MyContentExtensions.cs

using EPiServer;
using EPiServer.Core;
using EPiServer.Core.Html.StringParsing;
using EPiServer.DataAbstraction;
using EPiServer.Find;
using EPiServer.Find.Helpers.Text;
using EPiServer.ServiceLocation;
using Newtonsoft.Json;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Reflection;


namespace VisitorgroupsTest
{
    public static class MyContentExtensions
    {
        public static IDictionary<string, string> PersonalizedFragments(this IContent content)
        {
            var propertyDefinitionRepository = ServiceLocator.Current.GetInstance<IPropertyDefinitionRepository>();
            var personalizedFragments = new Dictionary<string, string>();

            // Find all top level XHtmlString fields
            foreach (var property in content.Property)
            {
                var xhtml = property.Value as XhtmlString;
                if (xhtml != null)
                {
                    // Check if the property is marked with <see cref="JsonIgnoreAttribute"/> and must be excluded when indexing
                    var typeProperty = content.GetOriginalType().GetProperty(property.Name);
                    if (typeProperty == null ||
                        typeProperty.GetCustomAttribute<JsonIgnoreAttribute>() != null)
                    {
                        continue;
                    }

                    var propertyDefinition = propertyDefinitionRepository.Load(property.PropertyDefinitionID);
                    if (propertyDefinition.Searchable)
                    {
                        personalizedFragments.addPersonalizedFragments(xhtml);
                    }
                }
            }

            return personalizedFragments;
        }

        private static void addPersonalizedFragments(this IDictionary<string, string> personalizedFragments, XhtmlString xhtml)
        {
            // Note, that we will not find nested data. A complete parser is out of scope for this example.
            foreach (var fragment in xhtml.Fragments.OfType<PersonalizedContentFragment>())
            {
                var text = string.Join(" ", fragment.Fragments.Where(x => x is StaticFragment).Select(x => x.InternalFormat)).StripHtml();

                foreach (var role in fragment.GetRoles())
                {
                    if (!personalizedFragments.ContainsKey(role))
                    {
                        personalizedFragments[role] = text;
                    }
                    else
                    {
                        personalizedFragments[role] += " " + text;
                    }
                }
            }

        }
    }
}

MyFindSearchExtensions.cs

using EPiServer.Core;
using EPiServer.Find;
using EPiServer.Find.Api.Querying.Queries;
using EPiServer.Find.UnifiedSearch;
using EPiServer.Personalization.VisitorGroups;
using EPiServer.ServiceLocation;
using System.Collections.Generic;
using System.Security.Principal;

namespace VisitorgroupsTest
{
    public static class MyFindSearchExtensions
    {
        // This extension method is targeted for UnifiedSearch (hence the ISearchContent) used in a CMS context (i.e. the cast to IContent)
        public static IQueriedSearch<ISearchContent, QueryStringQuery> AddPersonalizedFields(
            this IQueriedSearch<ISearchContent, QueryStringQuery> search, IPrincipal user)
        {
            var visitorgroupIds = GetVisitorGroupIdsByCurrentUser(user);

            // I might be good to put a cap here with a warnig if users suddenly qualify for a lot of visitor groups.
            foreach (var id in visitorgroupIds)
            {
                search = search.InField(x => (x as IContent).PersonalizedFragments()[id]);
            }
            return search;
        }

        private static List<string> GetVisitorGroupIdsByCurrentUser(IPrincipal user)
        {
            var visitorGroupId = new List<string>();

            var visitorGroupRepository = ServiceLocator.Current.GetInstance<IVisitorGroupRepository>();
            var visitorGroupRoleRepository = ServiceLocator.Current.GetInstance<IVisitorGroupRoleRepository>();

            var helper = new VisitorGroupHelper(visitorGroupRoleRepository);
            var groups = visitorGroupRepository.List();

            foreach (var visitorGroup in groups)
            {
                if (helper.IsPrincipalInGroup(user, visitorGroup.Name))
                {
                    visitorGroupId.Add(visitorGroup.Id.ToString());
                }
            }
            return visitorGroupId;
        }
    }
}