discourse/app/models/site.rb

# frozen_string_literal: true

# A class we can use to serialize the site data
class Site
  include ActiveModel::Serialization

  # Number of categories preloaded when lazy_load_categories is enabled
  LAZY_LOAD_CATEGORIES_LIMIT = 50

  cattr_accessor :preloaded_category_custom_fields

  def self.reset_preloaded_category_custom_fields
    self.preloaded_category_custom_fields = Set.new
  end
  reset_preloaded_category_custom_fields

  ##
  # Sometimes plugins need to have additional data or options available
  # when rendering custom markdown features/rules that are not available
  # on the default opts.discourse object. These additional options should
  # be namespaced to the plugin adding them.
  #
  # ```
  # Site.markdown_additional_options["chat"] = { limited_pretty_text_markdown_rules: [] }
  # ```
  #
  # These are passed down to markdown rules on opts.discourse.additionalOptions.
  cattr_accessor :markdown_additional_options
  self.markdown_additional_options = {}

  def self.add_categories_callbacks(&block)
    categories_callbacks << block
  end

  def self.categories_callbacks
    @categories_callbacks ||= []
  end

  def initialize(guardian)
    @guardian = guardian
  end

  def site_setting
    SiteSetting
  end

  def notification_types
    Notification.types
  end

  def trust_levels
    TrustLevel.levels
  end

  def user_fields
    UserField.includes(:user_field_options).order(:position).all
  end

  def self.categories_cache_key
    "site_categories_#{Discourse.git_version}"
  end

  def self.clear_cache
    Discourse.cache.delete(categories_cache_key)
  end

  def self.all_categories_cache
    # Categories do not change often so there is no need for us to run the
    # same query and spend time creating ActiveRecord objects for every requests.
    #
    # Do note that any new association added to the eager loading needs a
    # corresponding ActiveRecord callback to clear the categories cache.
    Discourse
      .cache
      .fetch(categories_cache_key, expires_in: 30.minutes) do
        categories =
          begin
            query =
              Category
                .includes(
                  :uploaded_logo,
                  :uploaded_logo_dark,
                  :uploaded_background,
                  :uploaded_background_dark,
                  :tags,
                  :tag_groups,
                  :form_templates,
                  category_required_tag_groups: :tag_group,
                )
                .joins("LEFT JOIN topics t on t.id = categories.topic_id")
                .select("categories.*, t.slug topic_slug")
                .order(:position)

            query =
              DiscoursePluginRegistry.apply_modifier(:site_all_categories_cache_query, query, self)

            query.to_a
          end

        if preloaded_category_custom_fields.present?
          Category.preload_custom_fields(categories, preloaded_category_custom_fields)
        end

        ActiveModel::ArraySerializer.new(
          categories,
          each_serializer: SiteCategorySerializer,
        ).as_json
      end
  end

  def categories
    @categories ||=
      begin
        categories = []

        self.class.all_categories_cache.each do |category|
          if @guardian.can_see_serialized_category?(
               category_id: category[:id],
               read_restricted: category[:read_restricted],
             )
            categories << category
          end

          if SiteSetting.lazy_load_categories && categories.size >= Site::LAZY_LOAD_CATEGORIES_LIMIT
            break
          end
        end

        with_children = Set.new
        categories.each { |c| with_children << c[:parent_category_id] if c[:parent_category_id] }

        allowed_topic_create = nil
        unless @guardian.is_admin?
          allowed_topic_create_ids =
            @guardian.anonymous? ? [] : Category.topic_create_allowed(@guardian).pluck(:id)
          allowed_topic_create = Set.new(allowed_topic_create_ids)
        end

        by_id = {}

        notification_levels = CategoryUser.notification_levels_for(@guardian.user)
        default_notification_level = CategoryUser.default_notification_level

        categories.each do |category|
          category[:notification_level] = notification_levels[category[:id]] ||
            default_notification_level
          category[:permission] = CategoryGroup.permission_types[
            :full
          ] if allowed_topic_create&.include?(category[:id]) || @guardian.is_admin?
          category[:has_children] = with_children.include?(category[:id])

          category[:can_edit] = @guardian.can_edit_serialized_category?(
            category_id: category[:id],
            read_restricted: category[:read_restricted],
          )

          by_id[category[:id]] = category
        end

        categories.reject! { |c| c[:parent_category_id] && !by_id[c[:parent_category_id]] }

        self.class.categories_callbacks.each { |callback| callback.call(categories, @guardian) }

        categories
      end
  end

  def groups
    query =
      Group.visible_groups(@guardian.user, "groups.name ASC", include_everyone: true).includes(
        :flair_upload,
      )
    query = DiscoursePluginRegistry.apply_modifier(:site_groups_query, query, self)

    query
  end

  def archetypes
    Archetype.list.reject { |t| t.id == Archetype.private_message }
  end

  def auth_providers
    Discourse.enabled_auth_providers
  end

  def self.json_for(guardian)
    if guardian.anonymous? && SiteSetting.login_required
      return(
        {
          periods: TopTopic.periods.map(&:to_s),
          filters: Discourse.filters.map(&:to_s),
          user_fields:
            UserField
              .includes(:user_field_options)
              .order(:position)
              .all
              .map { |userfield| UserFieldSerializer.new(userfield, root: false, scope: guardian) },
          auth_providers:
            Discourse.enabled_auth_providers.map do |provider|
              AuthProviderSerializer.new(provider, root: false, scope: guardian)
            end,
        }.to_json
      )
    end

    seq = nil

    if guardian.anonymous?
      seq = MessageBus.last_id("/site_json")

      cached_json, cached_seq, cached_version =
        Discourse.redis.mget("site_json", "site_json_seq", "site_json_version")

      if cached_json && seq == cached_seq.to_i && Discourse.git_version == cached_version
        return cached_json
      end
    end

    site = Site.new(guardian)
    json = MultiJson.dump(SiteSerializer.new(site, root: false, scope: guardian))

    if guardian.anonymous?
      Discourse.redis.multi do |transaction|
        transaction.setex "site_json", 1800, json
        transaction.set "site_json_seq", seq
        transaction.set "site_json_version", Discourse.git_version
      end
    end

    json
  end

  SITE_JSON_CHANNEL = "/site_json"

  def self.clear_anon_cache!
    # publishing forces the sequence up
    # the cache is validated based on the sequence
    MessageBus.publish(SITE_JSON_CHANNEL, "")
  end
end