Module: TaliaCore::DataTypes::IipLoader

Included in:
FileRecord
Defined in:
lib/talia_core/data_types/iip_loader.rb

Overview

Special module that contains the DataLoader methods to create IIP image data

Instance Method Summary collapse

Instance Method Details

#convert_original?(mime_type) ⇒ Boolean

Indicates if the given mime type requires a conversion for the original image

Returns:

  • (Boolean) 


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# File 'lib/talia_core/data_types/iip_loader.rb', line 45

def convert_original?(mime_type)
  !([:jpeg, :png].include?(mime_type.to_sym))
end

#create_from_files(location, file, records) ⇒ Object

Create the elements from a file



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# File 'lib/talia_core/data_types/iip_loader.rb', line 50

def create_from_files(location, file, records)
  records.each { |rec| rec.create_from_file(location, file) }
end

#create_from_stream(location, io, records) ⇒ Object

Create the elements from a stream



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# File 'lib/talia_core/data_types/iip_loader.rb', line 55

def create_from_stream(location, io, records)
  data = io.read
  records.each { |rec| rec.create_from_data(location, data)}
end

#create_iip(mime_type, location, source, is_file) ⇒ Object

Loads an image for the given file. This is a tad more complex than loading the data into a data record: It will create both an IIP data object and an Image data object.



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# File 'lib/talia_core/data_types/iip_loader.rb', line 13

def create_iip(mime_type, location, source, is_file)
  iip_record = TaliaCore::DataTypes::IipData.new
  image_record = TaliaCore::DataTypes::ImageData.new
  records = [iip_record, image_record]
  return records if(is_file && prepare_image_from_existing!(iip_record, image_record, source, location))

  if(convert_original?(mime_type))
    # We have an image that needs to be converted
    open_original_image(source, is_file, mime_type) do |io|
      create_from_stream(location, io, records)
      image_record.location = orig_location(location)
    end
  else
    if(is_file)
      create_from_files(location, source, records) 
    else 
      create_from_stream(location, source, records)
    end
  end
  # IipRecord is always a (multi-leve) tiff
  iip_record.mime = 'image/tiff'

  records
end

#open_original_image(thing, is_file, current_type, &block) ⇒ Object

Little helper to decide how to open the original image



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# File 'lib/talia_core/data_types/iip_loader.rb', line 89

def open_original_image(thing, is_file, current_type, &block)
  if(is_file)
    open_original_image_file(thing, &block) 
  else
    open_original_image_stream(thing, current_type, &block)
  end
end

#open_original_image_file(filename) ⇒ Object

Opens the “original” image for the given file. This will convert the image to PNG image and the yield the io object for the PNG.



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# File 'lib/talia_core/data_types/iip_loader.rb', line 114

def open_original_image_file(filename)
  converted_file = File.join(Dir.tmpdir, "talia_convert_#{rand 10E16}.png")
  begin
    TaliaUtil::ImageConversions.to_png(filename, converted_file)
    File.open(converted_file) do |io|
      yield(io)
    end
  ensure
    FileUtils.rm(converted_file) if(File.exist?(converted_file))
  end
end

#open_original_image_stream(io, type, &block) ⇒ Object

Same as open_original_image_file, but getting the data from a stream.



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# File 'lib/talia_core/data_types/iip_loader.rb', line 98

def open_original_image_stream(io, type, &block)
  # First load this from the web to a temp file
  tempfile = File.join(Dir.tmpdir, "talia_down_#{rand 10E16}.#{type.to_sym}")
  begin
    File.open(tempfile, 'w') do |fio|
      fio << io.read # Download the file
    end
    assit(File.exist?(tempfile))
    open_original_image_file(tempfile, &block)
  ensure
    FileUtils.rm(tempfile) if(File.exist?(tempfile))
  end
end

#orig_location(location) ⇒ Object

Rewrite the file location for original image files (to .png)



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# File 'lib/talia_core/data_types/iip_loader.rb', line 39

def orig_location(location)
  File.basename(location, File.extname(location)) + '.png'
end

#prepare_image_from_existing!(iip_record, image_record, url, location) ⇒ Object

Attempts to create an IipData object with pre-prepared images if possible Returns true if (and only if) the object has been created with existing data. Always fals if the data_record is not an IipData object or the :prepared_images option is not set.

Raises:

  • (ArgumentError) 


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# File 'lib/talia_core/data_types/iip_loader.rb', line 64

def prepare_image_from_existing!(iip_record, image_record, url, location)
return false unless(iip_record.is_a?(TaliaCore::DataTypes::IipData) && image_record.is_a?(TaliaCore::DataTypes::ImageData))
return false unless((prep = ENV['prepared_images']) && prep.to_s.downcase != 'no' && prep.to_s.downcase != 'false')

file_ext = File.extname(url)
file_base = File.basename(url, file_ext)

thumb_file = File.join( ENV['prepared_images'], 'thumbs', "#{file_base}.gif")
pyramid_file = File.join( ENV['prepared_images'], 'pyramids', "#{file_base}.tif")
orig_file_pattern = File.join(ENV['prepared_images'], 'originals', "#{file_base}.*")
# We need to fix the pattern, also the Dir[] doesn't like unescaped brackets
orig_file_pattern.gsub!(/\[/, '\\[')
  orig_file_pattern.gsub!(/\]/, '\\]')
  orig_file_l = Dir[orig_file_pattern]
  raise(ArgumentError, 'Original find not found for ' + url) unless(orig_file_l.size > 0)
  orig_file = orig_file_l.first
  assit_block { %w(.jpg .jpeg .png).include?(File.extname(orig_file).downcase) }

  iip_record.create_from_existing(thumb_file, pyramid_file)
  image_record.create_from_file(location, orig_file)

  true
end