in rails, how to return records as a csv file

Question

I have a simple database table called \"Entries\":

class CreateEntries < ActiveRecord::Migration
  def self.up
    create_table :entries do |t|
      t.st         


        

Answer 1

Take a look into the FasterCSV gem.

If all you need is excel support, you might also look into generating a xls directly. (See Spreadsheet::Excel)

gem install fastercsv
gem install spreadsheet-excel

I find these options good for opening the csv file in Windows Excel:

FasterCSV.generate(:col_sep => ";", :row_sep => "\r\n") { |csv| ... }

As for the ActiveRecord part, something like this would do:

CSV_FIELDS = %w[ title created_at etc ]
FasterCSV.generate do |csv|
  Entry.all.map { |r| CSV_FIELDS.map { |m| r.send m }  }.each { |row| csv << row }
end

Answer 2

I accepted (and voted up!) @Brian's answer, for first pointing me to FasterCSV. Then when I googled to find the gem, I also found a fairly complete example at this wiki page. Putting them together, I settled on the following code.

By the way, the command to install the gem is: sudo gem install fastercsv (all lower case)

require 'fastercsv'

class EntriesController < ApplicationController

  def getcsv
      entries = Entry.find(:all)
      csv_string = FasterCSV.generate do |csv| 
            csv << ["first","last"]
            entries.each do |e|
              csv << [e.firstName,e.lastName]
            end
          end
          send_data csv_string, :type => "text/plain", 
           :filename=>"entries.csv",
           :disposition => 'attachment'

  end


end

Answer 3

Take a look at the CSV Shaper gem.

https://github.com/paulspringett/csv_shaper

It has a nice DSL and works really well with Rails models. It also handles the response headers and allows filename customisation.

Answer 4

try a nice gem to generate CSV from Rails https://github.com/crafterm/comma

Answer 5

FasterCSV is definitely the way to go, but if you want to serve it directly from your Rails app, you'll want to set up some response headers, too.

I keep a method around to set up the filename and necessary headers:

def render_csv(filename = nil)
  filename ||= params[:action]
  filename += '.csv'

  if request.env['HTTP_USER_AGENT'] =~ /msie/i
    headers['Pragma'] = 'public'
    headers["Content-type"] = "text/plain" 
    headers['Cache-Control'] = 'no-cache, must-revalidate, post-check=0, pre-check=0'
    headers['Content-Disposition'] = "attachment; filename=\"#{filename}\"" 
    headers['Expires'] = "0" 
  else
    headers["Content-Type"] ||= 'text/csv'
    headers["Content-Disposition"] = "attachment; filename=\"#{filename}\"" 
  end

  render :layout => false
end

Using that makes it easy to have something like this in my controller:

respond_to do |wants|
  wants.csv do
    render_csv("users-#{Time.now.strftime("%Y%m%d")}")
  end
end

And have a view that looks like this: (generate_csv is from FasterCSV)

UserID,Email,Password,ActivationURL,Messages
<%= generate_csv do |csv|
  @users.each do |user|
    csv << [ user[:id], user[:email], user[:password], user[:url], user[:message] ]
  end
end %>

Answer 6

Another way to do this without using FasterCSV:

Require ruby's csv library in an initializer file like config/initializers/dependencies.rb

require "csv"

As some background the following code is based off of Ryan Bate's Advanced Search Form that creates a search resource. In my case the show method of the search resource will return the results of a previously saved search. It also responds to csv, and uses a view template to format the desired output.

  def show
    @advertiser_search = AdvertiserSearch.find(params[:id])
    @advertisers = @advertiser_search.search(params[:page])
    respond_to do |format|
      format.html # show.html.erb
      format.csv  # show.csv.erb
    end
  end

The show.csv.erb file looks like the following:

<%- headers = ["Id", "Name", "Account Number", "Publisher", "Product Name", "Status"] -%>
<%= CSV.generate_line headers %>
<%- @advertiser_search.advertisers.each do |advertiser| -%>
<%- advertiser.subscriptions.each do |subscription| -%>
<%- row = [ advertiser.id,
            advertiser.name,
            advertiser.external_id,
            advertiser.publisher.name,
            publisher_product_name(subscription),
            subscription.state ] -%>
<%=   CSV.generate_line row %>
<%- end -%>
<%- end -%>

On the html version of the report page I have a link to export the report that the user is viewing. The following is the link_to that returns the csv version of the report:

<%= link_to "Export Report", formatted_advertiser_search_path(@advertiser_search, :csv) %>