Add schema.org markup to SEO-enabled posts (#36075)

app/helpers/statuses_helper.rb

@@ -64,4 +64,16 @@ module StatusesHelper
   def prefers_autoplay?
     ActiveModel::Type::Boolean.new.cast(params[:autoplay]) || current_user&.setting_auto_play_gif
   end
+
+  def render_seo_schema(status)
+    json = ActiveModelSerializers::SerializableResource.new(
+      status,
+      serializer: SEO::SocialMediaPostingSerializer,
+      adapter: SEO::Adapter
+    ).to_json
+
+    # rubocop:disable Rails/OutputSafety
+    content_tag(:script, json_escape(json).html_safe, type: 'application/ld+json')
+    # rubocop:enable Rails/OutputSafety
+  end
 end

app/lib/seo/adapter.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+class SEO::Adapter < ActiveModelSerializers::Adapter::Base
+  def self.default_key_transform
+    :camel_lower
+  end
+
+  def self.transform_key_casing!(value, _options)
+    SEO::CaseTransform.camel_lower(value)
+  end
+
+  def serializable_hash(options = nil)
+    serialized_hash = serializer.serializable_hash(serialization_options(options))
+    self.class.transform_key_casing!(serialized_hash, instance_options)
+  end
+end

app/lib/seo/case_transform.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module SEO::CaseTransform
+  PREFIX_KEYS = %w(
+    context
+    id
+    type
+  ).freeze
+
+  class << self
+    def camel_lower_cache
+      @camel_lower_cache ||= {}
+    end
+
+    def camel_lower(value)
+      case value
+      when Array
+        value.map { |item| camel_lower(item) }
+      when Hash
+        value.deep_transform_keys! { |key| camel_lower(key) }
+      when Symbol
+        camel_lower(value.to_s).to_sym
+      when String
+        camel_lower_cache[value] ||= begin
+          if PREFIX_KEYS.include?(value.to_s)
+            "@#{value}"
+          else
+            value.underscore.camelize(:lower)
+          end
+        end
+      else
+        value
+      end
+    end
+  end
+end

app/serializers/seo/social_media_posting_serializer.rb

@@ -0,0 +1,127 @@
+# frozen_string_literal: true
+
+class SEO::SocialMediaPostingSerializer < ActiveModel::Serializer
+  include FormattingHelper
+  include RoutingHelper
+
+  attributes :context, :type, :url, :date_published, :date_modified,
+             :author, :text, :interaction_statistic
+
+  attribute :image, if: -> { object.ordered_media_attachments.any?(&:image?) }
+  attribute :video, if: -> { object.ordered_media_attachments.any? { |attachment| attachment.video? || attachment.gifv? } }
+  attribute :audio, if: -> { object.ordered_media_attachments.any?(&:audio?) }
+  attribute :shared_content, if: -> { object.with_preview_card? }
+
+  def context
+    'https://schema.org'
+  end
+
+  def type
+    'SocialMediaPosting'
+  end
+
+  def url
+    ActivityPub::TagManager.instance.url_for(object)
+  end
+
+  def date_published
+    object.created_at.iso8601
+  end
+
+  def date_modified
+    object.edited_at&.iso8601
+  end
+
+  def author
+    {
+      type: 'Person',
+      name: object.account.display_name.presence || object.account.username,
+      alternate_name: object.account.local_username_and_domain,
+      identifier: object.account.local_username_and_domain,
+      url: ActivityPub::TagManager.instance.url_for(object.account),
+      interaction_statistic: [
+        {
+          type: 'InteractionCounter',
+          interaction_type: 'https://schema.org/FollowAction',
+          user_interaction_count: object.account.followers_count,
+        },
+      ],
+    }
+  end
+
+  def text
+    status_content_format(object)
+  end
+
+  def interaction_statistic
+    [
+      {
+        type: 'InteractionCounter',
+        interaction_type: 'https://schema.org/LikeAction',
+        user_interaction_count: object.favourites_count,
+      },
+
+      {
+        type: 'InteractionCounter',
+        interaction_type: 'https://schema.org/ShareAction',
+        user_interaction_count: object.reblogs_count,
+      },
+
+      {
+        type: 'InteractionCounter',
+        interaction_type: 'https://schema.org/ReplyAction',
+        user_interaction_count: object.replies_count,
+      },
+    ]
+  end
+
+  def image
+    object.ordered_media_attachments.filter_map do |attachment|
+      next unless attachment.image?
+
+      {
+        type: 'ImageObject',
+        content_url: full_asset_url(attachment.file.url(:original, false)),
+        thumbnail_url: attachment.thumbnail.present? ? full_asset_url(attachment.thumbnail.url(:original)) : full_asset_url(attachment.file.url(:small)),
+        description: attachment.description,
+      }
+    end
+  end
+
+  def video
+    object.ordered_media_attachments.filter_map do |attachment|
+      next unless attachment.video? || attachment.gifv?
+
+      {
+        type: 'VideoObject',
+        upload_date: attachment.created_at.iso8601,
+        content_url: full_asset_url(attachment.file.url(:original, false)),
+        thumbnail_url: attachment.thumbnail.present? ? full_asset_url(attachment.thumbnail.url(:original)) : full_asset_url(attachment.file.url(:small)),
+        embed_url: medium_player_url(attachment),
+        description: attachment.description,
+      }
+    end
+  end
+
+  def audio
+    object.ordered_media_attachments.filter_map do |attachment|
+      next unless attachment.audio?
+
+      {
+        type: 'AudioObject',
+        upload_date: attachment.created_at.iso8601,
+        content_url: full_asset_url(attachment.file.url(:original, false)),
+        thumbnail_url: attachment.thumbnail.present? ? full_asset_url(attachment.thumbnail.url(:original)) : full_asset_url(attachment.file.url(:small)),
+        embed_url: medium_player_url(attachment),
+        description: attachment.description,
+      }
+    end
+  end
+
+  def shared_content
+    {
+      type: 'WebPage',
+      url: object.preview_card.url,
+    }
+  end
+end

app/views/statuses/show.html.haml

@@ -3,6 +3,8 @@
 - content_for :header_tags do
   - if @account.user_prefers_noindex?
     %meta{ name: 'robots', content: 'noindex, noarchive' }/
+  - else
+    = render_seo_schema @status
 
   %link{ rel: 'alternate', type: 'application/json+oembed', href: api_oembed_url(url: short_account_status_url(@account, @status), format: 'json') }/
   %link{ rel: 'alternate', type: 'application/activity+json', href: ActivityPub::TagManager.instance.uri_for(@status) }/

config/initializers/inflections.rb

@@ -27,6 +27,7 @@ ActiveSupport::Inflector.inflections(:en) do |inflect|
   inflect.acronym 'REST'
   inflect.acronym 'RSS'
   inflect.acronym 'StatsD'
+  inflect.acronym 'SEO'
   inflect.acronym 'TOC'
   inflect.acronym 'URL'