Simple CSV Exporter

readme.md

Usage

exporter = Exporter.new
exporter.header = ["Firstname", "Lastname", "Email"]
[%w(Vincent Durand vincent@foo.com), %w(Bob Marley bob@foo.com)].each do |user|
  exporter.add user
end
exporter.to_csv('ISO-8859-15//IGNORE', 'UTF-8')

exporter.rb

require 'iconv'

class Exporter

  def initialize(separator = ';')
    @separator = separator
    @header = []
    @body = []
  end
  
  def header=(columns)
    @header = columns.flatten
  end
  
  # Add value to body
  #
  # @param [Array] values
  # @return [Array] @body
  def add(values)
    @body << values.flatten.join(@separator)
  end
  alias_method :<<, :add
  
  # Build CSV
  # Iconv (http://www.ruby-doc.org/stdlib-1.9.3/libdoc/iconv/rdoc/Iconv.html)
  #
  # @param [String] to
  # @param [String] from
  # @return [String]
  def to_csv(to, from)
    csv = Iconv.new(to, from)
    csv.iconv header_as_string + body_as_string
  end
  
  private
  
  def body_as_string
    @body.join("\n")
  end
  
  def header_as_string
    @header.join(@separator).concat("\n")
  end
  
end

exporter_test.rb

require 'minitest/autorun'
require File.join(File.expand_path(File.dirname(__FILE__)), 'exporter.rb')

class TestExporter < MiniTest::Unit::TestCase
  def setup
    @exporter = Exporter.new
    @exporter.header = ["Foo", "Bar"]
    @exporter.add [1, 2]
  end

  def test_should_set_header
    assert_equal ["Foo", "Bar"], @exporter.instance_variable_get('@header')
  end

  def test_should_set_body
    assert_equal ["1;2"], @exporter.instance_variable_get('@body')
  end

  def test_should_add_to_body
    @exporter.add [3, 4]
    assert_equal ["1;2", "3;4"], @exporter.instance_variable_get('@body')
  end

  def test_should_add_to_body_with_aliased_method
    @exporter << [3, 4]
    assert_equal ["1;2", "3;4"], @exporter.instance_variable_get('@body')
  end

  def test_should_export_to_csv
    assert_equal "Foo;Bar\n1;2", @exporter.to_csv('ISO-8859-15//IGNORE', 'UTF-8')
  end

  def test_should_export_to_csv_with_empty
    assert_equal "\n", Exporter.new.to_csv('ISO-8859-15//IGNORE', 'UTF-8')
  end

  def test_should_set_header_with_non_flatten_array
    @exporter.header = ["Foo", ["Name1", "Name2"], "Bar"]
    assert_equal ["Foo", "Name1", "Name2", "Bar"], @exporter.instance_variable_get('@header')
  end

  def test_should_raise_error_with_invalid_header_paramter
    assert_raises(NoMethodError) { @exporter.header = "Foo" }
  end

  def test_should_raise_error_with_invalid_body_paramter
    assert_raises(NoMethodError) { @exporter << "Foo" }
  end

  def test_should_get_header_as_string
    assert_equal "Foo;Bar\n", @exporter.send(:header_as_string)
  end

  def test_should_get_body_as_string
    @exporter.add [2, 3]
    assert_equal "1;2\n2;3", @exporter.send(:body_as_string)
  end

  def test_should_customize_separator
    @exporter = Exporter.new(':')
    @exporter.header = ["Foo", "Bar"]
    @exporter.add [1, 2]
    assert_equal "Foo:Bar\n1:2", @exporter.to_csv('ISO-8859-15//IGNORE', 'UTF-8')
  end
end