Module: Premailer::Adapter::Nokogiri

Defined in:
lib/premailer/adapter/nokogiri.rb

Overview

Nokogiri adapter

Instance Method Summary collapse

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 183

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 = 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)
    HTML_ENTITIES.map do |entity, replacement|
      thing.gsub! entity, replacement
    end
  end
  # Default encoding is ASCII-8BIT (binary) per http://groups.google.com/group/nokogiri-talk/msg/0b81ef0dc180dc74
  # However, we really don't want to hardcode this. ASCII-8BIG should be the default, but not the only option.
  if thing.is_a?(String) and RUBY_VERSION =~ /1.9/
    thing = thing.force_encoding(@options[:input_encoding]).encode!
    doc = ::Nokogiri::HTML(thing, nil, @options[:input_encoding]) {|c| c.recover }
  else
    default_encoding = RUBY_PLATFORM == 'java' ? nil : 'BINARY'
    doc = ::Nokogiri::HTML(thing, nil, @options[:input_encoding] || default_encoding) {|c| c.recover }
  end

  # Fix for removing any CDATA tags inserted per https://github.com/sparklemotion/nokogiri/issues/311
  doc.search("style").children.each do |child|
    child.swap(child.text()) if child.cdata?
  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 11

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(selector, declaration), media_types) unless @options[:preserve_styles]
    else
      begin
        if selector =~ Premailer::RE_RESET_SELECTORS
          # 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(selector, 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
  if @options[:remove_scripts]
    doc.search("script").remove
  end

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

    declarations = []
    style.scan(/\[SPEC\=([\d]+)\[(.[^\]\]]*)\]\]/).each do |declaration|
      rs = CssParser::RuleSet.new(nil, declaration[1].to_s, declaration[0].to_i)
      declarations << rs
    end

    # Perform style folding
    merged = CssParser.merge(declarations)
    merged.expand_shorthand!

    # Duplicate CSS attributes as HTML attributes
    if Premailer::RELATED_ATTRIBUTES.has_key?(el.name)
      Premailer::RELATED_ATTRIBUTES[el.name].each do |css_att, html_att|
        el[html_att] = merged[css_att].gsub(/url\('(.*)'\)/,'\1').gsub(/;$/, '').strip if el[html_att].nil? and not merged[css_att].empty?
      end
    end

    # Collapse multiple rules into one as much as possible.
    merged.create_shorthand!

    # write the inline STYLE attribute
    el['style'] = Premailer.escape_string(merged.declarations_to_s).split(';').map(&:strip).sort.join('; ')
  end

  doc = write_unmergable_css_rules(doc, @unmergable_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::MD5.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::MD5.hexdigest(id))
      else
        el.remove_attribute('id')
      end
    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 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 160

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 172

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 body.

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 136

def write_unmergable_css_rules(doc, unmergable_rules) # :nodoc:
  styles = unmergable_rules.to_s

  unless styles.empty?
    style_tag = "<style type=\"text/css\">\n#{styles}</style>"
    if body = doc.search('body')
      if doc.at_css('body').children && !doc.at_css('body').children.empty?
        doc.at_css('body').children.before(::Nokogiri::XML.fragment(style_tag))
      else
        doc.at_css('body').add_child(::Nokogiri::XML.fragment(style_tag))
      end
    else
      doc.inner_html = style_tag += doc.inner_html
    end
  end
  doc
end