Class: MiniExiftool

Inherits:
Object
  • Object
show all
Defined in:
lib/mini_exiftool.rb

Overview

Simple OO access to the ExifTool command-line application.

Defined Under Namespace

Classes: Error, TagHash

Constant Summary collapse

VERSION =
'2.9.0'
@@cmd =

Name of the ExifTool command-line application

'exiftool'
@@opts =

Hash of the standard options used when call MiniExiftool.new

{ :numerical => false, :composite => true, :fast => false, :fast2 => false,
:ignore_minor_errors => false, :replace_invalid_chars => false,
:timestamps => Time }
@@fs_enc =

Encoding of the filesystem (filenames in command line)

Encoding.find('filesystem')
@@encoding_types =
%w(exif iptc xmp png id3 pdf photoshop quicktime aiff mie vorbis)
@@running_on_windows =
/mswin|mingw|cygwin/ === RbConfig::CONFIG['host_os']

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(filename_or_io = nil, opts = {}) ⇒ MiniExiftool

filename_or_io The kind of the parameter is determined via duck typing: if the argument responds to to_str it is interpreted as filename, if it responds to read it is interpreted es IO instance.

ATTENTION: If using an IO instance writing of meta data is not supported!

opts support at the moment

  • :numerical for numerical values, default is false

  • :composite for including composite tags while loading, default is true

  • :ignore_minor_errors ignore minor errors (See -m-option of the exiftool command-line application, default is false)

  • :coord_format set format for GPS coordinates (See -c-option of the exiftool command-line application, default is nil that means exiftool standard)

  • :fast useful when reading JPEGs over a slow network connection (See -fast-option of the exiftool command-line application, default is false)

  • :fast2 useful when reading JPEGs over a slow network connection (See -fast2-option of the exiftool command-line application, default is false)

  • :replace_invalid_chars replace string for invalid UTF-8 characters or false if no replacing should be done, default is false

  • :timestamps generating DateTime objects instead of Time objects if set to DateTime, default is Time

    ATTENTION: Time objects are created using Time.local therefore they use your local timezone, DateTime objects instead are created without timezone!

  • :exif_encoding, :iptc_encoding, :xmp_encoding, :png_encoding, :id3_encoding, :pdf_encoding, :photoshop_encoding, :quicktime_encoding, :aiff_encoding, :mie_encoding, :vorbis_encoding to set this specific encoding (see -charset option of the exiftool command-line application, default is nil: no encoding specified)


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# File 'lib/mini_exiftool.rb', line 104

def initialize filename_or_io=nil, opts={}
  @opts = @@opts.merge opts
  if @opts[:convert_encoding]
    warn 'Option :convert_encoding is not longer supported!'
    warn 'Please use the String#encod* methods.'
  end
  @filename = nil
  @io = nil
  @values = TagHash.new
  @changed_values = TagHash.new
  @errors = TagHash.new
  load filename_or_io unless filename_or_io.nil?
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(symbol, *args) ⇒ Object (private)


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# File 'lib/mini_exiftool.rb', line 419

def method_missing symbol, *args
  tag_name = symbol.id2name
  if tag_name.sub!(/=$/, '')
    self[tag_name] = args.first
  else
    self[tag_name]
  end
end

Instance Attribute Details

#errorsObject (readonly)

Returns the value of attribute errors


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# File 'lib/mini_exiftool.rb', line 53

def errors
  @errors
end

#filenameObject (readonly)

Returns the value of attribute filename


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# File 'lib/mini_exiftool.rb', line 53

def filename
  @filename
end

#ioObject (readonly)

Returns the value of attribute io


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# File 'lib/mini_exiftool.rb', line 53

def io
  @io
end

Class Method Details

.all_tagsObject

Returns a set of all known tags of ExifTool.


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# File 'lib/mini_exiftool.rb', line 326

def self.all_tags
  unless defined? @@all_tags
    @@all_tags = pstore_get :all_tags
  end
  @@all_tags
end

.commandObject

Returns the command name of the called ExifTool application.


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# File 'lib/mini_exiftool.rb', line 311

def self.command
  @@cmd
end

.command=(cmd) ⇒ Object

Setting the command name of the called ExifTool application.


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# File 'lib/mini_exiftool.rb', line 316

def self.command= cmd
  @@cmd = cmd
end

.encoding_opt(enc_type) ⇒ Object


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# File 'lib/mini_exiftool.rb', line 60

def self.encoding_opt enc_type
  (enc_type.to_s + '_encoding').to_sym
end

.exiftool_versionObject

Returns the version of the ExifTool command-line application.


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# File 'lib/mini_exiftool.rb', line 350

def self.exiftool_version
  Open3.popen3 "#{MiniExiftool.command} -ver" do |_inp, out, _err, _thr|
    out.read.chomp!
  end
rescue SystemCallError
  raise MiniExiftool::Error.new("Command '#{MiniExiftool.command}' not found")
end

.from_hash(hash, opts = {}) ⇒ Object

Create a MiniExiftool instance from a hash. Default value conversions will be applied if neccesary.


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# File 'lib/mini_exiftool.rb', line 290

def self.from_hash hash, opts={}
  instance = MiniExiftool.new nil, opts
  instance.initialize_from_hash hash
  instance
end

.from_json(json, opts = {}) ⇒ Object

Create a MiniExiftool instance from JSON data. Default value conversions will be applied if neccesary.


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# File 'lib/mini_exiftool.rb', line 298

def self.from_json json, opts={}
  instance = MiniExiftool.new nil, opts
  instance.initialize_from_json json
  instance
end

.from_yaml(yaml, opts = {}) ⇒ Object

Create a MiniExiftool instance from YAML data created with MiniExiftool#to_yaml


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# File 'lib/mini_exiftool.rb', line 306

def self.from_yaml yaml, opts={}
  MiniExiftool.from_hash YAML.load(yaml), opts
end

.optsObject

Returns the options hash.


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# File 'lib/mini_exiftool.rb', line 321

def self.opts
  @@opts
end

.opts_accessor(*attrs) ⇒ Object


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# File 'lib/mini_exiftool.rb', line 42

def self.opts_accessor *attrs
  attrs.each do |a|
    define_method a do
      @opts[a]
    end
    define_method "#{a}=" do |val|
      @opts[a] = val
    end
  end
end

.original_tag(tag) ⇒ Object

Returns the original ExifTool name of the given tag


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# File 'lib/mini_exiftool.rb', line 342

def self.original_tag tag
  unless defined? @@all_tags_map
    @@all_tags_map = pstore_get :all_tags_map
  end
  @@all_tags_map[tag]
end

.pstore_dirObject


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# File 'lib/mini_exiftool.rb', line 364

def self.pstore_dir
  unless defined? @@pstore_dir
    # This will hopefully work on *NIX and Windows systems
    home = ENV['HOME'] || ENV['HOMEDRIVE'] + ENV['HOMEPATH'] || ENV['USERPROFILE']
    subdir = @@running_on_windows ? '_mini_exiftool' : '.mini_exiftool'
    @@pstore_dir = File.join(home, subdir)
  end
  @@pstore_dir
end

.pstore_dir=(dir) ⇒ Object


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# File 'lib/mini_exiftool.rb', line 374

def self.pstore_dir= dir
  @@pstore_dir = dir
end

.unify(tag) ⇒ Object


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# File 'lib/mini_exiftool.rb', line 358

def self.unify tag
  tag.to_s.gsub(/[-_]/,'').downcase
end

.writable_tagsObject

Returns a set of all possible writable tags of ExifTool.


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# File 'lib/mini_exiftool.rb', line 334

def self.writable_tags
  unless defined? @@writable_tags
    @@writable_tags = pstore_get :writable_tags
  end
  @@writable_tags
end

Instance Method Details

#[](tag) ⇒ Object

Returns the value of a tag.


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# File 'lib/mini_exiftool.rb', line 170

def [] tag
  @changed_values[tag] || @values[tag]
end

#[]=(tag, val) ⇒ Object

Set the value of a tag.


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# File 'lib/mini_exiftool.rb', line 175

def []= tag, val
  @changed_values[tag] = val
end

#changed?(tag = false) ⇒ Boolean

Returns true if any tag value is changed or if the value of a given tag is changed.

Returns:

  • (Boolean)

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# File 'lib/mini_exiftool.rb', line 181

def changed? tag=false
  if tag
    @changed_values.include? tag
  else
    !@changed_values.empty?
  end
end

#changed_tagsObject

Returns an array of all changed tags.


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# File 'lib/mini_exiftool.rb', line 207

def changed_tags
  @changed_values.keys.map { |key| MiniExiftool.original_tag(key) }
end

#copy_tags_from(source_filename, tags) ⇒ Object


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# File 'lib/mini_exiftool.rb', line 258

def copy_tags_from(source_filename, tags)
  @errors.clear
  unless File.exist?(source_filename)
    raise MiniExiftool::Error.new("Source file #{source_filename} does not exist!")
  end
  params = '-q -P -overwrite_original '
  tags_params = Array(tags).map {|t| '-' << t.to_s}.join(' ')
  cmd = [@@cmd, params, '-tagsFromFile', escape(source_filename).encode(@@fs_enc), tags_params.encode('UTF-8'), escape(filename).encode(@@fs_enc)].join(' ')
  cmd.force_encoding('UTF-8')
  result = run(cmd)
  reload
  result
end

#initialize_from_hash(hash) ⇒ Object

:nodoc:


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# File 'lib/mini_exiftool.rb', line 118

def initialize_from_hash hash # :nodoc:
  set_values hash
  set_opts_by_heuristic
  self
end

#initialize_from_json(json) ⇒ Object

:nodoc:


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# File 'lib/mini_exiftool.rb', line 124

def initialize_from_json json # :nodoc:
  @output = json
  @errors.clear
  parse_output
  self
end

#load(filename_or_io) ⇒ Object

Load the tags of filename or io.


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# File 'lib/mini_exiftool.rb', line 132

def load filename_or_io
  if filename_or_io.respond_to? :to_str # String-like
    unless filename_or_io && File.exist?(filename_or_io)
      raise MiniExiftool::Error.new("File '#{filename_or_io}' does not exist.")
    end
    if File.directory?(filename_or_io)
      raise MiniExiftool::Error.new("'#{filename_or_io}' is a directory.")
    end
    @filename = filename_or_io.to_str
  elsif filename_or_io.respond_to? :read # IO-like
    @io = filename_or_io
    @filename = '-'
  else
    raise MiniExiftool::Error.new("Could not open filename_or_io.")
  end
  @values.clear
  @changed_values.clear
  params = '-j '
  params << (@opts[:numerical] ? '-n ' : '')
  params << (@opts[:composite] ? '' : '-e ')
  params << (@opts[:coord_format] ? "-c \"#{@opts[:coord_format]}\"" : '')
  params << (@opts[:fast] ? '-fast ' : '')
  params << (@opts[:fast2] ? '-fast2 ' : '')
  params << generate_encoding_params
  if run(cmd_gen(params, @filename))
    parse_output
  else
    raise MiniExiftool::Error.new(@error_text)
  end
  self
end

#reloadObject

Reload the tags of an already read file.


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# File 'lib/mini_exiftool.rb', line 165

def reload
  load @filename
end

#revert(tag = nil) ⇒ Object

Revert all changes or the change of a given tag.


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# File 'lib/mini_exiftool.rb', line 190

def revert tag=nil
  if tag
    val = @changed_values.delete(tag)
    res = val != nil
  else
    res = @changed_values.size > 0
    @changed_values.clear
  end
  res
end

#saveObject

Save the changes to the file.


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# File 'lib/mini_exiftool.rb', line 212

def save
  if @io
    raise MiniExiftool::Error.new('No writing support when using an IO.')
  end
  return false if @changed_values.empty?
  @errors.clear
  temp_file = Tempfile.new('mini_exiftool')
  temp_file.close
  temp_filename = temp_file.path
  FileUtils.cp filename.encode(@@fs_enc), temp_filename
  all_ok = true
  @changed_values.each do |tag, val|
    original_tag = MiniExiftool.original_tag(tag)
    arr_val = val.kind_of?(Array) ? val : [val]
    arr_val.map! {|e| convert_before_save(e)}
    params = '-q -P -overwrite_original '
    params << (arr_val.detect {|x| x.kind_of?(Numeric)} ? '-n ' : '')
    params << (@opts[:ignore_minor_errors] ? '-m ' : '')
    params << generate_encoding_params
    arr_val.each do |v|
      params << %Q(-#{original_tag}=#{escape(v)} )
    end
    result = run(cmd_gen(params, temp_filename))
    unless result
      all_ok = false
      @errors[tag] = @error_text.gsub(/Nothing to do.\n\z/, '').chomp
    end
  end
  if all_ok
    FileUtils.cp temp_filename, filename.encode(@@fs_enc)
    reload
  end
  temp_file.delete
  all_ok
end

#save!Object


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# File 'lib/mini_exiftool.rb', line 248

def save!
  unless save
    err = []
    @errors.each do |key, value|
      err << "(#{key}) #{value}"
    end
    raise MiniExiftool::Error.new("MiniExiftool couldn't save. The following errors occurred: #{err.empty? ? "None" : err.join(", ")}")
  end
end

#tagsObject

Returns an array of the tags (original tag names) of the read file.


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# File 'lib/mini_exiftool.rb', line 202

def tags
  @values.keys.map { |key| MiniExiftool.original_tag(key) }
end

#to_hashObject

Returns a hash of the original loaded values of the MiniExiftool instance.


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# File 'lib/mini_exiftool.rb', line 274

def to_hash
  result = {}
  @values.each do |k,v|
    result[MiniExiftool.original_tag(k)] = v
  end
  result
end

#to_yamlObject

Returns a YAML representation of the original loaded values of the MiniExiftool instance.


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# File 'lib/mini_exiftool.rb', line 284

def to_yaml
  to_hash.to_yaml
end