Is there a way (Firefox add-on or about:config setting) to send a custom HTTP header for requests to a certain host?
Example: Send the header
Foobar: true if (and only if) I request a resource from the host
Bonus points if the protocol can be specified, too (e.g. only send the header when requesting over HTTPS).
(see my question Use additional “password” in Referer to hide private site? on IT Security SE on why I’d like to do it)
What I found so far
- The question Browser extensions to automatically alter HTTP headers? is similar, but looking for any way how to accomplish this (e.g. with the help of local proxies) and also not necessarily for Firefox
- You can create custom headers with the add-on Modify Headers, but it doesn't allow me to restrict the hosts, so it will send the custom headers for all requests
- There are some add-ons that allow setting custom values for certain HTTP headers per-host:
- Related: questions on Stack Overflow how to set custom headers in Firefox add-ons