gitlabhq/lib/gitlab/asciidoc.rb

# frozen_string_literal: true

require 'asciidoctor'
require 'asciidoctor-plantuml'
require 'asciidoctor/extensions/asciidoctor_kroki/version'
require 'asciidoctor/extensions/asciidoctor_kroki/extension'
require 'asciidoctor/extensions'
require 'gitlab/asciidoc/html5_converter'
require 'gitlab/asciidoc/mermaid_block_processor'
require 'gitlab/asciidoc/syntax_highlighter/html_pipeline_adapter'

module Gitlab
  # Parser/renderer for the AsciiDoc format that uses Asciidoctor and filters
  # the resulting HTML through HTML pipeline filters.
  module Asciidoc
    # This value ensures a safe depth limit on the number of included files when using include
    # directives in Asciidoc. By considering the exponential growth effect that comes with
    # depth, a lower number results in a controlled number of included files.
    MAX_INCLUDE_DEPTH = 3
    RENDER_TIMEOUT = 10.seconds
    DEFAULT_ADOC_ATTRS = {
      'showtitle' => true,
      'sectanchors' => true,
      'idprefix' => Banzai::Renderer::USER_CONTENT_ID_PREFIX,
      'idseparator' => '-',
      'env' => 'gitlab',
      'env-gitlab' => '',
      'source-highlighter' => 'gitlab-html-pipeline',
      'icons' => 'font',
      'outfilesuffix' => '.adoc',
      'max-include-depth' => MAX_INCLUDE_DEPTH,
      # This feature is disabled because it relies on File#read to read the file.
      # If we want to enable this feature we will need to provide a "GitLab compatible" implementation.
      # This attribute is typically used to share common config (skinparam...) across all PlantUML diagrams.
      # The value can be a path or a URL.
      'kroki-plantuml-include!' => '',
      # This feature is disabled because it relies on the local file system to save diagrams retrieved from the Kroki server.
      'kroki-fetch-diagram!' => ''
    }.freeze

    def self.path_attrs(path)
      return {} unless path

      {
        # Set an empty docname if the path is a directory
        'docname' => if path[-1] == ::File::SEPARATOR
                       ''
                     else
                       ::File.basename(path, '.*')
                     end
      }
    end

    # Public: Converts the provided Asciidoc markup into HTML.
    #
    # input         - the source text in Asciidoc format
    # context       - :commit, :project, :ref, :requested_path
    #
    def self.render(input, context)
      extensions = proc do
        include_processor ::Gitlab::Asciidoc::IncludeProcessor.new(context)
        block ::Gitlab::Asciidoc::MermaidBlockProcessor
        ::Gitlab::Kroki.formats(Gitlab::CurrentSettings).each do |name|
          block ::AsciidoctorExtensions::KrokiBlockProcessor, name
        end
      end

      extra_attrs = path_attrs(context[:requested_path])
      asciidoc_opts = { safe: :secure,
                        backend: :gitlab_html5,
                        attributes: DEFAULT_ADOC_ATTRS
                                        .merge(extra_attrs)
                                        .merge({
                                          # Define the Kroki server URL from the settings.
                                          # This attribute cannot be overridden from the AsciiDoc document.
                                          'kroki-server-url' => Gitlab::CurrentSettings.kroki_url,
                                          'allow-uri-read' => Gitlab::CurrentSettings.wiki_asciidoc_allow_uri_includes
                                        }),
                        extensions: extensions }

      context[:pipeline] = :ascii_doc
      context[:max_includes] = [::Gitlab::CurrentSettings.asciidoc_max_includes, context[:max_includes]].compact.min

      Gitlab::Plantuml.configure

      html = begin
        Gitlab::RenderTimeout.timeout(foreground: RENDER_TIMEOUT) { ::Asciidoctor.convert(input, asciidoc_opts) }
      rescue Timeout::Error => e
        class_name = name.demodulize
        Gitlab::ErrorTracking.track_exception(e, project_id: context[:project]&.id, class_name: class_name)

        Banzai::Filter::SanitizationFilter::COMPLEX_MARKDOWN_MESSAGE
      end

      html = Banzai.render(html, context)
      html.html_safe
    end
  end
end