萨克斯管用 nokogiri 解析奇怪的元素 [英] Sax Parsing strange element with nokogiri

问题描述

我想在 nokogiri 中进行 sax 解析，但是当解析具有又长又疯狂的 xml 元素名称或属性的 xml 元素时......然后一切都会变得疯狂.

I want to sax-parse in nokogiri, but when it comes to parse xml element that have a long and crazy xml element name or a attribute on it.. then everthing goes crazy.

首先，如果我想解析这个 xml 文件并获取所有标题元素，我该如何使用 nokogiri-sax 做到这一点.

Fore instans if I like to parse this xml file and grab all the title element, how do I do that with nokogiri-sax.

<titles>
    <title xml:lang="sv">Arkivvetenskap</title>
    <title xml:lang="en">Archival science</title>
</titles>

推荐答案

在您的示例中，title 是元素的名称.xml:lang="sv" 是一个属性.此解析器假定标题元素内没有嵌套元素

In your example, title is the name of the element. xml:lang="sv" is an attribute. This parser assumes there are no elements nested inside of title elements

require 'rubygems'
require 'nokogiri'

class MyDocument < Nokogiri::XML::SAX::Document
  def start_element(name, attrs)
    @attrs = attrs
    @content = ''
  end
  def end_element(name)
    if name == 'title'
      puts Hash[@attrs]['xml:lang']
      puts @content.inspect
      @content = nil
    end
  end
  def characters(string)
    @content << string if @content
  end
  def cdata_block(string)
    characters(string)
  end
end

parser = Nokogiri::XML::SAX::Parser.new(MyDocument.new)
parser.parse(DATA)

__END__
<titles>
    <title xml:lang="sv">Arkivvetenskap</title>
    <title xml:lang="en">Archival science</title>
</titles>

打印出来

sv
"Arkivvetenskap"
en
"Archival science"

SAX 解析通常太复杂了.因此，我推荐 Nokogiri 的标准内存解析器，或者如果您确实需要速度和内存效率，Nokogiri 的阅读器解析器.

SAX parsing is usually way too complex. Because of that, I recommend Nokogiri's standard in-memory parser, or if you really need speed and memory efficiency, Nokogiri's Reader parser.

为了比较，这里是同一个文档的标准 Nokogiri 解析器

For comparison, here is a standard Nokogiri parser for the same document

require 'rubygems'
require 'nokogiri'

doc = Nokogiri::XML(DATA)
doc.css('title').each do |title|
  puts title['lang']
  puts title.text.to_s.inspect
end

__END__
<titles>
    <title xml:lang="sv">Arkivvetenskap</title>
    <title xml:lang="en">Archival science</title>
</titles>

这里是同一个文档的阅读器解析器

And here is a reader parser for the same document

require 'rubygems'
require 'nokogiri'

reader = Nokogiri::XML::Reader(DATA)
while reader.read
  if reader.name == 'title' && reader.node_type == Nokogiri::XML::Reader::TYPE_ELEMENT
    puts reader.attribute('xml:lang')
    puts reader.inner_xml.inspect # TODO xml decode this, if necessary.
  end
end

__END__
<titles>
    <title xml:lang="sv">Arkivvetenskap</title>
    <title xml:lang="en">Archival science</title>
</titles>

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