class Rack::Session::Cookie

Rack::Session::Cookie provides simple cookie based session management. By default, the session is a Ruby Hash stored as base64 encoded marshalled data set to :key (default: rack.session). The object that encodes the session data is configurable and must respond to encode and decode. Both methods must take a string and return a string.

When the secret key is set, cookie data is checked for data integrity. The old secret key is also accepted and allows graceful secret rotation.

Example:

use Rack::Session::Cookie, :key => 'rack.session',
                           :domain => 'foo.com',
                           :path => '/',
                           :expire_after => 2592000,
                           :secret => 'change_me',
                           :old_secret => 'also_change_me'

All parameters are optional.

Example of a cookie with no encoding:

Rack::Session::Cookie.new(application, {
  :coder => Rack::Session::Cookie::Identity.new
})

Example of a cookie with custom encoding:

Rack::Session::Cookie.new(application, {
  :coder => Class.new {
    def encode(str); str.reverse; end
    def decode(str); str.reverse; end
  }.new
})

# File lib/rack/session/cookie.rb, line 107
      def initialize(app, options = {})
        @secrets = options.values_at(:secret, :old_secret).compact
        @hmac = options.fetch(:hmac, OpenSSL::Digest::SHA1)

        warn <<-MSG unless secure?(options)
        SECURITY WARNING: No secret option provided to Rack::Session::Cookie.
        This poses a security threat. It is strongly recommended that you
        provide a secret to prevent exploits that may be possible from crafted
        cookies. This will not be supported in future versions of Rack, and
        future versions will even invalidate your existing user cookies.

        Called from: #{caller[0]}.
        MSG
        @coder = options[:coder] ||= Base64::Marshal.new
        super(app, options.merge!(cookie_only: true))
      end