• Move ActionCable::Server::Configuration to ::ActionCable::Configuration.

  The old constant remains available as an alias.

  Samuel Williams

• Respect calls to #reject in before_subscribe callbacks.

  It doesn't call #subscribed if a before_subscribe callback calls #reject.

  Joshua Young

• Extract low-level Action Cable server responsibilities into ::ActionCable::Server abstractions.

  This refactoring separates socket handling, concurrency primitives, and other transport-specific behavior from application-level connections and channels. It makes Action Cable more flexible as a framework and opens the door to alternative server implementations without changing user-facing channel and connection code.

  Vladimir Dementyev

• Fix Action Cable origin check to respect X-Forwarded-Host behind reverse proxies.

  The allow_same_origin_as_host check previously compared against the raw HTTP_HOST header, which fails when a proxy forwards requests with a different internal host. It now uses request.host_with_port, consistent with the rest of Rails.

  Jordan Brough

• Channel generator now detects which JS package manager to use when installing javascript dependencies.

  David Lowenfels

Please check 8-1-stable for previous changes.