Ruby ActiveRecord importing library

Question

In my Rails app I need to import some files from CSV and Excel files. I needed it in 2 models so I have written lib/importable.rb:

module Importable
 def self.included(base)
 base.send :extend, ActAsMethods
 end
 module ActAsMethods
 def act_as_importable(&block)
 @import_block = block
 send :extend, ImportableMethods
 end
 attr_reader :import_block
 end
 module ImportableMethods
 def import_from(file, *args)
 raise 'This model is not importable' if import_block.nil?
 send(:before_import, *args) if respond_to? :before_import
 sheet = open_spreadsheet(file)
 header = sheet.row(1).map(&:to_sym)
 (2..sheet.last_row).map do |i|
 row = Hash[header.zip(sheet.row(i))]
 import_block.call(row, *args)
 end
 end
 private
 def open_spreadsheet(file)
 logger.info "Importing file #{file.original_filename}"
 case File.extname(file.original_filename)
 when '.csv' then Csv.new(file.path, nil, :ignore)
 when '.xls' then Excel.new(file.path, nil, :ignore)
 when '.xlsx' then Excelx.new(file.path, nil, :ignore)
 when '.ods' then Openoffice.new(file.path, nil, :ignore)
 else raise "Unknown file type: #{file.original_filename}"
 end
 rescue
 raise "Cannot open file: #{file.original_filename}"
 end
 end
end
class ActiveRecord::Base
 include Importable
end

And in model I need to write, i.e.:

class Invoice < ActiveRecord::Base
 act_as_importable do |row, company|
 invoice = company.invoices.find_or_initialize_by_name(row[:name].to_s)
 vat_in = if row[:client].is_a? String
 row[:client]
 else
 row[:client].to_i
 end
 client = company.clients.find_by_vat_in(vat_in.to_s)
 invoice.client = client
 invoice.pay_date = row[:pay_date]
 invoice.full_amount = row[:full_amount].to_i
 invoice.paid_amount = row[:paid_amount].to_i
 invoice.save!
 invoice
 end
end

The importing in controller looks like:

 def save
 file = params[:file]
 logger.debug file.path
 Invoice.transaction do
 @invoices = Invoice.import_from(file, current_company)
 @invoices.each(&:save)
 end
 rescue RuntimeError => error
 logger.debug error
 redirect_to import_company_clients_path, alert: I18n.t('invalid_file')
 rescue ActiveRecord::RecordInvalid
 redirect_to import_company_clients_path, alert: I18n.t('invalid_record')
 else
 respond_to do |format|
 format.html
 format.json { render json: @invoices }
 end
 end

But IMHO it's a little overbloated. Have you any suggedtions to make it more reagable and Gemified?

Answer 1

Notes:

• Your code looks pretty good, but I personally wouldn't have written it as a mixable module, this code seemps completely independent from ActiveRecord. I'd write a SpreadSheetReader class and just use it from wherever you want (this way the code is more modular).

• Where is import_from called from? it seems some code is missing.

• This vat_in conditional seems too verbose. Which are the possible values of row[:client]?

I'd write something like:

company = company_from_somewhere_i_dont_know
columns = [:name, :client, <other columns>...]
SpreadSheetReader.rows(:columns => columns).map do |row|
 invoice = company.invoices.find_or_initialize_by_name(row[:name].to_s)
 vat_in = row[:client].is_a?(String) ? row[:client] : row[:client].to_i.to_s
 client = company.clients.find_by_vat_in!(vat_in)
 invoice.update_attributes!({
 :pay_date => row[:pay_date],
 :full_amount => row[:full_amount].to_i,
 :paid_amount => row[:paid_amount].to_i,
 })
 invoice
end