Module: Premailer::Adapter::Nokogiri

Includes:
AdapterHelper::RgbToHex
Defined in:
lib/premailer/adapter/nokogiri.rb

Overview

Nokogiri adapter

Constant Summary collapse

WIDTH_AND_HIGHT = 
['width', 'height'].freeze

Instance Method Summary collapse

Methods included from AdapterHelper::RgbToHex

#ensure_hex, #is_rgb?, #to_hex

Instance Method Details

#load_html(input) ⇒ ::Nokogiri::XML

Load the HTML file and convert it into an Nokogiri document.

Returns:

  • (::Nokogiri::XML) —

    a document.



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# File 'lib/premailer/adapter/nokogiri.rb', line 218

def load_html(input) # :nodoc:
  thing = nil

  # TODO: duplicate options
  if @options[:with_html_string] or @options[:inline] or input.respond_to?(:read)
    thing = input
  elsif @is_local_file
    @base_dir = File.dirname(input)
    thing = File.open(input, 'r')
  else
    thing = URI.open(input)
  end

  if thing.respond_to?(:read)
    thing = thing.read
  end

  return nil unless thing
  doc = nil

  # Handle HTML entities
  if @options[:replace_html_entities] == true and thing.is_a?(String)
    thing = +thing
    HTML_ENTITIES.map do |entity, replacement|
      thing.gsub! entity, replacement
    end
  end
  encoding = @options[:input_encoding] || (RUBY_PLATFORM == 'java' ? nil : 'BINARY')
  doc = if @options[:html_fragment]
    ::Nokogiri::HTML.fragment(thing, encoding)
  else
    ::Nokogiri::HTML(thing, nil, encoding) { |c| c.recover }
  end

  # Fix for removing any CDATA tags from both style and script tags inserted per
  # https://github.com/sparklemotion/nokogiri/issues/311 and
  # https://github.com/premailer/premailer/issues/199
  ['style', 'script'].each do |tag|
    doc.search(tag).children.each do |child|
      child.swap(child.text()) if child.cdata?
    end
  end

  doc
end

#to_inline_css ⇒ String

Merge CSS into the HTML document.

Returns:

  • (String) —

    an HTML.



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# File 'lib/premailer/adapter/nokogiri.rb', line 14

def to_inline_css
  doc = @processed_doc
  @unmergable_rules = CssParser::Parser.new

  # Give all styles already in style attributes a specificity of 1000
  # per http://www.w3.org/TR/CSS21/cascade.html#specificity
  doc.search("*[@style]").each do |el|
    el['style'] = '[SPEC=1000[' + el.attributes['style'] + ']]'
  end
  # Iterate through the rules and merge them into the HTML
  @css_parser.each_selector(:all) do |selector, declaration, specificity, media_types|
    # Save un-mergable rules separately
    selector.gsub!(/:link([\s]*)+/i) { |m| $1 }

    # Convert element names to lower case
    selector.gsub!(/([\s]|^)([\w]+)/) { |m| $1.to_s + $2.to_s.downcase }

    if Premailer.is_media_query?(media_types) || selector =~ Premailer::RE_UNMERGABLE_SELECTORS
      @unmergable_rules.add_rule_set!(CssParser::RuleSet.new(selectors: selector, block: declaration), media_types) unless @options[:preserve_styles]
    else
      begin
        if Premailer::RE_RESET_SELECTORS.match?(selector)
          # this is in place to preserve the MailChimp CSS reset: http://github.com/mailchimp/Email-Blueprints/
          # however, this doesn't mean for testing pur
          @unmergable_rules.add_rule_set!(CssParser::RuleSet.new(selectors: selector, block: declaration)) unless !@options[:preserve_reset]
        end

        # Change single ID CSS selectors into xpath so that we can match more
        # than one element.  Added to work around dodgy generated code.
        selector.gsub!(/\A\#([\w_\-]+)\Z/, '*[@id=\1]')

        doc.search(selector).each do |el|
          if el.elem? and (el.name != 'head' and el.parent.name != 'head')
            # Add a style attribute or append to the existing one
            block = "[SPEC=#{specificity}[#{declaration}]]"
            el['style'] = (el.attributes['style'].to_s ||= '') + ' ' + block
          end
        end
      rescue ::Nokogiri::SyntaxError, RuntimeError, ArgumentError
        $stderr.puts "CSS syntax error with selector: #{selector}" if @options[:verbose]
        next
      end
    end
  end

  # Remove script tags
  doc.search("script").remove if @options[:remove_scripts]

  # Read STYLE attributes and perform folding
  doc.search("*[@style]").each do |el|
    style = el.attributes['style'].to_s

    declarations = style.scan(/\[SPEC\=([\d]+)\[(.[^\]\]]*)\]\]/m).filter_map do |declaration|
      rs = Premailer::CachedRuleSet.new(block: declaration[1].to_s, specificity: declaration[0].to_i)
      rs.expand_shorthand!
      rs
    rescue ArgumentError => e
      raise e if @options[:rule_set_exceptions]
    end

    # Perform style folding
    merged = CssParser.merge(declarations)
    begin
      merged.expand_shorthand!
    rescue ArgumentError => e
      raise e if @options[:rule_set_exceptions]
    end

    # Duplicate CSS attributes as HTML attributes
    if Premailer::RELATED_ATTRIBUTES.has_key?(el.name) && @options[:css_to_attributes]
      Premailer::RELATED_ATTRIBUTES[el.name].each do |css_attr, html_attr|
        if el[html_attr].nil? and not merged[css_attr].empty?
          new_val = merged[css_attr].dup

          # Remove url() function wrapper
          new_val.gsub!(/url\((['"])(.*?)\1\)/, '\2')

          # Remove !important, trailing semi-colon, and leading/trailing whitespace
          new_val.gsub!(/;$|\s*!important/, '').strip!

          # For width and height tags, remove px units
          new_val.gsub!(/(\d+)px/, '\1') if WIDTH_AND_HIGHT.include?(html_attr)

          # For color-related tags, convert RGB to hex if specified by options
          new_val = ensure_hex(new_val) if css_attr.end_with?('color') && @options[:rgb_to_hex_attributes]

          el[html_attr] = new_val
        end

        unless @options[:preserve_style_attribute]
          merged.instance_variable_get(:@declarations).tap do |declarations|
            declarations.delete(css_attr)
          end
        end
      end
    end

    # Collapse multiple rules into one as much as possible.
    merged.create_shorthand! if @options[:create_shorthands]

    # write the inline STYLE attribute
    el['style'] = merged.declarations_to_s
  end

  doc = write_unmergable_css_rules(doc, @unmergable_rules) unless @options[:drop_unmergeable_css_rules]

  if @options[:remove_classes] or @options[:remove_comments]
    doc.traverse do |el|
      if el.comment? and @options[:remove_comments]
        el.remove
      elsif el.element?
        el.remove_attribute('class') if @options[:remove_classes]
      end
    end
  end

  if @options[:remove_ids]
    # find all anchor's targets and hash them
    targets = []
    doc.search("a[@href^='#']").each do |el|
      target = el.get_attribute('href')[1..-1]
      targets << target
      el.set_attribute('href', "#" + Digest::SHA256.hexdigest(target))
    end
    # hash ids that are links target, delete others
    doc.search("*[@id]").each do |el|
      id = el.get_attribute('id')
      if targets.include?(id)
        el.set_attribute('id', Digest::SHA256.hexdigest(id))
      else
        el.remove_attribute('id')
      end
    end
  end

  if @options[:reset_contenteditable]
    doc.search('*[@contenteditable]').each do |el|
      el.remove_attribute('contenteditable')
    end
  end

  @processed_doc = doc
  if is_xhtml?
    # we don't want to encode carriage returns
    @processed_doc.to_xhtml(:encoding => @options[:output_encoding]).gsub(/&\#(xD|13);/i, "\r")
  else
    @processed_doc.to_html(:encoding => @options[:output_encoding])
  end
end

#to_plain_text ⇒ String

Converts the HTML document to a format suitable for plain-text e-mail.

If present, uses the <body> element as its base; otherwise uses the whole document.

Returns:

  • (String) —

    a plain text.



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# File 'lib/premailer/adapter/nokogiri.rb', line 194

def to_plain_text
  html_src = ''
  begin
    html_src = @doc.at("body").inner_html
  rescue;
  end

  html_src = @doc.to_html unless html_src and not html_src.empty?
  convert_to_text(html_src, @options[:line_length], @html_encoding)
end

#to_s ⇒ String

Gets the original HTML as a string.

Returns:

  • (String) —

    HTML.



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# File 'lib/premailer/adapter/nokogiri.rb', line 207

def to_s
  if is_xhtml?
    @doc.to_xhtml(:encoding => nil)
  else
    @doc.to_html(:encoding => nil)
  end
end

#write_unmergable_css_rules(doc, unmergable_rules) ⇒ ::Nokogiri::XML

Create a style element with un-mergable rules (e.g. :hover) and write it into the head.

doc is an Nokogiri document and unmergable_css_rules is a Css::RuleSet.

Returns:

  • (::Nokogiri::XML) —

    a document.



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# File 'lib/premailer/adapter/nokogiri.rb', line 170

def write_unmergable_css_rules(doc, unmergable_rules) # :nodoc:
  styles = unmergable_rules.to_s
  unless styles.empty?
    if @options[:html_fragment]
      style_tag = ::Nokogiri::XML::Node.new("style", doc)
      style_tag.content = styles
      doc.add_child(style_tag)
    else
      style_tag = doc.create_element "style", "#{styles}"
      head = doc.at_css('head')
      head ||=  doc.root.first_element_child.add_previous_sibling(doc.create_element "head")  if doc.root && doc.root.first_element_child
      head ||=  doc.add_child(doc.create_element "head")
      head << style_tag
    end
  end
  doc
end