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

Direct Known Subclasses

UnsafeXMLWriter

Constant Summary collapse

COLLECTION_TAG =

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

%(<collection xmlns='#{MARC_NS}'
xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'
xsi:schemaLocation="#{MARC_NS} #{MARC_XSD}">).freeze

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

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

Returns a new instance of XMLWriter.



24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
 
# File 'lib/marc/xmlwriter.rb', line 24

def initialize(file, opts = {}, &blk)
  @writer = REXML::Formatters::Default.new
  if file.instance_of?(String)
    @fh = File.new(file, "w")
  elsif file.respond_to?(:write)
    @fh = file
  else
    raise ArgumentError, "must pass in file name or handle"
  end

  @stylesheet = opts[:stylesheet]

  @fh.write("<?xml version='1.0'?>\n")
  @fh.write(stylesheet_tag)
  @fh.write(COLLECTION_TAG)
  @fh.write("\n")

  if block_given?
    blk.call(self)
    self.close
  end
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.



90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
 
# File 'lib/marc/xmlwriter.rb', line 90

def self.encode(record, opts = {})
  single_char = Regexp.new('[\da-z ]{1}')
  subfield_char = Regexp.new('[\dA-Za-z!"#$%&\'()*+,-./:;<=>?{}_^`~\[\]\\\]{1}')
  control_field_tag = 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]

  leader_element = REXML::Element.new("leader")
  leader_element.add_text(fix_leader(record.leader))
  e.add_element(leader_element)

  record.each do |field|
    if field.instance_of?(MARC::DataField)
      datafield_elem = REXML::Element.new("datafield")

      ind1 = field.indicator1
      # If marc is leniently parsed, we may have some dirty data; using
      # the 'z' ind1 value should help us locate these later to fix
      ind1 = "z" if ind1.nil? || !ind1.match?(single_char)
      ind2 = field.indicator2
      # If marc is leniently parsed, we may have some dirty data; using
      # the 'z' ind2 value should help us locate these later to fix

      ind2 = "z" if field.indicator2.nil? || !ind2.match?(single_char)

      datafield_elem.add_attributes({
        "tag" => field.tag,
        "ind1" => ind1,
        "ind2" => ind2
      })

      field.subfields.each do |subfield|
        subfield_element = REXML::Element.new("subfield")

        code = subfield.code
        # If marc is leniently parsed, we may have some dirty data; using
        # the blank subfield code should help us locate these later to fix
        code = " " if subfield.code.match(subfield_char).nil?

        subfield_element.add_attribute("code", code)
        text = subfield.value
        subfield_element.add_text(text)
        datafield_elem.add_element(subfield_element)
      end

      e.add_element datafield_elem
    elsif field.instance_of?(MARC::ControlField)
      control_element = REXML::Element.new("controlfield")

      tag = field.tag
      # We need a marker for invalid tag values (we use 000)
      tag = "00z" unless tag.match(control_field_tag) || MARC::ControlField.control_tag?(tag)

      control_element.add_attribute("tag", tag)
      text = field.value
      control_element.add_text(text)
      e.add_element(control_element)
    end
  end

  # return xml
  e
end

.fix_leader(leader) ⇒ Object 



69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
 
# File 'lib/marc/xmlwriter.rb', line 69

def self.fix_leader(leader)
  fixed_leader = leader.gsub(/[^\w|^\s]/, "Z")

  # The leader must have at least 24 characters
  fixed_leader = fixed_leader.ljust(24) if fixed_leader.length < 24

  # MARCXML is particular about last four characters; ILSes aren't
  if fixed_leader[20..23] != "4500"
    fixed_leader[20..23] = "4500"
  end

  # MARCXML doesn't like a space here so we need a filler character: Z
  if fixed_leader[6..6] == " "
    fixed_leader[6..6] = "Z"
  end

  fixed_leader
end

Instance Method Details

#close ⇒ Object

close underlying filehandle



64
65
66
67
 
# File 'lib/marc/xmlwriter.rb', line 64

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

#stylesheet_tag ⇒ Object 



47
48
49
50
51
52
53
 
# File 'lib/marc/xmlwriter.rb', line 47

def stylesheet_tag
  if @stylesheet
    %(<?xml-stylesheet type="text/xsl" href="#{@stylesheet}"?>\n)
  else
    ""
  end
end

#write(record) ⇒ Object

write a record to the file or handle



57
58
59
60
 
# File 'lib/marc/xmlwriter.rb', line 57

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