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 config/environment.rb: # 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 session.model.id = session.session_id 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 return true 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