是否可以使用Nokogiri解析样式表？ [英] Is it possible to parse a stylesheet with Nokogiri?

问题描述

我花了我的必要的两个小时Googling这个，我找不到任何好的答案，所以让我们看看人类能否击败Google电脑。

I've spent my requisite two hours Googling this, and I can not find any good answers, so let's see if humans can beat Google computers.

以解析Ruby中的样式表，以便我可以将这些样式应用于文档中的元素（以使样式内联）。所以，我想采取像

I want to parse a stylesheet in Ruby so that I can apply those styles to elements in my document (to make the styles inlined). So, I want to take something like

<style>
.mystyle {
  color:white;
}
</style>

并且能够将其解压缩为某种类型的Nokogiri对象。

And be able to extract it into a Nokogiri object of some sort.

Nokogiri类CSS :: Parser（ http://nokogiri.rubyforge.org/nokogiri/Nokogiri/CSS/Parser.html ）肯定有一个有前途的名称，但我找不到任何文档，它是什么或它是如何工作的，所以我不知道它是否可以做我在这里之后。

The Nokogiri class "CSS::Parser" (http://nokogiri.rubyforge.org/nokogiri/Nokogiri/CSS/Parser.html) certainly has a promising name, but I can't find any documentation on what it is or how it works, so I have no idea if it can do what I'm after here.

我的最终目标是能够编写代码： p>

My end goal is to be able to write code something like:

a_web_page = Nokogiri::HTML(html_page_as_string)
parsed_styles = Nokogiri::CSS.parse(html_page_as_string)
parsed_styles.each do |style| 
  existing_inlined_style = a_web_page.css(style.declaration) || ''
  a_web_page.css(style.declaration)['css'] = existing_inlined_style + style.definition
end

这将从样式表中提取样式，并将它们全部作为内联样式添加到我的文档中。

Which would extract styles from a stylesheet and add them all as inlined styles to my document.

推荐答案

p> @molf肯定有一个很好的开始，但它仍然需要调试一些问题，使其在生产中工作。这是目前的测试版本：

@molf definitely had a great start there, but it still required debugging a handful of problems to get it working in production. Here is the current, tested version of this:

html = Nokogiri::HTML(html_string)
css = CssParser::Parser.new
css.add_block!(html_string) # Warning:  This line modifies the string passed into it.  In potentially bad ways.  Make sure the string has been duped and stored elsewhere before passing this.

css.each_selector do |selector, declarations, specificity|
  next unless selector =~ /^[\d\w\s\#\.\-]*$/ # Some of the selectors given by css_parser aren't actually selectors.
  begin
    elements = html.css(selector)
    elements.each do |match|
      match["style"] = [match["style"], declarations].compact.join(" ")
    end
  rescue
    logger.info("Couldn't parse selector '#{selector}'")
  end
end

html_with_inline_styles = html.to_s 

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