Class: Aspera::Preview::Generator

Inherits:
Object
  • Object
show all
Defined in:
lib/aspera/preview/generator.rb

Overview

generate one preview file for one format for one file at a time

Constant Summary collapse

PREVIEW_FORMATS =

values for preview_format : output format

%i[png mp4].freeze
FFMPEG_OPTIONS_LIST = 
%w[in out].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(src, dst, options, main_temp_dir, api_mime_type) ⇒ Generator

node API mime types are from: svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types supported preview type is one of Preview::PREVIEW_FORMATS the resulting preview file type is taken from destination file extension. conversion methods are provided by private methods: convert_<conversion_type>to<preview_format>

-> conversion_type is one of FileTypes::CONVERSION_TYPES
-> preview_format is one of Generator::PREVIEW_FORMATS

the conversion video->mp4 is implemented in methods: convert_video_to_mp4_using_<video_conversion>

-> conversion method is one of Generator::VIDEO_CONVERSION_METHODS

Parameters:

  • src —

    source file path

  • dst —

    destination file path

  • api_mime_type —

    optional mime type as provided by node api (or nil)



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# File 'lib/aspera/preview/generator.rb', line 38

def initialize(src, dst, options, main_temp_dir, api_mime_type)
  @source_file_path = src
  @destination_file_path = dst
  @options = options
  @temp_folder = File.join(main_temp_dir, @source_file_path.split('/').last.gsub(/\s/, '_').gsub(/\W/, ''))
  # extract preview format from extension of target file
  @preview_format_sym = File.extname(@destination_file_path).gsub(/^\./, '').to_sym
  conversion_type = FileTypes.instance.conversion_type(@source_file_path, api_mime_type)
  @processing_method = "convert_#{conversion_type}_to_#{@preview_format_sym}"
  if conversion_type.eql?(:video)
    case @preview_format_sym
    when :mp4
      @processing_method = "#{@processing_method}_using_#{@options.video_conversion}"
    when :png
      @processing_method = "#{@processing_method}_using_#{@options.video_png_conv}"
    end
  end
  @processing_method = @processing_method.to_sym
  Log.log.debug{"method: #{@processing_method}"}
  Aspera.assert(respond_to?(@processing_method, true)){"no processing know for #{conversion_type} -> #{@preview_format_sym}"}
end

Instance Attribute Details

#conversion_type ⇒ Object (readonly)

CLI needs to know conversion type to know if need skip it one of CONVERSION_TYPES



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# File 'lib/aspera/preview/generator.rb', line 25

def conversion_type
  @conversion_type
end

Instance Method Details

#generate ⇒ Object

create preview as specified in constructor



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# File 'lib/aspera/preview/generator.rb', line 61

def generate
  Log.log.info{"#{@source_file_path}->#{@destination_file_path} (#{@processing_method})"}
  begin
    send(@processing_method)
    # check that generated size does not exceed maximum
    result_size = File.size(@destination_file_path)
    Log.log.warn{"preview size exceeds maximum allowed #{result_size} > #{@options.max_size}"} if result_size > @options.max_size
  rescue StandardError => e
    Log.log.error{"Ignoring: #{e.message}"}
    Log.log.debug(e.backtrace.join("\n").red)
    FileUtils.cp(File.expand_path(@preview_format_sym.eql?(:mp4) ? 'video_error.png' : 'image_error.png', File.dirname(__FILE__)), @destination_file_path)
  ensure
    FileUtils.rm_rf(@temp_folder)
  end
end