# Singleton Pattern in RoR **URL:** \ **Category:** Rails\ **Created:** [October 16, 2006, 10:10pm UTC](https://www.ruby-forum.com/t/singleton-pattern-in-ror/72379 "2006-10-16T22:10:33Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![jsn1](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/7ea924/32.png) [@jsn1](https://www.ruby-forum.com/u/jsn1)\ **Post date:** [October 16, 2006, 10:10pm UTC](https://www.ruby-forum.com/t/singleton-pattern-in-ror/72379/1 "2006-10-16T22:10:33Z")
Hi all how can I implement the singleton patter in RoR? thanks ---
**Author:** ![jsn1](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/7ea924/32.png) [@jsn1](https://www.ruby-forum.com/u/jsn1)\ **Post date:** [October 16, 2006, 10:24pm UTC](https://www.ruby-forum.com/t/singleton-pattern-in-ror/72379/2 "2006-10-16T22:24:32Z")
On Oct 16, 2006, at 22:10, Jose P. wrote: > Hi all > > how can I implement the singleton patter in RoR? include Singleton – Jakob S. - [http://mentalized.net](http://mentalized.net) ---
**Author:** ![jsn1](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/7ea924/32.png) [@jsn1](https://www.ruby-forum.com/u/jsn1)\ **Post date:** [October 16, 2006, 10:47pm UTC](https://www.ruby-forum.com/t/singleton-pattern-in-ror/72379/3 "2006-10-16T22:47:15Z")
Hi Jose, The Singleton module that Jakob mentioned comes with Ruby, not rails. You can read about it in the ruby docs. Cheers Starr ---
**Author:** ![jsn1](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/7ea924/32.png) [@jsn1](https://www.ruby-forum.com/u/jsn1)\ **Post date:** [June 18, 2009, 4:41pm UTC](https://www.ruby-forum.com/t/singleton-pattern-in-ror/72379/4 "2009-06-18T16:41:01Z")
Justin F. wrote: > Starr wrote: > > > Hi Jose, > > > > The Singleton module that Jakob mentioned comes with Ruby, not rails. > > You can read about it in the ruby docs. > > Be aware that a Rails application that needs to handle concurrent > requests will do that by having multiple server processes (Mongrel, > FastCGI, SCGI, …) behind a web server or load balancer. Each server > process will have its own singleton instance. That is OK if you just > want a singleton holding fixed data, but won’t allow you to share > dynamic application state between requests and sessions. > > regards > > Justin F. Hi Justin, 2 years later … I’m looking for a non dirty way to implement a view with a progress bar who indicates the status of a certain task who takes some time to achieive. The task will be lunched in a thread. I first tried using a singleton class with the thread as an instance variable, but I realized that a different server thread serves each request, and so has one instance of the singleton. So it’s not a good option. Does anybody know how I should implement something like that ? I done it before passing by a file on disk to get the status of the thread. I posted a more detailed question here : [http://railsforum.com/viewtopic.php?pid=101201#p101201](http://railsforum.com/viewtopic.php?pid=101201#p101201) Thanks ---
**Author:** ![jsn1](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/7ea924/32.png) [@jsn1](https://www.ruby-forum.com/u/jsn1)\ **Post date:** [October 18, 2006, 9:27pm UTC](https://www.ruby-forum.com/t/singleton-pattern-in-ror/72379/5 "2006-10-18T21:27:02Z")
Starr wrote: > Hi Jose, > > The Singleton module that Jakob mentioned comes with Ruby, not rails. > You can read about it in the ruby docs. Be aware that a Rails application that needs to handle concurrent requests will do that by having multiple server processes (Mongrel, FastCGI, SCGI, …) behind a web server or load balancer. Each server process will have its own singleton instance. That is OK if you just want a singleton holding fixed data, but won’t allow you to share dynamic application state between requests and sessions. regards Justin F.