Class: MARC::XMLWriter

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

Overview

A class for writing MARC records as MARCXML. BIG CAVEAT! XMLWriter will not convert your MARC8 to UTF8 bug the authors to do this if you need it

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file, opts = {}) ⇒ XMLWriter

the constructor which you must pass a file path or an object that responds to a write message the second argument is a hash of options, currently only supporting one option, stylesheet

writer = XMLWriter.new ‘marc.xml’, :stylesheet => ‘style.xsl’ writer.write record



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# File 'lib/marc/xmlwriter.rb', line 21

def initialize(file, opts={})
  @writer = REXML::Formatters::Default.new
  if file.class == String
    @fh = File.new(file,"w")
  elsif file.respond_to?('write')
    @fh = file
  else
    throw "must pass in file name or handle"
  end
  
  @fh.write("<?xml version='1.0'?>\n")
  if opts[:stylesheet]
    @fh.write(
      %Q{<?xml-stylesheet type="text/xsl" href="#{opts[:stylesheet]}"?>\n})
  end
  @fh.write("<collection xmlns='" + MARC_NS + "' " +
    "xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' " +
    "xsi:schemaLocation='" + MARC_NS + " " + MARC_XSD + "'>")
  @fh.write("\n")
end

Class Method Details

.encode(record, opts = {}) ⇒ Object

a static method that accepts a MARC::Record object and returns a REXML::Document for the XML serialization.



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# File 'lib/marc/xmlwriter.rb', line 62

def self.encode(record, opts={})
  singleChar = Regexp.new('[\da-z ]{1}')
  ctrlFieldTag = Regexp.new('00[1-9A-Za-z]{1}')
  
  # Right now, this writer handles input from the strict and
  # lenient MARC readers. Because it can get 'loose' MARC in, it
  # attempts to do some cleanup on data values that are not valid
  # MARCXML.
  
  # TODO? Perhaps the 'loose MARC' checks should be split out
  # into a tolerant MARCXMLWriter allowing the main one to skip
  # this extra work.
  
  # TODO: At the very least there should be some logging
  # to record our attempts to account for less than perfect MARC.
  
  e = REXML::Element.new('record')
  e.add_namespace(MARC_NS) if opts[:include_namespace]

  # MARCXML only allows alphanumerics or spaces in the leader
  record.leader.gsub!(/[^\w|^\s]/, 'Z')
  
  # MARCXML is particular about last four characters; ILSes aren't
  if (record.leader[20..23] != "4500")
    record.leader[20..23] = "4500"
  end

  # MARCXML doesn't like a space here so we need a filler character: Z
  if (record.leader[6..6] == " ")
    record.leader[6..6] = "Z"
  end
  
  leader = REXML::Element.new("leader")
  leader.add_text(record.leader)
  e.add_element(leader)
  
  for field in record.fields
    if field.class == MARC::DataField 
      datafield_elem = REXML::Element.new("datafield")
      
      # If marc is leniently parsed, we may have some dirty data; using
      # the 'z' ind1 value should help us locate these later to fix
      if field.indicator1.nil? || (field.indicator1.match(singleChar) == nil)
        field.indicator1 = 'z'
      end
      
      # If marc is leniently parsed, we may have some dirty data; using
      # the 'z' ind2 value should help us locate these later to fix
      if field.indicator2.nil? || (field.indicator2.match(singleChar) == nil)
        field.indicator2 = 'z'
      end
      
      datafield_elem.add_attributes({
        "tag"=>field.tag,
        "ind1"=>field.indicator1,
        "ind2"=>field.indicator2
      })

      for subfield in field.subfields
        subfield_element = REXML::Element.new("subfield")
        
        # If marc is leniently parsed, we may have some dirty data; using
        # the blank subfield code should help us locate these later to fix
        if (subfield.code.match(singleChar) == nil)
          subfield.code = ' '
        end
        
        subfield_element.add_attribute("code", subfield.code)
        text = subfield.value
        subfield_element.add_text(text)
        datafield_elem.add_element(subfield_element)
      end
      
      e.add_element datafield_elem
    elsif field.class == MARC::ControlField
      control_element = REXML::Element.new("controlfield")
      
      # We need a marker for invalid tag values (we use 000)
      unless field.tag.match(ctrlFieldTag) or MARC::Field.control_tag?(ctrlFieldTag)
        field.tag = "00z"
      end
      
      control_element.add_attribute("tag", field.tag)
      text = field.value
      control_element.add_text(text)
      e.add_element(control_element)
    end
  end
  
  # return xml
  return e 
end

Instance Method Details

#close ⇒ Object

close underlying filehandle



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# File 'lib/marc/xmlwriter.rb', line 53

def close
  @fh.write("</collection>")
  @fh.close
end

#write(record) ⇒ Object

write a record to the file or handle



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# File 'lib/marc/xmlwriter.rb', line 45

def write(record)
  @writer.write(MARC::XMLWriter.encode(record), @fh)
  @fh.write("\n")
end