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 })
Attributes
Public Class Methods
Source
# 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
Calls superclass method
Rack::Session::Abstract::Persisted::new
Private Instance Methods
Source
# File lib/rack/session/cookie.rb, line 180 def delete_session(req, session_id, options) # Nothing to do here, data is in the client generate_sid unless options[:drop] end
Source
# File lib/rack/session/cookie.rb, line 185 def digest_match?(data, digest) return unless data && digest @secrets.any? do |secret| Rack::Utils.secure_compare(digest, generate_hmac(data, secret)) end end
Source
# File lib/rack/session/cookie.rb, line 132 def extract_session_id(request) unpacked_cookie_data(request)["session_id"] end
Source
# File lib/rack/session/cookie.rb, line 126 def find_session(req, sid) data = unpacked_cookie_data(req) data = persistent_session_id!(data) [data["session_id"], data] end
Source
# File lib/rack/session/cookie.rb, line 192 def generate_hmac(data, secret) OpenSSL::HMAC.hexdigest(@hmac.new, secret, data) end
Source
# File lib/rack/session/cookie.rb, line 149 def persistent_session_id!(data, sid = nil) data ||= {} data["session_id"] ||= sid || generate_sid data end
Source
# File lib/rack/session/cookie.rb, line 196 def secure?(options) @secrets.size >= 1 || (options[:coder] && options[:let_coder_handle_secure_encoding]) end
Source
# File lib/rack/session/cookie.rb, line 164 def write_session(req, session_id, session, options) session = session.merge("session_id" => session_id) session_data = coder.encode(session) if @secrets.first session_data << "--#{generate_hmac(session_data, @secrets.first)}" end if session_data.size > (4096 - @key.size) req.get_header(RACK_ERRORS).puts("Warning! Rack::Session::Cookie data size exceeds 4K.") nil else SessionId.new(session_id, session_data) end end