Redirect to https unless regex matches

Traefik Traefik v2 (latest)
1

I'm trying to get traefik to redirect to https unless a regex matches. For Nginx i was used to using negative lookahead, but that is not supported in Go.

I'm wondering if anyone has an example on how they got this to work?

Examples of paths that should redirect

http://example.com  -> https://example.com
http://example.com/page1  -> https://example.com/page1
http://example.com/new_system.xml  -> https://example.com/new_system.xml

While these insecure should be allowed not to redirect

http://example.com/allowed_insecure
http://example.com/other_insecure.xml
http://example.com/somewhereelse.strangeextension

Of course everything should be TLS encrypted, but some legacy system have their own voodoo encryption before/after transferring data over insecure http.