rails-docstore/app/jobs/content_generation_job.rb

class ContentGenerationJob < ApplicationJob
  require 'docsplit'

  queue_as :default

  # after_perform :generate_tags

  def perform(document_id)
    @document_id = document_id
    @document = Document.find(document_id)
    @content = @document.build_content

    generate_metadata
    generate_text
    generate_page_previews
  end

  private
    def generate_metadata
      length = Docsplit.extract_length(@document.doc.path, output: 'tmp/raw_content')
      @content.pagecount = length
      @content.save
    end

    def generate_text
      Docsplit.extract_text(@document.doc.path, output: 'tmp/raw_content')
      file_path = 'tmp/raw_content/' + File.basename(@document.doc.path, 'pdf') + 'txt'
      text = IO.read(file_path)
      @content.text = text
      @content.save!

      File.delete(file_path) if File.exist?(file_path)
    end

    def generate_page_previews
      file_basename = File.basename(@document.doc.path, '.pdf')
      folder_path = 'tmp/raw_content/' + file_basename
      Docsplit.extract_images(@document.doc.path, output: folder_path, size: '200x', format: :png)
      1.upto(@content.pagecount) do |page|
        file_name = folder_path + '/' + File.basename(@document.doc.path, '.pdf') + '_' + page.to_s + '.png'
        page_preview = @content.page_previews.build
        file = File.open(file_name, 'rb')
        page_preview.preview = file
        page_preview.pagenumber = page
        file.close
        page_preview.save
      end
      FileUtils.rm_rf(folder_path)
    end

    def generate_tags
      TagGenerationJob.perform_now @document_id
    end
end