리팩토링

 import express from "express";
 import socketIo, { Server as IoServer } from "socket.io";
 import { createServer } from "http";
-import { SocketHandler } from "./SocketHandler";
 import { RoomManager } from "./room/RoomManager";
+import { Connection } from "./connection/Connection";
+import { SocketIoWrapper } from "./connection/SocketWrapper";
 
 export class Server {
   public readonly port: number;
@@ -15,7 +16,6 @@ export class Server {
     const server = createServer(app);
     this.io = new socketIo.Server(server);
 
-    const handler = new SocketHandler();
     const roomManager = new RoomManager();
 
     roomManager.create("테스트 방 #1", 8);
@@ -23,7 +23,7 @@ export class Server {
     roomManager.create("테스트 방 #3", 2);
 
     this.io.on("connection", (socket) => {
-      handler.connected(socket);
+      new Connection(new SocketIoWrapper(socket), roomManager);
     });
 
     server.listen(port, () => console.log(`Listening on ${port}`));

-import { Socket } from "socket.io";
-import { ConnectionMapper } from "./connection/ConnectionMapper";
-
-export class SocketHandler {
-  private connectionMapper: ConnectionMapper;
-
-  constructor() {
-    this.connectionMapper = new ConnectionMapper();
-  }
-
-  public connected(socket: Socket) {
-    const connection = this.connectionMapper.get(socket);
-  }
-}

 import { Socket } from "socket.io";
-import { ServerOutboundMessage, ServerOutboundMessageKey } from "../../common";
-import { MessageHandlerChain } from "../message/MessageHandlerChain";
+import {
+  RawMessage,
+  ServerInboundMessage,
+  ServerInboundMessageKey,
+  ServerOutboundMessage,
+  ServerOutboundMessageKey,
+  ServerResponse,
+} from "../../common";
 import { Room } from "../room/Room";
+import { RoomManager } from "../room/RoomManager";
 import { User } from "../user/User";
+import { SocketWrapper } from "./SocketWrapper";
 
 export class Connection {
-  public readonly socket: Socket;
+  public readonly socket: SocketWrapper;
+  public readonly roomManager: RoomManager;
 
   public user?: User;
 
-  private messageHandlerChain: MessageHandlerChain;
-
-  constructor(socket: Socket) {
+  constructor(socket: SocketWrapper, roomManager: RoomManager) {
     this.socket = socket;
-    this.messageHandlerChain = new MessageHandlerChain(this);
+    this.roomManager = roomManager;
+    socket.setHandler((raw) => this.handleRaw(raw));
   }
 
   public send<T extends ServerOutboundMessageKey>(
     type: T,
     message: ServerOutboundMessage<T>
   ) {
-    this.socket.emit("msg", {
+    this.socket.send({
       type: type as string,
       message: message,
     });
   }
+
+  public handleRaw(raw: RawMessage): ServerResponse<any> {
+    const type = raw.type as ServerInboundMessageKey;
+    const message = raw.message;
+
+    // 유저 정보가 없으므로 로그인은 따로 핸들링
+    if (type === "login") {
+      return this.handleLogin(message);
+    }
+
+    // Game > Room > User 순으로 전달
+    if (this.user?.room) {
+      const response = this.user.room.handler.handle(type, this.user, message);
+      if (response) return response;
+    }
+    if (this.user) {
+      const response = this.user.handler.handle(type, this.user, message);
+      if (response) return response;
+    }
+    return { ok: false };
+  }
+
+  private handleLogin(
+    message: ServerInboundMessage<"login">
+  ): ServerResponse<"login"> {
+    this.user = new User(message.username, this);
+    console.log(`User ${message.username} has logged in!`);
+
+    return { ok: true };
+  }
 }

-import { Socket } from "socket.io";
-import { Connection } from "./Connection";
-
-export class ConnectionMapper {
-  private map: Map<Socket, Connection>;
-
-  constructor() {
-    this.map = new Map<Socket, Connection>();
-  }
-
-  public get(socket: Socket): Connection {
-    var value = this.map.get(socket);
-    if (value) {
-      return value;
-    }
-
-    value = new Connection(socket);
-    // FIXME: Register connection to the map
-    return value;
-  }
-
-  public close(socket: Socket): void {
-    this.map.delete(socket);
-  }
-}

+import { Socket } from "socket.io";
+import { RawMessage, ServerResponse } from "../../common";
+
+export interface SocketWrapper {
+  setHandler: (listener: (raw: RawMessage) => ServerResponse<any>) => void;
+  send: (raw: RawMessage) => void;
+}
+
+export class SocketIoWrapper implements SocketWrapper {
+  private socketIo: Socket;
+
+  constructor(socketIo: Socket) {
+    this.socketIo = socketIo;
+  }
+
+  public setHandler(listener: (raw: RawMessage) => ServerResponse<any>): void {
+    this.socketIo.on("msg", (raw: RawMessage, callback: Function) => {
+      callback(listener(raw));
+    });
+  }
+
+  public send(raw: RawMessage) {
+    this.socketIo.emit("msg", raw);
+  }
+}

-import { Connection } from "../connection/Connection";
 import {
   ServerInboundMessage,
   ServerInboundMessageKey,
@@ -23,13 +22,10 @@ export class MessageHandler {
   public handle(
     type: ServerInboundMessageKey,
     user: User,
-    message: any,
-    callback: Function
-  ): boolean {
+    message: any
+  ): ServerResponse<any> | undefined {
     const handler = this.handlers[type];
-    if (!handler) return false;
-    const response = handler(user, message);
-    callback(response);
-    return true;
+    if (!handler) return undefined;
+    return handler(user, message);
   }
 }

-import { Connection } from "../connection/Connection";
-import {
-  RawMessage,
-  ServerInboundMessage,
-  ServerInboundMessageKey,
-  ServerResponse,
-} from "../../common/index";
-import { User } from "../user/User";
-
-export class MessageHandlerChain {
-  connection: Connection;
-
-  constructor(connection: Connection) {
-    this.connection = connection;
-
-    this.connection.socket.on("msg", (raw: RawMessage, callback: Function) => {
-      this.handleRaw(connection, raw, callback);
-    });
-  }
-
-  private handleRaw(
-    connection: Connection,
-    raw: RawMessage,
-    callback: Function
-  ) {
-    const type = raw.type as ServerInboundMessageKey;
-    const message = raw.message;
-
-    // 유저 정보가 없으므로 로그인은 따로 핸들링
-    if (type === "login") {
-      this.handleLogin(connection, message, callback);
-      return;
-    }
-
-    // Game > Room > User 순으로 전달
-    if (
-      connection?.user?.room &&
-      connection.user.room.handler.handle(
-        type,
-        connection.user,
-        message,
-        callback
-      )
-    )
-      return;
-
-    if (
-      connection?.user &&
-      connection.user.handler.handle(type, connection.user, message, callback)
-    )
-      return;
-  }
-
-  private handleLogin(
-    connection: Connection,
-    message: ServerInboundMessage<"login">,
-    callback: Function
-  ) {
-    connection.user = new User(message.username, connection);
-    console.log(`User ${message.username} has logged in!`);
-
-    callback({ ok: true });
-  }
-}

 import { Connection } from "../connection/Connection";
 import { v4 as uuidv4 } from "uuid";
 import { User } from "../user/User";
-import { MessageHandlerChain } from "../message/MessageHandlerChain";
 import { MessageHandler } from "../message/MessageHandler";
 import {
   ServerInboundMessage,

@@ -2,19 +2,12 @@ import { RoomDescription } from "../../common/dataType";
 import { Room } from "./Room";
 
 export class RoomManager {
-  private static _instance: RoomManager;
-
   private rooms: Map<string, Room>;
 
   constructor() {
-    RoomManager._instance = this;
     this.rooms = new Map<string, Room>();
   }
 
-  public static instance(): RoomManager {
-    return RoomManager._instance;
-  }
-
   public create(name: string, maxConnections: number): Room {
     const room = new Room(name, maxConnections);
     this.rooms.set(room.uuid, room);

@@ -18,10 +18,10 @@ export class User {
     this.connection = connection;
     this.handler = new MessageHandler({
       roomList: (user, message) => {
-        return { ok: true, result: RoomManager.instance().list() };
+        return { ok: true, result: connection.roomManager.list() };
       },
       joinRoom: (user, message) => {
-        const room = RoomManager.instance().get(message.uuid);
+        const room = connection.roomManager.get(message.uuid);
         if (user.room || !room) {
           return { ok: false };
         }