CODEWITHSUNDEEP
ruby-on-railsasp.net-mvcruby-on-rails-3
rajansoft1
rajansoft1

Reputation: 1356

Is there any action filter in Rails for handling exceptions

I was working on asp.net mvc before, now i am working on Ruby on Rails.

in asp.net mvc we use to handle validation using action filters, i am wondering if same thing is available in rails too.

i want to create custom validation class to handle business validation, so that action filter can process the exception based on the type of exception it is.

Upvotes: 1

Views: 422

Answers (1)

steve
steve

Reputation: 2638

I'm not at all familiar with asp.net, and may be misunderstanding your question but here is a way to handle exceptions that might occur when in an action of a Controller.

A generic Controller with some actions:

class SomethingController < ApplicationController
  def show
    @user = User.find_by_id(params[:user_id])
  end
end

Notice that the SomethingController is inheriting from this ApplicationController:

class ApplicationController < ActionController::Base
  rescue_from ActiveRecord::RecordNotFound do |exception|
    return render :json => {:status => 'error', :message => "given id does 
      not correlate to a record", :code => 404}
  end
end

Because the SomethingController (along with most other controllers) inherit from ApplicationController most exception handlers can be placed in ApplicationController.

Now the actual exception is not generated in the controller, but rather comes from a model. In the example above, and assuming I only have 10 users, ActiveRecord::RecordNotFound is an exception that will be called when the User model calls the find_by_id method with parameter 1000. There is no user with id 1000, so an ActiveRecord::RecordNotFound exception will be returned to the calling controller. SomethingController doesn't know how to handle this action, and will thus refer to its parent which has an appropriate handler.

Upvotes: 3

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