HTML-PipelineHTML 格式转换过滤器-技术圈

HTML-Pipeline 是一个轻量级框架，可用于将用户的内容转换为 HTML 格式。

HTML-Pipeline 提供了一些可链接的、基于 DOM 的 HTML 过滤器，且支持将过滤器组成管道。

用法

过滤器采用 HTML 字符串或 Nokogiri::HTML::DocumentFragment，可以对内容进行操作，然后输出对应的结果。

如，将 Markdown 源代码转换为 Markdown HTML ：

require 'html/pipeline'

filter = HTML::Pipeline::MarkdownFilter.new("Hi **world**!")
filter.call

过滤器可以组合成一个管道，每个过滤器将输出传递给下一个过滤器的输入。如果你想让内容通过 Markdown 过滤且语法突出显示，可以创建以下管道:

pipeline = HTML::Pipeline.new [
  HTML::Pipeline::MarkdownFilter,
  HTML::Pipeline::SyntaxHighlightFilter
]
result = pipeline.call <<-CODE
This is *great*:

    some_code(:first)

CODE
result[:output].to_s

输出：

<p>This is <em>greatem>:p>

<pre><code>some_code(:first)
code>pre>

如果要为 HTML 格式的代码生成 CSS，请使用 Rouge CSS Theme #css方法。rouge是 SyntaxHighlightFilter的依赖项。

有些过滤器接受可选的上下文且/或结果哈希，用于在管道中的过滤器之间传递参数和元数据。例如，如果你不想使用 GitHub 格式的 Markdown，可以在上下文哈希中传递一个选项:

filter = HTML::Pipeline::MarkdownFilter.new("Hi **world**!", :gfm => false)
filter.call

用例

为应用的不同部分定义不同的管道。

# The context hash is how you pass options between different filters.
# See individual filter source for explanation of options.
context = {
  :asset_root => "http://your-domain.com/where/your/images/live/icons",
  :base_url   => "http://your-domain.com"
}

# Pipeline providing sanitization and image hijacking but no mention
# related features.
SimplePipeline = Pipeline.new [
  SanitizationFilter,
  TableOfContentsFilter, # add 'name' anchors to all headers and generate toc list
  CamoFilter,
  ImageMaxWidthFilter,
  SyntaxHighlightFilter,
  EmojiFilter,
  AutolinkFilter
], context

# Pipeline used for user provided content on the web
MarkdownPipeline = Pipeline.new [
  MarkdownFilter,
  SanitizationFilter,
  CamoFilter,
  ImageMaxWidthFilter,
  HttpsFilter,
  MentionFilter,
  EmojiFilter,
  SyntaxHighlightFilter
], context.merge(:gfm => true) # enable github formatted markdown


# Define a pipeline based on another pipeline's filters
NonGFMMarkdownPipeline = Pipeline.new(MarkdownPipeline.filters,
  context.merge(:gfm => false))

# Pipelines aren't limited to the web. You can use them for email
# processing also.
HtmlEmailPipeline = Pipeline.new [
  PlainTextInputFilter,
  ImageMaxWidthFilter
], {}

# Just emoji.
EmojiPipeline = Pipeline.new [
  PlainTextInputFilter,
  EmojiFilter
], context