如何使用 Nokogiri 在两个 HTML 注释之间抓取 HTML? [英] How do I scrape HTML between two HTML comments using Nokogiri?
问题描述
我有一些 HTML 页面，其中要提取的内容标有 HTML 注释，如下所示.
.....<!-- 开始内容--><div>一些文本</div><div><p>更多元素</p></div><!-- 结束内容-->...</html>我正在使用 Nokogiri 并尝试提取 和 之间的 HTML代码>注释.
我想提取这两个 HTML 注释之间的完整元素:
一些文字<div><p>更多元素</p></div>
我可以使用此字符回调获取纯文本版本:
class TextExtractor <Nokogiri::XML::SAX::Document定义初始化@有趣的=假@text = ""@html = ""结尾定义注释(字符串)case string.strip # 去除前导和尾随空格when/^begin content/# 匹配起始注释@有趣的=真的当/^结束内容/@interesting = false # 匹配结束评论结尾定义字符(字符串)@文本<<<字符串如果@interesting结尾结尾我使用 @text 获得纯文本版本，但我需要存储在 @html 中的完整 HTML.
在两个节点之间提取内容不是我们常做的事情；通常我们希望在特定节点内有内容.评论是节点，它们只是特殊类型的节点.
需要'nokogiri'doc = Nokogiri::HTML(<<EOT)<身体><!-- 开始内容--><div>一些文本</div><div><p>更多元素</p></div><!-- 结束内容-->EOT通过查找包含指定文本的注释，可以找到一个起始节点:
start_comment = doc.at("//comment()[contains(.,'begin content')]") # =>#<Nokogiri::XML::Comment:0x3fe94994268c开始内容">一旦找到，就需要一个循环来存储当前节点，然后查找下一个兄弟节点，直到找到另一个注释:
content = Nokogiri::XML::NodeSet.new(doc)contains_node = start_comment.next_sibling循环做如果包含_node.comment 则中断?内容<<包含节点contains_node = contains_node.next_sibling结尾content.to_html # =>"\n <div>一些文本</div>\n <div><p>更多的元素</p></div>\n"I have some HTML pages where the contents to be extracted are marked with HTML comments like below.
<html>
.....
<!-- begin content -->
<div>some text</div>
<div><p>Some more elements</p></div>
<!-- end content -->
...
</html>
I am using Nokogiri and trying to extract the HTML between the <!-- begin content --> and <!-- end content --> comments.
I want to extract the full elements between these two HTML comments:
<div>some text</div>
<div><p>Some more elements</p></div>
I can get the text-only version using this characters callback:
class TextExtractor < Nokogiri::XML::SAX::Document
def initialize
@interesting = false
@text = ""
@html = ""
end
def comment(string)
case string.strip # strip leading and trailing whitespaces
when /^begin content/ # match starting comment
@interesting = true
when /^end content/
@interesting = false # match closing comment
end
def characters(string)
@text << string if @interesting
end
end
I get the text-only version with @text but I need the full HTML stored in @html.
Extracting content between two nodes is not a normal thing we'd do; Normally we'd want content inside a particular node. Comments are nodes, they're just special types of nodes.
require 'nokogiri'
doc = Nokogiri::HTML(<<EOT)
<body>
<!-- begin content -->
<div>some text</div>
<div><p>Some more elements</p></div>
<!-- end content -->
</body>
EOT
By looking for a comment containing the specified text it's possible to find a starting node:
start_comment = doc.at("//comment()[contains(.,'begin content')]") # => #<Nokogiri::XML::Comment:0x3fe94994268c " begin content ">
Once that's found then a loop is needed that stores the current node, then looks for the next sibling until it finds another comment:
content = Nokogiri::XML::NodeSet.new(doc)
contained_node = start_comment.next_sibling
loop do
break if contained_node.comment?
content << contained_node
contained_node = contained_node.next_sibling
end
content.to_html # => "\n <div>some text</div>\n <div><p>Some more elements</p></div>\n"
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