MediaService Events

The MediaService class implements IMediaService. It provides access to operations involving IMedia.

Usage

Example usage of the MediaService events:

using System;
using Umbraco.Core;
using Umbraco.Core.Composing;
using Umbraco.Core.Models.Entities;
using Umbraco.Core.Services.Implement;

namespace Umbraco8.Components
{
    [RuntimeLevel(MinLevel = RuntimeLevel.Run)]
    public class SubscribeToMediaSavedEventComposer : ComponentComposer<SubscribeToMediaSavedEventComponent>
    {
    }

    public class SubscribeToMediaSavedEventComponent : IComponent
    {
        public void Initialize()
        {
            MediaService.Saved += MediaService_Saved;
        }

        private void MediaService_Saved(Umbraco.Core.Services.IMediaService sender, Umbraco.Core.Events.SaveEventArgs<Umbraco.Core.Models.IMedia> e)
        {
            foreach (var mediaItem in e.SavedEntities)
            {
                if (mediaItem.ContentType.Alias == "Image")
                {
                    //perhaps send to Azure for AI analysis of image contents or something...
                    SendToAzure(mediaItem);
                }
            }
        }

        public void Terminate()
        {
            //unsubscribe during shutdown
            MediaService.Saved -= MediaService_Saved;
        }
    }
}

Events

What happened to Creating and Created events?

Both the MediaService.Creating and MediaService.Created events have been obsoleted. Why? Because these events are not guaranteed to trigger and therefore should not be used. This is because these events only trigger when the MediaService.CreateMedia method is used which is an entirely optional way to create media entities. It is also possible to construct a new media item - which is generally the preferred and consistent way - and therefore the Creating/Created events will not execute when constructing media that way.

Further more, there's no reason to listen for the Creating/Created events because they are misleading. They don't trigger before and after the entity has been persisted. Instead they trigger inside the CreateMedia method which never persists the entity. It constructs a new media object.

What do we use instead?

The MediaService.Saving and MediaService.Saved events will always trigger before and after an entity has been persisted. You can determine if an entity is brand new in either of those events. In the Saving event - before the entity is persisted - you can check the entity's HasIdentity property which will be 'false' if it is brand new. In the Saved event you can check to see if the entity 'remembers being dirty'