Question

I have several controllers that take an instance of different classes each (Email, Call, Letter, etc) and they all have to go through this same substitution:

@email.message.gsub!("{FirstName}", @contact.first_name)
@email.message.gsub!("{Company}", @contact.company_name) 
@email.message.gsub!("{Colleagues}", @colleagues.to_sentence)
@email.message.gsub!("{NextWeek}", (Date.today + 7.days).strftime("%A, %B %d"))
@email.message.gsub!("{ContactTitle}", @contact.title )

So, for example, @call.message for Call, @letter.message for Letter, etcetera.

This isn’t very dry. I tried the following:

class ApplicationController < ActionController::Base
  helper :all # include all helpers, all the time

  def message_sub(asset, contact, colleagues)
    asset.message.gsub!("{FirstName}", contact.first_name)
    asset.message.gsub!("{Company}", contact.company_name) 
    asset.message.gsub!("{Colleagues}", colleagues.to_sentence)
    asset.message.gsub!("{NextWeek}", (Date.today + 7.days).strftime("%A, %B %d"))
    asset.message.gsub!("{ContactTitle}", contact.title )
  end
end

So in, say, the Letter Controller have this:

@letter = Letter.find(params[:letter]) #:letter was passed as a hash of the letter instance

message_sub(@letter, @contact, @colleagues)

@contact_letter.body = @letter.body

But the above doesn’t work.

Answer 1

To answer your question directly, you want a module. You can put it in your lib directory.

module MessageSubstitution

  def message_sub(asset, contact, colleagues)
    asset.message.gsub!("{FirstName}", contact.first_name)
    asset.message.gsub!("{Company}", contact.company_name) 
    asset.message.gsub!("{Colleagues}", colleagues.to_sentence)
    asset.message.gsub!("{NextWeek}", (Date.today + 7.days).strftime("%A, %B %d"))
    asset.message.gsub!("{ContactTitle}", contact.title )
  end

end

Then in your controller

class MyController < ApplicationController

  include MessageSubstitution


  def action

    ...

    message_sub(@letter, @contact, @colleagues)

  end

end

However, as some have already pointed out, this is probably better at the model level:

module MessageSubstitution

  def substituted_message(contact, colleagues)
    message.gsub("{FirstName}", contact.first_name).
           gsub("{Company}", contact.company_name).
           gsub("{Colleagues}", colleagues.to_sentence).
           gsub("{NextWeek}", (Date.today + 7.days).strftime("%A, %B %d")).
           gsub("{ContactTitle}", contact.title )
  end

end

Which you would then include at the model level, and then call in your controller like @letter.substituted_message(@contact, @colleagues)

However, I’m a little confused that what you posted didn’t work, though. If it’s defined on ApplicationController it should work. Module-based solution still better IMO.