EdgeItemCrawler.cs

namespace Foundation.Search.Crawlers
{
    using System;
    using Microsoft.Extensions.DependencyInjection;
    using Sitecore;
    using Sitecore.Abstractions;
    using Sitecore.ContentSearch;
    using Sitecore.ContentSearch.Events;
    using Sitecore.Data.Items;
    using Sitecore.Data.LanguageFallback;
    using Sitecore.DependencyInjection;
    using Sitecore.Diagnostics;
    using Sitecore.ExperienceEdge.Connector.Abstraction.DirectPublishing;

    /// <summary>
    /// This crawler mimics the behavior of the familiar Content Editor Warning
    ///
    /// e.g. "If you publish now, the selected version will not be visible on the Web site because it has been replaced by an older version."
    ///
    /// This crawler only indexes item versions that are in a publishable state. The same logic is used when publishing content to Edge and thus
    /// the index and Edge remain in sync. 
    /// </summary>
    public class EdgeItemCrawler : Sitecore.ContentSearch.SitecoreItemCrawler
    {
        /// <summary>
        /// This is confirmed to also be a singleton, thus this class is as well
        /// </summary>
        private readonly IItemPublishingManager itemPublishManager;

        private const string EdgePublishingTargetId = "{3013BEED-71CA-4DE3-A1D2-17DD871597F1}";

        public EdgeItemCrawler()
        {
            this.itemPublishManager = ServiceLocator.ServiceProvider.GetService<IItemPublishingManager>();
        }

        protected override void DoAdd(IProviderUpdateContext context, SitecoreIndexableItem indexable)
        {
            Assert.ArgumentNotNull(context, nameof(context));
            Assert.ArgumentNotNull(indexable, nameof(indexable));

            using (new LanguageFallbackItemSwitcher(context.Index.EnableItemLanguageFallback))
            {
                this.Index.Locator.GetInstance<BaseEventManager>().RaiseEvent(new AddingIndexingEvent().WithIndexName(context.Index.Name).WithUniqueId(indexable.UniqueId).WithPath(indexable.AbsolutePath));
                if (!this.IsExcludedFromIndex(indexable))
                {
                    foreach (var language in indexable.Item.Languages)
                    {
                        // delete by "groupId" to remove all versions of the item
                        base.Delete(context, indexable.UniqueId.GroupId);

                        if (indexable.Item?.Versions == null)
                        {
                            continue;
                        }

                        var latestVersion = this.itemPublishManager.GetPublishableVersion(indexable.Item, new Sitecore.Data.ID(EdgePublishingTargetId), false);

                        if (latestVersion == null)
                        {
                            continue;
                        }

                        indexable = latestVersion;

                        // add the single, publishable version
                        this.Operations.Add(indexable, context, this.index.Configuration);
                    }
                }
                this.Index.Locator.GetInstance<BaseEventManager>().RaiseEvent(new AddedIndexingEvent().WithIndexName(context.Index.Name).WithUniqueId(indexable.UniqueId).WithPath(indexable.AbsolutePath));
            }
        }

        protected override void DoUpdate(IProviderUpdateContext context, SitecoreIndexableItem indexable, IndexEntryOperationContext operationContext)
        {
            Assert.ArgumentNotNull(context, "context");
            Assert.ArgumentNotNull(indexable, "indexable");

            if (indexable.Item?.Versions == null)
            {
                return;
            }

            var latestVersion = this.itemPublishManager.GetPublishableVersion(indexable.Item, new Sitecore.Data.ID(EdgePublishingTargetId), false);

            if (latestVersion == null)
            {
                return;
            }

            base.Delete(context, indexable.UniqueId.GroupId);

            if (operationContext != null)
            {
                operationContext.NeedUpdatePreviousVersion = false;
                operationContext.NeedUpdateAllVersions = false;
            }
            base.DoUpdate(context, (SitecoreIndexableItem)latestVersion, operationContext);
        }

        public override void Update(IProviderUpdateContext context, IIndexableUniqueId indexableUniqueId, IndexEntryOperationContext operationContext, IndexingOptions indexingOptions = IndexingOptions.Default)
        {
            var item = this.GetItem(indexableUniqueId as SitecoreItemUniqueId);

            if (item?.Versions == null)
            {
                return;
            }

            var latestVersion = this.itemPublishManager.GetPublishableVersion(item, new Sitecore.Data.ID(EdgePublishingTargetId), false);

            if (latestVersion == null)
            {
                return;
            }

            base.Delete(context, indexableUniqueId.GroupId);

            if (operationContext != null)
            {
                operationContext.NeedUpdatePreviousVersion = false;
                operationContext.NeedUpdateAllVersions = false;
            }
            base.Update(context, ((SitecoreIndexableItem)latestVersion).UniqueId, operationContext, indexingOptions);
        }

        public override void Update(IProviderUpdateContext context, IIndexableUniqueId indexableUniqueId, IndexingOptions indexingOptions = IndexingOptions.Default)
        {
            var item = this.GetItem(indexableUniqueId as SitecoreItemUniqueId);

            if (item?.Versions == null)
            {
                return;
            }

            var latestVersion = this.itemPublishManager.GetPublishableVersion(item, new Sitecore.Data.ID(EdgePublishingTargetId), false);

            if (latestVersion == null)
            {
                return;
            }

            base.Delete(context, indexableUniqueId.GroupId);

            base.Update(context, ((SitecoreIndexableItem)latestVersion).UniqueId, indexingOptions);
        }

        protected override void UpdateItemVersion(IProviderUpdateContext context, Item version, IndexEntryOperationContext operationContext)
        {
            // item has a workflow defined, but no value for workflow state, do not index
            if (!String.IsNullOrEmpty(version[FieldIDs.DefaultWorkflow]) && String.IsNullOrEmpty(version[FieldIDs.WorkflowState]))
            {
                return;
            }

            if (version == null)
            {
                return;
            }

            var latestVersion = this.itemPublishManager.GetPublishableVersion(version, new Sitecore.Data.ID(EdgePublishingTargetId), false);


            if (latestVersion == null)
            {
                return;
            }

            var indexable = (SitecoreIndexableItem)latestVersion;

            // delete all versions of the item
            base.Delete(context, indexable.UniqueId.GroupId);

            // index only the publishable version
            if (operationContext != null)
            {
                operationContext.NeedUpdatePreviousVersion = false;
                operationContext.NeedUpdateAllVersions = false;
            }
            base.UpdateItemVersion(context, latestVersion, operationContext);
        }

        public override void Delete(
            IProviderUpdateContext context,
            IIndexableUniqueId indexableUniqueId,
            IndexingOptions indexingOptions = IndexingOptions.Default)
        {
            if (!this.ShouldStartIndexing(indexingOptions))
            {
                return;
            }

            var item = this.GetItem(indexableUniqueId as SitecoreItemUniqueId);

            if (item?.Versions == null)
            {
                return;
            }

            var latestVersion = this.itemPublishManager.GetPublishableVersion(item, new Sitecore.Data.ID(EdgePublishingTargetId), false);

            base.Delete(context, indexableUniqueId.GroupId);

            if (latestVersion == null)
            {
                return;
            }

            base.Update(context, ((SitecoreIndexableItem)latestVersion).UniqueId, indexingOptions);
        }
    }
}