require 'rack/utils'
require 'rack/request'
require 'action_dispatch/middleware/cookies'
require 'active_support/core_ext/object/blank'
module ActionDispatch
module Session
class SessionRestoreError < StandardError #:nodoc:
end
class AbstractStore
ENV_SESSION_KEY = 'rack.session'.freeze
ENV_SESSION_OPTIONS_KEY = 'rack.session.options'.freeze
# thin wrapper around Hash that allows us to lazily
# load session id into session_options
class OptionsHash < Hash
def initialize(by, env, default_options)
@by = by
@env = env
@session_id_loaded = false
merge!(default_options)
end
def [](key)
if key == :id
load_session_id! unless key?(:id) || has_session_id?
end
super
end
private
def has_session_id?
@session_id_loaded
end
def load_session_id!
self[:id] = @by.send(:extract_session_id, @env)
@session_id_loaded = true
end
end
class SessionHash < Hash
def initialize(by, env)
super()
@by = by
@env = env
@loaded = false
end
def [](key)
load_for_read!
super(key.to_s)
end
def has_key?(key)
load_for_read!
super(key.to_s)
end
def []=(key, value)
load_for_write!
super(key.to_s, value)
end
def clear
load_for_write!
super
end
def to_hash
load_for_read!
h = {}.replace(self)
h.delete_if { |k,v| v.nil? }
h
end
def update(hash)
load_for_write!
super(hash.stringify_keys)
end
def delete(key)
load_for_write!
super(key.to_s)
end
def inspect
load_for_read!
super
end
def exists?
return @exists if instance_variable_defined?(:@exists)
@exists = @by.send(:exists?, @env)
end
def loaded?
@loaded
end
def destroy
clear
@by.send(:destroy, @env) if defined?(@by) && @by
@env[ENV_SESSION_OPTIONS_KEY][:id] = nil if defined?(@env) && @env && @env[ENV_SESSION_OPTIONS_KEY]
@loaded = false
end
private
def load_for_read!
load! if !loaded? && exists?
end
def load_for_write!
load! unless loaded?
end
def load!
id, session = @by.send(:load_session, @env)
@env[ENV_SESSION_OPTIONS_KEY][:id] = id
replace(session.stringify_keys)
@loaded = true
end
end
DEFAULT_OPTIONS = {
:key => '_session_id',
:path => '/',
:domain => nil,
:expire_after => nil,
:secure => false,
:httponly => true,
:cookie_only => true
}
def initialize(app, options = {})
@app = app
@default_options = DEFAULT_OPTIONS.merge(options)
@key = @default_options.delete(:key).freeze
@cookie_only = @default_options.delete(:cookie_only)
ensure_session_key!
end
def call(env)
prepare!(env)
response = @app.call(env)
session_data = env[ENV_SESSION_KEY]
options = env[ENV_SESSION_OPTIONS_KEY]
if !session_data.is_a?(AbstractStore::SessionHash) || session_data.loaded? || options[:expire_after]
request = ActionDispatch::Request.new(env)
return response if (options[:secure] && !request.ssl?)
session_data.send(:load!) if session_data.is_a?(AbstractStore::SessionHash) && !session_data.loaded?
sid = options[:id] || generate_sid
session_data = session_data.to_hash
value = set_session(env, sid, session_data)
return response unless value
cookie = { :value => value }
if options[:expire_after]
cookie[:expires] = Time.now + options.delete(:expire_after)
end
set_cookie(request, cookie.merge!(options))
end
response
end
private
def prepare!(env)
env[ENV_SESSION_KEY] = SessionHash.new(self, env)
env[ENV_SESSION_OPTIONS_KEY] = OptionsHash.new(self, env, @default_options)
end
def generate_sid
ActiveSupport::SecureRandom.hex(16)
end
def set_cookie(request, options)
if request.cookie_jar[@key] != options[:value] || !options[:expires].nil?
request.cookie_jar[@key] = options
end
end
def load_session(env)
stale_session_check! do
sid = current_session_id(env)
sid, session = get_session(env, sid)
[sid, session]
end
end
def extract_session_id(env)
stale_session_check! do
request = ActionDispatch::Request.new(env)
sid = request.cookies[@key]
sid ||= request.params[@key] unless @cookie_only
sid
end
end
def current_session_id(env)
env[ENV_SESSION_OPTIONS_KEY][:id]
end
def ensure_session_key!
if @key.blank?
raise ArgumentError, 'A key is required to write a ' +
'cookie containing the session data. Use ' +
'config.session_store SESSION_STORE, { :key => ' +
'"_myapp_session" } in config/application.rb'
end
end
def stale_session_check!
yield
rescue ArgumentError => argument_error
if argument_error.message =~ %r{undefined class/module ([\w:]*\w)}
begin
# Note that the regexp does not allow $1 to end with a ':'
$1.constantize
rescue LoadError, NameError => const_error
raise ActionDispatch::Session::SessionRestoreError, "Session contains objects whose class definition isn't available.\nRemember to require the classes for all objects kept in the session.\n(Original exception: #{const_error.message} [#{const_error.class}])\n"
end
retry
else
raise
end
end
def exists?(env)
current_session_id(env).present?
end
def get_session(env, sid)
raise '#get_session needs to be implemented.'
end
def set_session(env, sid, session_data)
raise '#set_session needs to be implemented and should return ' <<
'the value to be stored in the cookie (usually the sid)'
end
def destroy(env)
raise '#destroy needs to be implemented.'
end
end
end
end