module ActiveRecord
# A session store backed by an Active Record class. A default class is
# provided, but any object duck-typing to an Active Record Session class
# with text +session_id+ and +data+ attributes is sufficient.
#
# The default assumes a +sessions+ tables with columns:
# +id+ (numeric primary key),
# +session_id+ (text, or longtext if your session data exceeds 65K), and
# +data+ (text or longtext; careful if your session data exceeds 65KB).
# The +session_id+ column should always be indexed for speedy lookups.
# Session data is marshaled to the +data+ column in Base64 format.
# If the data you write is larger than the column's size limit,
# ActionController::SessionOverflowError will be raised.
#
# You may configure the table name, primary key, and data column.
# For example, at the end of <tt>config/environment.rb</tt>:
# ActiveRecord::SessionStore::Session.table_name = 'legacy_session_table'
# ActiveRecord::SessionStore::Session.primary_key = 'session_id'
# ActiveRecord::SessionStore::Session.data_column_name = 'legacy_session_data'
# Note that setting the primary key to the +session_id+ frees you from
# having a separate +id+ column if you don't want it. However, you must
# set <tt>session.model.id = session.session_id</tt> by hand! A before filter
# on ApplicationController is a good place.
#
# Since the default class is a simple Active Record, you get timestamps
# for free if you add +created_at+ and +updated_at+ datetime columns to
# the +sessions+ table, making periodic session expiration a snap.
#
# You may provide your own session class implementation, whether a
# feature-packed Active Record or a bare-metal high-performance SQL
# store, by setting
# ActiveRecord::SessionStore.session_class = MySessionClass
# You must implement these methods:
# self.find_by_session_id(session_id)
# initialize(hash_of_session_id_and_data)
# attr_reader :session_id
# attr_accessor :data
# save
# destroy
#
# The example SqlBypass class is a generic SQL session store. You may
# use it as a basis for high-performance database-specific stores.
class SessionStore < ActionDispatch::Session::AbstractStore
# The default Active Record class.
class Session < ActiveRecord::Base
##
# :singleton-method:
# Customizable data column name. Defaults to 'data'.
cattr_accessor :data_column_name
self.data_column_name = 'data'
before_save :marshal_data!
before_save :raise_on_session_data_overflow!
class << self
def data_column_size_limit
@data_column_size_limit ||= columns_hash[@@data_column_name].limit
end
# Hook to set up sessid compatibility.
def find_by_session_id(session_id)
setup_sessid_compatibility!
find_by_session_id(session_id)
end
def marshal(data)
ActiveSupport::Base64.encode64(Marshal.dump(data)) if data
end
def unmarshal(data)
Marshal.load(ActiveSupport::Base64.decode64(data)) if data
end
def create_table!
connection.execute <<-end_sql
CREATE TABLE #{table_name} (
id INTEGER PRIMARY KEY,
#{connection.quote_column_name('session_id')} TEXT UNIQUE,
#{connection.quote_column_name(@@data_column_name)} TEXT(255)
)
end_sql
end
def drop_table!
connection.execute "DROP TABLE #{table_name}"
end
private
# Compatibility with tables using sessid instead of session_id.
def setup_sessid_compatibility!
# Reset column info since it may be stale.
reset_column_information
if columns_hash['sessid']
def self.find_by_session_id(*args)
find_by_sessid(*args)
end
define_method(:session_id) { sessid }
define_method(:session_id=) { |session_id| self.sessid = session_id }
else
def self.find_by_session_id(session_id)
find :first, :conditions => {:session_id=>session_id}
end
end
end
end
# Lazy-unmarshal session state.
def data
@data ||= self.class.unmarshal(read_attribute(@@data_column_name)) || {}
end
attr_writer :data
# Has the session been loaded yet?
def loaded?
!!@data
end
private
def marshal_data!
return false if !loaded?
write_attribute(@@data_column_name, self.class.marshal(self.data))
end
# Ensures that the data about to be stored in the database is not
# larger than the data storage column. Raises
# ActionController::SessionOverflowError.
def raise_on_session_data_overflow!
return false if !loaded?
limit = self.class.data_column_size_limit
if loaded? and limit and read_attribute(@@data_column_name).size > limit
raise ActionController::SessionOverflowError
end
end
end
# A barebones session store which duck-types with the default session
# store but bypasses Active Record and issues SQL directly. This is
# an example session model class meant as a basis for your own classes.
#
# The database connection, table name, and session id and data columns
# are configurable class attributes. Marshaling and unmarshaling
# are implemented as class methods that you may override. By default,
# marshaling data is
#
# ActiveSupport::Base64.encode64(Marshal.dump(data))
#
# and unmarshaling data is
#
# Marshal.load(ActiveSupport::Base64.decode64(data))
#
# This marshaling behavior is intended to store the widest range of
# binary session data in a +text+ column. For higher performance,
# store in a +blob+ column instead and forgo the Base64 encoding.
class SqlBypass
##
# :singleton-method:
# Use the ActiveRecord::Base.connection by default.
cattr_accessor :connection
##
# :singleton-method:
# The table name defaults to 'sessions'.
cattr_accessor :table_name
@@table_name = 'sessions'
##
# :singleton-method:
# The session id field defaults to 'session_id'.
cattr_accessor :session_id_column
@@session_id_column = 'session_id'
##
# :singleton-method:
# The data field defaults to 'data'.
cattr_accessor :data_column
@@data_column = 'data'
class << self
def connection
@@connection ||= ActiveRecord::Base.connection
end
# Look up a session by id and unmarshal its data if found.
def find_by_session_id(session_id)
if record = connection.select_one("SELECT * FROM #{@@table_name} WHERE #{@@session_id_column}=#{connection.quote(session_id)}")
new(:session_id => session_id, :marshaled_data => record['data'])
end
end
def marshal(data)
ActiveSupport::Base64.encode64(Marshal.dump(data)) if data
end
def unmarshal(data)
Marshal.load(ActiveSupport::Base64.decode64(data)) if data
end
def create_table!
@@connection.execute <<-end_sql
CREATE TABLE #{table_name} (
id INTEGER PRIMARY KEY,
#{@@connection.quote_column_name(session_id_column)} TEXT UNIQUE,
#{@@connection.quote_column_name(data_column)} TEXT
)
end_sql
end
def drop_table!
@@connection.execute "DROP TABLE #{table_name}"
end
end
attr_reader :session_id
attr_writer :data
# Look for normal and marshaled data, self.find_by_session_id's way of
# telling us to postpone unmarshaling until the data is requested.
# We need to handle a normal data attribute in case of a new record.
def initialize(attributes)
@session_id, @data, @marshaled_data = attributes[:session_id], attributes[:data], attributes[:marshaled_data]
@new_record = @marshaled_data.nil?
end
def new_record?
@new_record
end
# Lazy-unmarshal session state.
def data
unless @data
if @marshaled_data
@data, @marshaled_data = self.class.unmarshal(@marshaled_data) || {}, nil
else
@data = {}
end
end
@data
end
def loaded?
!!@data
end
def save
return false if !loaded?
marshaled_data = self.class.marshal(data)
if @new_record
@new_record = false
@@connection.update <<-end_sql, 'Create session'
INSERT INTO #{@@table_name} (
#{@@connection.quote_column_name(@@session_id_column)},
#{@@connection.quote_column_name(@@data_column)} )
VALUES (
#{@@connection.quote(session_id)},
#{@@connection.quote(marshaled_data)} )
end_sql
else
@@connection.update <<-end_sql, 'Update session'
UPDATE #{@@table_name}
SET #{@@connection.quote_column_name(@@data_column)}=#{@@connection.quote(marshaled_data)}
WHERE #{@@connection.quote_column_name(@@session_id_column)}=#{@@connection.quote(session_id)}
end_sql
end
end
def destroy
unless @new_record
@@connection.delete <<-end_sql, 'Destroy session'
DELETE FROM #{@@table_name}
WHERE #{@@connection.quote_column_name(@@session_id_column)}=#{@@connection.quote(session_id)}
end_sql
end
end
end
# The class used for session storage. Defaults to
# ActiveRecord::SessionStore::Session
cattr_accessor :session_class
self.session_class = Session
SESSION_RECORD_KEY = 'rack.session.record'.freeze
private
def get_session(env, sid)
Base.silence do
sid ||= generate_sid
session = find_session(sid)
env[SESSION_RECORD_KEY] = session
[sid, session.data]
end
end
def set_session(env, sid, session_data)
Base.silence do
record = get_session_model(env, sid)
record.data = session_data
return false unless record.save
session_data = record.data
if session_data && session_data.respond_to?(:each_value)
session_data.each_value do |obj|
obj.clear_association_cache if obj.respond_to?(:clear_association_cache)
end
end
end
sid
end
def get_session_model(env, sid)
if env[ENV_SESSION_OPTIONS_KEY][:id].nil?
env[SESSION_RECORD_KEY] = find_session(sid)
else
env[SESSION_RECORD_KEY] ||= find_session(sid)
end
end
def find_session(id)
@@session_class.find_by_session_id(id) ||
@@session_class.new(:session_id => id, :data => {})
end
end
end
