How to simplify the soft delete process with Ruby on Rails?

Just use a concern in rails 4

Example here

module SoftDeletable
  extend ActiveSupport::Concern


  included do
    default_scope { where(is_deleted: false) }
    scope :only_deleted, -> { unscope(where: :is_deleted).where(is_deleted: true) }
  end

  def delete
    update_column :is_deleted, true if has_attribute? :is_deleted
  end

  def destroy;
    callbacks_result = transaction do
      run_callbacks(:destroy) do
        delete
      end
    end
    callbacks_result ? self : false
  end

  def self.included(klazz)
    klazz.extend Callbacks
  end

  module Callbacks
    def self.extended(klazz)
      klazz.define_callbacks :restore
      klazz.define_singleton_method("before_restore") do |*args, &block|
        set_callback(:restore, :before, *args, &block)
      end
      klazz.define_singleton_method("around_restore") do |*args, &block|
        set_callback(:restore, :around, *args, &block)
      end
      klazz.define_singleton_method("after_restore") do |*args, &block|
        set_callback(:restore, :after, *args, &block)
      end
    end
  end

  def restore!(opts = {})
    self.class.transaction do
      run_callbacks(:restore) do
        update_column :is_deleted, false
        restore_associated_records if opts[:recursive]
      end
    end
    self
  end

  alias :restore :restore!

  def restore_associated_records
    destroyed_associations = self.class.reflect_on_all_associations.select do |association|
      association.options[:dependent] == :destroy
    end
    destroyed_associations.each do |association|
      association_data = send(association.name)
      unless association_data.nil?
        if association_data.is_deleted?
          if association.collection?
            association_data.only_deleted.each { |record| record.restore(recursive: true) }
          else
            association_data.restore(recursive: true)
          end
        end
      end
      if association_data.nil? && association.macro.to_s == 'has_one'
        association_class_name = association.options[:class_name].present? ? association.options[:class_name] : association.name.to_s.camelize
        association_foreign_key = association.options[:foreign_key].present? ? association.options[:foreign_key] : "#{self.class.name.to_s.underscore}_id"
        Object.const_get(association_class_name).only_deleted.where(association_foreign_key, self.id).first.try(:restore, recursive: true)
      end
    end
    clear_association_cache if destroyed_associations.present?
  end
end

Deletable

A rails concern to add soft deletes.

Very simple and flexible way to customise/ change

(You can change the delete column to be a timestamp and change the methods to call ActiveRecord touch ).

Best where you want to control code not have gems for simple tasks.

Usage

In your Tables add a boolean column is_deletable

class AddDeletedAtToUsers < ActiveRecord::Migration
  def change
    add_column :users, :is_deleted, :boolean
  end
end

In your models

class User < ActiveRecord::Base
  has_many :user_details, dependent: :destroy

  include SoftDeletable
end

Methods and callbacks available:

User.only_deleted
User.first.destroy
User.first.restore
User.first.restore(recursive: true)

Note: Focus Using update_column or touch if you decide to use a timestamp column.

---

Edited

If you are using rails <= 3.x (this example also use a DateTime field instead boolean), there are some differences:

module SoftDeletable
  extend ActiveSupport::Concern

  included do
    default_scope { where(deleted_at: nil }
    # In Rails <= 3.x to use only_deleted, do something like 'data = Model.unscoped.only_deleted'
    scope :only_deleted, -> { unscoped.where(table_name+'.deleted_at IS NOT NULL') }
  end

  def delete
    update_column :deleted_at, DateTime.now if has_attribute? :deleted_at
  end

  # ... ... ...
  # ... OTHERS IMPLEMENTATIONS ...
  # ... ... ...

  def restore!(opts = {})
    self.class.transaction do
      run_callbacks(:restore) do
        # Remove default_scope. "UPDATE ... WHERE (deleted_at IS NULL)"
        self.class.send(:unscoped) do
          update_column :deleted_at, nil
          restore_associated_records if opts[:recursive]
        end
      end
    end
    self
  end

  alias :restore :restore!

  def restore_associated_records
    destroyed_associations = self.class.reflect_on_all_associations.select do |association|
      association.options[:dependent] == :destroy
    end
    destroyed_associations.each do |association|
      association_data = send(association.name)
      unless association_data.nil?
        if association_data.deleted_at?
          if association.collection?
            association_data.only_deleted.each { |record| record.restore(recursive: true) }
          else
            association_data.restore(recursive: true)
          end
        end
      end
      if association_data.nil? && association.macro.to_s == 'has_one'
        association_class_name = association.options[:class_name].present? ? association.options[:class_name] : association.name.to_s.camelize
        association_foreign_key = association.options[:foreign_key].present? ? association.options[:foreign_key] : "#{self.class.name.to_s.underscore}_id"
        Object.const_get(association_class_name).only_deleted.where(association_foreign_key, self.id).first.try(:restore, recursive: true)
      end
    end
    clear_association_cache if destroyed_associations.present?
  end
end

Usage

In your Tables add a DateTime column deleted_at

class AddDeletedAtToUsers < ActiveRecord::Migration
  def change
    add_column :users, :deleted_at, :datetime
  end
end

Try this gem : https://github.com/technoweenie/acts_as_paranoid - ActiveRecord plugin allowing you to hide and restore records without actually deleting them