Export Records to CSV Files with Rails

Learn how to export records into CSV files using Ruby on Rails. Here are the steps.

Steps:

1. Add a controller and make sure you handle the csv request.
2. Add a route to point to your controller
3. Add a model with the class method to_csv

Lets code it!

Controller

# users_controller.rb

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

Routes

# routes.rb

...

resources :users, only: :index

...

Model

# user.rb

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

Core custom methods:

to_csv will map out the "id, email, name" values of your model collection and then generate a CSV string.

Rails core methods for this feature:

#send_data Sends the given binary data to the browser. This method is similar to render :text => data, but also allows you to specify whether the browser should display the response as a file attachment (i.e. in a download dialog) or as inline data. You may also set the content type, the apparent file name, and other things. Source