Upgrade-Insecure-Requests 标头
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since 2018年4月.
HTTP Upgrade-Insecure-Requests 请求标头向服务器发送一个信号，表明客户端偏好加密且经过认证的响应，并且客户端能够成功处理 upgrade-insecure-requests CSP 指令。
语法
http
Upgrade-Insecure-Requests: <boolean>
指令
<boolean>-
1表示“true”，并且是该字段唯一有效的值。
示例
使用 Upgrade-Insecure-Requests
客户端的请求会向服务器表明它支持 upgrade-insecure-requests 的升级机制：
http
GET / HTTP/1.1
Host: example.com
Upgrade-Insecure-Requests: 1
服务器现在可以将请求重定向到站点的安全版本。可以使用 Vary 标头，以避免缓存向不支持升级机制的客户端提供相同的站点内容。
http
Location: https://example.com/
Vary: Upgrade-Insecure-Requests
规范
| Specification |
|---|
| Upgrade Insecure Requests # preference |