> [TOC]

# 1、Websocket解决什么问题？

## 1.1、如何即使获取更新？

![image-20220813182212662](assets/image-20220813182212662.png)

## 1.2、如何分析Websocket

![image-20220813182649381](assets/image-20220813182649381.png)

## 1.3、定义

![image-20220813182958124](assets/image-20220813182958124.png)

# 2、Websocket的约束

## 2.1、Websocket的成本

![image-20220813183539131](assets/image-20220813183539131.png)

![image-20220813184000955](assets/image-20220813184000955.png)

![image-20220813184052353](assets/image-20220813184052353.png)

## 2.2、设计哲学

![image-20220813184115532](assets/image-20220813184115532.png)

# 3、Websocket协议格式

![image-20220813184344064](assets/image-20220813184344064.png)

![image-20220813184959440](assets/image-20220813184959440.png)

![image-20220813185012044](assets/image-20220813185012044.png)

![image-20220813185146477](assets/image-20220813185146477.png)

# 4、Websocket协议如何从HTTP升级？

## 4.1、提供的消息

![image-20220813185305956](assets/image-20220813185305956.png)

## 4.2、建立握手

![image-20220813185636652](assets/image-20220813185636652.png)

## 4.3、如何验证成功连接？

![image-20220813185841585](assets/image-20220813185841585.png)

# 5、传递消息的编码格式

## 5.1、定义

![image-20220813190052971](assets/image-20220813190052971.png)

![image-20220813191402368](assets/image-20220813191402368.png)

## 5.2、帧的长度

![image-20220813191624615](assets/image-20220813191624615.png)

## 5.3、发送消息

![image-20220813192052277](assets/image-20220813192052277.png)

# 6、掩码处理

## 6.1、为什么？

![image-20220813192251313](assets/image-20220813192251313.png)

## 6.2、定义

![image-20220813194103292](assets/image-20220813194103292.png)

## 6.3、原理

![image-20220813194123218](assets/image-20220813194123218.png)

# 7、如何维护会话？

![image-20220813194409362](assets/image-20220813194409362.png)

# 8、如何关闭会话？

![image-20220813194608277](assets/image-20220813194608277.png)

![image-20220813194616116](assets/image-20220813194616116.png)

![image-20220813194622025](assets/image-20220813194622025.png)