run script after initialize

[Guillem Vidal]

hi there!!

I'm just trying to run a script that adds certain methods to all
ActiveRecord::Base descendants, but what happens is that it seems that
all models are loaded after the application runs

ActiveRecord::Base.send(:descendants).each do |subclass|
#do stuff
end

ActiveRecord::Base.send(:descendants) and
ActiveRecord::Base.send(:subclasses) is allways empty [].

I've tried it on config/environment.rb and config/application.rb with no
success, can someone tell me what i can do about it?

Thanks!

--
Posted via http://www.ruby-forum.com/.

[Jeremy Walker]

You could just reopen ActiveRecord::Base. Create a new initializer (a ruby file in config/initializers) with:

class ActiveRecord::Base
def new_method
# do stuff
end
end

Does that help?
Jeremy Walker
http://www.ihid.co.uk

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>
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[Guillem Vidal]

Jeremy Walker wrote in post #1059748:

> On 6 May 2012, at 20:22, Guillem Vidal <li...@ruby-forum.com> wrote:
>
>> ActiveRecord::Base.send(:descendants) and
>> ActiveRecord::Base.send(:subclasses) is allways empty [].
>>
>> I've tried it on config/environment.rb and config/application.rb with no
>> success, can someone tell me what i can do about it?
>>
>
> You could just reopen ActiveRecord::Base. Create a new initializer (a
> ruby file in config/initializers) with:
>
> class ActiveRecord::Base
> def new_method
> # do stuff
> end
> end
>
> Does that help?
> Jeremy Walker
> http://www.ihid.co.uk

Not in my case. What I want to do is define different method names
depending on its relation, for example:

ActiveRecord::Base.send(:descendants).each do |subclass|

subclass.reflect_on_all_associations.each do |association|
macro = association.macro #:has_one, :has_many...
subclass.send(:define_method, "#{association.name}_tokens") do
read_attribute(__method__[0..-8])
end
end
end

[Guillem Vidal]

tryied something different, but no success again:

Dir[Rails.root.join('app/models/*.rb').to_s].each do |filename|
require filename #Connection not stablished...
klass = File.basename(filename).sub(/.rb$/,
'').classify.safe_constantize
next unless klass.nil? ||
klass.ancestors.include?(ActiveRecord::Base)
klass.reflect_on_all_associations.each do |association|
klass.send(:define_method, "#{association.name.to_s}_tokens")
do
read_attribute(__method__)
end
end
end

It raises connection not stablished.

Guillem Vidal wrote in post #1059754:

[Jeremy Walker]

OK, so two more suggestions:

1) Use an after_initialize block in your config (http://guides.rubyonrails.org/configuring.html#rails-general-configuration) to call your method_creation code.

2) Re-open the class (as per my prev suggestion) but write a create_association_tokens method that contains the code to define your reflected methods, and use ActiveRecord::Base's after_initialize method to call that method on an object, thus creating your methods on an object-by-object basis, rather than for the class.

I'm intrigued by the point of all this?

 

--
Posted via http://www.ruby-forum.com/.

[Rodrigo Vieira]

Well, I'd create a file and put it in /lib and include/initialize that file in the config.ru file before the actual app initialization (run YourApp::Application).

[Guillem Vidal]

Jeremy Walker wrote in post #1059759:

> On 6 May 2012 22:13, Guillem Vidal <li...@ruby-forum.com> wrote:
>
>> > You could just reopen ActiveRecord::Base. Create a new initializer (a

>> > http://www.ihid.co.uk

>> end
>> end
>>
>
> OK, so two more suggestions:
> 1) Use an after_initialize block in your config (
> http://guides.rubyonrails.org/configuring.html#rails-general-configuration)
> to call your method_creation code.
> 2) Re-open the class (as per my prev suggestion) but write a
> create_association_tokens method that contains the code to define your
> reflected methods, and use ActiveRecord::Base's after_initialize method
> to
> call that method on an object, thus creating your methods on an
> object-by-object basis, rather than for the class.
>
> I'm intrigued by the point of all this?

Sorry about the delay, I couldn't access to a computer since now :(.

Done it, but it raises me an error because i have a attr_writer, i need
to initialize the method.


module MyModule
def self.included(base)
base.send(:extend, InstanceMethods)
base.send(:after_initialize, :set_reader_writer_tokens)
end

module InstanceMethods
def set_reader_writer_tokens
class.reflect_on_all_associations.each do |association|
class.send(:define_method,"#{association.name.to_s}_tokens") do
attribute(__method__)
end
self.class.send(:define_method,
"#{association.name.to_s}_tokens=") do |value|
write_attribute(__method__, self.another_custom_method)
end
end
end
end


ActiveRecord::Base.send(:include, MyModule)

Loading development environment (Rails 3.2.2)
class OptionType < ActiveRecord::Base
belongs_to :type
end

OptionType.new(:type_tokens => "ba,b")
raises an unknown attribute :type_tokens.

But if I first initialize the record withouth accessing to the
attribute:

> OptionType.new
=> #<OptionType ...>
> OptionType.new(:type_tokens => "ba,b")
=> #<OptionType id: nil, name: nil, presentation: nil, created_at: nil,
updated_at: nil>

Then I can done it. The problem is that I need to set up that attribute
before the initialitzation of the class.

Is a very good approach, but still not enogh for a ruby on rails
application.

Maybe it can be done using method_missing... but I'm a little bit scared
of overwriting activerecord method_missing, also it's not clear.

[Guillem Vidal]

Rodrigo Vieira wrote in post #1059873:

> Well, I'd create a file and put it in /lib and include/initialize that
> file in the config.ru file before the actual app initialization (run
> YourApp::Application).

That worked! The problem is that this is only working when rails app
starts, not on rake tasks or test/units.

But from now on, what I need for my application is ok.



Just to know... Is it possible to do add those methods on the entire
application? (not only on the middleware)

[Rodrigo Vieira]

If the config.ru trick doesn't work for you, you should try the same but only initializing the file in config/boot.rb, instead. This should work for sure.

Sent from my iPod

On 06/05/2012, at 16:22, Guillem Vidal <li...@ruby-forum.com> wrote: