video_transcoding_worker.rb

# This worker's purpose is to get a transcoded / minified version of a video
# from the Filestack API for display on discussion pages
# See Filestack API docs: https://www.filestack.com/docs/api/processing/#audio-and-video

module FilestackUploadWorkers

  class VideoTranscodingWorker
    include Sidekiq::Worker
    sidekiq_options unique: :until_timeout, unique_job_expiration: 60 * 60 * 24

    attr_reader :resource_handle,:attachment_id,:attachment_class,:opts

    def perform(attachment_id, attachment_class, resource_handle)
      puts "VideoTranscodingWorker.perform: attachment_id, attachment_class, resource_handle #{attachment_id}, #{attachment_class}, #{resource_handle}"
      @attachment_id = attachment_id
      @attachment_class = attachment_class
      @resource_handle = resource_handle

      # Poll to see if the video transcoding is completed & update the record; otherwise reschedule
      poll_for_complete || reschedule_worker
    end

    # Find the discussion attachment by ID
    def discussion_attachment
      @discussion_attachment ||= attachment_class.find(attachment_id)
    end


    # Poll to Filestack transcoding API and return JSON response
    # TODO: Test me - post resource for transcoding
    def post_to_transcode
      puts "VideoTranscodingWorker.post_to_transcode"
      max_width, max_height = [600, 400]
      base_url = 'https://cdn.filestackcontent.com'
      conversion = "video_convert=width:#{max_width},height:#{max_height}"
      uri = URI.parse([base_url, conversion, resource_handle].join('/'))
      req = Net::HTTP::Get.new(uri)
      res = Net::HTTP.start(uri.hostname, uri.port) {|http| http.request(req) }
      res.body
    end

    # Is the returned JSON "data" field empty?
    def completed?(response)
      puts "VideoTranscodingWorker.completed?"
      JSON.parse(response)["data"].empty? ? false : true
    end

    # Reschedule the worker to poll again in 1 minute
    def reschedule_worker
      puts "VideoTranscodingWorker.reschedule_worker"
      VideoTranscodingWorker.perform_in(1.minute, attachment_class, attachment_id)
    end

    # Test the transcoding is complete. If so, save the new compressed_version_url.
    # Return false if returned JSON data is still empty
    def poll_for_complete
      puts "VideoTranscodingWorker.poll_for_complete"
      res = post_to_transcode
      puts "completed?(res):"
      if completed?(res)
        puts "TRUE"
        update_compressed_url(res)
        return true
      else
        puts "FALSE"
        return false
      end
    end

    # Update the attachment record with the new compressed_version_url
    def update_compressed_url(response)
      puts "VideoTranscodingWorker.update_compressed_url"
      new_url = response['data']['url']
      discussion_attachment.update_attribute(compressed_version_url: new_url)
    end

  end

end