Class: Rack::Session::Dalli
- Inherits:
-
Object
- Object
- Rack::Session::Dalli
- Defined in:
- lib/rack/session/dalli.rb
Constant Summary collapse
- DEFAULT_DALLI_OPTIONS =
{ :namespace => 'rack:session', :memcache_server => 'localhost:11211' }
Instance Attribute Summary collapse
-
#mutex ⇒ Object
readonly
Returns the value of attribute mutex.
-
#pool ⇒ Object
readonly
Returns the value of attribute pool.
Instance Method Summary collapse
- #delete_session(req, sid, options) ⇒ Object
- #destroy_session(env, session_id, options) ⇒ Object
- #find_session(req, sid) ⇒ Object
- #get_session(env, sid) ⇒ Object
-
#initialize(app, options = {}) ⇒ Dalli
constructor
Brings in a new Rack::Session::Dalli middleware with the given ‘:memcache_server`.
- #set_session(env, session_id, new_session, options) ⇒ Object
- #write_session(req, sid, session, options) ⇒ Object
Constructor Details
#initialize(app, options = {}) ⇒ Dalli
Brings in a new Rack::Session::Dalli middleware with the given ‘:memcache_server`. The server is either a hostname, or a host-with-port string in the form of “host_name:port”, or an array of such strings. For example:
use Rack::Session::Dalli,
:memcache_server => "mc.example.com:1234"
If no ‘:memcache_server` option is specified, Rack::Session::Dalli will connect to localhost, port 11211 (the default memcached port). If `:memcache_server` is set to nil, Dalli::Client will look for ENV and use that value if it is available, or fall back to the same default behavior described above.
Rack::Session::Dalli is intended to be a drop-in replacement for Rack::Session::Memcache. It accepts additional options that control the behavior of Rack::Session, Dalli::Client, and an optional ConnectionPool. First and foremost, if you wish to instantiate your own Dalli::Client (or ConnectionPool) and use that instead of letting Rack::Session::Dalli instantiate it on your behalf, simply pass it in as the ‘:cache` option. Please note that you will be responsible for setting the namespace and any other options on Dalli::Client.
Secondly, if you’re not using the ‘:cache` option, Rack::Session::Dalli accepts the same options as Dalli::Client, so it’s worth reviewing its documentation. Perhaps most importantly, if you don’t specify a ‘:namespace` option, Rack::Session::Dalli will default to using “rack:session”.
Whether you are using the ‘:cache` option or not, it is not recommend to set `:expires_in`. Instead, use `:expire_after`, which will control both the expiration of the client cookie as well as the expiration of the corresponding entry in memcached.
Rack::Session::Dalli also accepts a host of options that control how the sessions and session cookies are managed, including the aforementioned ‘:expire_after` option. Please see the documentation for Rack::Session::Abstract::Persisted for a detailed explanation of these options and their default values.
Finally, if your web application is multithreaded, the Rack::Session::Dalli middleware can become a source of contention. You can use a connection pool of Dalli clients by passing in the ‘:pool_size` and/or `:pool_timeout` options. For example:
use Rack::Session::Dalli,
:memcache_server => "mc.example.com:1234",
:pool_size => 10
You must include the ‘connection_pool` gem in your project if you wish to use pool support. Please see the documentation for ConnectionPool for more information about it and its default options (which would only be applicable if you supplied one of the two options, but not both).
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# File 'lib/rack/session/dalli.rb', line 69 def initialize(app, ={}) # Parent uses DEFAULT_OPTIONS to build @default_options for Rack::Session super # Determine the default TTL for newly-created sessions @default_ttl = ttl @default_options[:expire_after] # Normalize and validate passed options cache, mserv, mopts, popts = @pool = if cache # caller passed a Dalli::Client or ConnectionPool instance cache elsif popts # caller passed ConnectionPool options ConnectionPool.new(popts) { ::Dalli::Client.new(mserv, mopts) } else ::Dalli::Client.new(mserv, mopts) end if @pool.respond_to?(:alive!) # is a Dalli::Client @mutex = Mutex.new @pool.alive! end end |
Instance Attribute Details
#mutex ⇒ Object (readonly)
Returns the value of attribute mutex.
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# File 'lib/rack/session/dalli.rb', line 8 def mutex @mutex end |
#pool ⇒ Object (readonly)
Returns the value of attribute pool.
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# File 'lib/rack/session/dalli.rb', line 8 def pool @pool end |
Instance Method Details
#delete_session(req, sid, options) ⇒ Object
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# File 'lib/rack/session/dalli.rb', line 133 def delete_session(req, sid, ) destroy_session req.env, sid, end |
#destroy_session(env, session_id, options) ⇒ Object
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# File 'lib/rack/session/dalli.rb', line 117 def destroy_session(env, session_id, ) with_block(env) do |dc| dc.delete(session_id) generate_sid_with(dc) unless [:drop] end end |
#find_session(req, sid) ⇒ Object
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# File 'lib/rack/session/dalli.rb', line 125 def find_session(req, sid) get_session req.env, sid end |
#get_session(env, sid) ⇒ Object
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# File 'lib/rack/session/dalli.rb', line 95 def get_session(env, sid) with_block(env, [nil, {}]) do |dc| unless sid and !sid.empty? and session = dc.get(sid) old_sid, sid, session = sid, generate_sid_with(dc), {} unless dc.add(sid, session, @default_ttl) sid = old_sid redo # generate a new sid and try again end end [sid, session] end end |
#set_session(env, session_id, new_session, options) ⇒ Object
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# File 'lib/rack/session/dalli.rb', line 108 def set_session(env, session_id, new_session, ) return false unless session_id with_block(env, false) do |dc| dc.set(session_id, new_session, ttl([:expire_after])) session_id end end |
#write_session(req, sid, session, options) ⇒ Object
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# File 'lib/rack/session/dalli.rb', line 129 def write_session(req, sid, session, ) set_session req.env, sid, session, end |