marcxella

Marcxella

A simple interface to MARC-XML, for when you just need to parse some MARC-XML quickly.

Pronounce it "marc-sélla".

Installation

Add this line to your application's Gemfile:

gem 'marcxella'

And then execute:

$ bundle

Or install it yourself as:

$ gem install marcxella

Usage

Documents

records (Marcxella::Record) are the main objects you'll be dealing with. To get at the records, you'll probably create a document. This can be done from a filehandle:

> require "marcxella"
> file = File.open("spec/xml/1027474578.xml")
> marc = Marcxella::Document.new(file)

You can also create a document from a string of XML:

> xml = File.open("spec/xml/1027474578.xml").read
> marc = Marcxella::Document.new(xml)

Marxcella uses Nokogiri internally, so you can also just pass a Nokogiri document:

> doc = Nokogiri::XML(file)
> marc = Marcxella::Document.new(doc)

Once you have the document, you can get an array of the records:

> records = marc.records

If you want, you can create the records directly from Nokogiri nodes

> file = File.open("spec/xml/1027474578.xml")
> doc = Nokogiri::XML(file)
> records = doc.css('record').map{|r| Marcxella::Record.new(r)}

If the xml document contains collections, you can get the collections and then get the records from those.

> first_coll = marc.collections.first
> records = first_coll.records

If the document does contain collections, Marcxella::Document#records will simply ignore the collections and return an array of all the records from all the collections.

Records and fields

Once you have a record, you can get the fields by tag:

> rec = marc.records.first
> f = rec.field("001")

The #field method always returns an array, so even when you expect a single field, you have to get it from the array. There is no distinction made between repeating and non-repeating fields.

> control_number = rec.field("001").first
> title = rec.field("245").first
> subjects = rec.field("650")

Control fields and Data fields have different classes:

> control_number.class
 => Marcxella::ControlField
> title.class
 => Marcxella::DataField

All fields have tags and values:

> control_number.tag
 => "001"
> control_number.value
 => "1027474578"

> title.tag
 => "245"
> title.value
 => "Kindred /Octavia E. Butler."
 

#to_s returns the customary representation of the field data:

> control_number.to_s
 => "001    1027474578"

> title.to_s
 => "245  10$aKindred /$cOctavia E. Butler."
> puts title
245  10$aKindred /$cOctavia E. Butler.

Data fields have subfields. You can get an array of all of them or select an array of subfields by code.

> title.subfields.count
 => 2
> title.subfield("a").first.to_s
 => "$aKindred /"

For compatibility, control fields have these methods, too, which always return empty arrays:

> control_number.subfields
 => []
> control_number.subfield("a")
 => []

Subfields have codes, values, and string representations:

> subfield = rec.titleStatement.subfield("a").first
> subfield.code
 => "a"
> subfield.value
 => "Kindred /"
> subfield.to_s
 => "$aKindred /"
 

You can get all instances of a subfield of a given tag. For instance, to get all the ISBN numbers:

> rec.subfield("020", "a").map{|s| s.value}
 => ["9781472214812", "1472214811"]

Convenience methods

There are several methods to make it easier to get single fields or categories of fields. #mainEntry will return whichever of the 1XX fields the record has (as a DataField, not an array):

> rec.mainEntry.to_s
 => "100  1\#$aButler, Octavia Estelle$d(1947-2006).$4aut"

#titleStatement gets the 245 field (again, as a DataField and not an array):

> rec.titleStatement.value
 => "Kindred /Octavia E. Butler."

There are also methods to get an array of each of the main categories of fields. Each of these returns an array of all the fields in the record of the given category:

> rec.controlFields # 00X
> rec.codes         # 01X-09X
> rec.titles        # 20X-24X
> rec.edition       # 25X-28X
> rec.description   # 3XX
> rec.series        # 4XX
> rec.notes         # 5XX
> rec.subjects      # 6XX
> rec.addedEntries  # 70X-75X
> rec.linking       # 76X-78X
> rec.seriesAdded   # 80X-83X
> rec.holdings      # 841-88X

Some common numbers have convenience methods:

> record.lccn       # 010$a, String or nil
> record.isbns      # 020$a, Array of Strings, or []
> record.issns      # 022$a, Array of Strings, or []

Leader

You can get the record leader:

> rec.leader
 => "00000cam a2200000Mi 4500"

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/seanredmond/marcxella. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Marcxella project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.