Module: Traject::Macros::Marc21

Included in:
Indexer::MarcIndexer
Defined in:
lib/traject/macros/marc21.rb

Overview

Some of these may be generic for any MARC, but we haven't done the analytical work to think it through, some of this is def specific to Marc21.

Constant Summary collapse

EXTRACT_MARC_VALID_OPTIONS =

A list of symbols that are valid keys in the options hash

[:first, :trim_punctuation, :default,
:allow_duplicates, :separator, :translation_map,
:alternate_script]
SERIALZED_MARC_VALID_OPTIONS =
[:format, :binary_escape, :allow_oversized]
EXTRACT_ALL_MARC_VALID_OPTIONS =
[:separator, :from, :to]

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.apply_extraction_options(accumulator, options, translation_map = nil) ⇒ Object

Side-effect the accumulator with the options


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# File 'lib/traject/macros/marc21.rb', line 115

def self.apply_extraction_options(accumulator, options, translation_map=nil)
  only_first              = options[:first]
  trim_punctuation        = options[:trim_punctuation]
  default_value           = options[:default]
  allow_duplicates        = options[:allow_duplicates]

  if only_first
    accumulator.replace Array(accumulator[0])
  end

  if translation_map
    translation_map.translate_array! accumulator
  end

  if trim_punctuation
    accumulator.collect! {|s| Marc21.trim_punctuation(s)}
  end

  unless allow_duplicates
    accumulator.uniq!
  end

  if options.has_key?(:default) && accumulator.empty?
    accumulator << default_value
  end
end

.extract_marc(spec, options = {}) ⇒ Object

A macro that will extract data from marc according to a string field/substring specification.

First argument is a string spec suitable for the MarcExtractor, see Traject::MarcExtractor::Spec.

Second arg is optional options, including options valid on MarcExtractor.new, and others. By default, will de-duplicate results, but see :allow_duplicates

  • :allow_duplicates => boolean, default false, if set to true then will avoid de-duplicating the result array (array.uniq!)

  • :separator: (default ' ' (space)), what to use when joining multiple subfield matches from same field. Set to nil to leave them as separate values (which is actually default if only one subfield is given in spec, like 100a). See MarcExtractor docs for more info.

  • :alternate_script: (default true). True, automatically include 'alternate script' MARC 880 linked fields corresponding to matched specifications. false, do not include. :only include only linked 880s corresponding to spec, not base tags.

Soft-Deprecated options: post-processing transformations

These don't produce a deprecation warning and there is no planned horizon for them to go away, but the alternative of using additional transformation macros (from Traject::Macros::Transformation) composed with extract_marc is recommended.

  • :first => true: take only first value. Instead, use extract_marc(whatever), first_only

  • :translation_map => String: translate with named translation map looked up in load path, uses Tranject::TranslationMap.new(translation_map_arg). Instead, use extract_marc(whatever), translation_map(translation_map_arg)

  • :trim_punctuation => true; trims leading/trailing punctuation using standard algorithms that have shown themselves useful with Marc, using Marc21.trim_punctuation. Instead, use extract_marc(whatever), trim_punctuation

  • :default => String: if otherwise empty, add default value. Instead, use extract_marc(whatever), default("default value")

Examples:

to_field("title"), extract_marc("245abcd"), trim_punctuation
to_field("id"),    extract_marc("001"), first_only
to_field("geo"),   extract_marc("040a", :separator => nil), translation_map("marc040")

If you'd like extract_marc functionality but you're not creating an indexer step, see Traject::Macros::Marc21.extract_marc_from module method.


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# File 'lib/traject/macros/marc21.rb', line 62

def extract_marc(spec, options = {})

  # Raise an error if there are any invalid options, indicating a
  # misspelled or illegal option, using a string instead of a symbol, etc.

  unless (options.keys - EXTRACT_MARC_VALID_OPTIONS).empty?
    raise RuntimeError.new("Illegal/Unknown argument '#{(options.keys - EXTRACT_MARC_VALID_OPTIONS).join(', ')}' in extract_marc at #{Traject::Util.extract_caller_location(caller.first)}")
  end


  # We create the TranslationMap and the MarcExtractor here
  # on load, so the lambda can just refer to already created
  # ones, and not have to create a new one per-execution.
  #
  # Benchmarking shows for MarcExtractor at least, there is
  # significant performance advantage.

  if translation_map_arg  = options.delete(:translation_map)
    translation_map = Traject::TranslationMap.new(translation_map_arg)
  else
    translation_map = nil
  end


  extractor = Traject::MarcExtractor.new(spec, options)

  lambda do |record, accumulator, context|
    accumulator.concat extractor.extract(record)
    Marc21.apply_extraction_options(accumulator, options, translation_map)
  end
end

.extract_marc_from(record, spec, options = {}) ⇒ Object

Convenience method when you want extract_marc behavior, but NOT to create a lambda for an Indexer step, but instead just give it a record directly and get back an array of values.

array = Traject::Indexer::Marc21.extract_marc_from(record, "245ab", :trim_punctuation => true)

If you have a Traject::Indexer::Context and want to pass it in, you can:

array = Traject::Indexer::Marc21.extract_marc_from(record, "245ab", :trim_punctuation => true, :context => existing_context)


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# File 'lib/traject/macros/marc21.rb', line 104

def self.extract_marc_from(record, spec, options = {})
  output  = []
  # Nil context works, but if caller wants to pass one in
  # for better error reporting that's cool too.
  context = options.delete(:context) || nil

  extract_marc(spec, options).call(record, output, context)
  return output
end

.first!(arr) ⇒ Object


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# File 'lib/traject/macros/marc21.rb', line 273

def self.first!(arr)
  # kind of esoteric, but slice used this way does mutating first, yep
  arr.slice!(1, arr.length)
end

.trim_punctuation(str) ⇒ Object

Trims punctuation mostly from end, and occasionally from beginning of string. Not nearly as complex logic as SolrMarc's version, just pretty simple.

Removes

  • trailing: comma, slash, semicolon, colon (possibly preceded and followed by whitespace)
  • trailing period if it is preceded by at least three letters (possibly preceded and followed by whitespace)
  • single square bracket characters if they are the start and/or end chars and there are no internal square brackets.

Returns altered string, doesn't change original arg.


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# File 'lib/traject/macros/marc21.rb', line 252

def self.trim_punctuation(str)

  # If something went wrong and we got a nil, just return it
  return str unless str

  # trailing: comma, slash, semicolon, colon (possibly preceded and followed by whitespace)
  str = str.sub(/ *[ ,\/;:] *\Z/, '')

  # trailing period if it is preceded by at least three letters (possibly preceded and followed by whitespace)
  str = str.sub(/( *[[:word:]]{3,})\. *\Z/, '\1')

  # single square bracket characters if they are the start and/or end
  #   chars and there are no internal square brackets.
  str = str.sub(/\A\[?([^\[\]]+)\]?\Z/, '\1')

  # trim any leading or trailing whitespace
  str.strip!

  return str
end

Instance Method Details

#extract_all_marc_values(options = {}) ⇒ Object

Takes the whole record, by default from tags 100 to 899 inclusive, all subfields, and adds them to output. Subfields in a record are all joined by space by default.

options [:from] default '100', only tags >= lexicographically [:to] default '899', only tags <= lexicographically [:separator] how to join subfields, default space, nil means don't join

All fields in from-to must be marc DATA (not control fields), or weirdness

Can always run this thing multiple times on the same field if you need non-contiguous ranges of fields.


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# File 'lib/traject/macros/marc21.rb', line 213

def extract_all_marc_values(options = {})
  unless (options.keys - EXTRACT_ALL_MARC_VALID_OPTIONS).empty?
    raise RuntimeError.new("Illegal/Unknown argument '#{(options.keys - EXTRACT_ALL_MARC_VALID_OPTIONS).join(', ')}' in extract_all_marc at #{Traject::Util.extract_caller_location(caller.first)}")
  end
  options = {:from => "100", :to => "899", :separator => ' '}.merge(options)

  if [options[:from], options[:to]].map{|x| x.is_a? String}.any?{|x| x == false}
    raise ArgumentError.new("from/to options to extract_all_marc_values must be strings")
  end

  lambda do |record, accumulator, context|
    record.each do |field|
      next unless field.tag >= options[:from] && field.tag <= options[:to]
      subfield_values = field.subfields.collect {|sf| sf.value}
      next unless subfield_values.length > 0

      if options[:separator]
        accumulator << subfield_values.join( options[:separator])
      else
        accumulator.concat subfield_values
      end
    end
  end

end

#serialized_marc(options) ⇒ Object

Serializes complete marc record to a serialization format. required param :format, serialize_marc(:format => :binary)

formats: [xml] MarcXML [json] marc-in-json (http://dilettantes.code4lib.org/blog/2010/09/a-proposal-to-serialize-marc-in-json/) [binary] Standard ISO 2709 binary marc. By default WILL be base64-encoded, assumed destination a solr 'binary' field. * add option :binary_escape => false to do straight binary -- unclear what Solr's documented behavior is when you do this, and add a string with binary control chars to solr. May do different things in diff Solr versions, including raising exceptions. * add option :allow_oversized => true to pass that flat to the MARC::Writer. Oversized records will then still be serialized, with certain header bytes filled with ascii 0's -- technically illegal MARC, but can still be read by ruby MARC::Reader in permissive mode.

Raises:

  • (ArgumentError)

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# File 'lib/traject/macros/marc21.rb', line 174

def serialized_marc(options)
  unless (options.keys - SERIALZED_MARC_VALID_OPTIONS).empty?
    raise RuntimeError.new("Illegal/Unknown argument '#{(options.keys - SERIALZED_MARC_VALID_OPTIONS).join(', ')}' in seralized_marc at #{Traject::Util.extract_caller_location(caller.first)}")
  end

  format          = options[:format].to_s
  binary_escape   = (options[:binary_escape] != false)
  allow_oversized = (options[:allow_oversized] == true)

  raise ArgumentError.new("Need :format => [binary|xml|json] arg") unless %w{binary xml json}.include?(format)

  lambda do |record, accumulator, context|
    case format
    when "binary"
      binary = MARC::Writer.encode(record, allow_oversized)
      binary = Base64.encode64(binary) if binary_escape
      accumulator << binary
    when "xml"
      accumulator << MARC::FastXMLWriter.encode(record)
    when "json"
      accumulator << JSON.dump(record.to_hash)
    end
  end
end

#trim_punctuationObject

A transformation macro version of trim_punctuation -- heuristics for trimming punctuation from AACR2/MARC style values, to get bare values.


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# File 'lib/traject/macros/marc21.rb', line 144

def trim_punctuation
  lambda do |rec, accumulator|
    accumulator.collect! {|s| Marc21.trim_punctuation(s)}
  end
end