Retrieve string content from JSON properties with supplied names (Kentico)

SearchModule.cs

using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

using CMS;
using CMS.DataEngine;
using CMS.DocumentEngine;

using Example.Linq;
using Example.Search;

using Newtonsoft.Json.Linq;

[assembly: RegisterModule(typeof(SearchModule))]

namespace Example.Search
{
    public class SearchModule : Module
    {
        public SearchModule()
            : base(nameof(SearchModule))
        {
        }

        protected override void OnInit()
        {
            base.OnInit();

            DocumentEvents.GetContent.Execute += OnGetPageContent;
        }

        private static void OnGetPageContent(object sender, DocumentSearchEventArgs e)
        {
            // Example property names to be added to index
            var indexableProperties = new[] {"heading", "html", "text"};

            var node = e.Node;

            if (node == null)
            {
                return;
            }

            var pagebuilderJson = node.GetStringValue("DocumentPageBuilderWidgets", string.Empty);

            if (string.IsNullOrWhiteSpace(pagebuilderJson))
            {
                return;
            }

            var rootNode = JToken.Parse(pagebuilderJson);
            var searchTokens = GetSearchTokens(rootNode, indexableProperties);

            var pagebuilderContent = string.Join(" ", searchTokens.Select(RemoveTags));

            e.AddContent(pagebuilderContent);
        }

        private static IEnumerable<string> GetSearchTokens(JToken token, string[] propertyNames)
        {
            var searchTokens = new Stack<JToken>(token.Children());

            while (searchTokens.Any())
            {
                var currentToken = searchTokens.Pop();

                if (currentToken.Type == JTokenType.Property)
                {
                    var currentProperty = (JProperty)currentToken;
                    var value = currentProperty.Value.ToString();

                    if (propertyNames.Contains(currentProperty.Name)
                        && !string.IsNullOrWhiteSpace(value))
                    {
                        yield return value;
                    }
                }

                foreach (var child in currentToken)
                {
                    searchTokens.Push(child);
                }
            }
        }
        
        // Remove HTML from rich text
        private static string RemoveTags(string input)
        {
            return input == null
                ? string.Empty
                : Regex.Replace(input, "<[^>]+>", " ")
                    .Replace("\n", " ");
        }
    }
}