Exports records from a sample users model to csv by means of a controller action and `.csv` format. Ruby on Rails app

export_records_in_model_to_csv.rb

# Synchronously creates and sends records for download
# For scale, this would be better done async via a rake task, chron job, or something similar
# borrowed from https://gorails.com/episodes/export-to-csv

# sample controller
class UsersController < ApplicationController
  
  def index
    @users = User.all

    respond_to do |format|
      format.html
      format.csv { send_data @users.to_csv, filename: "users-#{Date.today}.csv" }
    end
  end
 
end

# sample model
class User < ActiveRecord::Base
  def self.to_csv
    attributes = %w{id email name}

    CSV.generate(headers: true) do |csv|
      csv << attributes

      all.each do |user|
        csv << attributes.map{ |attr| user.send(attr) }
      end
    end
  end

  def name
    "#{first_name} #{last_name}"
  end
end