Getting the request url about wp-update-server HOT 1 OPEN

As an alternative to query arguments, you can extract the site URL from the User-Agent HTTP header. WordPress automatically sets the user agent to something like this: WordPress/4.8; http://siteurl.com. The update server parses the header and stores the URL in the wpSiteUrl field of the current Wpup_Request instance. This means that if you're overriding one of the server methods that get a $request argument, you can get the URL from $request->wpSiteUrl.

However, it's possible to change the WordPress User-Agent with plugins, so it's not 100% reliable either. Some security-oriented plugins automatically remove the header or replace it with something generic.

As far as I know, there's no foolproof way to get the site URL. You could try using the IP address for verification, but even that can change occasionally.

from wp-update-server.