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

[:png,:mp4]

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options, src, dst, main_temp_dir, api_mime_type = nil, try_local_mime = true) ⇒ 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> (combi = combination of source file type and destination 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



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# File 'lib/aspera/preview/generator.rb', line 28

def initialize(options,src,dst,main_temp_dir,api_mime_type=nil,try_local_mime=true)
  @options=options
  @source_file_path=src
  @destination_file_path=dst
  @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_symb=File.extname(@destination_file_path).gsub(/^\./,'').to_sym
  @conversion_type=FileTypes.conversion_type(@source_file_path,api_mime_type,try_local_mime)
end

Instance Attribute Details

#conversion_type ⇒ Object (readonly)

CLI needs to know conversion type to know if need skip it



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# File 'lib/aspera/preview/generator.rb', line 14

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 62

def generate
  raise "could not detect type of file" if @conversion_type.nil?
  method_symb=processing_method_symb
  Log.log.info("#{@source_file_path}->#{@destination_file_path} (#{method_symb})")
  begin
    self.send(method_symb)
    # check that generated size does not exceed maximum
    result_size=File.size(@destination_file_path)
    if result_size > @options.max_size
      Log.log.warn("preview size exceeds maximum #{result_size} > #{@options.max_size}")
    end
  rescue => e
    Log.log.error("#{e.message}")
    Log.log.debug(e.backtrace.join("\n").red)
    FileUtils.cp(File.expand_path(@preview_format_symb.eql?(:mp4)?'video_error.png':'image_error.png',File.dirname(__FILE__)),@destination_file_path)
  ensure
    FileUtils.rm_rf(@temp_folder)
  end
end

#processing_method_symb ⇒ Object

name of processing method in this object combination of: conversion type and output format (and video_conversion for video)



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# File 'lib/aspera/preview/generator.rb', line 40

def processing_method_symb
  name="convert_#{@conversion_type}_to_#{@preview_format_symb}"
  if @conversion_type.eql?(:video)
    case @preview_format_symb
    when :mp4
      name="#{name}_using_#{@options.video_conversion}"
    when :png
      name="#{name}_using_#{@options.video_png_conv}"
    end
  end
  Log.log.debug("method: #{name}")
  return name.to_sym
end

#supported? ⇒ Boolean

for instance, plaintext to mp4 is not supported



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# File 'lib/aspera/preview/generator.rb', line 56

def supported?
  return false if @conversion_type.nil?
  return respond_to?(processing_method_symb,true)
end