Gem, custom save method for rails

Question

I cannot figure this out from what I have read on Google, but I want to make a gem that will alter the behavior of the module when it saves, but I don't know how to do this. How would I define in the Gem a save method that overrides the model's save method?

Update: I have found Rails 3: alias_method_chain still used?, which I will check into. It appears that alias_method_chain is deprecated for Rails 3.

alter the behaviour how? like gsub one of the attributes or something to that effect? — pjammer, Aug 02 '11 at 14:55
For example, check for true...if false abort save if not continue — Travis Pessetto, Aug 18 '11 at 16:24
your example can be accomplished with validations. You also have the 'before_save' callback hook, if your behavior is simple. Are you thinking of doing something crazier than that? — YenTheFirst, Aug 22 '11 at 06:28
@YenTheFirst I was thinking about doing something crazier. The reason I asked is because I want to modify a Gems behavior on everything. — Travis Pessetto, Aug 22 '11 at 13:48

score 2 · Accepted Answer · answered Aug 22 '11 at 06:47

I'd rather do this :

module YourModule

  def self.included(base)
    base.extend(InstanceMethods)
  end

  module InstanceMethods

    def save
      # Your behavior here
      super # Use this if you want to call the old save method
    end
  end
end

And then in the model :

class User < ActiveRecord::Base
  include YourModule
end

Hope it helps :)

Maurício Linhares · Answer 2 · 2011-08-02T22:22:31.780

1

Using alias_method_chain:

module YourModule

  def self.included( base )
    base.send(:include, YourModule::InstanceMethods )
    base.alias_method_chain :save, :action
  end

  module InstanceMethods

    def save_with_action
      # do something here
      save_without_action
    end

  end

end

Then you include the module in your AR object:

class User < ActiveRecord::Base
    include YourModule
end

edited Aug 02 '11 at 22:22

answered Aug 02 '11 at 14:26

Maurício Linhares

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I am not sure but I think alias_method_chain was deprecated with Rails 3. http://stackoverflow.com/questions/3689736/rails-3-alias-method-chain-still-used – Travis Pessetto Aug 18 '11 at 16:26
even if alias_method_chain itself is deprecated, you can still do the same behavior. instead of 'base.alias_method_chain', you'd just have two 'base.alias_method' calls. – YenTheFirst Aug 22 '11 at 06:27

Gem, custom save method for rails

2 Answers2