120 lines
4.2 KiB
Ruby
120 lines
4.2 KiB
Ruby
# AUTHOR: blink <blinketje@gmail.com>; blink#ruby-lang@irc.freenode.net
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require 'rack/session/abstract/id'
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require 'memcache'
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module Rack
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module Session
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# Rack::Session::Memcache provides simple cookie based session management.
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# Session data is stored in memcached. The corresponding session key is
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# maintained in the cookie.
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# You may treat Session::Memcache as you would Session::Pool with the
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# following caveats.
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#
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# * Setting :expire_after to 0 would note to the Memcache server to hang
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# onto the session data until it would drop it according to it's own
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# specifications. However, the cookie sent to the client would expire
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# immediately.
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#
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# Note that memcache does drop data before it may be listed to expire. For
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# a full description of behaviour, please see memcache's documentation.
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class Memcache < Abstract::ID
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attr_reader :mutex, :pool
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DEFAULT_OPTIONS = Abstract::ID::DEFAULT_OPTIONS.merge \
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:namespace => 'rack:session',
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:memcache_server => 'localhost:11211'
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def initialize(app, options={})
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super
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@mutex = Mutex.new
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mserv = @default_options[:memcache_server]
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mopts = @default_options.
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reject{|k,v| !MemCache::DEFAULT_OPTIONS.include? k }
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@pool = MemCache.new mserv, mopts
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unless @pool.active? and @pool.servers.any?{|c| c.alive? }
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raise 'No memcache servers'
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end
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end
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def generate_sid
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loop do
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sid = super
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break sid unless @pool.get(sid, true)
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end
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end
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def get_session(env, session_id)
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@mutex.lock if env['rack.multithread']
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unless session_id and session = @pool.get(session_id)
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session_id, session = generate_sid, {}
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unless /^STORED/ =~ @pool.add(session_id, session)
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raise "Session collision on '#{session_id.inspect}'"
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end
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end
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session.instance_variable_set '@old', @pool.get(session_id, true)
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return [session_id, session]
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rescue MemCache::MemCacheError, Errno::ECONNREFUSED
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# MemCache server cannot be contacted
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warn "#{self} is unable to find memcached server."
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warn $!.inspect
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return [ nil, {} ]
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ensure
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@mutex.unlock if @mutex.locked?
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end
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def set_session(env, session_id, new_session, options)
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expiry = options[:expire_after]
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expiry = expiry.nil? ? 0 : expiry + 1
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@mutex.lock if env['rack.multithread']
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if options[:renew] or options[:drop]
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@pool.delete session_id
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return false if options[:drop]
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session_id = generate_sid
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@pool.add session_id, {} # so we don't worry about cache miss on #set
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end
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session = @pool.get(session_id) || {}
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old_session = new_session.instance_variable_get '@old'
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old_session = old_session ? Marshal.load(old_session) : {}
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unless Hash === old_session and Hash === new_session
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env['rack.errors'].
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puts 'Bad old_session or new_session sessions provided.'
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else # merge sessions
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# alterations are either update or delete, making as few changes as
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# possible to prevent possible issues.
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# removed keys
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delete = old_session.keys - new_session.keys
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if $VERBOSE and not delete.empty?
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env['rack.errors'].
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puts "//@#{session_id}: delete #{delete*','}"
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end
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delete.each{|k| session.delete k }
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# added or altered keys
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update = new_session.keys.
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select{|k| new_session[k] != old_session[k] }
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if $VERBOSE and not update.empty?
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env['rack.errors'].puts "//@#{session_id}: update #{update*','}"
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end
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update.each{|k| session[k] = new_session[k] }
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end
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@pool.set session_id, session, expiry
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return session_id
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rescue MemCache::MemCacheError, Errno::ECONNREFUSED
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# MemCache server cannot be contacted
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warn "#{self} is unable to find memcached server."
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warn $!.inspect
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return false
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ensure
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@mutex.unlock if @mutex.locked?
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end
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end
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end
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end
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