attempt_1.rb

class ExampleController < ApplicationController
  def action_1
    if res1.eql?(false)
      render json: {message: 'Failed'}, status: 400 unless res_1
      return
    end
    # rest of the logic....
    render json: {data: '...'}, status: 200
  end

  def action_2
    if res1.eql?(false)
      render json: {message: 'Failed'}, status: 400 unless res_1
      return
    end
    # rest of the logic....
    render json: {data: '...'}, status: 200
  end

  def action_3
    if res2.eql?(false)
      render json: {message: 'Failed'}, status: 400 unless res_2
      return
    end
    # rest of the logic....
    render json: {data: '...'}, status: 200
  end

  def action_4
    if res2.eql?(false)
      render json: {message: 'Failed'}, status: 400 unless res_2
      return
    end
    # rest of the logic....
    render json: {data: '...'}, status: 200
  end
  
  private
  
  def res_1
    # perform some operations
    (operation1_successful?) ? true : false
  end
  
  def res_2
    # perform some operations
    (operation2_successful?) ? true : false
  end
end