接口返的数据结构做统一处理

把发消息写入数据库的时间都交给数据库来创建
完善websocket关闭连接功能
2026-09-30 16:22:49 +08:00 · 2026-09-29 17:01:34 +08:00 · 2026-09-29 14:13:11 +08:00 · 2026-09-29 11:14:09 +08:00 · 2026-09-28 11:07:06 +08:00 · 2026-09-24 10:45:31 +08:00
30 changed files with 6424 additions and 261 deletions
@@ -0,0 +1,208 @@
+# Chat Demo Server 设计说明
+
+## 1. 文档范围
+
+本文依据当前仓库中的代码和 SQL 脚本，记录聊天服务端现有结构、模块职责、接口和消息协议、数据模型及设计取舍。文中“当前行为”指代码已经实现的行为；代码中存在但可能导致运行失败或安全风险的部分会在“已知问题与建议”中单独说明，不将计划性改进描述为已有能力。
+
+## 2. 项目概述
+
+本项目是一个基于 Node.js 的单进程聊天服务端，提供 HTTP REST 接口和 WebSocket 实时连接。Express 和 WebSocket 共用同一个 HTTP Server，监听 3000 端口；MySQL 保存用户、联系人和聊天消息。
+
+当前实现的主要能力：
+
+- 用户注册、用户名密码登录，并在登录成功后签发 JWT。
+- 使用 JWT 中间件保护用户信息、联系人和聊天记录查询接口。
+- 查询联系人、每个联系人的最近一条消息，以及指定联系人的分页消息。
+- WebSocket 连接通过 JWT 验证身份，维护进程内在线用户连接表，并广播在线列表。
+- WebSocket 消息处理代码包含消息发送、投递和 ACK 转发逻辑。
+
+## 3. 技术栈与依赖
+
+| 技术/依赖 | 用途 |
+| --- | --- |
+| Node.js | JavaScript 服务端运行环境 |
+| Express 5 | HTTP 服务、JSON 请求体解析和路由分发 |
+| `http` | 创建与 Express 共用的 HTTP Server |
+| `ws` | WebSocket 服务端实现 |
+| `mysql2` | MySQL 单连接及参数化 SQL 查询 |
+| `jsonwebtoken` | JWT 签发和验证 |
+| `dotenv` | 将 `.env` 配置加载到 `process.env` |
+| `nodemon` | 开发时监视文件并重启服务 |
+
+项目使用 CommonJS 模块格式。`npm start` 执行 `node index.js`，`npm run dev` 执行 `nodemon index.js`。当前 `npm test` 是占位脚本，没有自动化测试。
+
+## 4. 代码结构
+
+```text
+index.js                     服务启动入口、HTTP 与 WebSocket 组装
+db/
+  mysql.js                   MySQL 连接创建与导出
+  sql.txt                    users、contacts、messages 的建表及样例数据脚本
+middleware/
+  authMiddleware.js          HTTP 请求 JWT 校验
+routes/
+  login.js                   注册和登录接口
+  user.js                    用户信息与联系人接口
+  message.js                 最近聊天、历史消息、REST 消息写入接口
+utils/
+  jwt.js                     JWT 签发和验证封装
+websocket/
+  index.js                   WebSocket 握手、协议分发和消息处理
+  connectionManager.js       进程内在线连接管理及广播
+```
+
+### 模块职责与依赖
+
+- `index.js`：加载环境变量，创建 Express 应用和 HTTP Server，启用 JSON 请求解析，注册 `/api` 路由并将同一个 Server 交给 WebSocket 初始化函数，最后监听 3000 端口。
+- `db/mysql.js`：创建一个 `mysql2` 单连接，并作为共享模块导出，路由和 WebSocket 处理器直接调用 `db.query`。
+- `routes/login.js`：处理公开的 `/login`、`/register`。登录成功后通过 JWT 工具生成 token。
+- `routes/user.js`：依赖 `authMiddleware`，从 `req.user.username` 识别当前用户并提供用户信息与联系人查询。
+- `routes/message.js`：历史记录及最近聊天查询依赖认证中间件；当前 REST `/sendMessage` 未挂载认证中间件。
+- `middleware/authMiddleware.js`：从 `Authorization` 请求头拆出 token，调用 JWT 验证，将 payload 放入 `req.user` 后继续处理请求。
+- `utils/jwt.js`：使用 `JWT_SECRET` 签发和验证 token，签发有效期为 10 分钟。
+- `websocket/index.js`：从连接 URL 查询参数读取 token 验证客户端身份；连接建立或关闭时广播在线用户列表；按消息 `type` 分发 WebSocket 消息。
+- `websocket/connectionManager.js`：使用模块级 `Map` 以用户名为键保存 WebSocket 连接。该状态仅存在于当前 Node 进程内。
+- `db/sql.txt`：描述用户、联系人、消息表，以及本地演示用数据。
+
+## 5. 总体架构与请求路径
+
+```mermaid
+flowchart LR
+    Client[客户端]
+    Entry[index.js / HTTP Server]
+    Express[Express 路由]
+    Auth[JWT 中间件与工具]
+    WS[WebSocket 服务]
+    Manager[在线连接 Map]
+    DB[(MySQL)]
+
+    Client -->|HTTP /api| Entry
+    Entry --> Express
+    Express --> Auth
+    Express --> DB
+    Client <-->|WebSocket| Entry
+    Entry --> WS
+    WS --> Auth
+    WS --> Manager
+    WS --> DB
+```
+
+HTTP 请求由 Express 根据 `/api` 前缀分发。需要认证的路由先运行 JWT 中间件，随后执行业务 SQL。WebSocket 则在握手后从 URL 查询参数读取 token，再在连接生命周期内以已验证的用户名处理消息。HTTP 与 WebSocket 最终都使用同一 MySQL 模块。
+
+## 6. 数据模型
+
+数据库脚本目标库为 `chat_mysql`，定义以下三张表：
+
+### `users`
+
+| 字段 | 类型 | 约束/用途 |
+| --- | --- | --- |
+| `username` | `VARCHAR(50)` | 主键，用户唯一标识 |
+| `password` | `VARCHAR(255)` | 非空；当前代码保存并直接比较明文密码 |
+
+### `contacts`
+
+| 字段 | 类型 | 约束/用途 |
+| --- | --- | --- |
+| `user_name` | `VARCHAR(50)` | 联系人所属用户，外键引用 `users.username` |
+| `contact_name` | `VARCHAR(50)` | 联系人用户名，外键引用 `users.username` |
+
+`(user_name, contact_name)` 为联合主键。同一用户不能重复添加同一联系人。脚本中的联系人关系按有向关系保存，双向关系需要分别插入两行。
+
+### `messages`
+
+| 字段 | 类型 | 约束/用途 |
+| --- | --- | --- |
+| `id` | `INT` | 自增主键 |
+| `sender_name` | `VARCHAR(50)` | 非空，外键引用发送者 |
+| `receiver_name` | `VARCHAR(50)` | 非空，外键引用接收者 |
+| `content` | `VARCHAR(1000)` | 非空，消息正文 |
+| `created_at` | `DATETIME` | 默认使用数据库当前时间 |
+
+消息以一条记录表示一次单向发送。双方聊天记录通过发送者和接收者字段组合查询；表中没有当前 WebSocket 处理器所写入的 `message_id` 字段。
+
+## 7. HTTP 接口设计
+
+所有路由统一挂载在 `/api` 下，JSON 请求体由 Express 解析。成功/失败响应大多采用 `{ code, message, data }` 结构，但不同接口的 HTTP 状态码与业务 `code` 使用并不完全一致。
+
+| 方法 | 路径 | 认证 | 输入/用途 |
+| --- | --- | --- | --- |
+| `POST` | `/api/register` | 否 | body：`username`、`password`；插入用户 |
+| `POST` | `/api/login` | 否 | body：`username`、`password`；验证凭据并返回 token、用户名 |
+| `GET` | `/api/userInfo` | 是 | 从 token 返回当前用户名 |
+| `GET` | `/api/contactsInfo` | 是 | 查询当前用户联系人，返回 `contacts` 数组 |
+| `GET` | `/api/recentChats` | 是 | 查询当前用户每个聊天对象的最新消息 |
+| `POST` | `/api/contactMessagesInfo` | 是 | body：`contactName`、`limit`、`offset`；分页查询双方消息 |
+| `POST` | `/api/sendMessage` | **否** | body：`senderName`、`receiverName`、`content`；将消息插入数据库 |
+
+### 认证约定
+
+HTTP 客户端应在受保护接口的请求头中传入 `Authorization: Bearer <token>`。登录接口响应的 token 字符串自身已带 `Bearer ` 前缀。当前中间件通过空格拆分请求头并取第二段作为 token；缺少请求头或验证失败时返回 401。
+
+JWT payload 当前包含 `username`，过期时间为 10 分钟。WebSocket 客户端把 token 放在连接 URL 查询参数 `token` 中。由于登录响应包含 `Bearer ` 前缀，而 WebSocket 端会直接将查询参数交给 `verifyToken`，客户端需要传纯 JWT 部分，不能把 `Bearer ` 前缀一并作为 token 值。
+
+## 8. WebSocket 协议与消息流程
+
+WebSocket 挂载在 HTTP Server 上，客户端连接地址的形式为 `ws://<host>:3000/?token=<JWT>`。连接验证通过后，服务端按用户名登记连接，并广播在线列表。
+
+### 服务端消息类型
+
+| `type` | 方向 | 当前代码行为 |
+| --- | --- | --- |
+| `userOnline` | 服务端 -> 所有在线客户端 | 连接建立或关闭后，携带 `userList` 在线用户名数组 |
+| `newMessage` | 服务端 -> 接收方 | 携带 `message` 对象，包括消息 ID、发送方、接收方和正文 |
+| `sendSuccess` | 服务端 -> 发送方 | 携带客户端提供的 `messageId`，表示发送成功 |
+| `sendError` | 服务端 -> 发送方 | 数据库写入回调报错时尝试发送，携带 `messageId` 和错误说明 |
+| `ack` | 服务端 -> 原发送方 | 将接收方确认的消息 ID 转发给发送方 |
+
+### 客户端消息类型
+
+- `sendMessage`：处理器读取 `messageId`、`receiverName`、`content`；发送者身份来自已验证 WebSocket 连接，不从消息体读取。
+- `ack`：处理器预期使用 `messageId` 和 `senderName` 将 ACK 转发给原发送者。
+
+### 预期发送流程
+
+1. 客户端建立携带 JWT 的 WebSocket 连接。
+2. 服务端校验 JWT，登记用户名与连接，并广播在线用户列表。
+3. 客户端发送 `sendMessage`，服务端使用连接身份确定发送者。
+4. 服务端尝试把消息持久化到 MySQL；接收方在线时向其推送 `newMessage`。
+5. 接收方返回 `ack` 后，服务端尝试通知原发送方。
+
+步骤 4 当前实现没有等待数据库回调成功再确认和推送；此外建表脚本与插入语句字段不匹配，因此此流程目前不能视为可靠送达流程。具体差异见第 10 节。
+
+## 9. 关键设计思路
+
+- **按职责拆分模块**：入口负责组装，路由负责 HTTP 接口，middleware 负责认证，utils 封装 JWT，websocket 目录处理长连接和连接表，db 统一导出数据库连接。
+- **用户名作为用户标识**：用户表以用户名为主键，联系人关系、消息发送接收双方及在线连接表均使用用户名关联。
+- **JWT 无服务端会话存储**：服务端通过签名和过期时间验证 token，HTTP 请求和 WebSocket 握手各自执行验证。
+- **聊天列表与历史消息分开查询**：`recentChats` 使用窗口函数按聊天对象分组并选出最新消息；历史消息接口按 limit/offset 分页，避免单次返回全部记录。
+- **在线状态在内存维护**：当前使用 Map 直接由用户名定位 WebSocket 连接，便于单进程内向在线用户推送消息，但没有跨进程共享能力。
+- **SQL 参数化**：业务查询使用 `?` 占位符与参数数组传值，避免把用户输入直接拼入 SQL 文本。
+
+## 10. 已知问题与后续建议
+
+以下内容是基于当前代码与脚本的直接核对结果，应在扩展功能或对外部署前处理：
+
+1. **数据库凭据写在源码中**：`db/mysql.js` 将 MySQL 账号、密码和数据库名直接传给连接创建函数。建议改为读取环境变量，轮换已经放入源码的凭据，并避免将真实密钥写入文档或版本库。
+2. **密码以明文存储和比对**：注册直接写入密码，登录 SQL 按用户名与明文密码匹配。应使用成熟密码哈希方案存储和校验，并考虑统一认证失败响应。
+3. **REST 消息写入缺少认证**：`/api/sendMessage` 未使用 `authMiddleware`，客户端可自行指定发送者。应要求认证并从 `req.user` 派生发送者身份，同时校验接收方及联系人关系。(已解决)
+4. **WebSocket 数据库写入字段不匹配**：`websocket/index.js` 插入 `message_id`，但 `db/sql.txt` 的 `messages` 表没有该列。需统一消息 ID 设计，例如新增唯一字段及迁移，或使用现有自增 `id` 并调整协议和查询。（已解决）
+5. **发送确认早于持久化结果**：`sendSuccess` 和接收方推送发生在异步 `db.query` 回调之前。应将成功确认和实时推送放到成功回调中；失败时只返回错误，不推送为已发送消息。（已解决）
+6. **连接管理器广播引用未定义的 `WebSocket`**：`connectionManager.js` 的 `broadcast` 检查 `WebSocket.OPEN`，但文件中没有导入 `ws`。当广播函数被调用时可能抛出 `ReferenceError`。应在此模块引入库常量，或由连接对象状态采用明确且可用的检查方式。（已解决）
+7. **ACK 参数调用不一致**：消息分发通过 `handleAck(data)` 调用，而函数签名是 `handleAck(receiverName, data)`；函数内部随后读取第二个参数，可能因 `data` 未定义而失败。应统一函数参数并以当前连接用户名作为 ACK 接收者身份。(已解决)
+8. **重复登录连接的关闭竞态**：同一用户名的新连接会覆盖 Map 中旧连接；旧连接关闭时无条件按用户名删除，可能把新连接也从 Map 移除。移除连接时应确认 Map 中仍是即将关闭的那个 WebSocket。（已解决）
+9. **分页和输入校验不足**：`contactMessagesInfo` 未验证 `contactName`、`limit`、`offset` 的类型与范围，也未约束最大页大小。建议验证请求参数并设置默认值和上限。
+10. **在线状态及可靠性受单进程限制**：Map 不支持多实例共享、服务重启恢复、离线消息投递或持久化 ACK 状态。若部署多实例，需要共享在线状态/消息协调机制；若要求可靠消息，应定义消息状态、幂等键、重试及离线投递策略。
+11. **配置与错误响应尚未统一**：数据库连接配置没有从 `.env` 读取；HTTP 接口混用 HTTP 状态码和响应体 `code`，空结果有时返回业务码 401。建议集中配置并统一 API 错误语义及日志策略。
+12. **SQL 初始化脚本需要整理验证**：脚本包含清空用户表的语句，执行前会删除该表全部用户数据。应将演示数据与建表迁移分离，并在测试数据库验证脚本。
+13. **缺少自动化测试**：当前测试脚本是占位命令。建议优先为认证边界、参数校验、消息持久化失败/成功和 WebSocket 连接生命周期补充测试。
+
+## 11. 本地运行与部署边界
+
+1. 安装 Node.js 及 MySQL，并在 MySQL 中准备 `chat_mysql` 数据库。
+2. 按需执行经过校验的建表脚本；注意当前 `sql.txt` 含删除数据语句，不应直接用于已有数据环境。
+3. 设置 `JWT_SECRET`。当前 MySQL 参数仍需在 `db/mysql.js` 中配置；建议先将连接参数迁移到环境变量，再部署。
+4. 执行 `npm install`，开发环境使用 `npm run dev`，普通启动使用 `npm start`。
+5. 服务监听 `http://localhost:3000`，根路径 `/` 返回运行提示；WebSocket 使用相同主机和端口。
+
+当前代码适用于本地演示和单进程验证，不具备生产环境所需的凭据管理、密码安全、输入校验、多实例在线状态和消息可靠性保障。
@@ -11,7 +11,7 @@ VALUES
 ('query', '123'),
 ('tom', '123'),
 ('jack', '123'),
-('lucy', '123')，
+('lucy', '123'),
 ('lily', '123');
 select * from chat_mysql.users;

@@ -37,13 +37,14 @@ VALUES
 ('query', 'admin'),
 ('query', 'tom'),
 ('tom', 'admin'),
-('tom', 'query')，
+('tom', 'query'),
 ('admin', 'lily'),
 ('lily', 'admin');
 select * from chat_mysql.contacts;

 CREATE TABLE chat_mysql.messages (
    id INT PRIMARY KEY AUTO_INCREMENT,
+    message_id VARCHAR(64) NOT NULL,
    sender_name VARCHAR(50) NOT NULL,
    receiver_name VARCHAR(50) NOT NULL,
    content VARCHAR(1000) NOT NULL,
@@ -55,103 +56,9 @@ CREATE TABLE chat_mysql.messages (
    FOREIGN KEY (receiver_name)
        REFERENCES chat_mysql.users(username)
 );
-INSERT INTO chat_mysql.messages
-(sender_name, receiver_name, content, created_at)
-VALUES
-- admin ↔ query
-('admin', 'query', '你好，最近怎么样？', '2026-09-20 10:00:00'),
-('query', 'admin', '挺好的，你呢？', '2026-09-20 10:01:00'),
-('admin', 'query', '我也不错，最近在做聊天项目。', '2026-09-20 10:02:00'),
-('query', 'admin', '听起来不错，是用 Vue 做的吗？', '2026-09-20 10:03:00'),
-('admin', 'query', '对，前端使用 Vue2，后端使用 Node.js。', '2026-09-20 10:04:00'),
-('query', 'admin', '那数据库使用 MySQL？', '2026-09-20 10:05:00'),
-('admin', 'query', '对，目前正在完善聊天功能。', '2026-09-20 10:06:00'),

-- admin ↔ tom
-('admin', 'tom', '你今天有空吗？', '2026-09-20 11:00:00'),
-('tom', 'admin', '有啊，怎么了？', '2026-09-20 11:01:00'),
-('admin', 'tom', '想和你讨论一下项目。', '2026-09-20 11:02:00'),
-('tom', 'admin', '可以，什么时间方便？', '2026-09-20 11:03:00'),
-('admin', 'tom', '下午三点怎么样？', '2026-09-20 11:04:00'),
-('tom', 'admin', '没问题。', '2026-09-20 11:05:00'),
-
-- admin ↔ jack
-('jack', 'admin', '周末一起吃饭吗？', '2026-09-20 12:00:00'),
-('admin', 'jack', '可以啊，去哪吃？', '2026-09-20 12:01:00'),
-('jack', 'admin', '附近找一家餐厅吧。', '2026-09-20 12:02:00'),
-('admin', 'jack', '好的，晚上六点怎么样？', '2026-09-20 12:03:00'),
-('jack', 'admin', '可以，到时候联系。', '2026-09-20 12:04:00'),
-
-- admin ↔ lucy
-('admin', 'lucy', '最近项目进展怎么样？', '2026-09-20 13:00:00'),
-('lucy', 'admin', '目前进展还不错。', '2026-09-20 13:01:00'),
-('admin', 'lucy', '还有哪些功能没有完成？', '2026-09-20 13:02:00'),
-('lucy', 'admin', '主要是消息通知和联系人功能。', '2026-09-20 13:03:00'),
-('admin', 'lucy', '好的，我这边也在做消息功能。', '2026-09-20 13:04:00'),
-
-- query ↔ tom
-('query', 'tom', '你知道聊天项目怎么做 WebSocket 吗？', '2026-09-20 14:00:00'),
-('tom', 'query', '知道一些，可以用来做实时消息。', '2026-09-20 14:01:00'),
-('query', 'tom', '我也准备把项目改成 WebSocket。', '2026-09-20 14:02:00'),
-('tom', 'query', '这样聊天消息可以实时推送。', '2026-09-20 14:03:00'),
-
-- tom ↔ query
-('tom', 'query', '联系人比较多的时候怎么办？', '2026-09-20 15:00:00'),
-('query', 'tom', '不需要每个联系人都创建一个 WebSocket。', '2026-09-20 15:01:00'),
-('tom', 'query', '一个用户维护一个 WebSocket 连接就可以了。', '2026-09-20 15:02:00');
-select * from chat_mysql.messages;
-
-INSERT INTO chat_mysql.messages
-(sender_name, receiver_name, content, created_at)
-VALUES
-- admin ↔ lily
-('admin', 'lily', '你好，最近怎么样？', '2026-09-20 10:00:00'),
-('lily', 'admin', '挺好的，你呢？', '2026-09-20 10:01:00'),
-('admin', 'lily', '我也不错，最近在做聊天项目。', '2026-09-20 10:02:00'),
-('lily', 'admin', '听起来不错，是用 Vue 做的吗？', '2026-09-20 10:03:00'),
-('admin', 'lily', '对，前端使用 Vue2，后端使用 Node.js。', '2026-09-20 10:04:00'),
-('lily', 'admin', '那数据库使用 MySQL？', '2026-09-20 10:05:00'),
-('admin', 'lily', '对，目前正在完善聊天功能。', '2026-09-20 10:06:00'),
-('lily', 'admin', '聊天记录是怎么保存的？', '2026-09-20 10:07:00'),
-('admin', 'lily', '目前是保存在 messages 表里面。', '2026-09-20 10:08:00'),
-('lily', 'admin', '一个消息对应一条数据吗？', '2026-09-20 10:09:00'),
-('admin', 'lily', '对，每条消息都有自己的 id。', '2026-09-20 10:10:00'),
-('lily', 'admin', '那发送人和接收人怎么区分？', '2026-09-20 10:11:00'),
-('admin', 'lily', '通过 sender_name 和 receiver_name 两个字段区分。', '2026-09-20 10:12:00'),
-('lily', 'admin', '这样查询两个人的聊天记录应该比较方便。', '2026-09-20 10:13:00'),
-('admin', 'lily', '对，只需要判断双方的用户名即可。', '2026-09-20 10:14:00'),
-('lily', 'admin', '比如查询 admin 和 lily 之间的消息？', '2026-09-20 10:15:00'),
-('admin', 'lily', '没错，可以使用 OR 和 AND 组合条件。', '2026-09-20 10:16:00'),
-('lily', 'admin', '那如果消息很多怎么办？', '2026-09-20 10:17:00'),
-('admin', 'lily', '不能一次把所有消息都返回给前端。', '2026-09-20 10:18:00'),
-('lily', 'admin', '应该使用分页查询吧？', '2026-09-20 10:19:00'),
-('admin', 'lily', '对，比如一次只查询 10 条或者 20 条。', '2026-09-20 10:20:00'),
-('lily', 'admin', '这样可以减少接口返回的数据量。', '2026-09-20 10:21:00'),
-('admin', 'lily', '也可以提高页面加载速度。', '2026-09-20 10:22:00'),
-('lily', 'admin', '最近聊天列表也是单独查询吗？', '2026-09-20 10:23:00'),
-('admin', 'lily', '对，最近聊天只需要获取每个联系人的最新消息。', '2026-09-20 10:24:00'),
-('lily', 'admin', '这样左边就不用加载完整聊天记录了。', '2026-09-20 10:25:00'),
-('admin', 'lily', '对，点击联系人之后再加载具体的聊天记录。', '2026-09-20 10:26:00'),
-('lily', 'admin', '这个设计比较合理。', '2026-09-20 10:27:00'),
-('admin', 'lily', '我现在就是准备按照这个思路修改。', '2026-09-20 10:28:00'),
-('lily', 'admin', '那 Vue 里面是不是也不用保存所有消息？', '2026-09-20 10:29:00'),
-('admin', 'lily', '是的，只需要保存当前联系人的消息数组。', '2026-09-20 10:30:00'),
-('lily', 'admin', '分页的时候再把历史消息添加进去？', '2026-09-20 10:31:00'),
-('admin', 'lily', '对，可以把下一页的数据添加到数组前面。', '2026-09-20 10:32:00'),
-('lily', 'admin', '那新发送的消息就添加到数组最后面？', '2026-09-20 10:33:00'),
-('admin', 'lily', '没错，因为新消息的时间是最新的。', '2026-09-20 10:34:00'),
-('lily', 'admin', '左边的最近聊天还需要移动到最上面。', '2026-09-20 10:35:00'),
-('admin', 'lily', '对，可以使用 unshift 把它移动到第一位。', '2026-09-20 10:36:00'),
-('lily', 'admin', '同时更新左边显示的最后一条消息。', '2026-09-20 10:37:00'),
-('admin', 'lily', '这样聊天列表就会实时更新了。', '2026-09-20 10:38:00'),
-('lily', 'admin', '如果切换联系人，消息数组怎么办？', '2026-09-20 10:39:00'),
-('admin', 'lily', '可以按照联系人 id 分别保存。', '2026-09-20 10:40:00'),
-('lily', 'admin', '比如 contactMessages[18] 保存 lily 的消息？', '2026-09-20 10:41:00'),
-('admin', 'lily', '对，contactMessages[20] 就可以保存另一个人的消息。', '2026-09-20 10:42:00'),
-('lily', 'admin', 'Vue2 动态增加这个属性需要注意响应式问题吧？', '2026-09-20 10:43:00'),
-('admin', 'lily', '对，可以使用 this.$set 来创建新的消息数组。', '2026-09-20 10:44:00'),
-('lily', 'admin', '这样切换联系人就比较方便了。', '2026-09-20 10:45:00'),
-('admin', 'lily', '对，聊天页面的数据结构基本就确定了。', '2026-09-20 10:46:00'),
-('lily', 'admin', '那接下来就可以测试分页加载了。', '2026-09-20 10:47:00'),
-('admin', 'lily', '嗯，先测试一次查询 10 条消息。', '2026-09-20 10:48:00'),
-('lily', 'admin', '然后再查询下一页历史消息。', '2026-09-20 10:49:00');
+#删除某个人的发送聊天数据
+SELECT *
+FROM chat_mysql.messages
+WHERE sender_name = 'test';
+DELETE FROM chat_mysql.messages WHERE sender_name = 'test';
@@ -1,25 +1,42 @@
+console.log("当前执行文件：", __filename);
 // .env 中的配置写入 Node.js 的全局环境变量对象，下面的文件都可以直接使用
 require('dotenv').config();

 // 搭建http服务器
 const express = require("express");
+const http = require("http");

 const app = express();

+// 创建HTTP服务器
+const server = http.createServer(app);
+
 // 服务器解析 JSON 请求体
 app.use(express.json());

+// 防止控制台打印404
+app.get("/", (req, res) => {
+  res.send("chat-demo-server运行正常");
+});
+
 // 接入路由
 const loginRouter = require("./routes/login");
 const userRouter = require("./routes/user");
+const messageRouter = require("./routes/message");

 // 所有接口，都统一加上 /api 前缀
 app.use("/api", loginRouter);
 app.use("/api", userRouter);
+app.use("/api", messageRouter);
+
+// 初始化WebSocket
+const initWebSocket = require("./websocket/index.js");
+initWebSocket(server);

 // 启动服务器，监听端口
-app.listen(3000, () => {
+server.listen(3000, () => {
    console.log("服务器启动成功：http://localhost:3000");
+    console.log("WebSocket服务器启动成功：ws://localhost:3000");
 });

 // index.js 就是 Node 后端的“总入口”：加载配置 → 创建 Express → 解析请求 → 加载路由 → 注册接口 → 启动 3000 端口服务器
@@ -1448,6 +1448,27 @@
      "resolved": "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz",
      "integrity": "sha512-l4Sp/DRseor9wL6EvV2+TuQn63dMkPjZ/sp9XkghTEbV9KlPS1xUsZ3u7/IQO4wxtcFB4bgpQPRcR3QCvezPcQ==",
      "license": "ISC"
+    },
+    "node_modules/ws": {
+      "version": "8.21.3",
+      "resolved": "https://registry.npmmirror.com/ws/-/ws-8.21.3.tgz",
+      "integrity": "sha512-201TZ/kPWxoPr/OKWjquZR1SWKXcvxdH+e1xrx89b3YbmzLMFCLfnaG1HFIgWzJOEWZ7MvpK++odZufgYR50Rw==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=10.0.0"
+      },
+      "peerDependencies": {
+        "bufferutil": "^4.0.1",
+        "utf-8-validate": ">=5.0.2"
+      },
+      "peerDependenciesMeta": {
+        "bufferutil": {
+          "optional": true
+        },
+        "utf-8-validate": {
+          "optional": true
+        }
+      }
    }
  }
 }
@@ -0,0 +1,20 @@
+Copyright (c) 2011 Einar Otto Stangvik <einaros@gmail.com>
+Copyright (c) 2013 Arnout Kazemier and contributors
+Copyright (c) 2016 Luigi Pinca and contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
@@ -0,0 +1,548 @@
+# ws: a Node.js WebSocket library
+
+[![Version npm](https://img.shields.io/npm/v/ws.svg?logo=npm)](https://www.npmjs.com/package/ws)
+[![CI](https://img.shields.io/github/actions/workflow/status/websockets/ws/ci.yml?branch=master&label=CI&logo=github)](https://github.com/websockets/ws/actions?query=workflow%3ACI+branch%3Amaster)
+[![Coverage Status](https://img.shields.io/coveralls/websockets/ws/master.svg?logo=coveralls)](https://coveralls.io/github/websockets/ws)
+
+ws is a simple to use, blazing fast, and thoroughly tested WebSocket client and
+server implementation.
+
+Passes the quite extensive Autobahn test suite: [server][server-report],
+[client][client-report].
+
+**Note**: This module does not work in the browser. The client in the docs is a
+reference to a backend with the role of a client in the WebSocket communication.
+Browser clients must use the native
+[`WebSocket`](https://developer.mozilla.org/en-US/docs/Web/API/WebSocket)
+object. To make the same code work seamlessly on Node.js and the browser, you
+can use one of the many wrappers available on npm, like
+[isomorphic-ws](https://github.com/heineiuo/isomorphic-ws).
+
+## Table of Contents
+
+- [Protocol support](#protocol-support)
+- [Installing](#installing)
+  - [Opt-in for performance](#opt-in-for-performance)
+    - [Legacy opt-in for performance](#legacy-opt-in-for-performance)
+- [API docs](#api-docs)
+- [WebSocket compression](#websocket-compression)
+- [Usage examples](#usage-examples)
+  - [Sending and receiving text data](#sending-and-receiving-text-data)
+  - [Sending binary data](#sending-binary-data)
+  - [Simple server](#simple-server)
+  - [External HTTP/S server](#external-https-server)
+  - [Multiple servers sharing a single HTTP/S server](#multiple-servers-sharing-a-single-https-server)
+  - [Client authentication](#client-authentication)
+  - [Server broadcast](#server-broadcast)
+  - [Round-trip time](#round-trip-time)
+  - [Use the Node.js streams API](#use-the-nodejs-streams-api)
+  - [Other examples](#other-examples)
+- [FAQ](#faq)
+  - [How to get the IP address of the client?](#how-to-get-the-ip-address-of-the-client)
+  - [How to detect and close broken connections?](#how-to-detect-and-close-broken-connections)
+  - [How to connect via a proxy?](#how-to-connect-via-a-proxy)
+- [Changelog](#changelog)
+- [License](#license)
+
+## Protocol support
+
+- **HyBi drafts 07-12** (Use the option `protocolVersion: 8`)
+- **HyBi drafts 13-17** (Current default, alternatively option
+  `protocolVersion: 13`)
+
+## Installing
+
+```
+npm install ws
+```
+
+### Opt-in for performance
+
+[bufferutil][] is an optional module that can be installed alongside the ws
+module:
+
+```
+npm install --save-optional bufferutil
+```
+
+This is a binary addon that improves the performance of certain operations such
+as masking and unmasking the data payload of the WebSocket frames. Prebuilt
+binaries are available for the most popular platforms, so you don't necessarily
+need to have a C++ compiler installed on your machine.
+
+To force ws to not use bufferutil, use the
+[`WS_NO_BUFFER_UTIL`](./doc/ws.md#ws_no_buffer_util) environment variable. This
+can be useful to enhance security in systems where a user can put a package in
+the package search path of an application of another user, due to how the
+Node.js resolver algorithm works.
+
+#### Legacy opt-in for performance
+
+If you are running on an old version of Node.js (prior to v18.14.0), ws also
+supports the [utf-8-validate][] module:
+
+```
+npm install --save-optional utf-8-validate
+```
+
+This contains a binary polyfill for [`buffer.isUtf8()`][].
+
+To force ws not to use utf-8-validate, use the
+[`WS_NO_UTF_8_VALIDATE`](./doc/ws.md#ws_no_utf_8_validate) environment variable.
+
+## API docs
+
+See [`/doc/ws.md`](./doc/ws.md) for Node.js-like documentation of ws classes and
+utility functions.
+
+## WebSocket compression
+
+ws supports the [permessage-deflate extension][permessage-deflate] which enables
+the client and server to negotiate a compression algorithm and its parameters,
+and then selectively apply it to the data payloads of each WebSocket message.
+
+The extension is disabled by default on the server and enabled by default on the
+client. It adds a significant overhead in terms of performance and memory
+consumption so we suggest to enable it only if it is really needed.
+
+Note that Node.js has a variety of issues with high-performance compression,
+where increased concurrency, especially on Linux, can lead to [catastrophic
+memory fragmentation][node-zlib-bug] and slow performance. If you intend to use
+permessage-deflate in production, it is worthwhile to set up a test
+representative of your workload and ensure Node.js/zlib will handle it with
+acceptable performance and memory usage.
+
+Tuning of permessage-deflate can be done via the options defined below. You can
+also use `zlibDeflateOptions` and `zlibInflateOptions`, which is passed directly
+into the creation of [raw deflate/inflate streams][node-zlib-deflaterawdocs].
+
+See [the docs][ws-server-options] for more options.
+
+```js
+import WebSocket, { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({
+  port: 8080,
+  perMessageDeflate: {
+    zlibDeflateOptions: {
+      // See zlib defaults.
+      chunkSize: 1024,
+      memLevel: 7,
+      level: 3
+    },
+    zlibInflateOptions: {
+      chunkSize: 10 * 1024
+    },
+    // Other options settable:
+    clientNoContextTakeover: true, // Defaults to negotiated value.
+    serverNoContextTakeover: true, // Defaults to negotiated value.
+    serverMaxWindowBits: 10, // Defaults to negotiated value.
+    // Below options specified as default values.
+    concurrencyLimit: 10, // Limits zlib concurrency for perf.
+    threshold: 1024 // Size (in bytes) below which messages
+    // should not be compressed if context takeover is disabled.
+  }
+});
+```
+
+The client will only use the extension if it is supported and enabled on the
+server. To always disable the extension on the client, set the
+`perMessageDeflate` option to `false`.
+
+```js
+import WebSocket from 'ws';
+
+const ws = new WebSocket('ws://www.host.com/path', {
+  perMessageDeflate: false
+});
+```
+
+## Usage examples
+
+### Sending and receiving text data
+
+```js
+import WebSocket from 'ws';
+
+const ws = new WebSocket('ws://www.host.com/path');
+
+ws.on('error', console.error);
+
+ws.on('open', function open() {
+  ws.send('something');
+});
+
+ws.on('message', function message(data) {
+  console.log('received: %s', data);
+});
+```
+
+### Sending binary data
+
+```js
+import WebSocket from 'ws';
+
+const ws = new WebSocket('ws://www.host.com/path');
+
+ws.on('error', console.error);
+
+ws.on('open', function open() {
+  const array = new Float32Array(5);
+
+  for (var i = 0; i < array.length; ++i) {
+    array[i] = i / 2;
+  }
+
+  ws.send(array);
+});
+```
+
+### Simple server
+
+```js
+import { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data) {
+    console.log('received: %s', data);
+  });
+
+  ws.send('something');
+});
+```
+
+### External HTTP/S server
+
+```js
+import { createServer } from 'https';
+import { readFileSync } from 'fs';
+import { WebSocketServer } from 'ws';
+
+const server = createServer({
+  cert: readFileSync('/path/to/cert.pem'),
+  key: readFileSync('/path/to/key.pem')
+});
+const wss = new WebSocketServer({ server });
+
+wss.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data) {
+    console.log('received: %s', data);
+  });
+
+  ws.send('something');
+});
+
+server.listen(8080);
+```
+
+### Multiple servers sharing a single HTTP/S server
+
+```js
+import { createServer } from 'http';
+import { WebSocketServer } from 'ws';
+
+const server = createServer();
+const wss1 = new WebSocketServer({ noServer: true });
+const wss2 = new WebSocketServer({ noServer: true });
+
+wss1.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  // ...
+});
+
+wss2.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  // ...
+});
+
+server.on('upgrade', function upgrade(request, socket, head) {
+  const { pathname } = new URL(request.url, 'wss://base.url');
+
+  if (pathname === '/foo') {
+    wss1.handleUpgrade(request, socket, head, function done(ws) {
+      wss1.emit('connection', ws, request);
+    });
+  } else if (pathname === '/bar') {
+    wss2.handleUpgrade(request, socket, head, function done(ws) {
+      wss2.emit('connection', ws, request);
+    });
+  } else {
+    socket.destroy();
+  }
+});
+
+server.listen(8080);
+```
+
+### Client authentication
+
+```js
+import { createServer } from 'http';
+import { WebSocketServer } from 'ws';
+
+function onSocketError(err) {
+  console.error(err);
+}
+
+const server = createServer();
+const wss = new WebSocketServer({ noServer: true });
+
+wss.on('connection', function connection(ws, request, client) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data) {
+    console.log(`Received message ${data} from user ${client}`);
+  });
+});
+
+server.on('upgrade', function upgrade(request, socket, head) {
+  socket.on('error', onSocketError);
+
+  // This function is not defined on purpose. Implement it with your own logic.
+  authenticate(request, function next(err, client) {
+    if (err || !client) {
+      socket.write('HTTP/1.1 401 Unauthorized\r\n\r\n');
+      socket.destroy();
+      return;
+    }
+
+    socket.removeListener('error', onSocketError);
+
+    wss.handleUpgrade(request, socket, head, function done(ws) {
+      wss.emit('connection', ws, request, client);
+    });
+  });
+});
+
+server.listen(8080);
+```
+
+Also see the provided [example][session-parse-example] using `express-session`.
+
+### Server broadcast
+
+A client WebSocket broadcasting to all connected WebSocket clients, including
+itself.
+
+```js
+import WebSocket, { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data, isBinary) {
+    wss.clients.forEach(function each(client) {
+      if (client.readyState === WebSocket.OPEN) {
+        client.send(data, { binary: isBinary });
+      }
+    });
+  });
+});
+```
+
+A client WebSocket broadcasting to every other connected WebSocket clients,
+excluding itself.
+
+```js
+import WebSocket, { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.on('error', console.error);
+
+  ws.on('message', function message(data, isBinary) {
+    wss.clients.forEach(function each(client) {
+      if (client !== ws && client.readyState === WebSocket.OPEN) {
+        client.send(data, { binary: isBinary });
+      }
+    });
+  });
+});
+```
+
+### Round-trip time
+
+```js
+import WebSocket from 'ws';
+
+const ws = new WebSocket('wss://websocket-echo.com/');
+
+ws.on('error', console.error);
+
+ws.on('open', function open() {
+  console.log('connected');
+  ws.send(Date.now());
+});
+
+ws.on('close', function close() {
+  console.log('disconnected');
+});
+
+ws.on('message', function message(data) {
+  console.log(`Round-trip time: ${Date.now() - data} ms`);
+
+  setTimeout(function timeout() {
+    ws.send(Date.now());
+  }, 500);
+});
+```
+
+### Use the Node.js streams API
+
+```js
+import WebSocket, { createWebSocketStream } from 'ws';
+
+const ws = new WebSocket('wss://websocket-echo.com/');
+
+const duplex = createWebSocketStream(ws, { encoding: 'utf8' });
+
+duplex.on('error', console.error);
+
+duplex.pipe(process.stdout);
+process.stdin.pipe(duplex);
+```
+
+### Other examples
+
+For a full example with a browser client communicating with a ws server, see the
+examples folder.
+
+Otherwise, see the test cases.
+
+## FAQ
+
+### How to get the IP address of the client?
+
+The remote IP address can be obtained from the raw socket.
+
+```js
+import { WebSocketServer } from 'ws';
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws, req) {
+  const ip = req.socket.remoteAddress;
+
+  ws.on('error', console.error);
+});
+```
+
+When the server runs behind a proxy like NGINX, the de-facto standard is to use
+the `X-Forwarded-For` header.
+
+```js
+wss.on('connection', function connection(ws, req) {
+  const ip = req.headers['x-forwarded-for'].split(',')[0].trim();
+
+  ws.on('error', console.error);
+});
+```
+
+### How to detect and close broken connections?
+
+Sometimes, the link between the server and the client can be interrupted in a
+way that keeps both the server and the client unaware of the broken state of the
+connection (e.g. when pulling the cord).
+
+In these cases, ping messages can be used as a means to verify that the remote
+endpoint is still responsive.
+
+```js
+import { WebSocketServer } from 'ws';
+
+function heartbeat() {
+  this.isAlive = true;
+}
+
+const wss = new WebSocketServer({ port: 8080 });
+
+wss.on('connection', function connection(ws) {
+  ws.isAlive = true;
+  ws.on('error', console.error);
+  ws.on('pong', heartbeat);
+});
+
+const interval = setInterval(function ping() {
+  wss.clients.forEach(function each(ws) {
+    if (ws.isAlive === false) return ws.terminate();
+
+    ws.isAlive = false;
+    ws.ping();
+  });
+}, 30000);
+
+wss.on('close', function close() {
+  clearInterval(interval);
+});
+```
+
+Pong messages are automatically sent in response to ping messages as required by
+the spec.
+
+Just like the server example above, your clients might as well lose connection
+without knowing it. You might want to add a ping listener on your clients to
+prevent that. A simple implementation would be:
+
+```js
+import WebSocket from 'ws';
+
+function heartbeat() {
+  clearTimeout(this.pingTimeout);
+
+  // Use `WebSocket#terminate()`, which immediately destroys the connection,
+  // instead of `WebSocket#close()`, which waits for the close timer.
+  // Delay should be equal to the interval at which your server
+  // sends out pings plus a conservative assumption of the latency.
+  this.pingTimeout = setTimeout(() => {
+    this.terminate();
+  }, 30000 + 1000);
+}
+
+const client = new WebSocket('wss://websocket-echo.com/');
+
+client.on('error', console.error);
+client.on('open', heartbeat);
+client.on('ping', heartbeat);
+client.on('close', function clear() {
+  clearTimeout(this.pingTimeout);
+});
+```
+
+### How to connect via a proxy?
+
+Use a custom `http.Agent` implementation like [https-proxy-agent][] or
+[socks-proxy-agent][].
+
+## Changelog
+
+We're using the GitHub [releases][changelog] for changelog entries.
+
+## License
+
+[MIT](LICENSE)
+
+[`buffer.isutf8()`]: https://nodejs.org/api/buffer.html#bufferisutf8input
+[bufferutil]: https://github.com/websockets/bufferutil
+[changelog]: https://github.com/websockets/ws/releases
+[client-report]: http://websockets.github.io/ws/autobahn/clients/
+[https-proxy-agent]: https://github.com/TooTallNate/node-https-proxy-agent
+[node-zlib-bug]: https://github.com/nodejs/node/issues/8871
+[node-zlib-deflaterawdocs]:
+  https://nodejs.org/api/zlib.html#zlib_zlib_createdeflateraw_options
+[permessage-deflate]: https://tools.ietf.org/html/rfc7692
+[server-report]: http://websockets.github.io/ws/autobahn/servers/
+[session-parse-example]: ./examples/express-session-parse
+[socks-proxy-agent]: https://github.com/TooTallNate/node-socks-proxy-agent
+[utf-8-validate]: https://github.com/websockets/utf-8-validate
+[ws-server-options]: ./doc/ws.md#new-websocketserveroptions-callback
@@ -0,0 +1,8 @@
+'use strict';
+
+module.exports = function () {
+  throw new Error(
+    'ws does not work in the browser. Browser clients must use the native ' +
+      'WebSocket object'
+  );
+};
@@ -0,0 +1,22 @@
+'use strict';
+
+const createWebSocketStream = require('./lib/stream');
+const extension = require('./lib/extension');
+const PerMessageDeflate = require('./lib/permessage-deflate');
+const Receiver = require('./lib/receiver');
+const Sender = require('./lib/sender');
+const subprotocol = require('./lib/subprotocol');
+const WebSocket = require('./lib/websocket');
+const WebSocketServer = require('./lib/websocket-server');
+
+WebSocket.createWebSocketStream = createWebSocketStream;
+WebSocket.extension = extension;
+WebSocket.PerMessageDeflate = PerMessageDeflate;
+WebSocket.Receiver = Receiver;
+WebSocket.Sender = Sender;
+WebSocket.Server = WebSocketServer;
+WebSocket.subprotocol = subprotocol;
+WebSocket.WebSocket = WebSocket;
+WebSocket.WebSocketServer = WebSocketServer;
+
+module.exports = WebSocket;
@@ -0,0 +1,131 @@
+'use strict';
+
+const { EMPTY_BUFFER } = require('./constants');
+
+const FastBuffer = Buffer[Symbol.species];
+
+/**
+ * Merges an array of buffers into a new buffer.
+ *
+ * @param {Buffer[]} list The array of buffers to concat
+ * @param {Number} totalLength The total length of buffers in the list
+ * @return {Buffer} The resulting buffer
+ * @public
+ */
+function concat(list, totalLength) {
+  if (list.length === 0) return EMPTY_BUFFER;
+  if (list.length === 1) return list[0];
+
+  const target = Buffer.allocUnsafe(totalLength);
+  let offset = 0;
+
+  for (let i = 0; i < list.length; i++) {
+    const buf = list[i];
+    target.set(buf, offset);
+    offset += buf.length;
+  }
+
+  if (offset < totalLength) {
+    return new FastBuffer(target.buffer, target.byteOffset, offset);
+  }
+
+  return target;
+}
+
+/**
+ * Masks a buffer using the given mask.
+ *
+ * @param {Buffer} source The buffer to mask
+ * @param {Buffer} mask The mask to use
+ * @param {Buffer} output The buffer where to store the result
+ * @param {Number} offset The offset at which to start writing
+ * @param {Number} length The number of bytes to mask.
+ * @public
+ */
+function _mask(source, mask, output, offset, length) {
+  for (let i = 0; i < length; i++) {
+    output[offset + i] = source[i] ^ mask[i & 3];
+  }
+}
+
+/**
+ * Unmasks a buffer using the given mask.
+ *
+ * @param {Buffer} buffer The buffer to unmask
+ * @param {Buffer} mask The mask to use
+ * @public
+ */
+function _unmask(buffer, mask) {
+  for (let i = 0; i < buffer.length; i++) {
+    buffer[i] ^= mask[i & 3];
+  }
+}
+
+/**
+ * Converts a buffer to an `ArrayBuffer`.
+ *
+ * @param {Buffer} buf The buffer to convert
+ * @return {ArrayBuffer} Converted buffer
+ * @public
+ */
+function toArrayBuffer(buf) {
+  if (buf.length === buf.buffer.byteLength) {
+    return buf.buffer;
+  }
+
+  return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.length);
+}
+
+/**
+ * Converts `data` to a `Buffer`.
+ *
+ * @param {*} data The data to convert
+ * @return {Buffer} The buffer
+ * @throws {TypeError}
+ * @public
+ */
+function toBuffer(data) {
+  toBuffer.readOnly = true;
+
+  if (Buffer.isBuffer(data)) return data;
+
+  let buf;
+
+  if (data instanceof ArrayBuffer) {
+    buf = new FastBuffer(data);
+  } else if (ArrayBuffer.isView(data)) {
+    buf = new FastBuffer(data.buffer, data.byteOffset, data.byteLength);
+  } else {
+    buf = Buffer.from(data);
+    toBuffer.readOnly = false;
+  }
+
+  return buf;
+}
+
+module.exports = {
+  concat,
+  mask: _mask,
+  toArrayBuffer,
+  toBuffer,
+  unmask: _unmask
+};
+
+/* istanbul ignore else  */
+if (!process.env.WS_NO_BUFFER_UTIL) {
+  try {
+    const bufferUtil = require('bufferutil');
+
+    module.exports.mask = function (source, mask, output, offset, length) {
+      if (length < 48) _mask(source, mask, output, offset, length);
+      else bufferUtil.mask(source, mask, output, offset, length);
+    };
+
+    module.exports.unmask = function (buffer, mask) {
+      if (buffer.length < 32) _unmask(buffer, mask);
+      else bufferUtil.unmask(buffer, mask);
+    };
+  } catch (e) {
+    // Continue regardless of the error.
+  }
+}
@@ -0,0 +1,19 @@
+'use strict';
+
+const BINARY_TYPES = ['nodebuffer', 'arraybuffer', 'fragments'];
+const hasBlob = typeof Blob !== 'undefined';
+
+if (hasBlob) BINARY_TYPES.push('blob');
+
+module.exports = {
+  BINARY_TYPES,
+  CLOSE_TIMEOUT: 30000,
+  EMPTY_BUFFER: Buffer.alloc(0),
+  GUID: '258EAFA5-E914-47DA-95CA-C5AB0DC85B11',
+  hasBlob,
+  kForOnEventAttribute: Symbol('kIsForOnEventAttribute'),
+  kListener: Symbol('kListener'),
+  kStatusCode: Symbol('status-code'),
+  kWebSocket: Symbol('websocket'),
+  NOOP: () => {}
+};
@@ -0,0 +1,292 @@
+'use strict';
+
+const { kForOnEventAttribute, kListener } = require('./constants');
+
+const kCode = Symbol('kCode');
+const kData = Symbol('kData');
+const kError = Symbol('kError');
+const kMessage = Symbol('kMessage');
+const kReason = Symbol('kReason');
+const kTarget = Symbol('kTarget');
+const kType = Symbol('kType');
+const kWasClean = Symbol('kWasClean');
+
+/**
+ * Class representing an event.
+ */
+class Event {
+  /**
+   * Create a new `Event`.
+   *
+   * @param {String} type The name of the event
+   * @throws {TypeError} If the `type` argument is not specified
+   */
+  constructor(type) {
+    this[kTarget] = null;
+    this[kType] = type;
+  }
+
+  /**
+   * @type {*}
+   */
+  get target() {
+    return this[kTarget];
+  }
+
+  /**
+   * @type {String}
+   */
+  get type() {
+    return this[kType];
+  }
+}
+
+Object.defineProperty(Event.prototype, 'target', { enumerable: true });
+Object.defineProperty(Event.prototype, 'type', { enumerable: true });
+
+/**
+ * Class representing a close event.
+ *
+ * @extends Event
+ */
+class CloseEvent extends Event {
+  /**
+   * Create a new `CloseEvent`.
+   *
+   * @param {String} type The name of the event
+   * @param {Object} [options] A dictionary object that allows for setting
+   *     attributes via object members of the same name
+   * @param {Number} [options.code=0] The status code explaining why the
+   *     connection was closed
+   * @param {String} [options.reason=''] A human-readable string explaining why
+   *     the connection was closed
+   * @param {Boolean} [options.wasClean=false] Indicates whether or not the
+   *     connection was cleanly closed
+   */
+  constructor(type, options = {}) {
+    super(type);
+
+    this[kCode] = options.code === undefined ? 0 : options.code;
+    this[kReason] = options.reason === undefined ? '' : options.reason;
+    this[kWasClean] = options.wasClean === undefined ? false : options.wasClean;
+  }
+
+  /**
+   * @type {Number}
+   */
+  get code() {
+    return this[kCode];
+  }
+
+  /**
+   * @type {String}
+   */
+  get reason() {
+    return this[kReason];
+  }
+
+  /**
+   * @type {Boolean}
+   */
+  get wasClean() {
+    return this[kWasClean];
+  }
+}
+
+Object.defineProperty(CloseEvent.prototype, 'code', { enumerable: true });
+Object.defineProperty(CloseEvent.prototype, 'reason', { enumerable: true });
+Object.defineProperty(CloseEvent.prototype, 'wasClean', { enumerable: true });
+
+/**
+ * Class representing an error event.
+ *
+ * @extends Event
+ */
+class ErrorEvent extends Event {
+  /**
+   * Create a new `ErrorEvent`.
+   *
+   * @param {String} type The name of the event
+   * @param {Object} [options] A dictionary object that allows for setting
+   *     attributes via object members of the same name
+   * @param {*} [options.error=null] The error that generated this event
+   * @param {String} [options.message=''] The error message
+   */
+  constructor(type, options = {}) {
+    super(type);
+
+    this[kError] = options.error === undefined ? null : options.error;
+    this[kMessage] = options.message === undefined ? '' : options.message;
+  }
+
+  /**
+   * @type {*}
+   */
+  get error() {
+    return this[kError];
+  }
+
+  /**
+   * @type {String}
+   */
+  get message() {
+    return this[kMessage];
+  }
+}
+
+Object.defineProperty(ErrorEvent.prototype, 'error', { enumerable: true });
+Object.defineProperty(ErrorEvent.prototype, 'message', { enumerable: true });
+
+/**
+ * Class representing a message event.
+ *
+ * @extends Event
+ */
+class MessageEvent extends Event {
+  /**
+   * Create a new `MessageEvent`.
+   *
+   * @param {String} type The name of the event
+   * @param {Object} [options] A dictionary object that allows for setting
+   *     attributes via object members of the same name
+   * @param {*} [options.data=null] The message content
+   */
+  constructor(type, options = {}) {
+    super(type);
+
+    this[kData] = options.data === undefined ? null : options.data;
+  }
+
+  /**
+   * @type {*}
+   */
+  get data() {
+    return this[kData];
+  }
+}
+
+Object.defineProperty(MessageEvent.prototype, 'data', { enumerable: true });
+
+/**
+ * This provides methods for emulating the `EventTarget` interface. It's not
+ * meant to be used directly.
+ *
+ * @mixin
+ */
+const EventTarget = {
+  /**
+   * Register an event listener.
+   *
+   * @param {String} type A string representing the event type to listen for
+   * @param {(Function|Object)} handler The listener to add
+   * @param {Object} [options] An options object specifies characteristics about
+   *     the event listener
+   * @param {Boolean} [options.once=false] A `Boolean` indicating that the
+   *     listener should be invoked at most once after being added. If `true`,
+   *     the listener would be automatically removed when invoked.
+   * @public
+   */
+  addEventListener(type, handler, options = {}) {
+    for (const listener of this.listeners(type)) {
+      if (
+        !options[kForOnEventAttribute] &&
+        listener[kListener] === handler &&
+        !listener[kForOnEventAttribute]
+      ) {
+        return;
+      }
+    }
+
+    let wrapper;
+
+    if (type === 'message') {
+      wrapper = function onMessage(data, isBinary) {
+        const event = new MessageEvent('message', {
+          data: isBinary ? data : data.toString()
+        });
+
+        event[kTarget] = this;
+        callListener(handler, this, event);
+      };
+    } else if (type === 'close') {
+      wrapper = function onClose(code, message) {
+        const event = new CloseEvent('close', {
+          code,
+          reason: message.toString(),
+          wasClean: this._closeFrameReceived && this._closeFrameSent
+        });
+
+        event[kTarget] = this;
+        callListener(handler, this, event);
+      };
+    } else if (type === 'error') {
+      wrapper = function onError(error) {
+        const event = new ErrorEvent('error', {
+          error,
+          message: error.message
+        });
+
+        event[kTarget] = this;
+        callListener(handler, this, event);
+      };
+    } else if (type === 'open') {
+      wrapper = function onOpen() {
+        const event = new Event('open');
+
+        event[kTarget] = this;
+        callListener(handler, this, event);
+      };
+    } else {
+      return;
+    }
+
+    wrapper[kForOnEventAttribute] = !!options[kForOnEventAttribute];
+    wrapper[kListener] = handler;
+
+    if (options.once) {
+      this.once(type, wrapper);
+    } else {
+      this.on(type, wrapper);
+    }
+  },
+
+  /**
+   * Remove an event listener.
+   *
+   * @param {String} type A string representing the event type to remove
+   * @param {(Function|Object)} handler The listener to remove
+   * @public
+   */
+  removeEventListener(type, handler) {
+    for (const listener of this.listeners(type)) {
+      if (listener[kListener] === handler && !listener[kForOnEventAttribute]) {
+        this.removeListener(type, listener);
+        break;
+      }
+    }
+  }
+};
+
+module.exports = {
+  CloseEvent,
+  ErrorEvent,
+  Event,
+  EventTarget,
+  MessageEvent
+};
+
+/**
+ * Call an event listener
+ *
+ * @param {(Function|Object)} listener The listener to call
+ * @param {*} thisArg The value to use as `this`` when calling the listener
+ * @param {Event} event The event to pass to the listener
+ * @private
+ */
+function callListener(listener, thisArg, event) {
+  if (typeof listener === 'object' && listener.handleEvent) {
+    listener.handleEvent.call(listener, event);
+  } else {
+    listener.call(thisArg, event);
+  }
+}
@@ -0,0 +1,203 @@
+'use strict';
+
+const { tokenChars } = require('./validation');
+
+/**
+ * Adds an offer to the map of extension offers or a parameter to the map of
+ * parameters.
+ *
+ * @param {Object} dest The map of extension offers or parameters
+ * @param {String} name The extension or parameter name
+ * @param {(Object|Boolean|String)} elem The extension parameters or the
+ *     parameter value
+ * @private
+ */
+function push(dest, name, elem) {
+  if (dest[name] === undefined) dest[name] = [elem];
+  else dest[name].push(elem);
+}
+
+/**
+ * Parses the `Sec-WebSocket-Extensions` header into an object.
+ *
+ * @param {String} header The field value of the header
+ * @return {Object} The parsed object
+ * @public
+ */
+function parse(header) {
+  const offers = Object.create(null);
+  let params = Object.create(null);
+  let mustUnescape = false;
+  let isEscaping = false;
+  let inQuotes = false;
+  let extensionName;
+  let paramName;
+  let start = -1;
+  let code = -1;
+  let end = -1;
+  let i = 0;
+
+  for (; i < header.length; i++) {
+    code = header.charCodeAt(i);
+
+    if (extensionName === undefined) {
+      if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (
+        i !== 0 &&
+        (code === 0x20 /* ' ' */ || code === 0x09) /* '\t' */
+      ) {
+        if (end === -1 && start !== -1) end = i;
+      } else if (code === 0x3b /* ';' */ || code === 0x2c /* ',' */) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        const name = header.slice(start, end);
+        if (code === 0x2c) {
+          push(offers, name, params);
+          params = Object.create(null);
+        } else {
+          extensionName = name;
+        }
+
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    } else if (paramName === undefined) {
+      if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (code === 0x20 || code === 0x09) {
+        if (end === -1 && start !== -1) end = i;
+      } else if (code === 0x3b || code === 0x2c) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        push(params, header.slice(start, end), true);
+        if (code === 0x2c) {
+          push(offers, extensionName, params);
+          params = Object.create(null);
+          extensionName = undefined;
+        }
+
+        start = end = -1;
+      } else if (code === 0x3d /* '=' */ && start !== -1 && end === -1) {
+        paramName = header.slice(start, i);
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    } else {
+      //
+      // The value of a quoted-string after unescaping must conform to the
+      // token ABNF, so only token characters are valid.
+      // Ref: https://tools.ietf.org/html/rfc6455#section-9.1
+      //
+      if (isEscaping) {
+        if (tokenChars[code] !== 1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+        if (start === -1) start = i;
+        else if (!mustUnescape) mustUnescape = true;
+        isEscaping = false;
+      } else if (inQuotes) {
+        if (tokenChars[code] === 1) {
+          if (start === -1) start = i;
+        } else if (code === 0x22 /* '"' */ && start !== -1) {
+          inQuotes = false;
+          end = i;
+        } else if (code === 0x5c /* '\' */) {
+          isEscaping = true;
+        } else {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+      } else if (code === 0x22 && header.charCodeAt(i - 1) === 0x3d) {
+        inQuotes = true;
+      } else if (end === -1 && tokenChars[code] === 1) {
+        if (start === -1) start = i;
+      } else if (start !== -1 && (code === 0x20 || code === 0x09)) {
+        if (end === -1) end = i;
+      } else if (code === 0x3b || code === 0x2c) {
+        if (start === -1) {
+          throw new SyntaxError(`Unexpected character at index ${i}`);
+        }
+
+        if (end === -1) end = i;
+        let value = header.slice(start, end);
+        if (mustUnescape) {
+          value = value.replace(/\\/g, '');
+          mustUnescape = false;
+        }
+        push(params, paramName, value);
+        if (code === 0x2c) {
+          push(offers, extensionName, params);
+          params = Object.create(null);
+          extensionName = undefined;
+        }
+
+        paramName = undefined;
+        start = end = -1;
+      } else {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+    }
+  }
+
+  if (start === -1 || inQuotes || code === 0x20 || code === 0x09) {
+    throw new SyntaxError('Unexpected end of input');
+  }
+
+  if (end === -1) end = i;
+  const token = header.slice(start, end);
+  if (extensionName === undefined) {
+    push(offers, token, params);
+  } else {
+    if (paramName === undefined) {
+      push(params, token, true);
+    } else if (mustUnescape) {
+      push(params, paramName, token.replace(/\\/g, ''));
+    } else {
+      push(params, paramName, token);
+    }
+    push(offers, extensionName, params);
+  }
+
+  return offers;
+}
+
+/**
+ * Builds the `Sec-WebSocket-Extensions` header field value.
+ *
+ * @param {Object} extensions The map of extensions and parameters to format
+ * @return {String} A string representing the given object
+ * @public
+ */
+function format(extensions) {
+  return Object.keys(extensions)
+    .map((extension) => {
+      let configurations = extensions[extension];
+      if (!Array.isArray(configurations)) configurations = [configurations];
+      return configurations
+        .map((params) => {
+          return [extension]
+            .concat(
+              Object.keys(params).map((k) => {
+                let values = params[k];
+                if (!Array.isArray(values)) values = [values];
+                return values
+                  .map((v) => (v === true ? k : `${k}=${v}`))
+                  .join('; ');
+              })
+            )
+            .join('; ');
+        })
+        .join(', ');
+    })
+    .join(', ');
+}
+
+module.exports = { format, parse };
@@ -0,0 +1,55 @@
+'use strict';
+
+const kDone = Symbol('kDone');
+const kRun = Symbol('kRun');
+
+/**
+ * A very simple job queue with adjustable concurrency. Adapted from
+ * https://github.com/STRML/async-limiter
+ */
+class Limiter {
+  /**
+   * Creates a new `Limiter`.
+   *
+   * @param {Number} [concurrency=Infinity] The maximum number of jobs allowed
+   *     to run concurrently
+   */
+  constructor(concurrency) {
+    this[kDone] = () => {
+      this.pending--;
+      this[kRun]();
+    };
+    this.concurrency = concurrency || Infinity;
+    this.jobs = [];
+    this.pending = 0;
+  }
+
+  /**
+   * Adds a job to the queue.
+   *
+   * @param {Function} job The job to run
+   * @public
+   */
+  add(job) {
+    this.jobs.push(job);
+    this[kRun]();
+  }
+
+  /**
+   * Removes a job from the queue and runs it if possible.
+   *
+   * @private
+   */
+  [kRun]() {
+    if (this.pending === this.concurrency) return;
+
+    if (this.jobs.length) {
+      const job = this.jobs.shift();
+
+      this.pending++;
+      job(this[kDone]);
+    }
+  }
+}
+
+module.exports = Limiter;
@@ -0,0 +1,530 @@
+'use strict';
+
+const zlib = require('zlib');
+
+const bufferUtil = require('./buffer-util');
+const Limiter = require('./limiter');
+const { kStatusCode } = require('./constants');
+
+const FastBuffer = Buffer[Symbol.species];
+const TRAILER = Buffer.from([0x00, 0x00, 0xff, 0xff]);
+const kPerMessageDeflate = Symbol('permessage-deflate');
+const kTotalLength = Symbol('total-length');
+const kCallback = Symbol('callback');
+const kBuffers = Symbol('buffers');
+const kError = Symbol('error');
+
+//
+// We limit zlib concurrency, which prevents severe memory fragmentation
+// as documented in https://github.com/nodejs/node/issues/8871#issuecomment-250915913
+// and https://github.com/websockets/ws/issues/1202
+//
+// Intentionally global; it's the global thread pool that's an issue.
+//
+let zlibLimiter;
+
+/**
+ * permessage-deflate implementation.
+ */
+class PerMessageDeflate {
+  /**
+   * Creates a PerMessageDeflate instance.
+   *
+   * @param {Object} [options] Configuration options
+   * @param {(Boolean|Number)} [options.clientMaxWindowBits] Advertise support
+   *     for, or request, a custom client window size
+   * @param {Boolean} [options.clientNoContextTakeover=false] Advertise/
+   *     acknowledge disabling of client context takeover
+   * @param {Number} [options.concurrencyLimit=10] The number of concurrent
+   *     calls to zlib
+   * @param {Boolean} [options.isServer=false] Create the instance in either
+   *     server or client mode
+   * @param {Number} [options.maxPayload=0] The maximum allowed message length
+   * @param {(Boolean|Number)} [options.serverMaxWindowBits] Request/confirm the
+   *     use of a custom server window size
+   * @param {Boolean} [options.serverNoContextTakeover=false] Request/accept
+   *     disabling of server context takeover
+   * @param {Number} [options.threshold=1024] Size (in bytes) below which
+   *     messages should not be compressed if context takeover is disabled
+   * @param {Object} [options.zlibDeflateOptions] Options to pass to zlib on
+   *     deflate
+   * @param {Object} [options.zlibInflateOptions] Options to pass to zlib on
+   *     inflate
+   */
+  constructor(options) {
+    this._options = options || {};
+    this._threshold =
+      this._options.threshold !== undefined ? this._options.threshold : 1024;
+    this._maxPayload = this._options.maxPayload | 0;
+    this._isServer = !!this._options.isServer;
+    this._deflate = null;
+    this._inflate = null;
+
+    this.params = null;
+
+    if (!zlibLimiter) {
+      const concurrency =
+        this._options.concurrencyLimit !== undefined
+          ? this._options.concurrencyLimit
+          : 10;
+      zlibLimiter = new Limiter(concurrency);
+    }
+  }
+
+  /**
+   * @type {String}
+   */
+  static get extensionName() {
+    return 'permessage-deflate';
+  }
+
+  /**
+   * Create an extension negotiation offer.
+   *
+   * @return {Object} Extension parameters
+   * @public
+   */
+  offer() {
+    const params = {};
+
+    if (this._options.serverNoContextTakeover) {
+      params.server_no_context_takeover = true;
+    }
+    if (this._options.clientNoContextTakeover) {
+      params.client_no_context_takeover = true;
+    }
+    if (this._options.serverMaxWindowBits) {
+      params.server_max_window_bits = this._options.serverMaxWindowBits;
+    }
+    if (this._options.clientMaxWindowBits) {
+      params.client_max_window_bits = this._options.clientMaxWindowBits;
+    } else if (this._options.clientMaxWindowBits == null) {
+      params.client_max_window_bits = true;
+    }
+
+    return params;
+  }
+
+  /**
+   * Accept an extension negotiation offer/response.
+   *
+   * @param {Array} configurations The extension negotiation offers/reponse
+   * @return {Object} Accepted configuration
+   * @public
+   */
+  accept(configurations) {
+    configurations = this.normalizeParams(configurations);
+
+    this.params = this._isServer
+      ? this.acceptAsServer(configurations)
+      : this.acceptAsClient(configurations);
+
+    return this.params;
+  }
+
+  /**
+   * Releases all resources used by the extension.
+   *
+   * @public
+   */
+  cleanup() {
+    if (this._inflate) {
+      this._inflate.close();
+      this._inflate = null;
+    }
+
+    if (this._deflate) {
+      const callback = this._deflate[kCallback];
+
+      this._deflate.close();
+      this._deflate = null;
+
+      if (callback) {
+        callback(
+          new Error(
+            'The deflate stream was closed while data was being processed'
+          )
+        );
+      }
+    }
+  }
+
+  /**
+   *  Accept an extension negotiation offer.
+   *
+   * @param {Array} offers The extension negotiation offers
+   * @return {Object} Accepted configuration
+   * @private
+   */
+  acceptAsServer(offers) {
+    const opts = this._options;
+    const accepted = offers.find((params) => {
+      if (
+        (opts.serverNoContextTakeover === false &&
+          params.server_no_context_takeover) ||
+        (params.server_max_window_bits &&
+          (opts.serverMaxWindowBits === false ||
+            (typeof opts.serverMaxWindowBits === 'number' &&
+              opts.serverMaxWindowBits > params.server_max_window_bits))) ||
+        (typeof opts.clientMaxWindowBits === 'number' &&
+          (typeof params.client_max_window_bits === 'number'
+            ? opts.clientMaxWindowBits > params.client_max_window_bits
+            : !params.client_max_window_bits))
+      ) {
+        return false;
+      }
+
+      return true;
+    });
+
+    if (!accepted) {
+      throw new Error('None of the extension offers can be accepted');
+    }
+
+    if (opts.serverNoContextTakeover) {
+      accepted.server_no_context_takeover = true;
+    }
+    if (opts.clientNoContextTakeover) {
+      accepted.client_no_context_takeover = true;
+    }
+    if (typeof opts.serverMaxWindowBits === 'number') {
+      accepted.server_max_window_bits = opts.serverMaxWindowBits;
+    }
+    if (typeof opts.clientMaxWindowBits === 'number') {
+      accepted.client_max_window_bits = opts.clientMaxWindowBits;
+    } else if (
+      accepted.client_max_window_bits === true ||
+      opts.clientMaxWindowBits === false
+    ) {
+      delete accepted.client_max_window_bits;
+    }
+
+    return accepted;
+  }
+
+  /**
+   * Accept the extension negotiation response.
+   *
+   * @param {Array} response The extension negotiation response
+   * @return {Object} Accepted configuration
+   * @private
+   */
+  acceptAsClient(response) {
+    const params = response[0];
+
+    if (
+      this._options.clientNoContextTakeover === false &&
+      params.client_no_context_takeover
+    ) {
+      throw new Error('Unexpected parameter "client_no_context_takeover"');
+    }
+
+    if (!params.client_max_window_bits) {
+      if (typeof this._options.clientMaxWindowBits === 'number') {
+        params.client_max_window_bits = this._options.clientMaxWindowBits;
+      }
+    } else if (
+      this._options.clientMaxWindowBits === false ||
+      (typeof this._options.clientMaxWindowBits === 'number' &&
+        params.client_max_window_bits > this._options.clientMaxWindowBits)
+    ) {
+      throw new Error(
+        'Unexpected or invalid parameter "client_max_window_bits"'
+      );
+    }
+
+    return params;
+  }
+
+  /**
+   * Normalize parameters.
+   *
+   * @param {Array} configurations The extension negotiation offers/reponse
+   * @return {Array} The offers/response with normalized parameters
+   * @private
+   */
+  normalizeParams(configurations) {
+    configurations.forEach((params) => {
+      Object.keys(params).forEach((key) => {
+        let value = params[key];
+
+        if (value.length > 1) {
+          throw new Error(`Parameter "${key}" must have only a single value`);
+        }
+
+        value = value[0];
+
+        if (key === 'client_max_window_bits') {
+          if (value !== true) {
+            const num = +value;
+            if (!Number.isInteger(num) || num < 8 || num > 15) {
+              throw new TypeError(
+                `Invalid value for parameter "${key}": ${value}`
+              );
+            }
+            value = num;
+          } else if (!this._isServer) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+        } else if (key === 'server_max_window_bits') {
+          const num = +value;
+          if (!Number.isInteger(num) || num < 8 || num > 15) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+          value = num;
+        } else if (
+          key === 'client_no_context_takeover' ||
+          key === 'server_no_context_takeover'
+        ) {
+          if (value !== true) {
+            throw new TypeError(
+              `Invalid value for parameter "${key}": ${value}`
+            );
+          }
+        } else {
+          throw new Error(`Unknown parameter "${key}"`);
+        }
+
+        params[key] = value;
+      });
+    });
+
+    return configurations;
+  }
+
+  /**
+   * Decompress data. Concurrency limited.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @public
+   */
+  decompress(data, fin, callback) {
+    zlibLimiter.add((done) => {
+      this._decompress(data, fin, (err, result) => {
+        done();
+        callback(err, result);
+      });
+    });
+  }
+
+  /**
+   * Compress data. Concurrency limited.
+   *
+   * @param {(Buffer|String)} data Data to compress
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @public
+   */
+  compress(data, fin, callback) {
+    zlibLimiter.add((done) => {
+      this._compress(data, fin, (err, result) => {
+        done();
+        callback(err, result);
+      });
+    });
+  }
+
+  /**
+   * Decompress data.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @private
+   */
+  _decompress(data, fin, callback) {
+    const endpoint = this._isServer ? 'client' : 'server';
+
+    if (!this._inflate) {
+      const key = `${endpoint}_max_window_bits`;
+      const windowBits =
+        typeof this.params[key] !== 'number'
+          ? zlib.Z_DEFAULT_WINDOWBITS
+          : this.params[key];
+
+      this._inflate = zlib.createInflateRaw({
+        ...this._options.zlibInflateOptions,
+        windowBits
+      });
+      this._inflate[kPerMessageDeflate] = this;
+      this._inflate[kTotalLength] = 0;
+      this._inflate[kBuffers] = [];
+      this._inflate.on('error', inflateOnError);
+      this._inflate.on('data', inflateOnData);
+    }
+
+    this._inflate[kCallback] = callback;
+
+    this._inflate.write(data);
+    if (fin) this._inflate.write(TRAILER);
+
+    this._inflate.flush(() => {
+      const err = this._inflate[kError];
+
+      if (err) {
+        this._inflate.close();
+        this._inflate = null;
+        callback(err);
+        return;
+      }
+
+      const data = bufferUtil.concat(
+        this._inflate[kBuffers],
+        this._inflate[kTotalLength]
+      );
+
+      if (this._inflate._readableState.endEmitted) {
+        this._inflate.close();
+        this._inflate = null;
+      } else {
+        this._inflate[kTotalLength] = 0;
+        this._inflate[kBuffers] = [];
+
+        if (fin && this.params[`${endpoint}_no_context_takeover`]) {
+          this._inflate.reset();
+        }
+      }
+
+      callback(null, data);
+    });
+  }
+
+  /**
+   * Compress data.
+   *
+   * @param {(Buffer|String)} data Data to compress
+   * @param {Boolean} fin Specifies whether or not this is the last fragment
+   * @param {Function} callback Callback
+   * @private
+   */
+  _compress(data, fin, callback) {
+    const endpoint = this._isServer ? 'server' : 'client';
+
+    if (!this._deflate) {
+      const key = `${endpoint}_max_window_bits`;
+      const windowBits =
+        typeof this.params[key] !== 'number'
+          ? zlib.Z_DEFAULT_WINDOWBITS
+          : this.params[key];
+
+      this._deflate = zlib.createDeflateRaw({
+        ...this._options.zlibDeflateOptions,
+        windowBits
+      });
+
+      this._deflate[kTotalLength] = 0;
+      this._deflate[kBuffers] = [];
+
+      this._deflate.on('data', deflateOnData);
+    }
+
+    this._deflate[kCallback] = callback;
+
+    this._deflate.write(data);
+    this._deflate.flush(zlib.Z_SYNC_FLUSH, () => {
+      if (!this._deflate) {
+        //
+        // The deflate stream was closed while data was being processed.
+        //
+        return;
+      }
+
+      let data = bufferUtil.concat(
+        this._deflate[kBuffers],
+        this._deflate[kTotalLength]
+      );
+
+      if (fin) {
+        data = new FastBuffer(data.buffer, data.byteOffset, data.length - 4);
+      }
+
+      //
+      // Ensure that the callback will not be called again in
+      // `PerMessageDeflate#cleanup()`.
+      //
+      this._deflate[kCallback] = null;
+
+      this._deflate[kTotalLength] = 0;
+      this._deflate[kBuffers] = [];
+
+      if (fin && this.params[`${endpoint}_no_context_takeover`]) {
+        this._deflate.reset();
+      }
+
+      callback(null, data);
+    });
+  }
+}
+
+module.exports = PerMessageDeflate;
+
+/**
+ * The listener of the `zlib.DeflateRaw` stream `'data'` event.
+ *
+ * @param {Buffer} chunk A chunk of data
+ * @private
+ */
+function deflateOnData(chunk) {
+  this[kBuffers].push(chunk);
+  this[kTotalLength] += chunk.length;
+}
+
+/**
+ * The listener of the `zlib.InflateRaw` stream `'data'` event.
+ *
+ * @param {Buffer} chunk A chunk of data
+ * @private
+ */
+function inflateOnData(chunk) {
+  this[kTotalLength] += chunk.length;
+
+  if (
+    this[kPerMessageDeflate]._maxPayload < 1 ||
+    this[kTotalLength] <= this[kPerMessageDeflate]._maxPayload
+  ) {
+    this[kBuffers].push(chunk);
+    return;
+  }
+
+  this[kError] = new RangeError('Max payload size exceeded');
+  this[kError].code = 'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH';
+  this[kError][kStatusCode] = 1009;
+  this.removeListener('data', inflateOnData);
+
+  //
+  // The choice to employ `zlib.reset()` over `zlib.close()` is dictated by the
+  // fact that in Node.js versions prior to 13.10.0, the callback for
+  // `zlib.flush()` is not called if `zlib.close()` is used. Utilizing
+  // `zlib.reset()` ensures that either the callback is invoked or an error is
+  // emitted.
+  //
+  this.reset();
+}
+
+/**
+ * The listener of the `zlib.InflateRaw` stream `'error'` event.
+ *
+ * @param {Error} err The emitted error
+ * @private
+ */
+function inflateOnError(err) {
+  //
+  // There is no need to call `Zlib#close()` as the handle is automatically
+  // closed when an error is emitted.
+  //
+  this[kPerMessageDeflate]._inflate = null;
+
+  if (this[kError]) {
+    this[kCallback](this[kError]);
+    return;
+  }
+
+  err[kStatusCode] = 1007;
+  this[kCallback](err);
+}
@@ -0,0 +1,743 @@
+'use strict';
+
+const { Writable } = require('stream');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const {
+  BINARY_TYPES,
+  EMPTY_BUFFER,
+  kStatusCode,
+  kWebSocket
+} = require('./constants');
+const { concat, toArrayBuffer, unmask } = require('./buffer-util');
+const { isValidStatusCode, isValidUTF8 } = require('./validation');
+
+const FastBuffer = Buffer[Symbol.species];
+
+const GET_INFO = 0;
+const GET_PAYLOAD_LENGTH_16 = 1;
+const GET_PAYLOAD_LENGTH_64 = 2;
+const GET_MASK = 3;
+const GET_DATA = 4;
+const INFLATING = 5;
+const DEFER_EVENT = 6;
+
+/**
+ * HyBi Receiver implementation.
+ *
+ * @extends Writable
+ */
+class Receiver extends Writable {
+  /**
+   * Creates a Receiver instance.
+   *
+   * @param {Object} [options] Options object
+   * @param {Boolean} [options.allowSynchronousEvents=true] Specifies whether
+   *     any of the `'message'`, `'ping'`, and `'pong'` events can be emitted
+   *     multiple times in the same tick
+   * @param {String} [options.binaryType=nodebuffer] The type for binary data
+   * @param {Object} [options.extensions] An object containing the negotiated
+   *     extensions
+   * @param {Boolean} [options.isServer=false] Specifies whether to operate in
+   *     client or server mode
+   * @param {Number} [options.maxBufferedChunks=0] The maximum number of
+   *     buffered data chunks
+   * @param {Number} [options.maxFragments=0] The maximum number of message
+   *     fragments
+   * @param {Number} [options.maxPayload=0] The maximum allowed message length
+   * @param {Boolean} [options.skipUTF8Validation=false] Specifies whether or
+   *     not to skip UTF-8 validation for text and close messages
+   */
+  constructor(options = {}) {
+    super();
+
+    this._allowSynchronousEvents =
+      options.allowSynchronousEvents !== undefined
+        ? options.allowSynchronousEvents
+        : true;
+    this._binaryType = options.binaryType || BINARY_TYPES[0];
+    this._extensions = options.extensions || {};
+    this._isServer = !!options.isServer;
+    this._maxBufferedChunks = options.maxBufferedChunks | 0;
+    this._maxFragments = options.maxFragments | 0;
+    this._maxPayload = options.maxPayload | 0;
+    this._skipUTF8Validation = !!options.skipUTF8Validation;
+    this[kWebSocket] = undefined;
+
+    this._bufferedBytes = 0;
+    this._buffers = [];
+
+    this._compressed = false;
+    this._payloadLength = 0;
+    this._mask = undefined;
+    this._fragmented = 0;
+    this._masked = false;
+    this._fin = false;
+    this._opcode = 0;
+
+    this._totalPayloadLength = 0;
+    this._messageLength = 0;
+    this._numFragments = 0;
+    this._fragments = [];
+
+    this._errored = false;
+    this._loop = false;
+    this._state = GET_INFO;
+  }
+
+  /**
+   * Implements `Writable.prototype._write()`.
+   *
+   * @param {Buffer} chunk The chunk of data to write
+   * @param {String} encoding The character encoding of `chunk`
+   * @param {Function} cb Callback
+   * @private
+   */
+  _write(chunk, encoding, cb) {
+    if (this._opcode === 0x08 && this._state == GET_INFO) return cb();
+
+    if (
+      this._maxBufferedChunks > 0 &&
+      this._buffers.length >= this._maxBufferedChunks
+    ) {
+      cb(
+        this.createError(
+          RangeError,
+          'Too many buffered chunks',
+          false,
+          1008,
+          'WS_ERR_TOO_MANY_BUFFERED_PARTS'
+        )
+      );
+      return;
+    }
+
+    this._bufferedBytes += chunk.length;
+    this._buffers.push(chunk);
+    this.startLoop(cb);
+  }
+
+  /**
+   * Consumes `n` bytes from the buffered data.
+   *
+   * @param {Number} n The number of bytes to consume
+   * @return {Buffer} The consumed bytes
+   * @private
+   */
+  consume(n) {
+    this._bufferedBytes -= n;
+
+    if (n === this._buffers[0].length) return this._buffers.shift();
+
+    if (n < this._buffers[0].length) {
+      const buf = this._buffers[0];
+      this._buffers[0] = new FastBuffer(
+        buf.buffer,
+        buf.byteOffset + n,
+        buf.length - n
+      );
+
+      return new FastBuffer(buf.buffer, buf.byteOffset, n);
+    }
+
+    const dst = Buffer.allocUnsafe(n);
+
+    do {
+      const buf = this._buffers[0];
+      const offset = dst.length - n;
+
+      if (n >= buf.length) {
+        dst.set(this._buffers.shift(), offset);
+      } else {
+        dst.set(new Uint8Array(buf.buffer, buf.byteOffset, n), offset);
+        this._buffers[0] = new FastBuffer(
+          buf.buffer,
+          buf.byteOffset + n,
+          buf.length - n
+        );
+      }
+
+      n -= buf.length;
+    } while (n > 0);
+
+    return dst;
+  }
+
+  /**
+   * Starts the parsing loop.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  startLoop(cb) {
+    this._loop = true;
+
+    do {
+      switch (this._state) {
+        case GET_INFO:
+          this.getInfo(cb);
+          break;
+        case GET_PAYLOAD_LENGTH_16:
+          this.getPayloadLength16(cb);
+          break;
+        case GET_PAYLOAD_LENGTH_64:
+          this.getPayloadLength64(cb);
+          break;
+        case GET_MASK:
+          this.getMask();
+          break;
+        case GET_DATA:
+          this.getData(cb);
+          break;
+        case INFLATING:
+        case DEFER_EVENT:
+          this._loop = false;
+          return;
+      }
+    } while (this._loop);
+
+    if (!this._errored) cb();
+  }
+
+  /**
+   * Reads the first two bytes of a frame.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  getInfo(cb) {
+    if (this._bufferedBytes < 2) {
+      this._loop = false;
+      return;
+    }
+
+    const buf = this.consume(2);
+
+    if ((buf[0] & 0x30) !== 0x00) {
+      const error = this.createError(
+        RangeError,
+        'RSV2 and RSV3 must be clear',
+        true,
+        1002,
+        'WS_ERR_UNEXPECTED_RSV_2_3'
+      );
+
+      cb(error);
+      return;
+    }
+
+    const compressed = (buf[0] & 0x40) === 0x40;
+
+    if (compressed && !this._extensions[PerMessageDeflate.extensionName]) {
+      const error = this.createError(
+        RangeError,
+        'RSV1 must be clear',
+        true,
+        1002,
+        'WS_ERR_UNEXPECTED_RSV_1'
+      );
+
+      cb(error);
+      return;
+    }
+
+    this._fin = (buf[0] & 0x80) === 0x80;
+    this._opcode = buf[0] & 0x0f;
+    this._payloadLength = buf[1] & 0x7f;
+
+    if (this._opcode === 0x00) {
+      if (compressed) {
+        const error = this.createError(
+          RangeError,
+          'RSV1 must be clear',
+          true,
+          1002,
+          'WS_ERR_UNEXPECTED_RSV_1'
+        );
+
+        cb(error);
+        return;
+      }
+
+      if (!this._fragmented) {
+        const error = this.createError(
+          RangeError,
+          'invalid opcode 0',
+          true,
+          1002,
+          'WS_ERR_INVALID_OPCODE'
+        );
+
+        cb(error);
+        return;
+      }
+
+      this._opcode = this._fragmented;
+    } else if (this._opcode === 0x01 || this._opcode === 0x02) {
+      if (this._fragmented) {
+        const error = this.createError(
+          RangeError,
+          `invalid opcode ${this._opcode}`,
+          true,
+          1002,
+          'WS_ERR_INVALID_OPCODE'
+        );
+
+        cb(error);
+        return;
+      }
+
+      this._compressed = compressed;
+    } else if (this._opcode > 0x07 && this._opcode < 0x0b) {
+      if (!this._fin) {
+        const error = this.createError(
+          RangeError,
+          'FIN must be set',
+          true,
+          1002,
+          'WS_ERR_EXPECTED_FIN'
+        );
+
+        cb(error);
+        return;
+      }
+
+      if (compressed) {
+        const error = this.createError(
+          RangeError,
+          'RSV1 must be clear',
+          true,
+          1002,
+          'WS_ERR_UNEXPECTED_RSV_1'
+        );
+
+        cb(error);
+        return;
+      }
+
+      if (
+        this._payloadLength > 0x7d ||
+        (this._opcode === 0x08 && this._payloadLength === 1)
+      ) {
+        const error = this.createError(
+          RangeError,
+          `invalid payload length ${this._payloadLength}`,
+          true,
+          1002,
+          'WS_ERR_INVALID_CONTROL_PAYLOAD_LENGTH'
+        );
+
+        cb(error);
+        return;
+      }
+    } else {
+      const error = this.createError(
+        RangeError,
+        `invalid opcode ${this._opcode}`,
+        true,
+        1002,
+        'WS_ERR_INVALID_OPCODE'
+      );
+
+      cb(error);
+      return;
+    }
+
+    if (!this._fin && !this._fragmented) this._fragmented = this._opcode;
+    this._masked = (buf[1] & 0x80) === 0x80;
+
+    if (this._isServer) {
+      if (!this._masked) {
+        const error = this.createError(
+          RangeError,
+          'MASK must be set',
+          true,
+          1002,
+          'WS_ERR_EXPECTED_MASK'
+        );
+
+        cb(error);
+        return;
+      }
+    } else if (this._masked) {
+      const error = this.createError(
+        RangeError,
+        'MASK must be clear',
+        true,
+        1002,
+        'WS_ERR_UNEXPECTED_MASK'
+      );
+
+      cb(error);
+      return;
+    }
+
+    if (this._payloadLength === 126) this._state = GET_PAYLOAD_LENGTH_16;
+    else if (this._payloadLength === 127) this._state = GET_PAYLOAD_LENGTH_64;
+    else this.haveLength(cb);
+  }
+
+  /**
+   * Gets extended payload length (7+16).
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  getPayloadLength16(cb) {
+    if (this._bufferedBytes < 2) {
+      this._loop = false;
+      return;
+    }
+
+    this._payloadLength = this.consume(2).readUInt16BE(0);
+    this.haveLength(cb);
+  }
+
+  /**
+   * Gets extended payload length (7+64).
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  getPayloadLength64(cb) {
+    if (this._bufferedBytes < 8) {
+      this._loop = false;
+      return;
+    }
+
+    const buf = this.consume(8);
+    const num = buf.readUInt32BE(0);
+
+    //
+    // The maximum safe integer in JavaScript is 2^53 - 1. An error is returned
+    // if payload length is greater than this number.
+    //
+    if (num > Math.pow(2, 53 - 32) - 1) {
+      const error = this.createError(
+        RangeError,
+        'Unsupported WebSocket frame: payload length > 2^53 - 1',
+        false,
+        1009,
+        'WS_ERR_UNSUPPORTED_DATA_PAYLOAD_LENGTH'
+      );
+
+      cb(error);
+      return;
+    }
+
+    this._payloadLength = num * Math.pow(2, 32) + buf.readUInt32BE(4);
+    this.haveLength(cb);
+  }
+
+  /**
+   * Payload length has been read.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  haveLength(cb) {
+    if (this._payloadLength && this._opcode < 0x08) {
+      this._totalPayloadLength += this._payloadLength;
+      if (this._totalPayloadLength > this._maxPayload && this._maxPayload > 0) {
+        const error = this.createError(
+          RangeError,
+          'Max payload size exceeded',
+          false,
+          1009,
+          'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH'
+        );
+
+        cb(error);
+        return;
+      }
+    }
+
+    if (this._masked) this._state = GET_MASK;
+    else this._state = GET_DATA;
+  }
+
+  /**
+   * Reads mask bytes.
+   *
+   * @private
+   */
+  getMask() {
+    if (this._bufferedBytes < 4) {
+      this._loop = false;
+      return;
+    }
+
+    this._mask = this.consume(4);
+    this._state = GET_DATA;
+  }
+
+  /**
+   * Reads data bytes.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  getData(cb) {
+    let data = EMPTY_BUFFER;
+
+    if (this._payloadLength) {
+      if (this._bufferedBytes < this._payloadLength) {
+        this._loop = false;
+        return;
+      }
+
+      data = this.consume(this._payloadLength);
+
+      if (
+        this._masked &&
+        (this._mask[0] | this._mask[1] | this._mask[2] | this._mask[3]) !== 0
+      ) {
+        unmask(data, this._mask);
+      }
+    }
+
+    if (this._opcode > 0x07) {
+      this.controlMessage(data, cb);
+      return;
+    }
+
+    if (this._maxFragments > 0 && ++this._numFragments > this._maxFragments) {
+      const error = this.createError(
+        RangeError,
+        'Too many message fragments',
+        false,
+        1008,
+        'WS_ERR_TOO_MANY_BUFFERED_PARTS'
+      );
+
+      cb(error);
+      return;
+    }
+
+    if (this._compressed) {
+      this._state = INFLATING;
+      this.decompress(data, cb);
+      return;
+    }
+
+    if (data.length) {
+      //
+      // This message is not compressed so its length is the sum of the payload
+      // length of all fragments.
+      //
+      this._messageLength = this._totalPayloadLength;
+      this._fragments.push(data);
+    }
+
+    this.dataMessage(cb);
+  }
+
+  /**
+   * Decompresses data.
+   *
+   * @param {Buffer} data Compressed data
+   * @param {Function} cb Callback
+   * @private
+   */
+  decompress(data, cb) {
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+
+    perMessageDeflate.decompress(data, this._fin, (err, buf) => {
+      if (err) return cb(err);
+
+      if (buf.length) {
+        this._messageLength += buf.length;
+        if (this._messageLength > this._maxPayload && this._maxPayload > 0) {
+          const error = this.createError(
+            RangeError,
+            'Max payload size exceeded',
+            false,
+            1009,
+            'WS_ERR_UNSUPPORTED_MESSAGE_LENGTH'
+          );
+
+          cb(error);
+          return;
+        }
+
+        this._fragments.push(buf);
+      }
+
+      this.dataMessage(cb);
+      if (this._state === GET_INFO) this.startLoop(cb);
+    });
+  }
+
+  /**
+   * Handles a data message.
+   *
+   * @param {Function} cb Callback
+   * @private
+   */
+  dataMessage(cb) {
+    if (!this._fin) {
+      this._state = GET_INFO;
+      return;
+    }
+
+    const messageLength = this._messageLength;
+    const fragments = this._fragments;
+
+    this._totalPayloadLength = 0;
+    this._messageLength = 0;
+    this._fragmented = 0;
+    this._numFragments = 0;
+    this._fragments = [];
+
+    if (this._opcode === 2) {
+      let data;
+
+      if (this._binaryType === 'nodebuffer') {
+        data = concat(fragments, messageLength);
+      } else if (this._binaryType === 'arraybuffer') {
+        data = toArrayBuffer(concat(fragments, messageLength));
+      } else if (this._binaryType === 'blob') {
+        data = new Blob(fragments);
+      } else {
+        data = fragments;
+      }
+
+      if (this._allowSynchronousEvents) {
+        this.emit('message', data, true);
+        this._state = GET_INFO;
+      } else {
+        this._state = DEFER_EVENT;
+        setImmediate(() => {
+          this.emit('message', data, true);
+          this._state = GET_INFO;
+          this.startLoop(cb);
+        });
+      }
+    } else {
+      const buf = concat(fragments, messageLength);
+
+      if (!this._skipUTF8Validation && !isValidUTF8(buf)) {
+        const error = this.createError(
+          Error,
+          'invalid UTF-8 sequence',
+          true,
+          1007,
+          'WS_ERR_INVALID_UTF8'
+        );
+
+        cb(error);
+        return;
+      }
+
+      if (this._state === INFLATING || this._allowSynchronousEvents) {
+        this.emit('message', buf, false);
+        this._state = GET_INFO;
+      } else {
+        this._state = DEFER_EVENT;
+        setImmediate(() => {
+          this.emit('message', buf, false);
+          this._state = GET_INFO;
+          this.startLoop(cb);
+        });
+      }
+    }
+  }
+
+  /**
+   * Handles a control message.
+   *
+   * @param {Buffer} data Data to handle
+   * @return {(Error|RangeError|undefined)} A possible error
+   * @private
+   */
+  controlMessage(data, cb) {
+    if (this._opcode === 0x08) {
+      if (data.length === 0) {
+        this._loop = false;
+        this.emit('conclude', 1005, EMPTY_BUFFER);
+        this.end();
+      } else {
+        const code = data.readUInt16BE(0);
+
+        if (!isValidStatusCode(code)) {
+          const error = this.createError(
+            RangeError,
+            `invalid status code ${code}`,
+            true,
+            1002,
+            'WS_ERR_INVALID_CLOSE_CODE'
+          );
+
+          cb(error);
+          return;
+        }
+
+        const buf = new FastBuffer(
+          data.buffer,
+          data.byteOffset + 2,
+          data.length - 2
+        );
+
+        if (!this._skipUTF8Validation && !isValidUTF8(buf)) {
+          const error = this.createError(
+            Error,
+            'invalid UTF-8 sequence',
+            true,
+            1007,
+            'WS_ERR_INVALID_UTF8'
+          );
+
+          cb(error);
+          return;
+        }
+
+        this._loop = false;
+        this.emit('conclude', code, buf);
+        this.end();
+      }
+
+      this._state = GET_INFO;
+      return;
+    }
+
+    if (this._allowSynchronousEvents) {
+      this.emit(this._opcode === 0x09 ? 'ping' : 'pong', data);
+      this._state = GET_INFO;
+    } else {
+      this._state = DEFER_EVENT;
+      setImmediate(() => {
+        this.emit(this._opcode === 0x09 ? 'ping' : 'pong', data);
+        this._state = GET_INFO;
+        this.startLoop(cb);
+      });
+    }
+  }
+
+  /**
+   * Builds an error object.
+   *
+   * @param {function(new:Error|RangeError)} ErrorCtor The error constructor
+   * @param {String} message The error message
+   * @param {Boolean} prefix Specifies whether or not to add a default prefix to
+   *     `message`
+   * @param {Number} statusCode The status code
+   * @param {String} errorCode The exposed error code
+   * @return {(Error|RangeError)} The error
+   * @private
+   */
+  createError(ErrorCtor, message, prefix, statusCode, errorCode) {
+    this._loop = false;
+    this._errored = true;
+
+    const err = new ErrorCtor(
+      prefix ? `Invalid WebSocket frame: ${message}` : message
+    );
+
+    Error.captureStackTrace(err, this.createError);
+    err.code = errorCode;
+    err[kStatusCode] = statusCode;
+    return err;
+  }
+}
+
+module.exports = Receiver;
@@ -0,0 +1,607 @@
+/* eslint no-unused-vars: ["error", { "varsIgnorePattern": "^Duplex" }] */
+
+'use strict';
+
+const { Duplex } = require('stream');
+const { randomFillSync } = require('crypto');
+const {
+  types: { isUint8Array }
+} = require('util');
+
+const PerMessageDeflate = require('./permessage-deflate');
+const { EMPTY_BUFFER, kWebSocket, NOOP } = require('./constants');
+const { isBlob, isValidStatusCode } = require('./validation');
+const { mask: applyMask, toBuffer } = require('./buffer-util');
+
+const kByteLength = Symbol('kByteLength');
+const maskBuffer = Buffer.alloc(4);
+const RANDOM_POOL_SIZE = 8 * 1024;
+let randomPool;
+let randomPoolPointer = RANDOM_POOL_SIZE;
+
+const DEFAULT = 0;
+const DEFLATING = 1;
+const GET_BLOB_DATA = 2;
+
+/**
+ * HyBi Sender implementation.
+ */
+class Sender {
+  /**
+   * Creates a Sender instance.
+   *
+   * @param {Duplex} socket The connection socket
+   * @param {Object} [extensions] An object containing the negotiated extensions
+   * @param {Function} [generateMask] The function used to generate the masking
+   *     key
+   */
+  constructor(socket, extensions, generateMask) {
+    this._extensions = extensions || {};
+
+    if (generateMask) {
+      this._generateMask = generateMask;
+      this._maskBuffer = Buffer.alloc(4);
+    }
+
+    this._socket = socket;
+
+    this._firstFragment = true;
+    this._compress = false;
+
+    this._bufferedBytes = 0;
+    this._queue = [];
+    this._state = DEFAULT;
+    this.onerror = NOOP;
+    this[kWebSocket] = undefined;
+  }
+
+  /**
+   * Frames a piece of data according to the HyBi WebSocket protocol.
+   *
+   * @param {(Buffer|String)} data The data to frame
+   * @param {Object} options Options object
+   * @param {Boolean} [options.fin=false] Specifies whether or not to set the
+   *     FIN bit
+   * @param {Function} [options.generateMask] The function used to generate the
+   *     masking key
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Buffer} [options.maskBuffer] The buffer used to store the masking
+   *     key
+   * @param {Number} options.opcode The opcode
+   * @param {Boolean} [options.readOnly=false] Specifies whether `data` can be
+   *     modified
+   * @param {Boolean} [options.rsv1=false] Specifies whether or not to set the
+   *     RSV1 bit
+   * @return {(Buffer|String)[]} The framed data
+   * @public
+   */
+  static frame(data, options) {
+    let mask;
+    let merge = false;
+    let offset = 2;
+    let skipMasking = false;
+
+    if (options.mask) {
+      mask = options.maskBuffer || maskBuffer;
+
+      if (options.generateMask) {
+        options.generateMask(mask);
+      } else {
+        if (randomPoolPointer === RANDOM_POOL_SIZE) {
+          /* istanbul ignore else  */
+          if (randomPool === undefined) {
+            //
+            // This is lazily initialized because server-sent frames must not
+            // be masked so it may never be used.
+            //
+            randomPool = Buffer.alloc(RANDOM_POOL_SIZE);
+          }
+
+          randomFillSync(randomPool, 0, RANDOM_POOL_SIZE);
+          randomPoolPointer = 0;
+        }
+
+        mask[0] = randomPool[randomPoolPointer++];
+        mask[1] = randomPool[randomPoolPointer++];
+        mask[2] = randomPool[randomPoolPointer++];
+        mask[3] = randomPool[randomPoolPointer++];
+      }
+
+      skipMasking = (mask[0] | mask[1] | mask[2] | mask[3]) === 0;
+      offset = 6;
+    }
+
+    let dataLength;
+
+    if (typeof data === 'string') {
+      if (
+        (!options.mask || skipMasking) &&
+        options[kByteLength] !== undefined
+      ) {
+        dataLength = options[kByteLength];
+      } else {
+        data = Buffer.from(data);
+        dataLength = data.length;
+      }
+    } else {
+      dataLength = data.length;
+      merge = options.mask && options.readOnly && !skipMasking;
+    }
+
+    let payloadLength = dataLength;
+
+    if (dataLength >= 65536) {
+      offset += 8;
+      payloadLength = 127;
+    } else if (dataLength > 125) {
+      offset += 2;
+      payloadLength = 126;
+    }
+
+    const target = Buffer.allocUnsafe(merge ? dataLength + offset : offset);
+
+    target[0] = options.fin ? options.opcode | 0x80 : options.opcode;
+    if (options.rsv1) target[0] |= 0x40;
+
+    target[1] = payloadLength;
+
+    if (payloadLength === 126) {
+      target.writeUInt16BE(dataLength, 2);
+    } else if (payloadLength === 127) {
+      target[2] = target[3] = 0;
+      target.writeUIntBE(dataLength, 4, 6);
+    }
+
+    if (!options.mask) return [target, data];
+
+    target[1] |= 0x80;
+    target[offset - 4] = mask[0];
+    target[offset - 3] = mask[1];
+    target[offset - 2] = mask[2];
+    target[offset - 1] = mask[3];
+
+    if (skipMasking) return [target, data];
+
+    if (merge) {
+      applyMask(data, mask, target, offset, dataLength);
+      return [target];
+    }
+
+    applyMask(data, mask, data, 0, dataLength);
+    return [target, data];
+  }
+
+  /**
+   * Sends a close message to the other peer.
+   *
+   * @param {Number} [code] The status code component of the body
+   * @param {(String|Buffer)} [data] The message component of the body
+   * @param {Boolean} [mask=false] Specifies whether or not to mask the message
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  close(code, data, mask, cb) {
+    let buf;
+
+    if (code === undefined) {
+      buf = EMPTY_BUFFER;
+    } else if (typeof code !== 'number' || !isValidStatusCode(code)) {
+      throw new TypeError('First argument must be a valid error code number');
+    } else if (data === undefined || !data.length) {
+      buf = Buffer.allocUnsafe(2);
+      buf.writeUInt16BE(code, 0);
+    } else {
+      const length = Buffer.byteLength(data);
+
+      if (length > 123) {
+        throw new RangeError('The message must not be greater than 123 bytes');
+      }
+
+      buf = Buffer.allocUnsafe(2 + length);
+      buf.writeUInt16BE(code, 0);
+
+      if (typeof data === 'string') {
+        buf.write(data, 2);
+      } else if (isUint8Array(data)) {
+        buf.set(data, 2);
+      } else {
+        throw new TypeError('Second argument must be a string or a Uint8Array');
+      }
+    }
+
+    const options = {
+      [kByteLength]: buf.length,
+      fin: true,
+      generateMask: this._generateMask,
+      mask,
+      maskBuffer: this._maskBuffer,
+      opcode: 0x08,
+      readOnly: false,
+      rsv1: false
+    };
+
+    if (this._state !== DEFAULT) {
+      this.enqueue([this.dispatch, buf, false, options, cb]);
+    } else {
+      this.sendFrame(Sender.frame(buf, options), cb);
+    }
+  }
+
+  /**
+   * Sends a ping message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Boolean} [mask=false] Specifies whether or not to mask `data`
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  ping(data, mask, cb) {
+    let byteLength;
+    let readOnly;
+
+    if (typeof data === 'string') {
+      byteLength = Buffer.byteLength(data);
+      readOnly = false;
+    } else if (isBlob(data)) {
+      byteLength = data.size;
+      readOnly = false;
+    } else {
+      data = toBuffer(data);
+      byteLength = data.length;
+      readOnly = toBuffer.readOnly;
+    }
+
+    if (byteLength > 125) {
+      throw new RangeError('The data size must not be greater than 125 bytes');
+    }
+
+    const options = {
+      [kByteLength]: byteLength,
+      fin: true,
+      generateMask: this._generateMask,
+      mask,
+      maskBuffer: this._maskBuffer,
+      opcode: 0x09,
+      readOnly,
+      rsv1: false
+    };
+
+    if (isBlob(data)) {
+      if (this._state !== DEFAULT) {
+        this.enqueue([this.getBlobData, data, false, options, cb]);
+      } else {
+        this.getBlobData(data, false, options, cb);
+      }
+    } else if (this._state !== DEFAULT) {
+      this.enqueue([this.dispatch, data, false, options, cb]);
+    } else {
+      this.sendFrame(Sender.frame(data, options), cb);
+    }
+  }
+
+  /**
+   * Sends a pong message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Boolean} [mask=false] Specifies whether or not to mask `data`
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  pong(data, mask, cb) {
+    let byteLength;
+    let readOnly;
+
+    if (typeof data === 'string') {
+      byteLength = Buffer.byteLength(data);
+      readOnly = false;
+    } else if (isBlob(data)) {
+      byteLength = data.size;
+      readOnly = false;
+    } else {
+      data = toBuffer(data);
+      byteLength = data.length;
+      readOnly = toBuffer.readOnly;
+    }
+
+    if (byteLength > 125) {
+      throw new RangeError('The data size must not be greater than 125 bytes');
+    }
+
+    const options = {
+      [kByteLength]: byteLength,
+      fin: true,
+      generateMask: this._generateMask,
+      mask,
+      maskBuffer: this._maskBuffer,
+      opcode: 0x0a,
+      readOnly,
+      rsv1: false
+    };
+
+    if (isBlob(data)) {
+      if (this._state !== DEFAULT) {
+        this.enqueue([this.getBlobData, data, false, options, cb]);
+      } else {
+        this.getBlobData(data, false, options, cb);
+      }
+    } else if (this._state !== DEFAULT) {
+      this.enqueue([this.dispatch, data, false, options, cb]);
+    } else {
+      this.sendFrame(Sender.frame(data, options), cb);
+    }
+  }
+
+  /**
+   * Sends a data message to the other peer.
+   *
+   * @param {*} data The message to send
+   * @param {Object} options Options object
+   * @param {Boolean} [options.binary=false] Specifies whether `data` is binary
+   *     or text
+   * @param {Boolean} [options.compress=false] Specifies whether or not to
+   *     compress `data`
+   * @param {Boolean} [options.fin=false] Specifies whether the fragment is the
+   *     last one
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Function} [cb] Callback
+   * @public
+   */
+  send(data, options, cb) {
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+    let opcode = options.binary ? 2 : 1;
+    let rsv1 = options.compress;
+
+    let byteLength;
+    let readOnly;
+
+    if (typeof data === 'string') {
+      byteLength = Buffer.byteLength(data);
+      readOnly = false;
+    } else if (isBlob(data)) {
+      byteLength = data.size;
+      readOnly = false;
+    } else {
+      data = toBuffer(data);
+      byteLength = data.length;
+      readOnly = toBuffer.readOnly;
+    }
+
+    if (this._firstFragment) {
+      this._firstFragment = false;
+      if (
+        rsv1 &&
+        perMessageDeflate &&
+        perMessageDeflate.params[
+          perMessageDeflate._isServer
+            ? 'server_no_context_takeover'
+            : 'client_no_context_takeover'
+        ]
+      ) {
+        rsv1 = byteLength >= perMessageDeflate._threshold;
+      }
+      this._compress = rsv1;
+    } else {
+      rsv1 = false;
+      opcode = 0;
+    }
+
+    if (options.fin) this._firstFragment = true;
+
+    const opts = {
+      [kByteLength]: byteLength,
+      fin: options.fin,
+      generateMask: this._generateMask,
+      mask: options.mask,
+      maskBuffer: this._maskBuffer,
+      opcode,
+      readOnly,
+      rsv1
+    };
+
+    if (isBlob(data)) {
+      if (this._state !== DEFAULT) {
+        this.enqueue([this.getBlobData, data, this._compress, opts, cb]);
+      } else {
+        this.getBlobData(data, this._compress, opts, cb);
+      }
+    } else if (this._state !== DEFAULT) {
+      this.enqueue([this.dispatch, data, this._compress, opts, cb]);
+    } else {
+      this.dispatch(data, this._compress, opts, cb);
+    }
+  }
+
+  /**
+   * Gets the contents of a blob as binary data.
+   *
+   * @param {Blob} blob The blob
+   * @param {Boolean} [compress=false] Specifies whether or not to compress
+   *     the data
+   * @param {Object} options Options object
+   * @param {Boolean} [options.fin=false] Specifies whether or not to set the
+   *     FIN bit
+   * @param {Function} [options.generateMask] The function used to generate the
+   *     masking key
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Buffer} [options.maskBuffer] The buffer used to store the masking
+   *     key
+   * @param {Number} options.opcode The opcode
+   * @param {Boolean} [options.readOnly=false] Specifies whether `data` can be
+   *     modified
+   * @param {Boolean} [options.rsv1=false] Specifies whether or not to set the
+   *     RSV1 bit
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  getBlobData(blob, compress, options, cb) {
+    this._bufferedBytes += options[kByteLength];
+    this._state = GET_BLOB_DATA;
+
+    blob
+      .arrayBuffer()
+      .then((arrayBuffer) => {
+        if (this._socket.destroyed) {
+          const err = new Error(
+            'The socket was closed while the blob was being read'
+          );
+
+          //
+          // `callCallbacks` is called in the next tick to ensure that errors
+          // that might be thrown in the callbacks behave like errors thrown
+          // outside the promise chain.
+          //
+          process.nextTick(callCallbacks, this, err, cb);
+          return;
+        }
+
+        this._bufferedBytes -= options[kByteLength];
+        const data = toBuffer(arrayBuffer);
+
+        if (!compress) {
+          this._state = DEFAULT;
+          this.sendFrame(Sender.frame(data, options), cb);
+          this.dequeue();
+        } else {
+          this.dispatch(data, compress, options, cb);
+        }
+      })
+      .catch((err) => {
+        //
+        // `onError` is called in the next tick for the same reason that
+        // `callCallbacks` above is.
+        //
+        process.nextTick(onError, this, err, cb);
+      });
+  }
+
+  /**
+   * Dispatches a message.
+   *
+   * @param {(Buffer|String)} data The message to send
+   * @param {Boolean} [compress=false] Specifies whether or not to compress
+   *     `data`
+   * @param {Object} options Options object
+   * @param {Boolean} [options.fin=false] Specifies whether or not to set the
+   *     FIN bit
+   * @param {Function} [options.generateMask] The function used to generate the
+   *     masking key
+   * @param {Boolean} [options.mask=false] Specifies whether or not to mask
+   *     `data`
+   * @param {Buffer} [options.maskBuffer] The buffer used to store the masking
+   *     key
+   * @param {Number} options.opcode The opcode
+   * @param {Boolean} [options.readOnly=false] Specifies whether `data` can be
+   *     modified
+   * @param {Boolean} [options.rsv1=false] Specifies whether or not to set the
+   *     RSV1 bit
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  dispatch(data, compress, options, cb) {
+    if (!compress) {
+      this.sendFrame(Sender.frame(data, options), cb);
+      return;
+    }
+
+    const perMessageDeflate = this._extensions[PerMessageDeflate.extensionName];
+
+    this._bufferedBytes += options[kByteLength];
+    this._state = DEFLATING;
+    perMessageDeflate.compress(data, options.fin, (_, buf) => {
+      if (this._socket.destroyed) {
+        const err = new Error(
+          'The socket was closed while data was being compressed'
+        );
+
+        callCallbacks(this, err, cb);
+        return;
+      }
+
+      this._bufferedBytes -= options[kByteLength];
+      this._state = DEFAULT;
+      options.readOnly = false;
+      this.sendFrame(Sender.frame(buf, options), cb);
+      this.dequeue();
+    });
+  }
+
+  /**
+   * Executes queued send operations.
+   *
+   * @private
+   */
+  dequeue() {
+    while (this._state === DEFAULT && this._queue.length) {
+      const params = this._queue.shift();
+
+      this._bufferedBytes -= params[3][kByteLength];
+      Reflect.apply(params[0], this, params.slice(1));
+    }
+  }
+
+  /**
+   * Enqueues a send operation.
+   *
+   * @param {Array} params Send operation parameters.
+   * @private
+   */
+  enqueue(params) {
+    this._bufferedBytes += params[3][kByteLength];
+    this._queue.push(params);
+  }
+
+  /**
+   * Sends a frame.
+   *
+   * @param {(Buffer | String)[]} list The frame to send
+   * @param {Function} [cb] Callback
+   * @private
+   */
+  sendFrame(list, cb) {
+    if (list.length === 2) {
+      this._socket.cork();
+      this._socket.write(list[0]);
+      this._socket.write(list[1], cb);
+      this._socket.uncork();
+    } else {
+      this._socket.write(list[0], cb);
+    }
+  }
+}
+
+module.exports = Sender;
+
+/**
+ * Calls queued callbacks with an error.
+ *
+ * @param {Sender} sender The `Sender` instance
+ * @param {Error} err The error to call the callbacks with
+ * @param {Function} [cb] The first callback
+ * @private
+ */
+function callCallbacks(sender, err, cb) {
+  if (typeof cb === 'function') cb(err);
+
+  for (let i = 0; i < sender._queue.length; i++) {
+    const params = sender._queue[i];
+    const callback = params[params.length - 1];
+
+    if (typeof callback === 'function') callback(err);
+  }
+}
+
+/**
+ * Handles a `Sender` error.
+ *
+ * @param {Sender} sender The `Sender` instance
+ * @param {Error} err The error
+ * @param {Function} [cb] The first pending callback
+ * @private
+ */
+function onError(sender, err, cb) {
+  callCallbacks(sender, err, cb);
+  sender.onerror(err);
+}
@@ -0,0 +1,161 @@
+/* eslint no-unused-vars: ["error", { "varsIgnorePattern": "^WebSocket$" }] */
+'use strict';
+
+const WebSocket = require('./websocket');
+const { Duplex } = require('stream');
+
+/**
+ * Emits the `'close'` event on a stream.
+ *
+ * @param {Duplex} stream The stream.
+ * @private
+ */
+function emitClose(stream) {
+  stream.emit('close');
+}
+
+/**
+ * The listener of the `'end'` event.
+ *
+ * @private
+ */
+function duplexOnEnd() {
+  if (!this.destroyed && this._writableState.finished) {
+    this.destroy();
+  }
+}
+
+/**
+ * The listener of the `'error'` event.
+ *
+ * @param {Error} err The error
+ * @private
+ */
+function duplexOnError(err) {
+  this.removeListener('error', duplexOnError);
+  this.destroy();
+  if (this.listenerCount('error') === 0) {
+    // Do not suppress the throwing behavior.
+    this.emit('error', err);
+  }
+}
+
+/**
+ * Wraps a `WebSocket` in a duplex stream.
+ *
+ * @param {WebSocket} ws The `WebSocket` to wrap
+ * @param {Object} [options] The options for the `Duplex` constructor
+ * @return {Duplex} The duplex stream
+ * @public
+ */
+function createWebSocketStream(ws, options) {
+  let terminateOnDestroy = true;
+
+  const duplex = new Duplex({
+    ...options,
+    autoDestroy: false,
+    emitClose: false,
+    objectMode: false,
+    writableObjectMode: false
+  });
+
+  ws.on('message', function message(msg, isBinary) {
+    const data =
+      !isBinary && duplex._readableState.objectMode ? msg.toString() : msg;
+
+    if (!duplex.push(data)) ws.pause();
+  });
+
+  ws.once('error', function error(err) {
+    if (duplex.destroyed) return;
+
+    // Prevent `ws.terminate()` from being called by `duplex._destroy()`.
+    //
+    // - If the `'error'` event is emitted before the `'open'` event, then
+    //   `ws.terminate()` is a noop as no socket is assigned.
+    // - Otherwise, the error is re-emitted by the listener of the `'error'`
+    //   event of the `Receiver` object. The listener already closes the
+    //   connection by calling `ws.close()`. This allows a close frame to be
+    //   sent to the other peer. If `ws.terminate()` is called right after this,
+    //   then the close frame might not be sent.
+    terminateOnDestroy = false;
+    duplex.destroy(err);
+  });
+
+  ws.once('close', function close() {
+    if (duplex.destroyed) return;
+
+    duplex.push(null);
+  });
+
+  duplex._destroy = function (err, callback) {
+    if (ws.readyState === ws.CLOSED) {
+      callback(err);
+      process.nextTick(emitClose, duplex);
+      return;
+    }
+
+    let called = false;
+
+    ws.once('error', function error(err) {
+      called = true;
+      callback(err);
+    });
+
+    ws.once('close', function close() {
+      if (!called) callback(err);
+      process.nextTick(emitClose, duplex);
+    });
+
+    if (terminateOnDestroy) ws.terminate();
+  };
+
+  duplex._final = function (callback) {
+    if (ws.readyState === ws.CONNECTING) {
+      ws.once('open', function open() {
+        duplex._final(callback);
+      });
+      return;
+    }
+
+    // If the value of the `_socket` property is `null` it means that `ws` is a
+    // client websocket and the handshake failed. In fact, when this happens, a
+    // socket is never assigned to the websocket. Wait for the `'error'` event
+    // that will be emitted by the websocket.
+    if (ws._socket === null) return;
+
+    if (ws._socket._writableState.finished) {
+      callback();
+      if (duplex._readableState.endEmitted) duplex.destroy();
+    } else {
+      ws._socket.once('finish', function finish() {
+        // `duplex` is not destroyed here because the `'end'` event will be
+        // emitted on `duplex` after this `'finish'` event. The EOF signaling
+        // `null` chunk is, in fact, pushed when the websocket emits `'close'`.
+        callback();
+      });
+      ws.close();
+    }
+  };
+
+  duplex._read = function () {
+    if (ws.isPaused) ws.resume();
+  };
+
+  duplex._write = function (chunk, encoding, callback) {
+    if (ws.readyState === ws.CONNECTING) {
+      ws.once('open', function open() {
+        duplex._write(chunk, encoding, callback);
+      });
+      return;
+    }
+
+    ws.send(chunk, callback);
+  };
+
+  duplex.on('end', duplexOnEnd);
+  duplex.on('error', duplexOnError);
+  return duplex;
+}
+
+module.exports = createWebSocketStream;
@@ -0,0 +1,62 @@
+'use strict';
+
+const { tokenChars } = require('./validation');
+
+/**
+ * Parses the `Sec-WebSocket-Protocol` header into a set of subprotocol names.
+ *
+ * @param {String} header The field value of the header
+ * @return {Set} The subprotocol names
+ * @public
+ */
+function parse(header) {
+  const protocols = new Set();
+  let start = -1;
+  let end = -1;
+  let i = 0;
+
+  for (i; i < header.length; i++) {
+    const code = header.charCodeAt(i);
+
+    if (end === -1 && tokenChars[code] === 1) {
+      if (start === -1) start = i;
+    } else if (
+      i !== 0 &&
+      (code === 0x20 /* ' ' */ || code === 0x09) /* '\t' */
+    ) {
+      if (end === -1 && start !== -1) end = i;
+    } else if (code === 0x2c /* ',' */) {
+      if (start === -1) {
+        throw new SyntaxError(`Unexpected character at index ${i}`);
+      }
+
+      if (end === -1) end = i;
+
+      const protocol = header.slice(start, end);
+
+      if (protocols.has(protocol)) {
+        throw new SyntaxError(`The "${protocol}" subprotocol is duplicated`);
+      }
+
+      protocols.add(protocol);
+      start = end = -1;
+    } else {
+      throw new SyntaxError(`Unexpected character at index ${i}`);
+    }
+  }
+
+  if (start === -1 || end !== -1) {
+    throw new SyntaxError('Unexpected end of input');
+  }
+
+  const protocol = header.slice(start, i);
+
+  if (protocols.has(protocol)) {
+    throw new SyntaxError(`The "${protocol}" subprotocol is duplicated`);
+  }
+
+  protocols.add(protocol);
+  return protocols;
+}
+
+module.exports = { parse };
@@ -0,0 +1,152 @@
+'use strict';
+
+const { isUtf8 } = require('buffer');
+
+const { hasBlob } = require('./constants');
+
+//
+// Allowed token characters:
+//
+// '!', '#', '$', '%', '&', ''', '*', '+', '-',
+// '.', 0-9, A-Z, '^', '_', '`', a-z, '|', '~'
+//
+// tokenChars[32] === 0 // ' '
+// tokenChars[33] === 1 // '!'
+// tokenChars[34] === 0 // '"'
+// ...
+//
+// prettier-ignore
+const tokenChars = [
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0 - 15
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 16 - 31
+  0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, // 32 - 47
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, // 48 - 63
+  0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 64 - 79
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, // 80 - 95
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 96 - 111
+  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0 // 112 - 127
+];
+
+/**
+ * Checks if a status code is allowed in a close frame.
+ *
+ * @param {Number} code The status code
+ * @return {Boolean} `true` if the status code is valid, else `false`
+ * @public
+ */
+function isValidStatusCode(code) {
+  return (
+    (code >= 1000 &&
+      code <= 1014 &&
+      code !== 1004 &&
+      code !== 1005 &&
+      code !== 1006) ||
+    (code >= 3000 && code <= 4999)
+  );
+}
+
+/**
+ * Checks if a given buffer contains only correct UTF-8.
+ * Ported from https://www.cl.cam.ac.uk/%7Emgk25/ucs/utf8_check.c by
+ * Markus Kuhn.
+ *
+ * @param {Buffer} buf The buffer to check
+ * @return {Boolean} `true` if `buf` contains only correct UTF-8, else `false`
+ * @public
+ */
+function _isValidUTF8(buf) {
+  const len = buf.length;
+  let i = 0;
+
+  while (i < len) {
+    if ((buf[i] & 0x80) === 0) {
+      // 0xxxxxxx
+      i++;
+    } else if ((buf[i] & 0xe0) === 0xc0) {
+      // 110xxxxx 10xxxxxx
+      if (
+        i + 1 === len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i] & 0xfe) === 0xc0 // Overlong
+      ) {
+        return false;
+      }
+
+      i += 2;
+    } else if ((buf[i] & 0xf0) === 0xe0) {
+      // 1110xxxx 10xxxxxx 10xxxxxx
+      if (
+        i + 2 >= len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i + 2] & 0xc0) !== 0x80 ||
+        (buf[i] === 0xe0 && (buf[i + 1] & 0xe0) === 0x80) || // Overlong
+        (buf[i] === 0xed && (buf[i + 1] & 0xe0) === 0xa0) // Surrogate (U+D800 - U+DFFF)
+      ) {
+        return false;
+      }
+
+      i += 3;
+    } else if ((buf[i] & 0xf8) === 0xf0) {
+      // 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
+      if (
+        i + 3 >= len ||
+        (buf[i + 1] & 0xc0) !== 0x80 ||
+        (buf[i + 2] & 0xc0) !== 0x80 ||
+        (buf[i + 3] & 0xc0) !== 0x80 ||
+        (buf[i] === 0xf0 && (buf[i + 1] & 0xf0) === 0x80) || // Overlong
+        (buf[i] === 0xf4 && buf[i + 1] > 0x8f) ||
+        buf[i] > 0xf4 // > U+10FFFF
+      ) {
+        return false;
+      }
+
+      i += 4;
+    } else {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+/**
+ * Determines whether a value is a `Blob`.
+ *
+ * @param {*} value The value to be tested
+ * @return {Boolean} `true` if `value` is a `Blob`, else `false`
+ * @private
+ */
+function isBlob(value) {
+  return (
+    hasBlob &&
+    typeof value === 'object' &&
+    typeof value.arrayBuffer === 'function' &&
+    typeof value.type === 'string' &&
+    typeof value.stream === 'function' &&
+    (value[Symbol.toStringTag] === 'Blob' ||
+      value[Symbol.toStringTag] === 'File')
+  );
+}
+
+module.exports = {
+  isBlob,
+  isValidStatusCode,
+  isValidUTF8: _isValidUTF8,
+  tokenChars
+};
+
+if (isUtf8) {
+  module.exports.isValidUTF8 = function (buf) {
+    return buf.length < 24 ? _isValidUTF8(buf) : isUtf8(buf);
+  };
+} /* istanbul ignore else  */ else if (!process.env.WS_NO_UTF_8_VALIDATE) {
+  try {
+    const isValidUTF8 = require('utf-8-validate');
+
+    module.exports.isValidUTF8 = function (buf) {
+      return buf.length < 32 ? _isValidUTF8(buf) : isValidUTF8(buf);
+    };
+  } catch (e) {
+    // Continue regardless of the error.
+  }
+}
@@ -0,0 +1,562 @@
+/* eslint no-unused-vars: ["error", { "varsIgnorePattern": "^Duplex$", "caughtErrors": "none" }] */
+
+'use strict';
+
+const EventEmitter = require('events');
+const http = require('http');
+const { Duplex } = require('stream');
+const { createHash } = require('crypto');
+
+const extension = require('./extension');
+const PerMessageDeflate = require('./permessage-deflate');
+const subprotocol = require('./subprotocol');
+const WebSocket = require('./websocket');
+const { CLOSE_TIMEOUT, GUID, kWebSocket } = require('./constants');
+
+const keyRegex = /^[+/0-9A-Za-z]{22}==$/;
+
+const RUNNING = 0;
+const CLOSING = 1;
+const CLOSED = 2;
+
+/**
+ * Class representing a WebSocket server.
+ *
+ * @extends EventEmitter
+ */
+class WebSocketServer extends EventEmitter {
+  /**
+   * Create a `WebSocketServer` instance.
+   *
+   * @param {Object} options Configuration options
+   * @param {Boolean} [options.allowSynchronousEvents=true] Specifies whether
+   *     any of the `'message'`, `'ping'`, and `'pong'` events can be emitted
+   *     multiple times in the same tick
+   * @param {Boolean} [options.autoPong=true] Specifies whether or not to
+   *     automatically send a pong in response to a ping
+   * @param {Number} [options.backlog=511] The maximum length of the queue of
+   *     pending connections
+   * @param {Boolean} [options.clientTracking=true] Specifies whether or not to
+   *     track clients
+   * @param {Number} [options.closeTimeout=30000] Duration in milliseconds to
+   *     wait for the closing handshake to finish after `websocket.close()` is
+   *     called
+   * @param {Function} [options.handleProtocols] A hook to handle protocols
+   * @param {String} [options.host] The hostname where to bind the server
+   * @param {Number} [options.maxBufferedChunks=262144] The maximum number of
+   *     buffered data chunks
+   * @param {Number} [options.maxFragments=16384] The maximum number of message
+   *     fragments
+   * @param {Number} [options.maxPayload=104857600] The maximum allowed message
+   *     size
+   * @param {Boolean} [options.noServer=false] Enable no server mode
+   * @param {String} [options.path] Accept only connections matching this path
+   * @param {(Boolean|Object)} [options.perMessageDeflate=false] Enable/disable
+   *     permessage-deflate
+   * @param {Number} [options.port] The port where to bind the server
+   * @param {(http.Server|https.Server)} [options.server] A pre-created HTTP/S
+   *     server to use
+   * @param {Boolean} [options.skipUTF8Validation=false] Specifies whether or
+   *     not to skip UTF-8 validation for text and close messages
+   * @param {Function} [options.verifyClient] A hook to reject connections
+   * @param {Function} [options.WebSocket=WebSocket] Specifies the `WebSocket`
+   *     class to use. It must be the `WebSocket` class or class that extends it
+   * @param {Function} [callback] A listener for the `listening` event
+   */
+  constructor(options, callback) {
+    super();
+
+    options = {
+      allowSynchronousEvents: true,
+      autoPong: true,
+      maxBufferedChunks: 256 * 1024,
+      maxFragments: 16 * 1024,
+      maxPayload: 100 * 1024 * 1024,
+      skipUTF8Validation: false,
+      perMessageDeflate: false,
+      handleProtocols: null,
+      clientTracking: true,
+      closeTimeout: CLOSE_TIMEOUT,
+      verifyClient: null,
+      noServer: false,
+      backlog: null, // use default (511 as implemented in net.js)
+      server: null,
+      host: null,
+      path: null,
+      port: null,
+      WebSocket,
+      ...options
+    };
+
+    if (
+      (options.port == null && !options.server && !options.noServer) ||
+      (options.port != null && (options.server || options.noServer)) ||
+      (options.server && options.noServer)
+    ) {
+      throw new TypeError(
+        'One and only one of the "port", "server", or "noServer" options ' +
+          'must be specified'
+      );
+    }
+
+    if (options.port != null) {
+      this._server = http.createServer((req, res) => {
+        const body = http.STATUS_CODES[426];
+
+        res.writeHead(426, {
+          'Content-Length': body.length,
+          'Content-Type': 'text/plain'
+        });
+        res.end(body);
+      });
+      this._server.listen(
+        options.port,
+        options.host,
+        options.backlog,
+        callback
+      );
+    } else if (options.server) {
+      this._server = options.server;
+    }
+
+    if (this._server) {
+      const emitConnection = this.emit.bind(this, 'connection');
+
+      this._removeListeners = addListeners(this._server, {
+        listening: this.emit.bind(this, 'listening'),
+        error: this.emit.bind(this, 'error'),
+        upgrade: (req, socket, head) => {
+          this.handleUpgrade(req, socket, head, emitConnection);
+        }
+      });
+    }
+
+    if (options.perMessageDeflate === true) options.perMessageDeflate = {};
+    if (options.clientTracking) {
+      this.clients = new Set();
+      this._shouldEmitClose = false;
+    }
+
+    this.options = options;
+    this._state = RUNNING;
+  }
+
+  /**
+   * Returns the bound address, the address family name, and port of the server
+   * as reported by the operating system if listening on an IP socket.
+   * If the server is listening on a pipe or UNIX domain socket, the name is
+   * returned as a string.
+   *
+   * @return {(Object|String|null)} The address of the server
+   * @public
+   */
+  address() {
+    if (this.options.noServer) {
+      throw new Error('The server is operating in "noServer" mode');
+    }
+
+    if (!this._server) return null;
+    return this._server.address();
+  }
+
+  /**
+   * Stop the server from accepting new connections and emit the `'close'` event
+   * when all existing connections are closed.
+   *
+   * @param {Function} [cb] A one-time listener for the `'close'` event
+   * @public
+   */
+  close(cb) {
+    if (this._state === CLOSED) {
+      if (cb) {
+        this.once('close', () => {
+          cb(new Error('The server is not running'));
+        });
+      }
+
+      process.nextTick(emitClose, this);
+      return;
+    }
+
+    if (cb) this.once('close', cb);
+
+    if (this._state === CLOSING) return;
+    this._state = CLOSING;
+
+    if (this.options.noServer || this.options.server) {
+      if (this._server) {
+        this._removeListeners();
+        this._removeListeners = this._server = null;
+      }
+
+      if (this.clients) {
+        if (!this.clients.size) {
+          process.nextTick(emitClose, this);
+        } else {
+          this._shouldEmitClose = true;
+        }
+      } else {
+        process.nextTick(emitClose, this);
+      }
+    } else {
+      const server = this._server;
+
+      this._removeListeners();
+      this._removeListeners = this._server = null;
+
+      //
+      // The HTTP/S server was created internally. Close it, and rely on its
+      // `'close'` event.
+      //
+      server.close(() => {
+        emitClose(this);
+      });
+    }
+  }
+
+  /**
+   * See if a given request should be handled by this server instance.
+   *
+   * @param {http.IncomingMessage} req Request object to inspect
+   * @return {Boolean} `true` if the request is valid, else `false`
+   * @public
+   */
+  shouldHandle(req) {
+    if (this.options.path) {
+      const index = req.url.indexOf('?');
+      const pathname = index !== -1 ? req.url.slice(0, index) : req.url;
+
+      if (pathname !== this.options.path) return false;
+    }
+
+    return true;
+  }
+
+  /**
+   * Handle a HTTP Upgrade request.
+   *
+   * @param {http.IncomingMessage} req The request object
+   * @param {Duplex} socket The network socket between the server and client
+   * @param {Buffer} head The first packet of the upgraded stream
+   * @param {Function} cb Callback
+   * @public
+   */
+  handleUpgrade(req, socket, head, cb) {
+    socket.on('error', socketOnError);
+
+    const key = req.headers['sec-websocket-key'];
+    const upgrade = req.headers.upgrade;
+    const version = +req.headers['sec-websocket-version'];
+
+    if (req.method !== 'GET') {
+      const message = 'Invalid HTTP method';
+      abortHandshakeOrEmitwsClientError(this, req, socket, 405, message);
+      return;
+    }
+
+    if (upgrade === undefined || upgrade.toLowerCase() !== 'websocket') {
+      const message = 'Invalid Upgrade header';
+      abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
+      return;
+    }
+
+    if (key === undefined || !keyRegex.test(key)) {
+      const message = 'Missing or invalid Sec-WebSocket-Key header';
+      abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
+      return;
+    }
+
+    if (version !== 13 && version !== 8) {
+      const message = 'Missing or invalid Sec-WebSocket-Version header';
+      abortHandshakeOrEmitwsClientError(this, req, socket, 400, message, {
+        'Sec-WebSocket-Version': '13, 8'
+      });
+      return;
+    }
+
+    if (!this.shouldHandle(req)) {
+      abortHandshake(socket, 400);
+      return;
+    }
+
+    const secWebSocketProtocol = req.headers['sec-websocket-protocol'];
+    let protocols = new Set();
+
+    if (secWebSocketProtocol !== undefined) {
+      try {
+        protocols = subprotocol.parse(secWebSocketProtocol);
+      } catch (err) {
+        const message = 'Invalid Sec-WebSocket-Protocol header';
+        abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
+        return;
+      }
+    }
+
+    const secWebSocketExtensions = req.headers['sec-websocket-extensions'];
+    const extensions = {};
+
+    if (
+      this.options.perMessageDeflate &&
+      secWebSocketExtensions !== undefined
+    ) {
+      const perMessageDeflate = new PerMessageDeflate({
+        ...this.options.perMessageDeflate,
+        isServer: true,
+        maxPayload: this.options.maxPayload
+      });
+
+      try {
+        const offers = extension.parse(secWebSocketExtensions);
+
+        if (offers[PerMessageDeflate.extensionName]) {
+          perMessageDeflate.accept(offers[PerMessageDeflate.extensionName]);
+          extensions[PerMessageDeflate.extensionName] = perMessageDeflate;
+        }
+      } catch (err) {
+        const message =
+          'Invalid or unacceptable Sec-WebSocket-Extensions header';
+        abortHandshakeOrEmitwsClientError(this, req, socket, 400, message);
+        return;
+      }
+    }
+
+    //
+    // Optionally call external client verification handler.
+    //
+    if (this.options.verifyClient) {
+      const info = {
+        origin:
+          req.headers[`${version === 8 ? 'sec-websocket-origin' : 'origin'}`],
+        secure: !!(req.socket.authorized || req.socket.encrypted),
+        req
+      };
+
+      if (this.options.verifyClient.length === 2) {
+        this.options.verifyClient(info, (verified, code, message, headers) => {
+          if (!verified) {
+            return abortHandshake(socket, code || 401, message, headers);
+          }
+
+          this.completeUpgrade(
+            extensions,
+            key,
+            protocols,
+            req,
+            socket,
+            head,
+            cb
+          );
+        });
+        return;
+      }
+
+      if (!this.options.verifyClient(info)) return abortHandshake(socket, 401);
+    }
+
+    this.completeUpgrade(extensions, key, protocols, req, socket, head, cb);
+  }
+
+  /**
+   * Upgrade the connection to WebSocket.
+   *
+   * @param {Object} extensions The accepted extensions
+   * @param {String} key The value of the `Sec-WebSocket-Key` header
+   * @param {Set} protocols The subprotocols
+   * @param {http.IncomingMessage} req The request object
+   * @param {Duplex} socket The network socket between the server and client
+   * @param {Buffer} head The first packet of the upgraded stream
+   * @param {Function} cb Callback
+   * @throws {Error} If called more than once with the same socket
+   * @private
+   */
+  completeUpgrade(extensions, key, protocols, req, socket, head, cb) {
+    //
+    // Destroy the socket if the client has already sent a FIN packet.
+    //
+    if (!socket.readable || !socket.writable) return socket.destroy();
+
+    if (socket[kWebSocket]) {
+      throw new Error(
+        'server.handleUpgrade() was called more than once with the same ' +
+          'socket, possibly due to a misconfiguration'
+      );
+    }
+
+    if (this._state > RUNNING) return abortHandshake(socket, 503);
+
+    const digest = createHash('sha1')
+      .update(key + GUID)
+      .digest('base64');
+
+    const headers = [
+      'HTTP/1.1 101 Switching Protocols',
+      'Upgrade: websocket',
+      'Connection: Upgrade',
+      `Sec-WebSocket-Accept: ${digest}`
+    ];
+
+    const ws = new this.options.WebSocket(null, undefined, this.options);
+
+    if (protocols.size) {
+      //
+      // Optionally call external protocol selection handler.
+      //
+      const protocol = this.options.handleProtocols
+        ? this.options.handleProtocols(protocols, req)
+        : protocols.values().next().value;
+
+      if (protocol) {
+        headers.push(`Sec-WebSocket-Protocol: ${protocol}`);
+        ws._protocol = protocol;
+      }
+    }
+
+    if (extensions[PerMessageDeflate.extensionName]) {
+      const params = extensions[PerMessageDeflate.extensionName].params;
+      const value = extension.format({
+        [PerMessageDeflate.extensionName]: [params]
+      });
+      headers.push(`Sec-WebSocket-Extensions: ${value}`);
+      ws._extensions = extensions;
+    }
+
+    //
+    // Allow external modification/inspection of handshake headers.
+    //
+    this.emit('headers', headers, req);
+
+    socket.write(headers.concat('\r\n').join('\r\n'));
+    socket.removeListener('error', socketOnError);
+
+    ws.setSocket(socket, head, {
+      allowSynchronousEvents: this.options.allowSynchronousEvents,
+      maxBufferedChunks: this.options.maxBufferedChunks,
+      maxFragments: this.options.maxFragments,
+      maxPayload: this.options.maxPayload,
+      skipUTF8Validation: this.options.skipUTF8Validation
+    });
+
+    if (this.clients) {
+      this.clients.add(ws);
+      ws.on('close', () => {
+        this.clients.delete(ws);
+
+        if (this._shouldEmitClose && !this.clients.size) {
+          process.nextTick(emitClose, this);
+        }
+      });
+    }
+
+    cb(ws, req);
+  }
+}
+
+module.exports = WebSocketServer;
+
+/**
+ * Add event listeners on an `EventEmitter` using a map of <event, listener>
+ * pairs.
+ *
+ * @param {EventEmitter} server The event emitter
+ * @param {Object.<String, Function>} map The listeners to add
+ * @return {Function} A function that will remove the added listeners when
+ *     called
+ * @private
+ */
+function addListeners(server, map) {
+  for (const event of Object.keys(map)) server.on(event, map[event]);
+
+  return function removeListeners() {
+    for (const event of Object.keys(map)) {
+      server.removeListener(event, map[event]);
+    }
+  };
+}
+
+/**
+ * Emit a `'close'` event on an `EventEmitter`.
+ *
+ * @param {EventEmitter} server The event emitter
+ * @private
+ */
+function emitClose(server) {
+  server._state = CLOSED;
+  server.emit('close');
+}
+
+/**
+ * Handle socket errors.
+ *
+ * @private
+ */
+function socketOnError() {
+  this.destroy();
+}
+
+/**
+ * Close the connection when preconditions are not fulfilled.
+ *
+ * @param {Duplex} socket The socket of the upgrade request
+ * @param {Number} code The HTTP response status code
+ * @param {String} [message] The HTTP response body
+ * @param {Object} [headers] Additional HTTP response headers
+ * @private
+ */
+function abortHandshake(socket, code, message, headers) {
+  //
+  // The socket is writable unless the user destroyed or ended it before calling
+  // `server.handleUpgrade()` or in the `verifyClient` function, which is a user
+  // error. Handling this does not make much sense as the worst that can happen
+  // is that some of the data written by the user might be discarded due to the
+  // call to `socket.end()` below, which triggers an `'error'` event that in
+  // turn causes the socket to be destroyed.
+  //
+  message = message || http.STATUS_CODES[code];
+  headers = {
+    Connection: 'close',
+    'Content-Type': 'text/html',
+    'Content-Length': Buffer.byteLength(message),
+    ...headers
+  };
+
+  socket.once('finish', socket.destroy);
+
+  socket.end(
+    `HTTP/1.1 ${code} ${http.STATUS_CODES[code]}\r\n` +
+      Object.keys(headers)
+        .map((h) => `${h}: ${headers[h]}`)
+        .join('\r\n') +
+      '\r\n\r\n' +
+      message
+  );
+}
+
+/**
+ * Emit a `'wsClientError'` event on a `WebSocketServer` if there is at least
+ * one listener for it, otherwise call `abortHandshake()`.
+ *
+ * @param {WebSocketServer} server The WebSocket server
+ * @param {http.IncomingMessage} req The request object
+ * @param {Duplex} socket The socket of the upgrade request
+ * @param {Number} code The HTTP response status code
+ * @param {String} message The HTTP response body
+ * @param {Object} [headers] The HTTP response headers
+ * @private
+ */
+function abortHandshakeOrEmitwsClientError(
+  server,
+  req,
+  socket,
+  code,
+  message,
+  headers
+) {
+  if (server.listenerCount('wsClientError')) {
+    const err = new Error(message);
+    Error.captureStackTrace(err, abortHandshakeOrEmitwsClientError);
+
+    server.emit('wsClientError', err, socket, req);
+  } else {
+    abortHandshake(socket, code, message, headers);
+  }
+}
@@ -0,0 +1,74 @@
+{
+  "name": "ws",
+  "version": "8.21.3",
+  "description": "Simple to use, blazing fast and thoroughly tested websocket client and server for Node.js",
+  "keywords": [
+    "HyBi",
+    "Push",
+    "RFC-6455",
+    "WebSocket",
+    "WebSockets",
+    "real-time"
+  ],
+  "homepage": "https://github.com/websockets/ws",
+  "bugs": "https://github.com/websockets/ws/issues",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/websockets/ws.git"
+  },
+  "author": "Einar Otto Stangvik <einaros@gmail.com> (http://2x.io)",
+  "license": "MIT",
+  "main": "index.js",
+  "exports": {
+    ".": {
+      "browser": "./browser.js",
+      "import": "./wrapper.mjs",
+      "require": "./index.js"
+    },
+    "./package.json": "./package.json"
+  },
+  "browser": "browser.js",
+  "engines": {
+    "node": ">=10.0.0"
+  },
+  "files": [
+    "browser.js",
+    "index.js",
+    "lib/*.js",
+    "wrapper.mjs"
+  ],
+  "scripts": {
+    "test": "nyc --reporter=lcov --reporter=text mocha --throw-deprecation test/*.test.js",
+    "integration": "mocha --throw-deprecation test/*.integration.js",
+    "lint": "eslint . && prettier --check --ignore-path .gitignore \"**/*.{json,md,yaml,yml}\""
+  },
+  "peerDependencies": {
+    "bufferutil": "^4.0.1",
+    "utf-8-validate": ">=5.0.2"
+  },
+  "peerDependenciesMeta": {
+    "bufferutil": {
+      "optional": true
+    },
+    "utf-8-validate": {
+      "optional": true
+    }
+  },
+  "devDependencies": {
+    "@eslint/js": "^10.0.1",
+    "benchmark": "^2.1.4",
+    "bufferutil": "^4.0.1",
+    "eslint": "^10.0.1",
+    "eslint-config-prettier": "^10.0.1",
+    "eslint-plugin-prettier": "^5.0.0",
+    "globals": "^17.0.0",
+    "mocha": "^8.4.0",
+    "nyc": "^15.0.0",
+    "prettier": "^3.0.0",
+    "utf-8-validate": "^6.0.0"
+  },
+  "allowScripts": {
+    "bufferutil": true,
+    "utf-8-validate": true
+  }
+}
@@ -0,0 +1,21 @@
+import createWebSocketStream from './lib/stream.js';
+import extension from './lib/extension.js';
+import PerMessageDeflate from './lib/permessage-deflate.js';
+import Receiver from './lib/receiver.js';
+import Sender from './lib/sender.js';
+import subprotocol from './lib/subprotocol.js';
+import WebSocket from './lib/websocket.js';
+import WebSocketServer from './lib/websocket-server.js';
+
+export {
+  createWebSocketStream,
+  extension,
+  PerMessageDeflate,
+  Receiver,
+  Sender,
+  subprotocol,
+  WebSocket,
+  WebSocketServer
+};
+
+export default WebSocket;
@@ -12,7 +12,8 @@
        "dotenv": "^17.4.2",
        "express": "^5.2.1",
        "jsonwebtoken": "^9.0.3",
-        "mysql2": "^3.24.2"
+        "mysql2": "^3.24.2",
+        "ws": "^8.21.3"
      },
      "devDependencies": {
        "nodemon": "^3.1.14"
@@ -1477,6 +1478,27 @@
      "resolved": "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz",
      "integrity": "sha512-l4Sp/DRseor9wL6EvV2+TuQn63dMkPjZ/sp9XkghTEbV9KlPS1xUsZ3u7/IQO4wxtcFB4bgpQPRcR3QCvezPcQ==",
      "license": "ISC"
+    },
+    "node_modules/ws": {
+      "version": "8.21.3",
+      "resolved": "https://registry.npmmirror.com/ws/-/ws-8.21.3.tgz",
+      "integrity": "sha512-201TZ/kPWxoPr/OKWjquZR1SWKXcvxdH+e1xrx89b3YbmzLMFCLfnaG1HFIgWzJOEWZ7MvpK++odZufgYR50Rw==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=10.0.0"
+      },
+      "peerDependencies": {
+        "bufferutil": "^4.0.1",
+        "utf-8-validate": ">=5.0.2"
+      },
+      "peerDependenciesMeta": {
+        "bufferutil": {
+          "optional": true
+        },
+        "utf-8-validate": {
+          "optional": true
+        }
+      }
    }
  }
 }
@@ -16,7 +16,8 @@
    "dotenv": "^17.4.2",
    "express": "^5.2.1",
    "jsonwebtoken": "^9.0.3",
-    "mysql2": "^3.24.2"
+    "mysql2": "^3.24.2",
+    "ws": "^8.21.3"
  },
  "devDependencies": {
    "nodemon": "^3.1.14"
@@ -70,6 +70,7 @@ router.post("/register", (req, res) => {
            return res.status(500).json({
                code: 500,
                message: "注册失败",
+                data: null
            });
        }

@@ -0,0 +1,167 @@
+const express = require("express");
+const router = express.Router();
+const db = require("../db/mysql");
+const authMiddleware = require("../middleware/authMiddleware");
+
+// 获取最近联系人的最后一条聊天消息
+router.get(
+    "/recentChats",
+    authMiddleware,
+    (req, res) => {    
+        const currentUserName = req.user.username;     
+        const sql = `
+            SELECT
+                contact_name,
+                content,
+                created_at
+            FROM (
+                SELECT
+                    CASE
+                        WHEN sender_name = ? THEN receiver_name
+                        ELSE sender_name
+                    END AS contact_name,
+                    content,
+                    created_at,
+                    ROW_NUMBER() OVER (
+                        PARTITION BY
+                            CASE
+                                WHEN sender_name = ? THEN receiver_name
+                                ELSE sender_name
+                            END
+                        ORDER BY created_at DESC
+                    ) AS rn
+                FROM chat_mysql.messages
+                WHERE sender_name = ?
+                OR receiver_name = ?
+            ) t
+            WHERE rn = 1
+            ORDER BY created_at DESC;
+        `;
+        db.query(sql, [currentUserName, currentUserName, currentUserName, currentUserName], (error, results) => {
+            if (error) {
+                console.error("数据库查询失败：", error);
+
+                return res.status(500).json({
+                    code: 500,
+                    message: "查询失败",
+                    data: null
+                });
+            }
+            if (results.length > 0) {
+                res.json({
+                    code: 200,
+                    message: "查询成功",
+                    data: {
+                        recentChats: results.map(message => ({
+                            contactName: message.contact_name,
+                            content: message.content,
+                            createdAt: message.created_at
+                        }))
+                    },
+                });
+            } else {
+                res.json({
+                    code: 401,
+                    message: "未找到联系人消息",
+                    data: {
+                        recentChats: []
+                    }
+                });
+            }
+        });
+
+    }
+);
+
+// 获取某个联系人的最近n条聊天消息，分页获取
+router.post(
+    "/contactMessagesInfo",
+    authMiddleware,
+    (req, res) => {    
+        const currentUserName = req.user.username;  
+        const { contactName, limit, offset } = req.body;  
+        const sql = `
+            SELECT
+                id,
+                sender_name,
+                receiver_name,
+                content,
+                created_at
+            FROM chat_mysql.messages
+            WHERE (sender_name = ? OR receiver_name = ?) AND (sender_name = ? OR receiver_name = ?)
+            ORDER BY created_at DESC LIMIT ? OFFSET ?;
+        `;
+        db.query(sql, [currentUserName, currentUserName, contactName, contactName, limit, offset], (error, results) => {
+            if (error) {
+                console.error("数据库查询失败：", error);
+
+                return res.status(500).json({
+                    code: 500,
+                    message: "查询失败",
+                    data: null
+                });
+            }
+            if (results.length > 0) {
+                res.json({
+                    code: 200,
+                    message: "查询成功",
+                    data: {
+                        messages: results.map(message => ({
+                            messageId: message.id,
+                            senderName: message.sender_name,
+                            receiverName: message.receiver_name,
+                            content: message.content,
+                            createdAt: message.created_at
+                        }))
+                    },
+                });
+            } else {
+                res.json({
+                    code: 401,
+                    message: "未找到联系人消息",
+                    data: {
+                        messages: []
+                    }
+                });
+            }
+        });
+
+    }
+);
+
+// 写入聊天消息
+router.post(
+    "/sendMessage",
+    authMiddleware,
+    (req, res) => {
+    const message = req.body;
+    const sql = `
+        INSERT INTO messages
+        (sender_name, receiver_name, content)
+        VALUES (?, ?, ?)
+    `;
+
+    db.query(sql, [
+        message.senderName,
+        message.receiverName,
+        message.content
+    ], (error, result) => {
+        if (error) {
+            console.error(error);
+
+            return res.status(500).json({
+                code: 500,
+                message: "发送消息失败",
+                data: null
+            });
+        }
+
+        res.json({
+            code: 200,
+            message: "发送消息成功",
+            data: null
+        });
+    });
+});
+
+module.exports = router;
@@ -11,6 +11,7 @@ router.get(
    (req, res) => {
        res.json({
            code: 200,
+            message: "查询成功",
            data: {
                username: req.user.username
            }
@@ -30,7 +31,8 @@ router.get(
            FROM chat_mysql.contacts c
            JOIN chat_mysql.users u
                ON c.contact_name = u.username
-            WHERE c.user_name = ?;
+            WHERE c.user_name = ?
+            ORDER BY contact_name ASC;;
        `;
        db.query(sql, [req.user.username], (error, results) => {
            if (error) {
@@ -39,6 +41,7 @@ router.get(
                return res.status(500).json({
                    code: 500,
                    message: "查询失败",
+                    data: null
                });
            }
            if (results.length > 0) {
@@ -65,160 +68,4 @@ router.get(
    }
 );

-// 获取最近联系人的最后一条聊天消息
-router.get(
-    "/recentChats",
-    authMiddleware,
-    (req, res) => {    
-        const currentUserName = req.user.username;     
-        const sql = `
-            SELECT
-                contact_name,
-                content,
-                created_at
-            FROM (
-                SELECT
-                    CASE
-                        WHEN sender_name = ? THEN receiver_name
-                        ELSE sender_name
-                    END AS contact_name,
-                    content,
-                    created_at,
-                    ROW_NUMBER() OVER (
-                        PARTITION BY
-                            CASE
-                                WHEN sender_name = ? THEN receiver_name
-                                ELSE sender_name
-                            END
-                        ORDER BY created_at DESC
-                    ) AS rn
-                FROM chat_mysql.messages
-                WHERE sender_name = ?
-                OR receiver_name = ?
-            ) t
-            WHERE rn = 1
-            ORDER BY created_at DESC;
-        `;
-        db.query(sql, [currentUserName, currentUserName, currentUserName, currentUserName], (error, results) => {
-            if (error) {
-                console.error("数据库查询失败：", error);
-
-                return res.status(500).json({
-                    code: 500,
-                    message: "查询失败",
-                });
-            }
-            if (results.length > 0) {
-                res.json({
-                    code: 200,
-                    message: "查询成功",
-                    data: {
-                        recentChats: results.map(message => ({
-                            contactName: message.contact_name,
-                            content: message.content,
-                            createdAt: message.created_at
-                        }))
-                    },
-                });
-            } else {
-                res.json({
-                    code: 401,
-                    message: "未找到联系人消息",
-                    data: {
-                        recentChats: []
-                    }
-                });
-            }
-        });
-
-    }
-);
-
-// 获取某个联系人的最近n条聊天消息，分页获取
-router.post(
-    "/contactMessagesInfo",
-    authMiddleware,
-    (req, res) => {    
-        const currentUserName = req.user.username;  
-        const { contactName, limit, offset } = req.body;  
-        const sql = `
-            SELECT
-                id,
-                sender_name,
-                receiver_name,
-                content,
-                created_at
-            FROM chat_mysql.messages
-            WHERE (sender_name = ? OR receiver_name = ?) AND (sender_name = ? OR receiver_name = ?)
-            ORDER BY created_at DESC LIMIT ? OFFSET ?;
-        `;
-        db.query(sql, [currentUserName, currentUserName, contactName, contactName, limit, offset], (error, results) => {
-            if (error) {
-                console.error("数据库查询失败：", error);
-
-                return res.status(500).json({
-                    code: 500,
-                    message: "查询失败",
-                });
-            }
-            if (results.length > 0) {
-                res.json({
-                    code: 200,
-                    message: "查询成功",
-                    data: {
-                        messages: results.map(message => ({
-                            messageId: message.id,
-                            senderName: message.sender_name,
-                            receiverName: message.receiver_name,
-                            content: message.content,
-                            createdAt: message.created_at
-                        }))
-                    },
-                });
-            } else {
-                res.json({
-                    code: 401,
-                    message: "未找到联系人消息",
-                    data: {
-                        messages: []
-                    }
-                });
-            }
-        });
-
-    }
-);
-
-// 写入聊天消息
-router.post("/sendMessage", (req, res) => {
-    const message = req.body;
-    const sql = `
-        INSERT INTO messages
-        (sender_name, receiver_name, content)
-        VALUES (?, ?, ?)
-    `;
-
-    db.query(sql, [
-        message.senderName,
-        message.receiverName,
-        message.content
-    ], (error, result) => {
-        if (error) {
-            console.error(error);
-
-            return res.status(500).json({
-                code: 500,
-                message: "发送消息失败",
-            });
-        }
-
-        res.json({
-            code: 200,
-            message: "发送消息成功",
-            data: null
-        });
-    });
-});
-
-
 module.exports = router;
@@ -0,0 +1,56 @@
+const WebSocket = require("ws");
+
+const onlineUsers = new Map();
+
+// 保存用户连接
+function addConnection(username, ws) {
+  onlineUsers.set(username, ws);
+
+  console.log(`用户 ${username} 已连接`);
+  console.log("当前在线用户：", [...onlineUsers.keys()]);
+}
+
+// 获取用户连接
+function getConnection(username) {
+  return onlineUsers.get(username);
+}
+
+// 删除用户连接
+function removeConnection(username, ws) {
+  const currentWs = onlineUsers.get(username);
+
+  // 只有 Map 里面存的还是这个连接，才允许删除
+  if (currentWs === ws) {
+    onlineUsers.delete(username);
+  }
+  console.log(`用户 ${username} 已断开`);
+  console.log("当前在线用户：", [...onlineUsers.keys()]);
+}
+
+// 获取所有在线用户
+function getOnlineUsers() {
+  return Array.from(onlineUsers.keys());
+}
+
+// 广播所有在线用户
+function broadcast(data) {
+  const message = JSON.stringify(data);
+
+  for (const [username, ws] of onlineUsers) {
+    if (ws.readyState === WebSocket.OPEN) {
+      ws.send(message, (error) => {
+        if (error) {
+          console.error(`向用户 ${username} 广播失败：`, error);
+        }
+      });
+    }
+  }
+}
+
+module.exports = {
+  addConnection,
+  getConnection,
+  removeConnection,
+  getOnlineUsers,
+  broadcast
+};
@@ -0,0 +1,299 @@
+const WebSocket = require("ws");
+const url = require("url");
+const db = require("../db/mysql");
+
+const { verifyToken } = require("../utils/jwt");
+
+const {
+  addConnection,
+  getConnection,
+  removeConnection,
+  getOnlineUsers,
+  broadcast
+} = require("./connectionManager");
+
+// 创建WebSocket服务
+function initWebSocket(server) {
+  const wss = new WebSocket.Server({
+    server,
+  });
+
+  wss.on("connection", (ws, request) => {
+    console.log("有新的WebSocket连接");
+
+    // 获取URL中的token
+    const query = url.parse(request.url, true).query;
+    const token = query.token;
+
+    if (!token) {
+      console.log("没有提供token");
+      ws.close();
+      return;
+    }
+
+    // 验证JWT
+    let user;
+    try {
+      user = verifyToken(token);
+    } catch (error) {
+      console.log("JWT验证失败：", error.message);
+      ws.close();
+      return;
+    }
+    console.log("WebSocket用户：", user);
+
+    const username = user.username;
+    ws.username = username;
+    // 保存连接
+    addConnection(username, ws);
+
+    // 通知所有在线用户当前在线用户列表
+    broadcast({
+      type: "userOnline",
+      userList: getOnlineUsers()
+    });
+
+    // 接收客户端消息
+    ws.on("message", (message) => {
+      try {
+        const data = JSON.parse(message.toString());
+        console.log("收到WebSocket消息：", data);
+
+        // websocket收到消息，必须通过解析data内容才知道谁是发送者谁是接收者
+        handleMessage(data, ws);
+      } catch (error) {
+        console.error("WebSocket消息处理失败：", error);
+      }
+    });
+
+    // 连接关闭
+    ws.on("close", () => {
+      removeConnection(username, ws);
+
+      // 通知所有在线用户当前在线用户列表
+      broadcast({
+        type: "userOnline",
+        userList: getOnlineUsers()
+      });
+    });
+
+    // WebSocket错误
+    ws.on("error", (error) => {
+      console.error(`用户 ${username} WebSocket错误：`, error);
+    });
+  });
+
+  console.log("WebSocket服务已启动");
+
+  return wss;
+}
+
+// 处理WebSocket消息
+function handleMessage(data, ws) {
+  switch (data.type) {
+    case "sendMessage":
+      handleSendMessage(data, ws);
+      break;
+    case "ack":
+      handleAck(data, ws);
+      break;
+
+    default:
+      console.log("未知消息类型：", data.type);
+  }
+}
+
+// 处理发送消息
+function handleSendMessage(data, ws) {
+  const senderName = ws.username;
+  const messageId = data.messageId;
+  const receiverName = data.receiverName;
+  const content = data.content;
+
+  if (!messageId) {
+    console.log("消息缺少 messageId");
+    return;
+  }
+
+  if (!receiverName) {
+    console.log("消息缺少接收者");
+    return;
+  }
+
+  if (!content) {
+    console.log("消息内容为空");
+    return;
+  }
+
+  console.log(
+    `${senderName} → ${receiverName}：${content}`
+  );
+
+  const insertSql = `
+    INSERT INTO messages
+    (message_id, sender_name, receiver_name, content)
+    VALUES (?, ?, ?, ?)
+  `;
+  db.query(insertSql, [
+    messageId,
+    senderName,
+    receiverName,
+    content
+  ], (error, result) => {
+    const senderWs = getConnection(senderName);
+    if (error) {
+      console.error(error);
+
+      if (senderWs) {
+        senderWs.send(
+          JSON.stringify({
+            type: "sendError",
+            messageId: messageId,
+            message: "消息保存失败"
+          })
+        );
+      }
+      return;
+    }
+
+    // 插入新消息之后，用messageID查询这条新消息的时间点（为了使用数据库插入时创建的时间点，不能用前端自己生成的）
+    const timeSql = `
+      SELECT created_at
+      FROM messages
+      WHERE message_id = ?
+    `;
+    db.query(timeSql, [messageId], (error, results) => {
+      if (error) {
+        console.error("查询消息失败：", error);
+
+        if (senderWs) {
+          senderWs.send(
+            JSON.stringify({
+              type: "sendError",
+              messageId: messageId,
+              message: "获取消息失败"
+            })
+          );
+        }
+        return;
+      }
+
+      if (results.length === 0) {
+        if (senderWs) {
+          senderWs.send(
+            JSON.stringify({
+              type: "sendError",
+              messageId: messageId,
+              message: "获取消息失败"
+            })
+          );
+        }
+        return;
+      }
+
+      const createdAt = results[0].created_at;
+
+      // 数据库确认写入后，才把成功写入的消息推送给发送者
+      if (senderWs) {
+        senderWs.send(
+          JSON.stringify({
+            type: "sendSuccess",
+            message: {
+              messageId,
+              senderName,
+              receiverName,
+              content,
+              createdAt
+            }
+          })
+        );
+      }
+
+      // 把写入的新消息推送给接收者，如果接收者不在线，就不用发送websocket消息给他了，但数据库里是有的
+      const receiverWs = getConnection(receiverName);
+      if (!receiverWs) {
+        console.log(`${receiverName} 当前不在线`);
+        return;
+      }
+
+      receiverWs.send(
+        JSON.stringify({
+          type: "newMessage",
+          message: {
+            messageId,
+            senderName,
+            receiverName,
+            content,
+            createdAt
+          },
+        })
+      );
+    });
+  });
+}
+
+function handleAck(data, ws) {
+  const messageId = data.messageId;
+
+  // 当前 WebSocket 对应的真实用户
+  const ackUser = ws.username;
+
+  if (!messageId) {
+    console.log("ACK 缺少 messageId");
+    return;
+  }
+
+  const sql = `
+    SELECT sender_name, receiver_name
+    FROM messages
+    WHERE message_id = ?
+  `;
+  db.query(sql, [messageId], (error, results) => {
+    if (error) {
+      console.error("查询消息失败：", error);
+      return;
+    }
+
+    if (results.length === 0) {
+      console.log(`消息 ${messageId} 不存在`);
+      return;
+    }
+
+    const message = results[0];
+    // 当前用户必须是这条消息的接收者
+    if (message.receiver_name !== ackUser) {
+      console.log(
+        `${ackUser} 无权确认消息 ${messageId}`
+      );
+      return;
+    }
+
+    // 原消息发送者
+    const originalSender = message.sender_name;
+    console.log(
+      `${ackUser} 已收到来自 ${originalSender} 的消息 ${messageId}，发送 ACK`
+    );
+
+    const senderWs = getConnection(originalSender);
+    if (!senderWs) {
+      console.log(
+        `${originalSender} 当前不在线`
+      );
+      return;
+    }
+
+    senderWs.send(
+      JSON.stringify({
+        type: "ack",
+        messageId: messageId
+      })
+    );
+
+    console.log(
+      `ACK ${messageId} 已发送给 ${originalSender}`
+    );
+  });
+}
+
+
+module.exports = initWebSocket;
Author	SHA1	Message	Date
Seven	2f5a8698e3	接口返的数据结构做统一处理	2026-09-30 16:22:49 +08:00
Seven	3dba76cd4a	把发消息写入数据库的时间都交给数据库来创建	2026-09-29 17:01:34 +08:00
Seven	fa7e908a08	完善websocket关闭连接功能	2026-09-29 14:13:11 +08:00
Seven	9dc511f08b	完善websocket消息确认机制	2026-09-29 11:14:09 +08:00
Seven	5e57920039	ai生成设计书文档，并解决文档中指出的部分bug	2026-09-28 11:07:06 +08:00
Seven	3eb4bfcd5d	联系人按照a-z排序	2026-09-24 10:45:31 +08:00
Seven	4c3b99edac	添加用户在线状态更新	2026-09-24 10:31:27 +08:00
Seven	74ed1535ed	增加ack确认消息机制	2026-09-23 15:45:27 +08:00
Seven	aedd5d1f3f	优化websocket监听消息	2026-09-23 10:20:56 +08:00
Seven	d02a2c7d5a	添加websocket连接	2026-09-22 16:27:22 +08:00
Seven	991993e0c2	优化文件结构，将接口分类	2026-09-22 15:00:46 +08:00