Add experimental server-side notification grouping (#29889)

app/controllers/api/v2_alpha/notifications_controller.rb

@@ -0,0 +1,91 @@
+# frozen_string_literal: true
+
+class Api::V2Alpha::NotificationsController < Api::BaseController
+  before_action -> { doorkeeper_authorize! :read, :'read:notifications' }, except: [:clear, :dismiss]
+  before_action -> { doorkeeper_authorize! :write, :'write:notifications' }, only: [:clear, :dismiss]
+  before_action :require_user!
+  after_action :insert_pagination_headers, only: :index
+
+  DEFAULT_NOTIFICATIONS_LIMIT = 40
+
+  def index
+    with_read_replica do
+      @notifications = load_notifications
+      @group_metadata = load_group_metadata
+      @relationships = StatusRelationshipsPresenter.new(target_statuses_from_notifications, current_user&.account_id)
+    end
+
+    render json: @notifications.map { |notification| NotificationGroup.from_notification(notification) }, each_serializer: REST::NotificationGroupSerializer, relationships: @relationships, group_metadata: @group_metadata
+  end
+
+  def show
+    @notification = current_account.notifications.without_suspended.find_by!(group_key: params[:id])
+    render json: NotificationGroup.from_notification(@notification), serializer: REST::NotificationGroupSerializer
+  end
+
+  def clear
+    current_account.notifications.delete_all
+    render_empty
+  end
+
+  def dismiss
+    current_account.notifications.where(group_key: params[:id]).destroy_all
+    render_empty
+  end
+
+  private
+
+  def load_notifications
+    notifications = browserable_account_notifications.includes(from_account: [:account_stat, :user]).to_a_grouped_paginated_by_id(
+      limit_param(DEFAULT_NOTIFICATIONS_LIMIT),
+      params_slice(:max_id, :since_id, :min_id)
+    )
+
+    Notification.preload_cache_collection_target_statuses(notifications) do |target_statuses|
+      preload_collection(target_statuses, Status)
+    end
+  end
+
+  def load_group_metadata
+    return {} if @notifications.empty?
+
+    browserable_account_notifications
+      .where(group_key: @notifications.filter_map(&:group_key))
+      .where(id: (@notifications.last.id)..(@notifications.first.id))
+      .group(:group_key)
+      .pluck(:group_key, 'min(notifications.id) as min_id', 'max(notifications.id) as max_id', 'max(notifications.created_at) as latest_notification_at')
+      .to_h { |group_key, min_id, max_id, latest_notification_at| [group_key, { min_id: min_id, max_id: max_id, latest_notification_at: latest_notification_at }] }
+  end
+
+  def browserable_account_notifications
+    current_account.notifications.without_suspended.browserable(
+      types: Array(browserable_params[:types]),
+      exclude_types: Array(browserable_params[:exclude_types]),
+      include_filtered: truthy_param?(:include_filtered)
+    )
+  end
+
+  def target_statuses_from_notifications
+    @notifications.filter_map(&:target_status)
+  end
+
+  def next_path
+    api_v2_alpha_notifications_url pagination_params(max_id: pagination_max_id) unless @notifications.empty?
+  end
+
+  def prev_path
+    api_v2_alpha_notifications_url pagination_params(min_id: pagination_since_id) unless @notifications.empty?
+  end
+
+  def pagination_collection
+    @notifications
+  end
+
+  def browserable_params
+    params.permit(:include_filtered, types: [], exclude_types: [])
+  end
+
+  def pagination_params(core_params)
+    params.slice(:limit, :types, :exclude_types, :include_filtered).permit(:limit, :include_filtered, types: [], exclude_types: []).merge(core_params)
+  end
+end