mt_parser.rb

class MtParser

  attr_reader :mt_records, :file_path, :is_parseing_body

  def self.import
    parser = new("#{Rails.root}/app/models/webuilder240.hatenablog.com.export.txt")
    parser.parse
    records = parser.mt_records
    ActiveRecord::Base.transaction do
      records.each do |mt_record|
        Blog.create!(
          title: mt_record.title,
          content: mt_record.body,
          is_publish: mt_record.status == "Publish",
          first_published_at: mt_record.date
        )
      end
    end
  end

  def initialize(file_path)
    @file_path = file_path
    @mt_records = []
    @is_parseing_body = false
  end

  def parse
    open(file_path) do |file|
      @current_record = MtRecord.new()
      file.each_line do |line|
        if line == MtRecord::POST_PERIOD
          @mt_records << @current_record
          @current_record = MtRecord.new()
          next
        end
        
        if @is_parseing_body
          if line == MtRecord::SECTION_PERIOD
            @is_parseing_body = false
          else 
            current_record.body << line
          end
          next
        end

        MtRecord::MT_ATTRIBUTES.each do |mt_attr|
          if line =~ /^#{mt_attr}\:/
            if mt_attr == "BODY"
              @is_parseing_body = true
              current_record.body = ""
            else 
              line.chomp!
              line.gsub!(/^#{mt_attr}\: /, "")
              current_record.send("#{mt_attr.downcase}=", line)
            end
          end
        end
      end
    end
  end

  private 

  attr_reader :current_record
end

mt_record.rb

class MtRecord
  MT_ATTRIBUTES = %W(TITLE AUTHOR STATUS DATE BODY)
  POST_PERIOD = "--------\n"
  SECTION_PERIOD = "-----\n"
  attr_accessor :title, :author, :base_name, :date, :body, :status
end