address);
             }
 
+            Grasscutter.getLogger().info(loggerMessage);
             return response;
         }
     }
@@ -127,7 +147,10 @@ public final class DefaultAuthenticators {
             
             boolean successfulLogin;
             String address = request.getRequest().ip();
+            String loggerMessage;
+            int playerCount = Grasscutter.getGameServer().getPlayers().size();
 
+            if (ACCOUNT.maxPlayer <= -1 || playerCount < ACCOUNT.maxPlayer) {
                 // Get account from database.
                 Account account = DatabaseHelper.getAccountById(loginData.uid);
 
@@ -142,15 +165,23 @@ public final class DefaultAuthenticators {
                     response.data.combo_token = account.generateLoginToken();
 
                     // Log the login.
-                Grasscutter.getLogger().info(translate("messages.dispatch.account.combo_token_success", address));
+                    loggerMessage = translate("messages.dispatch.account.combo_token_success", address);
+
                 } else {
                     response.retcode = -201;
                     response.message = translate("messages.dispatch.account.session_key_error");
 
                     // Log the failure.
-                Grasscutter.getLogger().info(translate("messages.dispatch.account.combo_token_error", address));
+                    loggerMessage = translate("messages.dispatch.account.combo_token_error", address);
+                }
+            } else {
+                response.retcode = -201;
+                response.message = translate("messages.dispatch.account.server_max_player_limit");
+
+                loggerMessage = translate("messages.dispatch.account.login_max_player_limit", address);
             }
 
+            Grasscutter.getLogger().info(loggerMessage);
             return response;
         }
     }

src/main/java/emu/grasscutter/server/http/handlers/GenericHandler.java

@@ -9,6 +9,8 @@ import express.http.Request;
 import express.http.Response;
 import io.javalin.Javalin;
 
+import static emu.grasscutter.Configuration.ACCOUNT;
+
 /**
  * Handles all generic, hard-coded responses.
  */
@@ -48,8 +50,9 @@ public final class GenericHandler implements Router {
     
     private static void serverStatus(Request request, Response response) {
         int playerCount = Grasscutter.getGameServer().getPlayers().size();
+        int maxPlayer = ACCOUNT.maxPlayer;
         String version = GameConstants.VERSION;
 
-        response.send("{\"retcode\":0,\"status\":{\"playerCount\":" + playerCount + ",\"version\":\"" + version + "\"}}");
+        response.send("{\"retcode\":0,\"status\":{\"playerCount\":" + playerCount + ",\"maxPlayer\":" + maxPlayer + ",\"version\":\"" + version + "\"}}");
     }
 }

src/main/java/emu/grasscutter/server/packet/recv/HandlerPlayerLoginReq.java

 package emu.grasscutter.server.packet.recv;
 
+import emu.grasscutter.Grasscutter;
 import emu.grasscutter.database.DatabaseHelper;
 import emu.grasscutter.game.player.Player;
 import emu.grasscutter.net.packet.BasePacket;
@@ -12,6 +13,8 @@ import emu.grasscutter.server.game.GameSession.SessionState;
 import emu.grasscutter.server.packet.send.PacketPlayerLoginRsp;
 import emu.grasscutter.server.packet.send.PacketTakeAchievementRewardReq;
 
+import static emu.grasscutter.Configuration.ACCOUNT;
+
 @Opcodes(PacketOpcodes.PlayerLoginReq) // Sends initial data packets
 public class HandlerPlayerLoginReq extends PacketHandler {
 	
@@ -22,6 +25,11 @@ public class HandlerPlayerLoginReq extends PacketHandler {
 			return;
 		}
 
+		// Max players limit
+		if (ACCOUNT.maxPlayer > -1 && Grasscutter.getGameServer().getPlayers().size() >= ACCOUNT.maxPlayer) {
+			return;
+		}
+
 		// Parse request
 		PlayerLoginReq req = PlayerLoginReq.parseFrom(payload);
 		

src/main/java/emu/grasscutter/utils/ConfigContainer.java

@@ -110,6 +110,7 @@ public class ConfigContainer {
     public static class Account {
         public boolean autoCreate = false;
         public String[] defaultPermissions = {};
+        public int maxPlayer = -1;
     }
 
     /* Server options. */

src/main/resources/languages/en-US.json

@@ -24,6 +24,7 @@
       "account": {
         "login_attempt": "[Dispatch] Client %s is trying to log in.",
         "login_success": "[Dispatch] Client %s logged in as %s.",
+        "login_max_player_limit": "[Dispatch] Client %s failed to log in: The number of online players has reached the limit",
         "login_token_attempt": "[Dispatch] Client %s is trying to log in via token.",
         "login_token_error": "[Dispatch] Client %s failed to log in via token.",
         "login_token_success": "[Dispatch] Client %s logged in via token as %s.",
@@ -35,7 +36,8 @@
         "account_cache_error": "Game account cache information error.",
         "session_key_error": "Wrong session key.",
         "username_error": "Username not found.",
-        "username_create_error": "Username not found, create failed."
+        "username_create_error": "Username not found, create failed.",
+        "server_max_player_limit": "The number of online players has reached the limit"
       },
       "router_error": "[Dispatch] Unable to attach router."
     },

src/main/resources/languages/pl-PL.json

@@ -21,6 +21,7 @@
       "account": {
         "login_attempt": "[Dispatch] Klient %s próbuje się zalogować",
         "login_success": "[Dispatch] Klient %s zalogował się jako %s",
+        "login_max_player_limit": "[Dispatch] Klient %s nie powiodło się: Liczba graczy online osiągnęła limit",
         "login_token_attempt": "[Dispatch] Klient %s próbuje się zalogować poprzez token",
         "login_token_error": "[Dispatch] Klient %s nie mógł się zalogować poprzez token",
         "login_token_success": "[Dispatch] Klient %s zalogował się poprzez token jako %s",
@@ -32,7 +33,8 @@
         "account_cache_error": "Błąd pamięci cache konta gry",
         "session_key_error": "Błędny klucz sesji.",
         "username_error": "Nazwa użytkownika nie znaleziona.",
-        "username_create_error": "Nazwa użytkownika nie znaleziona, tworzenie nie powiodło się."
+        "username_create_error": "Nazwa użytkownika nie znaleziona, tworzenie nie powiodło się.",
+        "server_max_player_limit": "Liczba graczy online osiągnęła limit"
       }
     },
     "status": {

src/main/resources/languages/zh-CN.json

@@ -24,6 +24,7 @@
       "account": {
         "login_attempt": "[Dispatch] 客户端 %s 正在尝试登录",
         "login_success": "[Dispatch] 客户端 %s 已登录，UID 为 %s",
+        "login_max_player_limit": "[Dispatch] 客户端 %s 登录失败：在线人数已满",
         "login_token_attempt": "[Dispatch] 客户端 %s 正在尝试使用 token 登录",
         "login_token_error": "[Dispatch] 客户端 %s 使用 token 登录失败",
         "login_token_success": "[Dispatch] 客户端 %s 已通过 token 登录，UID 为 %s",
@@ -35,7 +36,8 @@
         "account_cache_error": "游戏账号缓存信息错误",
         "session_key_error": "会话密钥错误",
         "username_error": "未找到此用户名",
-        "username_create_error": "未找到用户名，建立连接失败"
+        "username_create_error": "未找到用户名，建立连接失败",
+        "server_max_player_limit": "服务器在线人数已满"
       },
       "router_error": "[Dispatch] 无法连接路由"
     },

src/main/resources/languages/zh-TW.json

@@ -24,6 +24,7 @@
       "account": {
         "login_attempt": "[Dispatch] 客戶端 %s 正在嘗試登入",
         "login_success": "[Dispatch] 客戶端 %s 已登入，UID為 %s",
+        "login_max_player_limit": "[Dispatch] 客戶端 %s 登入失敗：在綫人數已滿",
         "login_token_attempt": "[Dispatch] 客戶端 %s 正在嘗試用憑證登入",
         "login_token_error": "[Dispatch] 客戶端 %s 使用憑證登入失敗",
         "login_token_success": "[Dispatch] 客戶端 %s 已透過憑證登入，UID為 %s",
@@ -35,7 +36,8 @@
         "account_cache_error": "遊戲帳號緩存資訊錯誤",
         "session_key_error": "對話密鑰不符。",
         "username_error": "未找到此用戶名。",
-        "username_create_error": "未找到用戶名，建立失敗。"
+        "username_create_error": "未找到用戶名，建立失敗。",
+        "server_max_player_limit": "服務器在綫人數已滿"
       }
     },
     "status": {