Class: RelationalExporter::Runner

Inherits:
Object
  • Object
show all
Defined in:
lib/relational_exporter.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ Runner

Returns a new instance of Runner.



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# File 'lib/relational_exporter.rb', line 11

def initialize(options={})
  @logger = options[:logger] ? options[:logger] : Logger.new(STDERR)

  @connection_config = options[:connection_config]
  begin
    ActiveRecord::Base.establish_connection @connection_config
    ActiveRecord::Base.connection.active?
  rescue Exception => e
    raise "Database connection failed: #{e.message}"
  end

  @schema = Hashie::Mash.new(options[:schema] || YAML.load_file(options[:schema_file]))

  load_models
end

Instance Attribute Details

#logger ⇒ Object

Returns the value of attribute logger.



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# File 'lib/relational_exporter.rb', line 9

def logger
  @logger
end

#schema ⇒ Object

Returns the value of attribute schema.



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# File 'lib/relational_exporter.rb', line 9

def schema
  @schema
end

Instance Method Details

#export(output_config, &block) ⇒ Object 



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# File 'lib/relational_exporter.rb', line 27

def export(output_config, &block)
  ActiveRecord::Base.logger = @logger

  output_config = Hashie::Mash.new output_config

  main_klass = output_config.output.model.to_s.classify.constantize

  main_klass.set_scope_from_hash output_config.output.scope.as_json

  header_row = []
  max_associations = {}

  csv_options = {headers: true}
  if output_config.file_path.blank?
    csv_method = :instance
    csv_args = [STDOUT, csv_options]
  else
    csv_method = :open
    csv_args = [output_config.file_path, 'wb', csv_options]
  end

  ::CSV.send(csv_method, *csv_args) do |csv|
    main_klass.find_all_by_scope(output_config.output.scope.as_json).find_in_batches do |batch|
      batch.each do |single|
        if block_given?
          yield single

          return unless single
        end

        row = []

        # Add main record headers
        serialized_attributes(single).each do |field, value|
          header_row << [main_klass.to_s.underscore, field].join('_').classify if csv.header_row?
          row << value
        end

        output_config.output.associations.each do |association_accessor, association_options|
          association_accessor = association_accessor.to_s.to_sym
          association_klass = association_accessor.to_s.classify.constantize
          scope = symbolize_options association_options.scope

          associated = single.send association_accessor
          # TODO - this might suck for single associations (has_one) because they don't return an ar::associations::collectionproxy
          associated = associated.find_all_by_scope(scope) unless scope.blank? || !associated.respond_to?(:find_all_by_scope)

          if associated.is_a? Hash
            associated = [ associated ]
          elsif associated.blank?
            associated = []
          end

          foreign_key = main_klass.reflections[association_accessor].foreign_key rescue nil

          fields = serialized_attributes(association_klass).keys

          fields.reject! {|v| v == foreign_key } if foreign_key

          if csv.header_row?
            case main_klass.reflections[association_accessor].macro
            when :has_many
              max_associated = association_klass.find_all_by_scope(scope)
                                                .joins(main_klass.table_name.to_sym)
                                                .order('count_all desc')
                                                .group(foreign_key)
                                                .limit(1).count.flatten[1]
            when :has_one
              max_associated = 1
            end

            max_associated = 0 if max_associated.nil?

            max_associations[association_accessor] = max_associated

            max_associated.times do |i|
              fields.each do |field|
                header_row << [association_klass.to_s.underscore, i+1, field].join('_').classify
              end
            end
          end

          get_row_arr(associated, fields, max_associations[association_accessor]) {|field| row << field}
        end

        csv << header_row if csv.header_row?
        if row.count != header_row.count
          @logger.error "Encountered invalid row, skipping."
        end
        csv << row
      end
    end
  end
end