Using ruby SAX parsers for GB2312 encoded xml - ruby

Question

Good day,
I have a lot of big xml files that i need to parse, but problems is they have 'gb2312' encoding. I would normaly use SAX parser for this.
So here is in example of xml:
<?xml version="1.0" encoding="gb2312"?>
<Root>
<ValueList Count="112290" FieldCount="11">
<Item1 Value1="23743" Value2="Дипломатия � Пустой кувшин" Value3="1" Value4="" Value5="6" Value6="0" Value7="0" Value8="0" Value9="0" Value10="0" Value11="0"/>
<Item2 Value1="6611" Value2="ДЛ � 018 омела � золотой кинжал" Value3="1" Value4="" Value5="6" Value6="0" Value7="0" Value8="0" Value9="0" Value10="0" Value11="0"/>
<Item3 Value1="6608" Value2="Наука (ДЛ)�круг фей 021�тяпка" Value3="1" Value4="" Value5="6" Value6="0" Value7="0" Value8="0" Value9="0" Value10="0" Value11="0"/>
<Item4 Value1="6612" Value2="Знаки ДЛ � 003руны � разрушение" Value3="1" Value4="" Value5="6" Value6="0" Value7="0" Value8="0" Value9="0" Value10="0" Value11="0"/>
....
</Root>
I'm trying to use Nokogiri SAX (also tried libxml-ruby with same result) parser:
require 'nokogiri'
class SchemaParser < Nokogiri::XML::SAX::Document
def initialize
#cnt = 0
end
def start_element name, attrs =[]
if name == "Item1"
#cnt+= 1
puts #cnt
end
end
end
parser = Nokogiri::XML::SAX::Parser.new(SchemaParser.new)
parser.parse_io(File.open('2_4_EQUIPMENT_ESSENCE.xml'), 'gb2312')
But this gives error "`check_encoding': 'GB2312' is not a valid encoding (ArgumentError)". If I remove encoding declaration and let Nokogiri detect encoding himself, I will receive this error:
encoding error : input conversion failed due to input error, bytes 0xA8 0x43 0x20 0xA7
encoding error : input conversion failed due to input error, bytes 0xA8 0x43 0x20 0xA7
I/O error : encoder error
I also tried to open File with proper encoding, but that didn't help SAX parser:
[3] pry(main)> f = File.open('2_4_EQUIPMENT_ESSENCE.xml', "r:gb2312")
=> #<File:2_4_EQUIPMENT_ESSENCE.xml>
[4] pry(main)> f.external_encoding.name
=> "GB2312"
Did anyone use 'gb2312' encoding with SAX parsers in ruby? Any recommendations how to proceed?

Answer 1

It seems the issue is that Libxml2 does not support the GB2312 encoding (see here for a list of supported encodings).
I'm not sure if you have tried this, but I think you can work around this by removing the encoding declaration from the XML files (so Libxml2 does not try to transcode the data) and set the external encoding of the File object to GB2312, because then Ruby will transcode the file to UTF-8 as it is read, and from then on everything will remain as UTF-8.

Answer 2

So, here is my workaround.
Problems:
Some of characters presented in xml are not 'gb2312' encoding, I have found that 'GB18030' would be a better choice with full Chinese characters.
I converted all xml's to utf8, so i can use SAX parser.
I ended up with this rake task:
desc "convert chinese xml files to utf-8"
task :convert do
rm_rf 'data/utf8'
mkdir 'data/utf8'
Dir.foreach('data') {|f|
if f.end_with?('.xml')
puts "converted:: data/utf8/#{f}" if system("iconv -f GB18030 -t UTF-8 data/#{f} > data/utf8/#{f}")
end
}
#replace encodings for xml files
system("bundle exec ruby -pi -e \"gsub(/gb2312/, 'UTF-8')\" data/utf8/*.xml")
end