Efficient way to retrieve list of created/updated and deleted items during Publish

While we are familiar with publish:itemProcessed event that will be triggered once per processed item during publish, there might be instances where we might be looking to work on the entire list of published items all at once to accomplish the desired operations efficiently.

Sitecore has introduced ProcessedPublishingCandidates property (previously it was ProcessedItems which is obsolete now), which accumulates the processed items within the PublishItem pipeline. The PublishItem pipeline holds the responsibility of publishing a single item from the publish queue (this pipeline can also be intercepted with publish:itemProcessed, publish:itemProcessing events). The ProcessedPublishingCandidates property is accessible within the Publish pipeline as well (this pipeline manages the entire publish operation). This behavior enables us to retrieve the list of published items by intercepting the Publish Pipeline using ProcessedPublishingCandidates property.

Sitecore has also added DeleteCandidates property which
will be helpful if you are just looking to retrieve only the deleted items.

Here is the code snippet,

class CustomPublishProcessor : PublishProcessor
{
    public override void Process(PublishContext context)
    {
        Assert.ArgumentNotNull(context, "context");

        if (context.Aborted)
            return;
	
        //Fetches List of Processed(Created/Updated/Deleted) Items
        var processedItems = context.ProcessedPublishingCandidates.Keys
                .Select(i => context.PublishOptions.TargetDatabase.GetItem(i.ItemId)).Where(j => j != null);

        //Fetches List of Deleted Items
        var deletedItems = context.DeleteCandidates;
    }
}

<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
  <sitecore>
    <pipelines>
      <publish>
        <processor patch:after="*[@type='Sitecore.Publishing.Pipelines.Publish.ProcessQueue, Sitecore.Kernel']" type="Assembly.Pipelines.CustomPublishProcessor, Assembly"/>
      </publish>
    </pipelines>
  </sitecore>
</configuration>

Please note that we do have another property ‘CustomData’ which is available within PublishContext, hence it is shared across all the pipeline steps. This allows us to store any custom data specific to a processed item within CustomData property during PublishItem pipeline and can then be utilized across other steps within PublishItem and Publish pipelines if needed.