Class: SilkLayout::HTML::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/silk_layout/html/parser.rb

Class Method Summary collapse

Class Method Details

.base_uri_for(document, url) ⇒ Object 



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# File 'lib/silk_layout/html/parser.rb', line 45

def self.base_uri_for(document, url)
  doc_uri = normalize_document_url(url)

  base_href = document.at_css("base[href]")&.[]("href")
  return doc_uri unless base_href

  normalize_href(base_href.to_s, doc_uri)
end

.default_workdir_uri ⇒ Object 



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# File 'lib/silk_layout/html/parser.rb', line 67

def self.default_workdir_uri
  file_uri_for(Pathname.pwd)
end

.extract_stylesheets!(document, base_uri) ⇒ Object 



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# File 'lib/silk_layout/html/parser.rb', line 19

def self.extract_stylesheets!(document, base_uri)
  stylesheets = []
  cache = {}

  document.css("style, link").each do |node|
    if node.name == "style"
      stylesheets << node.content.to_s
      node.remove
      next
    end

    next unless node.name == "link"

    rel = node["rel"].to_s.downcase.split
    next unless rel.include?("stylesheet")

    href = node["href"].to_s.strip
    next if href.empty?

    stylesheets << fetch_stylesheet(href, base_uri, cache)
    node.remove
  end

  stylesheets
end

.fetch_http(uri) ⇒ Object 



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# File 'lib/silk_layout/html/parser.rb', line 113

def self.fetch_http(uri)
  current = uri
  redirects = 0

  loop do
    http = Net::HTTP.new(current.host, current.port)
    http.use_ssl = (current.scheme == "https")
    http.open_timeout = 10
    http.read_timeout = 10

    request = Net::HTTP::Get.new(current)
    request["User-Agent"] = "SilkLayout/#{SilkLayout::VERSION}"

    response = http.request(request)

    case response
    when Net::HTTPSuccess
      return response.body.to_s
    when Net::HTTPRedirection
      location = response["location"].to_s
      raise "Missing redirect location for #{current}" if location.empty?

      redirects += 1
      raise "Too many redirects fetching #{uri}" if redirects > 5

      current = URI.join(current.to_s, location)
    else
      raise "Failed to fetch #{current} (HTTP #{response.code})"
    end
  end
end

.fetch_stylesheet(href, base_uri, cache) ⇒ Object 



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# File 'lib/silk_layout/html/parser.rb', line 81

def self.fetch_stylesheet(href, base_uri, cache)
  resolved = normalize_href(href, base_uri)
  key = resolved.to_s
  return cache[key] if cache.key?(key)

  css =
    case resolved.scheme
    when "file", nil
      path = uri_unescape(resolved.path)
      raise "Stylesheet not found: #{path}" unless File.exist?(path)

      File.read(path)
    when "http", "https"
      fetch_http(resolved)
    else
      raise "Unsupported stylesheet scheme: #{resolved.scheme} (#{resolved})"
    end

  css = inline_css_imports(css, resolved, cache)
  cache[key] = css
end

.file_uri_for(path) ⇒ Object 



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# File 'lib/silk_layout/html/parser.rb', line 71

def self.file_uri_for(path)
  p = path
  p = p.dirname if p.file?

  dir = p.to_s
  dir = "#{dir}/" unless dir.end_with?("/")

  URI::Generic.build(scheme: "file", path: dir)
end

.inline_css_imports(css, stylesheet_uri, cache) ⇒ Object 



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# File 'lib/silk_layout/html/parser.rb', line 145

def self.inline_css_imports(css, stylesheet_uri, cache)
  return css unless css.include?("@import")

  base = stylesheet_base_uri(stylesheet_uri)
  remaining = css.dup
  inlined = +""
  seen = {}

  20.times do
    m = remaining.match(/@import\s+(?:url\()?
      \s*['"]?([^'")\s;]+)['"]?
      \s*\)?\s*;/ix)
    break unless m

    href = m[1]
    break if seen[href]

    seen[href] = true
    import_uri = normalize_href(href, base)
    imported = fetch_stylesheet(import_uri.to_s, base, cache)

    inlined << imported.to_s << "\n"
    remaining.sub!(m[0], "")
  end

  (inlined + remaining)
end

.normalize_document_url(url) ⇒ Object 



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# File 'lib/silk_layout/html/parser.rb', line 54

def self.normalize_document_url(url)
  return default_workdir_uri unless url

  uri = URI.parse(url.to_s)
  return uri if uri.scheme

  path = Pathname.new(url.to_s).expand_path
  file_uri_for(path)
rescue URI::InvalidURIError
  path = Pathname.new(url.to_s).expand_path
  file_uri_for(path)
end

.normalize_href(href, base_uri) ⇒ Object 



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# File 'lib/silk_layout/html/parser.rb', line 103

def self.normalize_href(href, base_uri)
  href = href.to_s
  uri = URI.parse(href)
  return uri if uri.scheme

  URI.join(base_uri.to_s, href)
rescue URI::InvalidURIError
  URI.join(base_uri.to_s, URI::DEFAULT_PARSER.escape(href))
end

.parse_document(html, url: nil) ⇒ Object 



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# File 'lib/silk_layout/html/parser.rb', line 10

def self.parse_document(html, url: nil)
  document = Nokogiri::HTML(html)

  base_uri = base_uri_for(document, url)
  stylesheets = extract_stylesheets!(document, base_uri)

  [Node.from_nokogiri(document.root), stylesheets]
end

.stylesheet_base_uri(stylesheet_uri) ⇒ Object 



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# File 'lib/silk_layout/html/parser.rb', line 173

def self.stylesheet_base_uri(stylesheet_uri)
  if stylesheet_uri.scheme == "file"
    file_uri_for(Pathname.new(uri_unescape(stylesheet_uri.path)))
  else
    uri = stylesheet_uri.dup
    uri.path = uri.path.to_s.sub(/[^\/]+\z/, "")
    uri
  end
end

.uri_unescape(value) ⇒ Object 



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# File 'lib/silk_layout/html/parser.rb', line 183

def self.uri_unescape(value)
  URI::RFC2396_PARSER.unescape(value.to_s)
end