Set rel="canonical" for query strings and redirects?

Question

I have a fedora40 system with apache-2.4.62 and GSC is reporting many of our URLs that are images, redirects or contain query strings are "duplicate without user-selected canonical."

I've created this method to label PDFs and images with the canonical tag:

RewriteRule (.+)\.(pdf|jpg|webp)$ - [E=FILENAME:$1\.$2]
<FilesMatch "\.(pdf|jpg|webp)$">
   Header add Link "<https://linuxsecurity.com/%{FILENAME}e>; rel=\"canonical\""
</FilesMatch>

However, I have other URLs that contain query strings and can't figure out how to add the above header to them. Here are a few examples.

This one is a redirect. The redirected link is properly defined as being canonical, but apparently the redirected link does not, so GSC thinks the canonical for this link is some external site.

https://www.linuxsecurity.com/resource_files/documentation/virus-writing-HOWTO/_html/rst.html

This one has the canonical set properly without the query string, but GSC is complaining the version with the query string does not.

https://linuxsecurity.com/news?format=feed&type=atom

I think one of the issues is that the two examples above are not "files" so won't work.

Answer 1

Its probably because each version of an link with different params is looked at as a separate url.

Apply canonical to the url without the query string does not apply to one with the query string.