Using a custom session key for some subdomains

[strika]

We're working on a Rails application that uses subdomains. We need to have a different session for different subdomains:

• app.example.com should use the "default" session
• abc.example.com should use a session that's only for the abc domain
• demo.example.com should use a session that's only for the demo domain
• all other subdomains should use the default session

One potential solution is to change the session key before each request based on the subdomain. The idea is to do that in a middleware.

A similar question was asked before - rack/rack#1155.

The proposed solution was to change the key by accessing the session options:

env["rack.session.options"][:key] = "my_cookie_name"

However, as the author of the previous question/issue explained:

The abstract session store implementation (lib/rack/session/abstract/id.rb) uses an instance variable, initialized at startup, to determine the name of the cookie it will use to fetch/set a session's id.

Latter, the instance variable is used to fetch the session ID.

So, changing the session key like this:

env["rack.session.options"][:key] = "my_cookie_name"

Doesn't have any effect on the instance variable.

At the moment, we're using Rack 2.2.8.

Is there something obvious that we're missing? Thank you.