Rails - Oct 2005 - environment.rb read only once?

Hi,

I have model called Player, it looks something like this:

class Player < ActiveRecord::Base

   @@image_path = ''''

   def self.image_path=(path)
     @@image_path = path
   end


   def path_to_images
     @@image_path + id.to_s + "/"
   end

end

In environment.rb I want to set the path where images are stored:

Player.image_path = "/images/players/"

This works on the first request, but not on any subsequent requests. 
@@image_path is reset to '''' after the first request. It works
when I
reboot WEBrick, but again in the 2nd request it stops working.

Any way to overcome this?

Jeroen

Hi,

I have model called Player, it looks something like this:

class Player < ActiveRecord::Base

   @@image_path = ''''

   def self.image_path=(path)
     @@image_path = path
   end


   def path_to_images
     @@image_path + id.to_s + "/"
   end

end

In environment.rb I want to set the path where images are stored:

Player.image_path = "/images/players/"

This works on the first request, but not on any subsequent requests. 
@@image_path is reset to '''' after the first request. It works
when I
reboot WEBrick, but again in the 2nd request it stops working.

Any way to overcome this?

Jeroen

Jeroen,

This is a consequence of the "reload" feature in development mode.  
The environment.rb is read only once (as is the Rails framework  
itself), but the classes are reloaded with every request, resulting  
in the behavior you described.

One solution I''ve used is to have to have a separate
"configuration"
module for the persistent configuration:

   class Player < ActiveRecord::Base
     module Configuration
       @@image_path = ''''
       mattr_accessor :image_path
     end

     def path_to_images
       "#{Configuration.image_path}#{id.to_s}/"
     end
   end

   ...

   Player::Configuration.image_path = "/blah/blah/blah"

Another option is to set the image path as a constant in your  
environment.rb:

   IMAGE_PATH = "/blah/blah/blah"

But I find this less attractive than the module-based approach,  
especially when there are multiple configuration options per class.

- Jamis

On Oct 21, 2005, at 6:53 AM, Jeroen Houben wrote:
> Hi,
>
> I have model called Player, it looks something like this:
>
> class Player < ActiveRecord::Base
>
>   @@image_path = ''''
>
>   def self.image_path=(path)
>     @@image_path = path
>   end
>
>
>   def path_to_images
>     @@image_path + id.to_s + "/"
>   end
>
> end
>
> In environment.rb I want to set the path where images are stored:
>
> Player.image_path = "/images/players/"
>
> This works on the first request, but not on any subsequent  
> requests. @@image_path is reset to '''' after the first
request. It
> works when I reboot WEBrick, but again in the 2nd request it stops  
> working.
>
> Any way to overcome this?
>
> Jeroen
>
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

Jamis Buck wrote:
> Jeroen,
>
> This is a consequence of the "reload" feature in development
mode.
> The environment.rb is read only once (as is the Rails framework  
> itself), but the classes are reloaded with every request, resulting  
> in the behavior you described.
>
Thanks James.
So in production mode classes are also read just once? That''s pretty 
sweet (I''m usually developing in PHP5 where classes everything is read 
on each request, unless you use some sort of bytecode caching module).
> One solution I''ve used is to have to have a separate
"configuration"
> module for the persistent configuration:
>
>   class Player < ActiveRecord::Base
>     module Configuration
>       @@image_path = ''''
>       mattr_accessor :image_path
>     end
>
>     def path_to_images
>       "#{Configuration.image_path}#{id.to_s}/"
>     end
>   end
>
>   ...
>
>   Player::Configuration.image_path = "/blah/blah/blah"
>
> Another option is to set the image path as a constant in your  
> environment.rb:
>
>   IMAGE_PATH = "/blah/blah/blah"
>
> But I find this less attractive than the module-based approach,  
> especially when there are multiple configuration options per class.
I agree.
So suppose another one of my Active record classes also needs an 
image_path configuration, would doing exactly the same for say a Match 
class cause a clash? Or is the Configuration Module a seperate entity in 
each class? Disclaimer: I''m just getting to know Ruby ;-)

Jeroen

On Oct 21, 2005, at 12:03 PM, Jeroen Houben wrote:
> Jamis Buck wrote:
>
>> One solution I''ve used is to have to have a separate  
>> "configuration"  module for the persistent configuration:
>>
>>   class Player < ActiveRecord::Base
>>     module Configuration
>>       @@image_path = ''''
>>       mattr_accessor :image_path
>>     end
>>
>>     def path_to_images
>>       "#{Configuration.image_path}#{id.to_s}/"
>>     end
>>   end
>>
>>   ...
>>
>>   Player::Configuration.image_path = "/blah/blah/blah"
>>
>> Another option is to set the image path as a constant in your   
>> environment.rb:
>>
>>   IMAGE_PATH = "/blah/blah/blah"
>>
>> But I find this less attractive than the module-based approach,   
>> especially when there are multiple configuration options per class.
>>
>
> I agree.
> So suppose another one of my Active record classes also needs an  
> image_path configuration, would doing exactly the same for say a  
> Match class cause a clash? Or is the Configuration Module a  
> seperate entity in each class? Disclaimer: I''m just getting to
know
> Ruby ;-)
The containing class (or module) acts as a namespace, so you can have  
identically named modules as long as they exist in separate classes/ 
modules, i.e.:

   class Player < ActiveRecord::Base
     module Configuration
       ...
     end
   end

   class Match < ActiveRecord::Base
     module Configuration
       ...
     end
   end

Both Configuration modules are distinct. You would access them as  
Player::Configuration and Match::Configuration, respectively.

- Jamis