class ActiveRecord::SessionStore::ClassMethods::HybridSerializer

Transparently migrates existing session values from Marshal to JSON

def self.load(value) 

def self.load(value)
  if needs_migration?(value)
    Marshal.load(::Base64.decode64(value))
  else
    super
  end
end

def self.needs_migration?(value) 

def self.needs_migration?(value)
  value.start_with?(MARSHAL_SIGNATURE)
end