Actions: Sessions

Enable Sessions

Sessions are available in Hanami applications, but not enabled by default. If we want to turn on this feature, we just need to uncomment a line of code.

# apps/web/application.rb
module Web
  class Application < Hanami::Application
    configure do
      # ...
      sessions :cookie, secret: ENV['WEB_SESSIONS_SECRET']
    end
  end
end

The first argument is the name of the adapter for the session storage. The default value is :cookie, that uses Rack::Session::Cookie.

The name of the session adapter is the underscored version of the class name under Rack::Session namespace. Example: :cookie for Rack::Session::Cookie.

We can use a different storage compatible with Rack sessions. Let’s say we want to use Redis. We should bundle redis-rack and specify the name of the adapter: :redis. Hanami is able to autoload the adapter and use it when the application is started.

Custom storage technologies are autoloaded via require "rack/session/#{ adapter_name }".

The second argument passed to sessions is a Hash of options that are passed to the adapter. We find only a default :secret, but we can specify all the values that are supported by the current adapter.

Usage

Sessions behave like a Hash: we can read, assign and remove values.

# apps/web/controllers/dashboard/index.rb
module Web
  module Controllers
    module Dashboard
      class Index
        include Web::Action

        def call(params)
          session[:b]         # read
          session[:a] = 'foo' # assign
          session[:c] = nil   # remove
        end
      end
    end
  end
end