gitlab-org--gitlab-foss/lib/banzai/filter/kroki_filter.rb

59 lines
1.9 KiB
Ruby

# frozen_string_literal: true
require "nokogiri"
require "asciidoctor/extensions/asciidoctor_kroki/extension"
module Banzai
module Filter
# HTML that replaces all diagrams supported by Kroki with the corresponding img tags.
# If the source content is large then the hidden attribute is added to the img tag.
class KrokiFilter < HTML::Pipeline::Filter
MAX_CHARACTER_LIMIT = 2000
def call
return doc unless settings.kroki_enabled
diagram_selectors = ::Gitlab::Kroki.formats(settings)
.map { |diagram_type| %(pre[lang="#{diagram_type}"] > code) }
.join(', ')
xpath = Gitlab::Utils::Nokogiri.css_to_xpath(diagram_selectors)
return doc unless doc.at_xpath(xpath)
diagram_format = "svg"
doc.xpath(xpath).each do |node|
diagram_type = node.parent['lang']
diagram_src = node.content
image_src = create_image_src(diagram_type, diagram_format, diagram_src)
img_tag = Nokogiri::HTML::DocumentFragment.parse(%(<img src="#{image_src}" />))
img_tag = img_tag.children.first
unless img_tag.nil?
lazy_load = diagram_src.length > MAX_CHARACTER_LIMIT
img_tag.set_attribute('hidden', '') if lazy_load
img_tag.set_attribute('class', 'js-render-kroki')
img_tag.set_attribute('data-diagram', node.parent['lang'])
img_tag.set_attribute('data-diagram-src', "data:text/plain;base64,#{Base64.strict_encode64(node.content)}")
node.parent.replace(img_tag)
end
end
doc
end
private
def create_image_src(type, format, text)
::AsciidoctorExtensions::KrokiDiagram.new(type, format, text)
.get_diagram_uri(settings.kroki_url)
end
def settings
Gitlab::CurrentSettings.current_application_settings
end
end
end
end