chore: hostHeaders default value is empty string (#5412)

closes #5411

Author: fengmk2

site/docs/basics/controller.md

@@ -605,9 +605,10 @@ Specially when we set `config.proxy = true` to deploy the application behind the
 
 #### `ctx.host`
 
-Reads the header's value configured by `config.hostHeaders` firstly, if fails, then it tries to get the value of host header, if fails again, it returns an empty string.
+Reads the header's value configured by `config.hostHeaders` firstly, if fails, then it tries to get the value of `host` header, if fails again, it returns an empty string.
 
-`config.hostHeaders` defaults to `x-forwarded-host`.
+`config.hostHeaders` defaults to `''`.
+If the application is deployed behind a reverse proxy and `config.proxy = true` is configured, a correct value needs to be configured here, such as `x-forwarded-host`. Please configure it according to the actual value of the proxy.
 
 #### `ctx.protocol`
 

site/docs/basics/controller.zh-CN.md

@@ -596,7 +596,8 @@ module.exports = {
 
 此 Getter 优先读取 `config.hostHeaders` 中配置的 header 值。若无法获取，则尝试读取 `host` 这个 header 的值。若仍旧获取不到，则返回空字符串。
 
-`config.hostHeaders` 的默认配置为 `x-forwarded-host`。
+`config.hostHeaders` 的默认配置为 `''` 空字符串。
+如果应用部署在反向代理后面，并且配置了 `config.proxy = true`，需要在这里配置一个正确的值，例如 `x-forwarded-host`，请按照代理真实值配置。
 
 #### `ctx.protocol`
 
@@ -1077,4 +1078,4 @@ exports.security = {
 };
 ```
 
-如果没有配置 `domainWhiteList` 或 `domainWhiteList` 数组为空，则默认允许所有跳转请求，等同于使用 `ctx.unsafeRedirect(url)`。
+如果没有配置 `domainWhiteList` 或 `domainWhiteList` 数组为空，则默认允许所有跳转请求，等同于使用 `ctx.unsafeRedirect(url)`。