.toml file versus docker labels

Specifically for middleware and such. Can I specify a middleware in the relatively easy to use .toml file and then have traefik find the docker port by label and complete the process?

As per a post yesterday. If you define the middleware in one provider and want to utilise it in another suffix the middleware with @provider i.e.

...
services:
  foo:
  ...
  labels:
    traefik.http.routers.foo.middlewares: mymiddleware@file