download.rb

def download_all_post_contents
    posts = @campaign.posts
    if posts.present?
      folder = "/tmp"
      file = "/tmp/archive#{Time.now.to_i}_.zip"
      urls = []

      posts.each do |post|
        urls << post.filestack_image_url if post.filestack_image_url.present?
        urls << post.photo_attributes('original')['url'] if post.photo.present?
        urls << post.filestack_video_url if post.filestack_video_url.present?
        urls << post.video_attributes('remote')['url'] if post.video.present?
      end

      urls = urls.collect {|url| download_url(url) }.compact

      Zip::File.open(file, Zip::File::CREATE) do |zipfile|
        urls.each do |filename|
          zipfile.add(filename, File.join(folder, filename.path.split('/').last))
        end
      end
      send_file(file, :type => 'application/zip', :filename => 'post_contents.zip')
    else
      redirect_to brands_campaign_path(@campaign), notice: 'This campaign has no post.'
    end
  end