Upload a Tempfile to Carrierwave in Rails

Question

I am trying to create a Tempfile using some user-inputted information in one of my models:

after_create :form_to_csv

def form_to_csv
  temp_file = Tempfile.new('test_temp.csv', encoding: 'utf-8')

  begin
    self.input_data.split('\n').each do |line|
      temp_file.write line
    end

    temp_file.rewind
    self.build_input_data_file(file: Rails.root.join("temp_file.path}").open)
  ensure
    temp_file.close
    temp_file.unlink
  end
end

The form data is stored in the input_data field as text. I get to write my data to the Tempfile successfully but attaching it to the model is cumbersome - I keep trying to attach nil to my model. My main problem is that the file I generate has a path like:

/var/folders/jw/7pjlw_212qd3s4ddfj1zvnpr0000gn/T/test_temp.csv20170502-78762-1eh23ml

and it won't work with Rails.root.join and with the attachment method propose in CarrierWave docs here (Upload from a local file).

Answer 1

My mistake was that I tried to assign a .csv extension within the filename parameter of the Tempfile object. Instead I needed to pass an array like this:

def form_to_csv
  temp_file = Tempfile.new(['test_temp', '.csv'], encoding: 'utf-8')

  begin
    self.input_data.split('\n').each do |line|
      temp_file.write line
    end

    temp_file.rewind

    self.build_input_data_file(file: Rails.root.join(temp_file.path).open)
  ensure
    temp_file.close
    temp_file.unlink
  end
end