Class: Assembly::ObjectFile

Inherits:
Object
  • Object
show all
Defined in:
lib/assembly/object_file.rb,
lib/assembly/object_file/version.rb

Overview

This class contains generic methods to operate on any file.

Constant Summary collapse

VALID_MIMETYPE_METHODS = 
%i[override exif file extension].freeze
VERSION =

Gem version

'2.1.0'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(path, params = {}) ⇒ ObjectFile

Returns a new instance of ObjectFile.

Examples:

Assembly::ObjectFile.new('/input/path_to_file.tif')

Parameters:

  • path (String) —

    full path to the file to be worked with

  • params (Hash<Symbol => Object>) (defaults to: {}) —

    options used during content metadata generation

Options Hash (params):

  • :file_attributes (Hash<Symbol => ['yes', 'no']>) —

    e.g.: :preserve=>‘yes’,:shelve=>‘no’,:publish=>‘no’, defaults pulled from mimetype

  • :label (String) —

    a resource label (files bundled together will just get the first file’s label attribute if set)

  • :provider_md5 (String) —

    pre-computed MD5 checksum

  • :provider_sha1 (String) —

    pre-computed SHA1 checksum

  • :relative_path (String) —

    if you want the file ids in the content metadata it can be set, otherwise content metadata will get the full path

  • :mime_type_order (Array) —

    can be set to the order in which you want mimetypes to be determined options are :override (from manual overide mapping if exists),

    :exif (from exif if exists)
:extension (from file extension)
:file (from unix file system command)

    the default is defined in the private ‘default_mime_type_order` method but you can override to set your own order



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# File 'lib/assembly/object_file.rb', line 57

def initialize(path, params = {})
  @path = path
  @label = params[:label]
  @file_attributes = params[:file_attributes]
  @relative_path = params[:relative_path]
  @provider_md5 = params[:provider_md5]
  @provider_sha1 = params[:provider_sha1]
  @mime_type_order = params[:mime_type_order] || default_mime_type_order
end

Instance Attribute Details

#file_attributes ⇒ Object

Returns the value of attribute file_attributes.



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# File 'lib/assembly/object_file.rb', line 33

def file_attributes
  @file_attributes
end

#label ⇒ Object

Returns the value of attribute label.



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# File 'lib/assembly/object_file.rb', line 33

def label
  @label
end

#mime_type_order ⇒ Object

Returns the value of attribute mime_type_order.



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# File 'lib/assembly/object_file.rb', line 33

def mime_type_order
  @mime_type_order
end

#path ⇒ Object

Returns the value of attribute path.



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# File 'lib/assembly/object_file.rb', line 33

def path
  @path
end

#provider_md5 ⇒ Object

Returns the value of attribute provider_md5.



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# File 'lib/assembly/object_file.rb', line 33

def provider_md5
  @provider_md5
end

#provider_sha1 ⇒ Object

Returns the value of attribute provider_sha1.



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# File 'lib/assembly/object_file.rb', line 33

def provider_sha1
  @provider_sha1
end

#relative_path ⇒ Object

Returns the value of attribute relative_path.



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# File 'lib/assembly/object_file.rb', line 33

def relative_path
  @relative_path
end

Class Method Details

.common_path(strings) ⇒ String

Class level method that given an array of strings, return the longest common initial path. Useful for removing a common path from a set of filenames when producing content metadata

Example:

puts Assembly::ObjectFile.common_prefix(['/Users/peter/00/test.tif','/Users/peter/05/test.jp2'])
# => '/Users/peter/0'

Parameters:

  • strings (Array) —

    Array of filenames with paths to operate on

Returns:

  • (String) —

    longest common initial part of path of filenames passed in



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# File 'lib/assembly/object_file.rb', line 19

def self.common_path(strings)
  return nil if strings.empty?

  n = 0
  x = strings.last
  n += 1 while strings.all? { |s| s[n] && (s[n] == x[n]) }
  common_prefix = x[0...n]
  if common_prefix[-1, 1] == '/' # check if last element of the common string is the end of a directory
    common_prefix # if not, split string along directories, and reject last one
  else
    "#{common_prefix.split('/')[0..-2].join('/')}/" # if it was, then return the common prefix directly
  end
end

Instance Method Details

#dirname ⇒ String

Returns base directory.

Examples:

source_file = Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_file.dirname # "/input"

Returns:

  • (String) —

    base directory



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# File 'lib/assembly/object_file.rb', line 79

def dirname
  File.dirname(path)
end

#exif ⇒ MiniExiftool

Returns exif information stored as a hash and an object.

Examples:

source_file = Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_file.exif # hash with exif information

Returns:

  • (MiniExiftool) —

    exif information stored as a hash and an object



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# File 'lib/assembly/object_file.rb', line 103

def exif
  @exif ||= begin
    check_for_file
    MiniExiftool.new(path, replace_invalid_chars: '?')
  end
end

#ext ⇒ String

Returns filename extension.

Examples:

source_file = Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_file.ext # ".tif"

Returns:

  • (String) —

    filename extension



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# File 'lib/assembly/object_file.rb', line 87

def ext
  File.extname(path)
end

#file_exists? ⇒ Boolean

Determines if the file exists (and is not a directory)

Examples:

source_file = Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_file.file_exists? # true

Returns:

  • (Boolean) —

    file exists



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# File 'lib/assembly/object_file.rb', line 207

def file_exists?
  @file_exists ||= (File.exist?(path) && !File.directory?(path))
end

#filename ⇒ String

Returns base filename.

Examples:

source_file = Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_file.filename # "path_to_file.tif"

Returns:

  • (String) —

    base filename



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# File 'lib/assembly/object_file.rb', line 71

def filename
  File.basename(path)
end

#filename_without_ext ⇒ String

Returns base filename without extension.

Examples:

source_file = Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_file.filename # "path_to_file"

Returns:

  • (String) —

    base filename without extension



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# File 'lib/assembly/object_file.rb', line 95

def filename_without_ext
  File.basename(path, ext)
end

#filesize ⇒ Integer

Returns file size information for the current file in bytes.

Examples:

source_file = Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_file.filesize # 1345

Returns:

  • (Integer) —

    file size in bytes



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# File 'lib/assembly/object_file.rb', line 197

def filesize
  check_for_file
  @filesize ||= File.size(path)
end

#image? ⇒ Boolean

Returns if object is an image.

Examples:

source_file = Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_file.image? # true

Returns:

  • (Boolean) —

    if object is an image



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# File 'lib/assembly/object_file.rb', line 162

def image?
  object_type == :image
end

#jp2able? ⇒ Boolean

Examines the input image for validity to create a jp2. Same as valid_image? but also confirms the existence of a profile description and further restricts mimetypes. It is used by the assembly robots to decide if a jp2 will be created and is also called before you create a jp2 using assembly-image.

Examples:

source_img = Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_img.jp2able? # true

Returns:

  • (Boolean) —

    true if image should have a jp2 created, false if not.



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# File 'lib/assembly/object_file.rb', line 186

def jp2able?
  return false unless exif

  Assembly::VALID_IMAGE_MIMETYPES.include?(mimetype)
end

#md5 ⇒ String

Computes md5 checksum or returns cached value

Examples:

source_file = Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_file.md5 # 'XXX123XXX1243XX1243'

Returns:

  • (String) —

    md5 checksum



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# File 'lib/assembly/object_file.rb', line 115

def md5
  check_for_file unless @md5
  @md5 ||= Digest::MD5.file(path).hexdigest
end

#mimetype ⇒ String

Returns mimetype information for the current file based on the ordering set in default_mime_type_order

We stop computing mimetypes as soon as we have a method that returns a value

Examples:

source_file = Assembly::ObjectFile.new('/input/path_to_file.txt')
puts source_file.mimetype # 'text/plain'

Returns:

  • (String) —

    mime type



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# File 'lib/assembly/object_file.rb', line 136

def mimetype
  @mimetype ||= begin
    check_for_file
    mimetype = ''
    mime_type_order.each do |mime_type_method|
      mimetype = send("#{mime_type_method}_mimetype") if VALID_MIMETYPE_METHODS.include?(mime_type_method)
      break if mimetype.present?
    end
    mimetype
  end
end

#object_type ⇒ Symbol

Returns the type of object, could be :application (for PDF or Word, etc), :audio, :image, :message, :model, :multipart, :text or :video.

Examples:

source_file = Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_file.object_type # :image

Returns:

  • (Symbol) —

    the type of object, could be :application (for PDF or Word, etc), :audio, :image, :message, :model, :multipart, :text or :video



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# File 'lib/assembly/object_file.rb', line 153

def object_type
  lookup = MIME::Types[mimetype][0]
  lookup.nil? ? :other : lookup.media_type.to_sym
end

#sha1 ⇒ String

Computes sha1 checksum or return cached value

Examples:

source_file = Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_file.sha1 # 'XXX123XXX1243XX1243'

Returns:

  • (String) —

    sha1 checksum



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# File 'lib/assembly/object_file.rb', line 125

def sha1
  check_for_file unless @sha1
  @sha1 ||= Digest::SHA1.file(path).hexdigest
end

#valid_image? ⇒ Boolean

Examines the input image for validity. Used to determine if image is a valid and useful image. If image is not a jp2, also checks if it is jp2able?

Examples:

source_img = Assembly::ObjectFile.new('/input/path_to_file.tif')
puts source_img.valid_image? # true

Returns:

  • (Boolean) —

    true if image is valid, false if not.



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# File 'lib/assembly/object_file.rb', line 172

def valid_image?
  return false unless image?

  mimetype == 'image/jp2' || jp2able?
end