Question

I’ve a field in my database called IP where I put the user IP (in #create method) when he send a message in my blog built in Rails.

But the field is visible when I want to see the articles in another format (JSON).
How can I hide the field IP?

Answer 1

You can do it in a format block in your controller like this:

respond_to do |format|
  format.json { render :json => @user, :except=> [:ip] } # or without format block: @user.to_json(:except => :ip)
end

If you want to generally exclude specific fields, just overwrite the to_json method in your user model:

class User < ActiveRecord::Base
  def to_json(options={})
    options[:except] ||= [:ip]
    super(options)
  end
end

Update: In Rails 6, the method became as_json:

class User < ApplicationRecord
  def as_json(options={})
    options[:except] ||= [:ip]
    super(options)
  end
end