$google_host

Description

The `$google_host` variable is part of the NGINX Module for Google, specifically designed for creating mirrors of Google services. This variable is dynamically set during a request when the Google mirror functionality is enabled. Essentially, it extracts the host part of the incoming request URL directed at Google, thus allowing servers to manipulate or log the host as needed. It is typically utilized in locations where response manipulations or logging based on the Google host are necessary. When the Google filter is activated, the module hooks into the request lifecycle, capturing the request details including the host information. If the request is made to a valid Google service, this variable will reflect that service's host name (like `www.google.com`, `news.google.com`, etc.). The variable is marked as changeable, meaning it can be adjusted or updated during request processing, allowing for real-time adjustments based on application logic or conditions within different request contexts.

Config Example

location / {
    google on;
    add_header X-Google-Host $google_host;
}