run script after initialize

rubyonrails-talk
1

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!

2

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?

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

3

Jeremy Walker wrote in post #1059748:

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

4

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:

5

Jeremy Walker wrote in post #1059748:

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](http://association.name)}_tokens") do

        read_attribute(__method__[0..-8])

      end

   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?

6

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).

7

Jeremy Walker wrote in post #1059759:

> 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 ( Configuring Rails Applications — Ruby on Rails Guides) 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.

8

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)

9

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.