在创建`Nokogiri :: XML`或`Nokogiri :: HTML`对象时如何避免创建不重要的空白文本节点 [英] How to avoid creating non-significant white space text nodes when creating a `Nokogiri::XML` or `Nokogiri::HTML` object
问题描述
在解析缩进XML的同时，从结束标记和开始标记之间的空白创建了不重要的空白文本节点.例如，来自以下XML:
While parsing an indented XML, non-significant white space text nodes are created from the white spaces between a closing and an opening tag. For example, from the following XML:
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>
其字符串表示如下，
"<note>\n <to>Tove</to>\n <from>Jani</from>\n <heading>Reminder</heading>\n <body>Don't forget me this weekend!</body>\n</note>\n"
创建以下Document:
#(Document:0x3fc07e4540d8 {
name = "document",
children = [
#(Element:0x3fc07ec8629c {
name = "note",
children = [
#(Text "\n "),
#(Element:0x3fc07ec8089c {
name = "to",
children = [ #(Text "Tove")]
}),
#(Text "\n "),
#(Element:0x3fc07e8d8064 {
name = "from",
children = [ #(Text "Jani")]
}),
#(Text "\n "),
#(Element:0x3fc07e8d588c {
name = "heading",
children = [ #(Text "Reminder")]
}),
#(Text "\n "),
#(Element:0x3fc07e8cf590 {
name = "body",
children = [ #(Text "Don't forget me this weekend!")]
}),
#(Text "\n")]
})]
})
在这里，有很多类型为Nokogiri::XML::Text的空白节点.
Here, there are lots of white space nodes of type Nokogiri::XML::Text.
我想计算Nokogiri XML Document中每个节点的children，并访问第一个或最后一个子节点，不包括不重要的空格.我不希望解析它们，也不希望在那些和重要的文本节点(例如元素<to>中的那些文本节点，例如"Tove")之间进行区分.这是我正在寻找的rspec:
I would like to count the children of each node in a Nokogiri XML Document, and access the first or last child, excluding non-significant white spaces. I wish not to parse them, or distinguish between those and significant text nodes such as those inside the element <to>, like "Tove". Here is an rspec of what I am looking for:
require 'nokogiri'
require_relative 'spec_helper'
xml_text = <<XML
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>
XML
xml = Nokogiri::XML(xml_text)
def significant_nodes(node)
return 0
end
describe "Stackoverflow Question" do
it "should return the number of significant nodes in nokogiri." do
expect(significant_nodes(xml.css('note'))).to eq 4
end
end
我想知道如何创建significant_nodes函数.
I want to know how to create the significant_nodes function.
如果我将XML更改为:
If I change the XML to:
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
<footer></footer>
</note>
然后，当我创建Document时，我仍然希望页脚表示；不能使用config.noblanks.
then when I create the Document, I still would like the footer represented; using config.noblanks is not an option.
推荐答案
您可以使用 NOBLANKS选项用于解析XML字符串，请考虑以下示例:
You can use the NOBLANKS option for parsing the XML string, consider this example:
require 'nokogiri'
string = "<foo>\n <bar>bar</bar>\n</foo>"
puts string
# <foo>
# <bar>bar</bar>
# </foo>
document_with_blanks = Nokogiri::XML.parse(s)
document_without_blanks = Nokogiri::XML.parse(s) do |config|
config.noblanks
end
document_with_blanks.root.children.each { |child| p child }
#<Nokogiri::XML::Text:0x3ffa4e153dac "\n ">
#<Nokogiri::XML::Element:0x3fdce3f78488 name="bar" children=[#<Nokogiri::XML::Text:0x3fdce3f781f4 "bar">]>
#<Nokogiri::XML::Text:0x3ffa4e15335c "\n">
document_without_blanks.root.children.each { |child| p child }
#<Nokogiri::XML::Element:0x3f81bef42034 name="bar" children=[#<Nokogiri::XML::Text:0x3f81bef43ee8 "bar">]>
NOBLANKS不应删除空节点:
The NOBLANKS shouldn't remove empty nodes:
doc = Nokogiri.XML('<foo><bar></bar></foo>') do |config|
config.noblanks
end
doc.root.children.each { |child| p child }
#<Nokogiri::XML::Element:0x3fad0fafbfa8 name="bar">
OP指出了Nokogiri网站上的文档(以及 libxml网站上的文档)关于解析器选项的解释很神秘，遵循NOBLANKS选项的行为规范:
As OP pointed out the documentation on the Nokogiri website (and also on the libxml website) about the parser options is quite cryptic, following a specification of the behaviour ot the NOBLANKS option:
require 'rspec/autorun'
require 'nokogiri'
def parse_xml(xml_string)
Nokogiri.XML(xml_string) { |config| config.noblanks }
end
describe "Nokogiri NOBLANKS parser option" do
it "removes whitespace nodes if they have siblings" do
doc = parse_xml("<root>\n <child></child></root>")
expect(doc.root.children.size).to eq(1)
expect(doc.root.children.first).to be_kind_of(Nokogiri::XML::Node)
end
it "doesn't remove whitespaces nodes if they have no siblings" do
doc = parse_xml("<root>\n </root>")
expect(doc.root.children.size).to eq(1)
expect(doc.root.children.first).to be_kind_of(Nokogiri::XML::Text)
end
it "doesn't remove empty nodes" do
doc = parse_xml('<root><child></child></root>')
expect(doc.root.children.size).to eq(1)
expect(doc.root.children.first).to be_kind_of(Nokogiri::XML::Node)
end
end
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