# Preloading a controller just once **URL:** \ **Category:** Rails\ **Created:** [February 2, 2007, 6:33pm UTC](https://www.ruby-forum.com/t/preloading-a-controller-just-once/84252 "2007-02-02T18:33:00Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![wickie](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/w/ba9def/32.png) [@wickie](https://www.ruby-forum.com/u/wickie)\ **Post date:** [February 2, 2007, 6:33pm UTC](https://www.ruby-forum.com/t/preloading-a-controller-just-once/84252/1 "2007-02-02T18:33:00Z")
I’m looking for a way to have a controller pre-loaded at application startup and even in the development environment have it loaded just once. I’ll make it a bit more concrete. I’m in the process of writing a little plugin for interrogating the state of a Rails app. Among other things, it ties into request handling and provides a hook for gathering statistics. The code for calculating a statistic I’d like to define within a controller. Currently it looks like this class StatusController \< ApplicationController include HealthCheck ``` define_check :database_available do ActiveRecord::Base.connection != nil end define_statistic :request_count, :accumulator => [0] do | ``` accumulator, \*ignored| accumulator[0] += 1 end end With Rails working as it does, this code is only loaded when the status controller is accessed for the first time through a request. Only from then on are the defined statistics updated. In the development environment the accumulated values are forgotten again on the next request as classes are reloaded then. To circumvent these issues, I’d like to load this particular controller on startup and don’t have it reloaded again. Any suggestions on how to achieve this? Michael – Michael S. [mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) [http://www.schuerig.de/michael/](http://www.schuerig.de/michael/) ---
**Author:** ![wickie](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/w/ba9def/32.png) [@wickie](https://www.ruby-forum.com/u/wickie)\ **Post date:** [February 2, 2007, 6:40pm UTC](https://www.ruby-forum.com/t/preloading-a-controller-just-once/84252/2 "2007-02-02T18:40:01Z")
Hello Michael, 2007/2/2, Michael S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > To circumvent these issues, I’d like to load this particular controller > on startup and don’t have it reloaded again. Any suggestions on how to > achieve this? Did you try to require or reference StatusController in environment.rb ? That would at least load the controller. Then, the reloading part… [http://dev.rubyonrails.org/browser/trunk/activesupport/lib/active\_support/dependencies.rb#L44](http://dev.rubyonrails.org/browser/trunk/activesupport/lib/active_support/dependencies.rb#L44) We have a way to unload constants, but not the reverse. Maybe this will help: #will\_unload? [http://dev.rubyonrails.org/browser/trunk/activesupport/lib/active\_support/dependencies.rb#L288](http://dev.rubyonrails.org/browser/trunk/activesupport/lib/active_support/dependencies.rb#L288) ## Hope that helps ! François Beausoleil [http://blog.teksol.info/](http://blog.teksol.info/) [http://piston.rubyforge.org/](http://piston.rubyforge.org/) ---
**Author:** ![wickie](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/w/ba9def/32.png) [@wickie](https://www.ruby-forum.com/u/wickie)\ **Post date:** [February 2, 2007, 10:26pm UTC](https://www.ruby-forum.com/t/preloading-a-controller-just-once/84252/3 "2007-02-02T22:26:27Z")
Hello Michael, 2007/2/2, Michael S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > When I require StatusController in environment.rb, reloading is no > longer a problem. But as I said above, I don’t like that I have to > require ApplicationController in addition. This appears to be causing > other mayhem, too. Just randomly clicking around in the app gave me an > exception: ArgumentError “A copy of AuthenticatedSystem has been > removed from the module tree but is still active!”. I’m pretty sure > this is related to the explicit require for ApplicationController, > which includes AuthenticatedSystem. Instead of requiring “application”, try to reference ApplicationController instead. ## Bye ! François Beausoleil [http://blog.teksol.info/](http://blog.teksol.info/) [http://piston.rubyforge.org/](http://piston.rubyforge.org/) ---
**Author:** ![wickie](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/w/ba9def/32.png) [@wickie](https://www.ruby-forum.com/u/wickie)\ **Post date:** [February 2, 2007, 8:59pm UTC](https://www.ruby-forum.com/t/preloading-a-controller-just-once/84252/4 "2007-02-02T20:59:18Z")
On Friday 02 February 2007 18:39, Francois B. wrote: > Hello Michael, Hi Francois, thanks for helping. > 2007/2/2, Michael S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > > > To circumvent these issues, I’d like to load this particular > > controller on startup and don’t have it reloaded again. Any > > suggestions on how to achieve this? > > Did you try to require or reference StatusController in > environment.rb ? That would at least load the controller. Yes, either results in an exception as the ApplicationController, the superclass of StatusController, is not yet loaded and can’t be autoloaded either, apparently. I can require ‘application’, of course, but that prevents reloading of ApplicationController even in the development environment, I gather. > Then, the reloading part… When I require StatusController in environment.rb, reloading is no longer a problem. But as I said above, I don’t like that I have to require ApplicationController in addition. This appears to be causing other mayhem, too. Just randomly clicking around in the app gave me an exception: ArgumentError “A copy of AuthenticatedSystem has been removed from the module tree but is still active!”. I’m pretty sure this is related to the explicit require for ApplicationController, which includes AuthenticatedSystem. Michael – Michael S. [mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) [http://www.schuerig.de/michael/](http://www.schuerig.de/michael/) ---
**Author:** ![wickie](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/w/ba9def/32.png) [@wickie](https://www.ruby-forum.com/u/wickie)\ **Post date:** [February 2, 2007, 11:17pm UTC](https://www.ruby-forum.com/t/preloading-a-controller-just-once/84252/5 "2007-02-02T23:17:33Z")
On Friday 02 February 2007 22:25, Francois B. wrote: > > ApplicationController, which includes AuthenticatedSystem. > > Instead of requiring “application”, try to reference > ApplicationController instead. This immediately results in an exception: “uninitialized constant ApplicationController (NameError)”. I’ve tried it on a freshly generated project, too, and got the same exception. Michael – Michael S. [mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) [http://www.schuerig.de/michael/](http://www.schuerig.de/michael/)