add entity updates over network!

client/src/JumpStorm.ts

@@ -1,5 +1,5 @@
 import { Game } from '@engine/Game';
-import { Entity, Floor } from '@engine/entities';
+import { Entity } from '@engine/entities';
 import { Grid } from '@engine/structures';
 import {
   WallBounds,
@@ -16,11 +16,10 @@ import {
   type MessageProcessor,
   type Message,
   type EntityAddBody,
-  MessageType
+  MessageType,
+  type EntityUpdateBody
 } from '@engine/network';
 import { stringify, parse } from '@engine/utils';
-import { BoundingBox, Sprite } from '@engine/components';
-import { Miscellaneous } from '@engine/config';
 
 class ClientMessageProcessor implements MessageProcessor {
   private game: Game;
@@ -34,17 +33,24 @@ class ClientMessageProcessor implements MessageProcessor {
       case MessageType.NEW_ENTITIES:
         const entityAdditions = message.body as unknown as EntityAddBody[];
         entityAdditions.forEach((addBody) =>
-          this.game.addEntity(Entity.from(addBody.entityName, addBody.args))
+          this.game.addEntity(
+            Entity.from(addBody.entityName, addBody.id, addBody.args)
+          )
         );
         break;
       case MessageType.REMOVE_ENTITIES:
         const ids = message.body as unknown as string[];
         ids.forEach((id) => this.game.removeEntity(id));
         break;
+      case MessageType.UPDATE_ENTITIES:
+        const entityUpdates = message.body as unknown as EntityUpdateBody[];
+        entityUpdates.forEach(
+          ({ id, args }) => this.game.getEntity(id)?.setFrom(args)
+        );
+        break;
       default:
         break;
     }
-    console.log(message);
   }
 }
 
@@ -85,9 +91,12 @@ class ClientSocketMessagePublisher implements MessagePublisher {
   }
 
   public publish() {
+    if (this.socket.readyState == WebSocket.OPEN) {
       this.messages.forEach((message: Message) =>
         this.socket.send(stringify(message))
       );
+      this.messages = [];
+    }
   }
 }
 
@@ -105,19 +114,9 @@ export class JumpStorm {
     wsMethod: string,
     host: string
   ) {
-    await fetch(`${httpMethod}://${host}/assign`)
+    this.clientId = await this.getAssignedCookie(
-      .then((resp) => {
+      `${httpMethod}://${host}/assign`
-        if (resp.ok) {
+    );
-          return resp.text();
-        }
-        throw resp;
-      })
-      .then((cookie) => {
-        this.clientId = cookie;
-      });
-
-    const grid = new Grid();
-
     const socket = new WebSocket(`${wsMethod}://${host}/game`);
     const clientSocketMessageQueueProvider =
       new ClientSocketMessageQueueProvider(socket);
@@ -125,33 +124,25 @@ export class JumpStorm {
       socket
     );
     const clientMessageProcessor = new ClientMessageProcessor(this.game);
+
+    const inputSystem = new Input(this.clientId, clientSocketMessagePublisher);
+    this.addWindowEventListenersToInputSystem(inputSystem);
+
+    const grid = new Grid();
+
     [
-      this.createInputSystem(),
-      new FacingDirection(),
-      new Physics(),
-      new Collision(grid),
-      new WallBounds(),
       new NetworkUpdate(
         clientSocketMessageQueueProvider,
         clientSocketMessagePublisher,
         clientMessageProcessor
       ),
+      inputSystem,
+      new FacingDirection(),
+      new Physics(),
+      new Collision(grid),
+      new WallBounds(),
       new Render(ctx)
     ].forEach((system) => this.game.addSystem(system));
-
-    const floor = new Floor(160);
-    const floorHeight = 40;
-
-    floor.addComponent(
-      new BoundingBox(
-        {
-          x: Miscellaneous.WIDTH / 2,
-          y: Miscellaneous.HEIGHT - floorHeight / 2
-        },
-        { width: Miscellaneous.WIDTH, height: floorHeight }
-      )
-    );
-    this.game.addEntity(floor);
   }
 
   public play() {
@@ -164,17 +155,26 @@ export class JumpStorm {
     requestAnimationFrame(loop);
   }
 
-  private createInputSystem(): Input {
+  private addWindowEventListenersToInputSystem(input: Input) {
-    const inputSystem = new Input(this.clientId);
-
     window.addEventListener('keydown', (e) => {
       if (!e.repeat) {
-        inputSystem.keyPressed(e.key);
+        input.keyPressed(e.key.toLowerCase());
       }
     });
 
-    window.addEventListener('keyup', (e) => inputSystem.keyReleased(e.key));
+    window.addEventListener('keyup', (e) =>
+      input.keyReleased(e.key.toLowerCase())
+    );
+  }
 
-    return inputSystem;
+  private async getAssignedCookie(endpoint: string): Promise<string> {
+    return fetch(endpoint)
+      .then((resp) => {
+        if (resp.ok) {
+          return resp.text();
+        }
+        throw resp;
+      })
+      .then((cookie) => cookie);
   }
 }

client/vite.config.ts

@@ -5,9 +5,10 @@ import { fileURLToPath, URL } from 'node:url';
 // https://vitejs.dev/config/
 export default defineConfig({
   server: {
+    host: '0.0.0.0',
     proxy: {
       '/api': {
-        target: 'http://localhost:8080',
+        target: 'http://10.0.0.237:8080',
         ws: true,
         rewrite: (path) => path.replace(/^\/api/, '')
       }

engine/components/BoundingBox.ts

@@ -15,7 +15,6 @@ export class BoundingBox extends Component {
     this.rotation = rotation ?? 0;
   }
 
-  // https://en.wikipedia.org/wiki/Hyperplane_separation_theorem
   public isCollidingWith(box: BoundingBox): boolean {
     if (this.rotation == 0 && box.rotation == 0) {
       const thisTopLeft = this.getTopLeft();
@@ -36,6 +35,7 @@ export class BoundingBox extends Component {
       return true;
     }
 
+    // https://en.wikipedia.org/wiki/Hyperplane_separation_theorem
     const boxes = [this.getVertices(), box.getVertices()];
     for (const poly of boxes) {
       for (let i = 0; i < poly.length; i++) {
@@ -89,6 +89,8 @@ export class BoundingBox extends Component {
     let rads = this.getRotationInPiOfUnitCircle();
     const { width, height } = this.dimension;
 
+    if (rads == 0) return this.dimension;
+
     if (rads <= Math.PI / 2) {
       return {
         width: Math.abs(height * Math.sin(rads) + width * Math.cos(rads)),

engine/components/Control.ts

@@ -3,6 +3,7 @@ import { Component, ComponentNames, Velocity } from '.';
 export class Control extends Component {
   public controlVelocityComponent: Velocity;
   public controllableBy: string;
+  public isControllable: boolean; // computed each update in the input system
 
   constructor(
     controllableBy: string,
@@ -12,5 +13,6 @@ export class Control extends Component {
 
     this.controllableBy = controllableBy;
     this.controlVelocityComponent = controlVelocityComponent;
+    this.isControllable = false;
   }
 }

engine/components/NetworkUpdateable.ts

@@ -1,13 +1,7 @@
 import { Component, ComponentNames } from '.';
 
 export class NetworkUpdateable extends Component {
-  public isPublish: boolean;
+  constructor() {
-  public isSubscribe: boolean;
-
-  constructor(isPublish: boolean, isSubscribe: boolean) {
     super(ComponentNames.NetworkUpdateable);
-
-    this.isPublish = isPublish;
-    this.isSubscribe = isSubscribe;
   }
 }

engine/config/constants.ts

@@ -3,13 +3,13 @@ import { Action } from '../interfaces';
 export namespace KeyConstants {
   export const KeyActions: Record<string, Action> = {
     a: Action.MOVE_LEFT,
-    ArrowLeft: Action.MOVE_LEFT,
+    arrowleft: Action.MOVE_LEFT,
 
     d: Action.MOVE_RIGHT,
-    ArrowRight: Action.MOVE_RIGHT,
+    arrowright: Action.MOVE_RIGHT,
 
     w: Action.JUMP,
-    ArrowUp: Action.JUMP,
+    arrowup: Action.JUMP,
 
     ' ': Action.JUMP
   };
@@ -18,7 +18,7 @@ export namespace KeyConstants {
   export const ActionKeys: Map<Action, string[]> = Object.keys(
     KeyActions
   ).reduce((acc: Map<Action, string[]>, key) => {
-    const action = KeyActions[key];
+    const action = KeyActions[key.toLowerCase()];
 
     if (acc.has(action)) {
       acc.get(action)!.push(key);
@@ -33,7 +33,7 @@ export namespace KeyConstants {
 export namespace PhysicsConstants {
   export const MAX_JUMP_TIME_MS = 150;
   export const GRAVITY = 0.0075;
-  export const PLAYER_MOVE_VEL = 1;
+  export const PLAYER_MOVE_VEL = 0.8;
   export const PLAYER_JUMP_ACC = -0.008;
   export const PLAYER_JUMP_INITIAL_VEL = -1;
 }

engine/entities/Entity.ts

@@ -1,12 +1,15 @@
-import { EntityNames, Player } from '.';
+import { EntityNames, Floor, Player } from '.';
-import type { Component } from '../components';
+import { type Component } from '../components';
+
+const randomId = () =>
+  (performance.now() + Math.random() * 10_000_000).toString();
 
 export abstract class Entity {
   public id: string;
   public components: Map<string, Component>;
   public name: string;
 
-  constructor(name: string, id: string = crypto.randomUUID()) {
+  constructor(name: string, id: string = randomId()) {
     this.name = name;
     this.id = id;
     this.components = new Map();
@@ -31,14 +34,29 @@ export abstract class Entity {
     return this.components.has(name);
   }
 
-  static from(entityName: string, args: any): Entity {
+  public static from(entityName: string, id: string, args: any): Entity {
+    let entity: Entity;
+
     switch (entityName) {
       case EntityNames.Player:
-        const player = new Player(args.playerId);
+        const player = new Player();
-        player.id = args.id;
+        player.setFrom(args);
-        return player;
+        entity = player;
+        break;
+      case EntityNames.Floor:
+        const floor = new Floor(args.floorWidth);
+        floor.setFrom(args);
+        entity = floor;
+        break;
       default:
         throw new Error('.from() Entity type not implemented: ' + entityName);
     }
+
+    entity.id = id;
+    return entity;
   }
+
+  public abstract setFrom(args: Record<string, any>): void;
+
+  public abstract serialize(): Record<string, any>;
 }

engine/entities/Floor.ts

@@ -1,5 +1,5 @@
 import { IMAGES, SPRITE_SPECS, Sprites, type SpriteSpec } from '../config';
-import { BoundingBox, Sprite } from '../components';
+import { BoundingBox, ComponentNames, Sprite } from '../components';
 import { TopCollidable } from '../components/TopCollidable';
 import { Entity, EntityNames } from '../entities';
 
@@ -8,9 +8,13 @@ export class Floor extends Entity {
     Sprites.FLOOR
   ) as SpriteSpec;
 
+  private width: number;
+
   constructor(width: number) {
     super(EntityNames.Floor);
 
+    this.width = width;
+
     this.addComponent(
       new Sprite(
         IMAGES.get((Floor.spriteSpec?.states?.get(width) as SpriteSpec).sheet),
@@ -23,4 +27,22 @@ export class Floor extends Entity {
 
     this.addComponent(new TopCollidable());
   }
+
+  public serialize() {
+    return {
+      floorWidth: this.width,
+      boundingBox: this.getComponent<BoundingBox>(ComponentNames.BoundingBox)
+    };
+  }
+
+  public setFrom(args: any) {
+    const { boundingBox } = args;
+    this.addComponent(
+      new BoundingBox(
+        boundingBox.center,
+        boundingBox.dimension,
+        boundingBox.rotation
+      )
+    );
+  }
 }

engine/entities/Player.ts

@@ -10,9 +10,10 @@ import {
   WallBounded,
   Forces,
   Collide,
-  Control,
   Mass,
-  Moment
+  Moment,
+  ComponentNames,
+  Control
 } from '../components';
 import { Direction } from '../interfaces';
 
@@ -24,14 +25,14 @@ export class Player extends Entity {
     Sprites.COFFEE
   ) as SpriteSpec;
 
-  constructor(playerId: string) {
+  constructor() {
     super(EntityNames.Player);
 
     this.addComponent(
       new BoundingBox(
         {
-          x: 300,
+          x: 0,
-          y: 100
+          y: 0
         },
         { width: Player.spriteSpec.width, height: Player.spriteSpec.height },
         0
@@ -48,7 +49,6 @@ export class Player extends Entity {
     this.addComponent(new Gravity());
 
     this.addComponent(new Jump());
-    this.addComponent(new Control(playerId));
 
     this.addComponent(new Collide());
     this.addComponent(new WallBounded());
@@ -69,6 +69,36 @@ export class Player extends Entity {
     );
 
     this.addComponent(new FacingDirection(leftSprite, rightSprite));
-    this.addComponent(leftSprite); // face Left by default
+    this.addComponent(leftSprite); // face left by default
+  }
+
+  public serialize(): Record<string, any> {
+    return {
+      control: this.getComponent<Control>(ComponentNames.Control),
+      boundingBox: this.getComponent<BoundingBox>(ComponentNames.BoundingBox),
+      velocity: this.getComponent<Velocity>(ComponentNames.Velocity),
+      forces: this.getComponent<Forces>(ComponentNames.Forces)
+    };
+  }
+
+  public setFrom(args: Record<string, any>) {
+    const { control, velocity, forces, boundingBox } = args;
+
+    let center = boundingBox.center;
+
+    const myCenter = this.getComponent<BoundingBox>(
+      ComponentNames.BoundingBox
+    ).center;
+    const distance = Math.sqrt(
+      Math.pow(center.y - myCenter.y, 2) + Math.pow(center.x - myCenter.x, 2)
+    );
+    if (distance < 30) center = myCenter;
+
+    [
+      Object.assign(new Control(control.controllableBy), control),
+      new Velocity(velocity.velocity),
+      new Forces(forces.forces),
+      new BoundingBox(center, boundingBox.dimension, boundingBox.rotation)
+    ].forEach((component) => this.addComponent(component));
   }
 }

engine/network/index.ts

@@ -1,12 +1,20 @@
 export enum MessageType {
   NEW_ENTITIES = 'NEW_ENTITIES',
   REMOVE_ENTITIES = 'REMOVE_ENTITIES',
-  UPDATE_ENTITY = 'UPDATE_ENTITY'
+  UPDATE_ENTITIES = 'UPDATE_ENTITIES',
+  NEW_INPUT = 'NEW_INPUT',
+  REMOVE_INPUT = 'REMOVE_INPUT'
 }
 
 export type EntityAddBody = {
   entityName: string;
-  args: any;
+  id: string;
+  args: Record<string, any>;
+};
+
+export type EntityUpdateBody = {
+  id: string;
+  args: Record<string, any>;
 };
 
 export type Message = {

engine/systems/Input.ts

@@ -10,41 +10,62 @@ import { Game } from '../Game';
 import { KeyConstants, PhysicsConstants } from '../config';
 import { Action } from '../interfaces';
 import { System, SystemNames } from '.';
+import { MessagePublisher, MessageType } from '../network';
+import { Entity } from '../entities';
 
 export class Input extends System {
   public clientId: string;
+
   private keys: Set<string>;
   private actionTimeStamps: Map<Action, number>;
+  private messagePublisher?: MessagePublisher;
 
-  constructor(clientId: string) {
+  constructor(clientId: string, messagePublisher?: MessagePublisher) {
     super(SystemNames.Input);
 
     this.clientId = clientId;
-    this.keys = new Set<string>();
+    this.keys = new Set();
-    this.actionTimeStamps = new Map<Action, number>();
+    this.actionTimeStamps = new Map();
+
+    this.messagePublisher = messagePublisher;
   }
 
   public keyPressed(key: string) {
     this.keys.add(key);
+
+    if (this.messagePublisher) {
+      this.messagePublisher.addMessage({
+        type: MessageType.NEW_INPUT,
+        body: key
+      });
+    }
   }
 
   public keyReleased(key: string) {
     this.keys.delete(key);
-  }
 
-  private hasSomeKey(keys?: string[]): boolean {
+    if (this.messagePublisher) {
-    if (keys) {
+      this.messagePublisher.addMessage({
-      return keys.some((key) => this.keys.has(key));
+        type: MessageType.REMOVE_INPUT,
+        body: key
+      });
     }
-    return false;
   }
 
   public update(_dt: number, game: Game) {
-    game.forEachEntityWithComponent(ComponentNames.Control, (entity) => {
+    game.forEachEntityWithComponent(ComponentNames.Control, (entity) =>
+      this.handleInput(entity)
+    );
+  }
+
+  public handleInput(entity: Entity) {
     const controlComponent = entity.getComponent<Control>(
       ComponentNames.Control
     );
-      if (controlComponent.controllableBy != this.clientId) return;
+    controlComponent.isControllable =
+      controlComponent.controllableBy === this.clientId;
+
+    if (!controlComponent.isControllable) return;
 
     if (this.hasSomeKey(KeyConstants.ActionKeys.get(Action.MOVE_RIGHT))) {
       controlComponent.controlVelocityComponent.velocity.dCartesian.dx +=
@@ -56,13 +77,20 @@ export class Input extends System {
         -PhysicsConstants.PLAYER_MOVE_VEL;
     }
 
-      if (entity.hasComponent(ComponentNames.Jump)) {
+    if (
+      entity.hasComponent(ComponentNames.Jump) &&
+      this.hasSomeKey(KeyConstants.ActionKeys.get(Action.JUMP))
+    ) {
+      this.performJump(entity);
+    }
+  }
+
+  private performJump(entity: Entity) {
     const velocity = entity.getComponent<Velocity>(
       ComponentNames.Velocity
     ).velocity;
     const jump = entity.getComponent<Jump>(ComponentNames.Jump);
 
-        if (this.hasSomeKey(KeyConstants.ActionKeys.get(Action.JUMP))) {
     if (jump.canJump) {
       this.actionTimeStamps.set(Action.JUMP, performance.now());
 
@@ -88,7 +116,11 @@ export class Input extends System {
         ?.forces.push(jumpForce);
     }
   }
+
+  private hasSomeKey(keys?: string[]): boolean {
+    if (keys) {
+      return keys.some((key) => this.keys.has(key));
     }
-    });
+    return false;
   }
 }

engine/systems/NetworkUpdate.ts

@@ -1,10 +1,12 @@
 import { System, SystemNames } from '.';
 import { Game } from '../Game';
-import { ComponentNames, NetworkUpdateable } from '../components';
+import { ComponentNames } from '../components';
 import {
   type MessageQueueProvider,
   type MessagePublisher,
-  type MessageProcessor
+  type MessageProcessor,
+  MessageType,
+  EntityUpdateBody
 } from '../network';
 
 export class NetworkUpdate extends System {
@@ -12,6 +14,8 @@ export class NetworkUpdate extends System {
   private publisher: MessagePublisher;
   private messageProcessor: MessageProcessor;
 
+  private entityUpdateTimers: Map<string, number>;
+
   constructor(
     queueProvider: MessageQueueProvider,
     publisher: MessagePublisher,
@@ -22,23 +26,47 @@ export class NetworkUpdate extends System {
     this.queueProvider = queueProvider;
     this.publisher = publisher;
     this.messageProcessor = messageProcessor;
+
+    this.entityUpdateTimers = new Map();
   }
 
-  public update(_dt: number, game: Game) {
+  public update(dt: number, game: Game) {
+    // 1. process new messages
     this.queueProvider
       .getNewMessages()
       .forEach((message) => this.messageProcessor.process(message));
     this.queueProvider.clearMessages();
 
+    // 2. send entity updates
+    const updateMessages: EntityUpdateBody[] = [];
     game.forEachEntityWithComponent(
       ComponentNames.NetworkUpdateable,
       (entity) => {
-        const networkUpdateComponent = entity.getComponent<NetworkUpdateable>(
+        let timer = this.entityUpdateTimers.get(entity.id) ?? dt;
-          ComponentNames.NetworkUpdateable
+        timer -= dt;
-        );
+        this.entityUpdateTimers.set(entity.id, timer);
+
+        if (timer > 0) return;
+        this.entityUpdateTimers.set(entity.id, this.getNextUpdateTimeMs());
+
+        if (entity.hasComponent(ComponentNames.NetworkUpdateable)) {
+          updateMessages.push({
+            id: entity.id,
+            args: entity.serialize()
+          });
+        }
       }
     );
+    this.publisher.addMessage({
+      type: MessageType.UPDATE_ENTITIES,
+      body: updateMessages
+    });
 
+    // 3. publish changes
     this.publisher.publish();
   }
+
+  private getNextUpdateTimeMs() {
+    return Math.random() * 70 + 50;
+  }
 }

engine/systems/Physics.ts

@@ -99,7 +99,7 @@ export class Physics extends System {
           : boundingBox.rotation) % 360;
 
       // clear the control velocity
-      if (control) {
+      if (control && control.isControllable) {
         control.controlVelocityComponent = new Velocity();
       }
     });

server/src/main.ts

@@ -2,28 +2,55 @@ import { Grid } from '@engine/structures';
 import {
   ServerMessageProcessor,
   ServerSocketMessagePublisher,
-  ServerSocketMessageReceiver
+  ServerSocketMessageReceiver,
+  MemorySessionManager,
+  SessionInputSystem
 } from './network';
 import { Collision, NetworkUpdate, Physics, WallBounds } from '@engine/systems';
 import { Game } from '@engine/Game';
 import { Constants } from './constants';
 import { GameServer } from './server';
-
+import { Floor } from '@engine/entities';
-const messageReceiver = new ServerSocketMessageReceiver();
+import { BoundingBox } from '@engine/components';
-const messagePublisher = new ServerSocketMessagePublisher();
+import { Miscellaneous } from '@engine/config';
-const messageProcessor = new ServerMessageProcessor();
 
 const game = new Game();
 
-const server = new GameServer(game, messageReceiver, messagePublisher);
+const sessionManager = new MemorySessionManager();
+
+const messageReceiver = new ServerSocketMessageReceiver();
+const messagePublisher = new ServerSocketMessagePublisher();
+const messageProcessor = new ServerMessageProcessor(game, sessionManager);
+
+const server = new GameServer(
+  game,
+  messageReceiver,
+  messagePublisher,
+  sessionManager
+);
 
 [
+  new SessionInputSystem(sessionManager),
+  new NetworkUpdate(messageReceiver, messagePublisher, messageProcessor),
   new Physics(),
   new Collision(new Grid()),
-  new WallBounds(),
+  new WallBounds()
-  new NetworkUpdate(messageReceiver, messagePublisher, messageProcessor)
 ].forEach((system) => game.addSystem(system));
 
+const floor = new Floor(160);
+const floorHeight = 200;
+
+floor.addComponent(
+  new BoundingBox(
+    {
+      x: Miscellaneous.WIDTH / 2,
+      y: Miscellaneous.HEIGHT + floorHeight / 2
+    },
+    { width: Miscellaneous.WIDTH, height: floorHeight }
+  )
+);
+game.addEntity(floor);
+
 game.start();
 setInterval(() => {
   game.doGameLoop(performance.now());

server/src/network/MessageProcessor.ts

@@ -1,8 +1,36 @@
-import { MessageProcessor } from '@engine/network';
+import {
-import { ServerMessage } from '.';
+  EntityUpdateBody,
+  MessageProcessor,
+  MessageType
+} from '@engine/network';
+import { ServerMessage, SessionManager } from '.';
+import { Game } from '@engine/Game';
 
 export class ServerMessageProcessor implements MessageProcessor {
-  constructor() {}
+  private game: Game;
+  private sessionManager: SessionManager;
 
-  public process(_message: ServerMessage) {}
+  constructor(game: Game, sessionManager: SessionManager) {
+    this.game = game;
+    this.sessionManager = sessionManager;
+  }
+
+  public process(message: ServerMessage) {
+    switch (message.type) {
+      case MessageType.NEW_INPUT: {
+        const { sessionId } = message.sessionData;
+        const session = this.sessionManager.getSession(sessionId);
+        session?.inputSystem.keyPressed(message.body as string);
+        break;
+      }
+      case MessageType.REMOVE_INPUT: {
+        const { sessionId } = message.sessionData;
+        const session = this.sessionManager.getSession(sessionId);
+        session?.inputSystem.keyReleased(message.body as string);
+        break;
+      }
+      default:
+        break;
+    }
+  }
 }

server/src/network/SessionInputSystem.ts

@@ -0,0 +1,32 @@
+import { Game } from '@engine/Game';
+import { SessionManager } from '.';
+import { System } from '@engine/systems';
+import { BoundingBox, ComponentNames, Control } from '@engine/components';
+
+export class SessionInputSystem extends System {
+  private sessionManager: SessionManager;
+
+  constructor(sessionManager: SessionManager) {
+    super('SessionInputSystem');
+
+    this.sessionManager = sessionManager;
+  }
+
+  public update(_dt: number, game: Game) {
+    this.sessionManager.getSessions().forEach((sessionId) => {
+      const session = this.sessionManager.getSession(sessionId);
+
+      if (!session) return;
+
+      const { inputSystem } = session;
+      session.controllableEntities.forEach((entityId) => {
+        const entity = game.getEntity(entityId);
+        if (!entity) return;
+
+        if (entity.hasComponent(ComponentNames.Control)) {
+          inputSystem.handleInput(entity);
+        }
+      });
+    });
+  }
+}

server/src/network/SessionManager.ts

@@ -0,0 +1,33 @@
+import { Session, SessionManager } from '.';
+
+export class MemorySessionManager implements SessionManager {
+  private sessions: Map<string, Session>;
+
+  constructor() {
+    this.sessions = new Map();
+  }
+
+  public getSessions() {
+    return Array.from(this.sessions.keys());
+  }
+
+  public uniqueSessionId() {
+    return crypto.randomUUID();
+  }
+
+  public getSession(id: string) {
+    return this.sessions.get(id);
+  }
+
+  public putSession(id: string, session: Session) {
+    return this.sessions.set(id, session);
+  }
+
+  public numSessions() {
+    return this.sessions.size;
+  }
+
+  public removeSession(id: string) {
+    this.sessions.delete(id);
+  }
+}

server/src/network/index.ts

@@ -1,16 +1,29 @@
 import { Message } from '@engine/network';
+import { Input } from '@engine/systems';
 
 export * from './MessageProcessor';
 export * from './MessagePublisher';
 export * from './MessageReceiver';
+export * from './SessionManager';
+export * from './SessionInputSystem';
 
 export type SessionData = { sessionId: string };
 
 export type Session = {
   sessionId: string;
   controllableEntities: Set<string>;
+  inputSystem: Input;
 };
 
 export interface ServerMessage extends Message {
   sessionData: SessionData;
 }
+
+export interface SessionManager {
+  uniqueSessionId(): string;
+  getSession(id: string): Session | undefined;
+  getSessions(): string[];
+  putSession(id: string, session: Session): void;
+  removeSession(id: string): void;
+  numSessions(): number;
+}

server/src/server.ts

@@ -1,35 +1,38 @@
 import { Game } from '@engine/Game';
-import { EntityNames, Player } from '@engine/entities';
+import { Player } from '@engine/entities';
-import { MessageType } from '@engine/network';
+import { Message, MessageType } from '@engine/network';
 import { Constants } from './constants';
 import {
   ServerSocketMessageReceiver,
   ServerSocketMessagePublisher,
   SessionData,
   ServerMessage,
-  Session
+  Session,
+  SessionManager
 } from './network';
 import { parse } from '@engine/utils';
 import { Server, ServerWebSocket } from 'bun';
+import { Input } from '@engine/systems';
+import { Control, NetworkUpdateable } from '@engine/components';
+import { stringify } from '@engine/utils';
 
 export class GameServer {
-  private sessions: Map<string, Session>;
-
   private server?: Server;
   private game: Game;
   private messageReceiver: ServerSocketMessageReceiver;
   private messagePublisher: ServerSocketMessagePublisher;
+  private sessionManager: SessionManager;
 
   constructor(
     game: Game,
     messageReceiver: ServerSocketMessageReceiver,
-    messagePublisher: ServerSocketMessagePublisher
+    messagePublisher: ServerSocketMessagePublisher,
+    sessionManager: SessionManager
   ) {
-    this.sessions = new Map();
-
     this.game = game;
     this.messageReceiver = messageReceiver;
     this.messagePublisher = messagePublisher;
+    this.sessionManager = sessionManager;
   }
 
   public serve() {
@@ -64,10 +67,12 @@ export class GameServer {
   private closeWebsocket(websocket: ServerWebSocket<SessionData>) {
     const { sessionId } = websocket.data;
 
-    const sessionEntities = this.sessions.get(sessionId)!.controllableEntities;
+    const sessionEntities =
-    this.sessions.delete(sessionId);
+      this.sessionManager.getSession(sessionId)!.controllableEntities;
+    this.sessionManager.removeSession(sessionId);
 
     if (!sessionEntities) return;
+    sessionEntities.forEach((id) => this.game.removeEntity(id));
 
     this.messagePublisher.addMessage({
       type: MessageType.REMOVE_ENTITIES,
@@ -79,28 +84,51 @@ export class GameServer {
     websocket.subscribe(Constants.GAME_TOPIC);
 
     const { sessionId } = websocket.data;
-    if (this.sessions.has(sessionId)) {
+    if (this.sessionManager.getSession(sessionId)) {
       return;
     }
 
-    this.sessions.set(sessionId, {
+    const newSession: Session = {
       sessionId,
-      controllableEntities: new Set()
+      controllableEntities: new Set(),
-    });
+      inputSystem: new Input(sessionId)
+    };
 
-    const player = new Player(sessionId);
+    const player = new Player();
+    player.addComponent(new Control(sessionId));
+    player.addComponent(new NetworkUpdateable());
     this.game.addEntity(player);
-    this.messagePublisher.addMessage({
+
+    newSession.controllableEntities.add(player.id);
+    this.sessionManager.putSession(sessionId, newSession);
+
+    const addCurrentEntities: Message[] = [
+      {
+        type: MessageType.NEW_ENTITIES,
+        body: Array.from(this.game.entities.values())
+          .filter((entity) => entity.id != player.id)
+          .map((entity) => {
+            return {
+              id: entity.id,
+              entityName: entity.name,
+              args: entity.serialize()
+            };
+          })
+      }
+    ];
+    websocket.sendText(stringify(addCurrentEntities));
+
+    const addNewPlayer: Message = {
       type: MessageType.NEW_ENTITIES,
       body: [
         {
-          entityName: EntityNames.Player,
+          id: player.id,
-          args: { playerId: sessionId, id: player.id }
+          entityName: player.name,
+          args: player.serialize()
         }
       ]
-    });
+    };
-
+    this.messagePublisher.addMessage(addNewPlayer);
-    this.sessions.get(sessionId)!.controllableEntities.add(player.id);
   }
 
   private fetchHandler(req: Request, server: Server): Response {
@@ -110,7 +138,7 @@ export class GameServer {
     headers.set('Access-Control-Allow-Origin', '*');
 
     if (url.pathname == '/assign') {
-      if (this.sessions.size > Constants.MAX_PLAYERS)
+      if (this.sessionManager.numSessions() > Constants.MAX_PLAYERS)
         return new Response('too many players', { headers, status: 400 });
 
       const sessionId = crypto.randomUUID();
@@ -127,10 +155,6 @@ export class GameServer {
     const sessionId = cookie.split(';').at(0)!.split('SessionId=').at(1);
 
     if (url.pathname == '/game') {
-      headers.set(
-        'Set-Cookie',
-        `SessionId=${sessionId}; HttpOnly; SameSite=Strict;`
-      );
       server.upgrade(req, {
         headers,
         data: {