CRUD Concern for Rails Controllers

crud_concern_rails.rb

module CrudConcern
  extend ActiveSupport::Concern
  # Rails version < 5

  ##################################################################
  #      This module take cares the CRUD controller methods        #
  #                                                                #
  # Note: add skip_before_action if you want to ignore any of the  #
  # above action to be loaded from module                          #
  ##################################################################

  included do
    before_action :init_resource
    before_action :load_resources, only: [:index]
    before_action :load_resource, only: [:new, :edit, :update, :delete, :create, :show]
  end

  def index
  end

  def new
  end

  def show
  end

  def create
    instance_variable_get("@#{@resource}").save(send("#{@resource}_params"))
    redirect_to send("#{@resources}_path")
  end

  def edit
  end

  def update
    instance_variable_get("@#{@resource}").update_attributes(send("#{@resource}_params"))
    redirect_to send("#{@resources}_path")
  end

  def destroy
    instance_variable_get("@#{@resource}").destroy
    redirect_to send("#{@resources}_path")
  end

  private

  def init_resource
    @resources = controller_name
    @resource = @resources.singularize
  end

  def load_resource
    if params[:action] == "create"
      instance_variable_set "@#{@resource}", @resources.classify.constantize.new(send("#{@resource}_params"))
    else
      instance_variable_set "@#{@resource}", @resources.classify.constantize.find_or_initialize_by(id: params[:id])
    end
  end

  def load_resources
    instance_variable_set "@#{@resources}", @resources.classify.constantize.all.page(params[:page])
  end
end

crud_concern_rails5.rb

module CrudConcern
  extend ActiveSupport::Concern
  # rails version >= 5

  ##################################################################
  #      This module take cares the CRUD controller methods        #
  #                                                                #
  # Note: add skip_before_action if you want to ignore any of the  #
  # above action to be loaded from module                          #
  # additional feature has confirm verification before deleting a  #
  # record.                                                       #
  #                                                                #
  ##################################################################

  included do
    before_action :init_resource
    before_action :load_resources, only: [:index, :filter]
    before_action :load_resource, only: [:new, :edit, :update, :destroy, :create, :show]
  end

  def index
  end

  def filter
    render 'index'
  end

  def new
  end

  def show
  end

  def create
    if instance_variable_get("@#{@resource}").save(send("#{@resource}_params"))
      flash[:success] = "Created a #{@resource.camelize} successfully"
      redirect_to send("#{@resources}_path")
    else
      flash[:alert] = instance_variable_get("@#{@resource}").errors.full_messages.first
      redirect_back fallback_location: send("#{@resources}_path")
    end
  end

  def edit
  end

  def update
    if instance_variable_get("@#{@resource}").update!(send("#{@resource}_params"))
      flash[:success] = "Updated a #{@resource.camelize} successfully"
    end
    redirect_back fallback_location: send("edit_#{@resource}_path", instance_variable_get("@#{@resource}"))
  end

  def destroy
    respond_to do |format|
      format.html {
        if current_user.valid_password?(authenticate_params[:password])
          instance_variable_get("@#{@resource}").destroy
          flash[:success] = "Deleted a #{@resource.camelize} successfully"
        else
          flash[:error] = 'Invalid Password'
        end
        redirect_to send("#{@resources}_path")
      }
      format.js {
        @path = send("#{@resource}_path", instance_variable_get("@#{@resource}"))
        render 'shared/delete'
      }
    end 
  end

  private

  def init_resource
    @resources = controller_name
    @resource = @resources.singularize
  end

  def load_resource
    if params[:action] == "create"
      instance_variable_set "@#{@resource}", @resources.classify.constantize.new(send("#{@resource}_params"))
    else
      instance_variable_set "@#{@resource}", @resources.classify.constantize.find_or_initialize_by(id: params[:id])
    end
  end

  def load_resources
    if params[:action] == 'filter'
      instance_variable_set "@#{@resources}", @resources.classify.constantize.unscoped.filter(send("#{@resource}_filter_params")).page(params[:page])
    else
      instance_variable_set "@#{@resources}", @resources.classify.constantize.unscoped.all.page(params[:page])
    end
  end

  def authenticate_params
    params.require(:authenticate).permit(:password)
  end
end