HTML-PipelineHTML 格式轉(zhuǎn)換過濾器

HTML-Pipeline 是一個輕量級框架，可用于將用戶的內(nèi)容轉(zhuǎn)換為 HTML 格式。

HTML-Pipeline 提供了一些可鏈接的、基于 DOM 的 HTML 過濾器，且支持將過濾器組成管道。

用法

過濾器采用 HTML 字符串或 Nokogiri::HTML::DocumentFragment，可以對內(nèi)容進行操作，然后輸出對應(yīng)的結(jié)果。

如，將 Markdown 源代碼轉(zhuǎn)換為 Markdown HTML ：

require 'html/pipeline'

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

過濾器可以組合成一個管道，每個過濾器將輸出傳遞給下一個過濾器的輸入。如果你想讓內(nèi)容通過 Markdown 過濾且語法突出顯示，可以創(chuàng)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

輸出：

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

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

如果要為 HTML 格式的代碼生成 CSS，請使用 Rouge CSS Theme #css方法。rouge是 SyntaxHighlightFilter的依賴項。

有些過濾器接受可選的上下文 且/或 結(jié)果 哈希，用于在管道中的過濾器之間傳遞參數(shù)和元數(shù)據(jù)。例如，如果你不想使用 GitHub 格式的 Markdown，可以在上下文哈希中傳遞一個選項:

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

用例

為應(yīng)用的不同部分定義不同的管道。

# 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