Synthesis: How to generate CSV files in Rails

How to generate CSV files in Rails

sbecker — Thu, 07 Jun 2007 16:21:00 -0700

A while back someone posted on rubyonrails-talk asking how to export to CSV from Rails. I posted a solution, and people seemed to dig it, so I’ll share it again here.

Use FasterCSV

Get the FasterCSV gem. Why? It’s faster, and easier to use. Once you’ve got it, require it in environment.rb. Here’s an abbreviated version of my working controller method. Copy/paste/modify. And you’re done!


def export_to_csv
  @users = User.find(:all)

  csv_string = FasterCSV.generate do |csv|
    # header row
    csv << ["id", "first_name", "last_name"]

    # data rows
    @users.each do |user|
      csv << [user.id, user.first_name, user.last_name]
    end
  end

  # send it to the browsah
  send_data csv_string,
            :type => 'text/csv; charset=iso-8859-1; header=present',
            :disposition => "attachment; filename=users.csv"
end

HTML or CSV, have it your way

Now, if we wanted to get all clever about it, we could go further and serve both html and CSV data with only one action, using respond_to. This also requires that you add a RESTful route (map.resources :users) to your routes.rb file:

def index
  @users = User.find(:all)

  respond_to do |wants|
    wants.html
    wants.csv do
      csv_string = FasterCSV.generate do |csv|
        # header row
        csv << ["id", "first_name", "last_name"]

        # data rows
        @users.each do |user|
          csv << [user.id, user.first_name, user.last_name]
        end
      end

      # send it to the browsah
      send_data csv_string,
                :type => 'text/csv; charset=iso-8859-1; header=present',
                :disposition => "attachment; filename=users.csv"
    end
  end

end

Now if the user requests:

/users

she’ll get HTML. If she requests:

/users.csv

You get the point.

"How to generate CSV files in Rails" by Jill

Wed, 07 May 2008 12:08:31 -0700

Good tutorial, thanks!

"How to generate CSV files in Rails" by תוכנת תיווך

Sat, 05 Apr 2008 01:51:40 -0700

Sweet nifty little tip. I was actually rebooting and using windows every time I needed to do a .csv . You just saved me a lot of time Scott.

Thanks a lot.

Michal

"How to generate CSV files in Rails" by Gregory Brown

Wed, 27 Jun 2007 07:27:50 -0700

Using Ruport:

class User < ActiveRecord::Base
  acts_as_reportable :only => ["id, "first_name", "last_name"]
end

# in controller
def export_to_csv
   User.report_table.to_csv
end

Of course, maybe overkill if that’s all you need, but Ruport + acts_as_reportable also handles all associations and whatnot. (And uses FCSV under the hood)

"How to generate CSV files in Rails" by Meekish

Fri, 08 Jun 2007 07:32:09 -0700

Now that’s hot :)

"How to generate CSV files in Rails" by Scott Becker

Thu, 07 Jun 2007 21:45:04 -0700

@Meekish – Updated with a respond_to example.

"How to generate CSV files in Rails" by Scott Becker

Thu, 07 Jun 2007 20:57:38 -0700

@Meekish – Good idea. That would be more Rails 2.0ish, wouldn’t it. Maybe I will post another example using respond_to soon.

"How to generate CSV files in Rails" by Meekish

Thu, 07 Jun 2007 20:51:39 -0700

That’s very nice.

How about making UsersController#index respond_to .csv instead of creating an entire action for it?

"How to generate CSV files in Rails" by Jason Perry

Thu, 07 Jun 2007 20:11:25 -0700

I’ve got a little ruby class that encapsulates to dumping of csv files out to disk. I use this to generate some regular reports.

Report.create "District Participation" do
  data = District.find(:all, :order => "number").map do |district|
    profiles = district.profiles
    ratings  = profiles.collect { |p| p.ratings.size }
    [district.county, profiles.size, ratings.sum]
  end
  [["District", "Respondants", "Ratings"]] + data
end

Report.create "Subject Area Participation" do
  data = Subject.find(:all, :order => "area").map do |subject|
    profiles = subject.profiles
    ratings  = profiles.collect { |p| p.ratings.size }
    [subject.area, profiles.size, ratings.sum]
  end
  [["Subject Area", "Respondants", "Ratings"]] + data
end

It needs somework, to clean up the way reports are defined, but it works well.