flowchart LR U[用户<br/>微信小程序] --> W[外网服务器] subgraph PUBLIC[外网环境] W -->|查询缓存| DB DB -->|返回课表/成绩| W end subgraph PRIVATE[内网环境] I[内网服务器] SYS[教务系统] end W <-->|frp隧道| I W -->|无缓存时请求| I I -->|爬取/查询数据| SYS SYS --> I