How to clear cache when publish sitecore item programmatically in Sitecore 9.3?

Question

I have a private method to publish an item to the Sitecore Web database programmatically. It's publishing the item to the Web database but not clearing the cache. I still see the data from the older version of the published item. I was under the impression that the Sitecore publishing module in Sitecore 9.3 version automatically clears the cache when the item is published.

Do I have to explicitly write a line of code to clear the cache or is there a better way to do this?

I did try to add this line but it did not work for me Sitecore.Caching.CacheManager.ClearAllCaches()

private void PublishItem(Sitecore.Data.Items.Item item)
{
    PublishOptions publishOptions = 
        new PublishOptions(item.Database,
        Database.GetDatabase("web"),
        PublishMode.SingleItem,
        item.Language,
        DateTime.Now)
    {
        UserName = "sitecore\\admin"
    };
    Publisher publisher = new Publisher(publishOptions);
    publisher.Options.RootItem = item;
    publisher.Options.Deep = true;
    publisher.PublishAsync();

    item.Publishing.ClearPublishingCache();
}

Answer 1

This is how item caching works before hitting the database:

For my Sitecore 9.3 scaled solution I use this helper to clear item's cache (after some item is changed programmatically):

public static class CacheHelper
{
    public static void ClearItemCache(this Database database,  ID itemId)
    {
        var prefetchCache = CacheManager.FindCacheByName<ID>("SqlDataProvider - Prefetch data(" + database + ")");
        if (prefetchCache != null)
        {
            prefetchCache.Remove(itemId);
        }
        CacheManager.GetItemCache(database).RemoveItem(itemId);
        database.Caches.ItemCache.RemoveItem(itemId);
        database.Caches.DataCache.RemoveItemInformation(itemId);
    }
}

Example of usage:

var db = Database.GetDatabase("web");
db.ClearItemCache(itemId);

But it is strange that Sitecore.Caching.CacheManager.ClearAllCaches() does not work in your case. Maybe the problem is not in caches. As @Jeroen mentioned it seems that you clear cache before publish is finished because you use PublishAsync. Try to use async/await or ContinueWith to be sure that your cache is clear when publishing is finished.

Answer 2

As @Jeroen pointed out that we had to wait for the publish to complete before clearing the cache. I used PublishManager.WaitFor() method to wait for the publishing to complete. It published the item to CD and cleared the cache. Please see the updated code below.

private void PublishItem(Sitecore.Data.Items.Item item)
{
    PublishOptions publishOptions = 
        new PublishOptions(item.Database,
        Database.GetDatabase("web"),
        PublishMode.SingleItem,
        item.Language,
        DateTime.Now)
    {
        UserName = "sitecore\\admin"
    };
    publishOptions.RootItem = item;
    publishOptions.Deep = true;
    publishOptions.PublishRelatedItems = true;
    publishOptions.CompareRevisions = true;       

    var handle = PublishManager.Publish(new PublishOptions[] { publishOptions });
    PublishManager.WaitFor(handle);
    item.Publishing.ClearPublishingCache();
}