Reference event service implementation (#811)

* Reference event service implementation

* Fix IReferenceable implementation of Id

* add structure to event body

src/Core/Services/Implementations/AzureQueueReferenceEventService.cs

@@ -0,0 +1,49 @@
+using System.Threading.Tasks;
+using Azure.Storage.Queues;
+using Bit.Core.Models.Business;
+using Newtonsoft.Json;
+
+namespace Bit.Core.Services
+{
+    public class AzureQueueReferenceEventService : IReferenceEventService
+    {
+        private const string _queueName = "reference-events";
+
+        private readonly QueueClient _queueClient;
+        private readonly GlobalSettings _globalSettings;
+        private readonly JsonSerializerSettings _jsonSerializerSettings = new JsonSerializerSettings
+        {
+            NullValueHandling = NullValueHandling.Ignore,
+        };
+
+        public AzureQueueReferenceEventService (
+            GlobalSettings globalSettings)
+        {
+            _queueClient = new QueueClient(globalSettings.Storage.ConnectionString, _queueName);
+            _globalSettings = globalSettings;
+        }
+
+        public async Task RaiseEventAsync(ReferenceEvent referenceEvent)
+        {
+            await SendMessageAsync(referenceEvent);
+        }
+
+        private async Task SendMessageAsync(ReferenceEvent referenceEvent)
+        {
+            if (_globalSettings.SelfHosted || string.IsNullOrWhiteSpace(referenceEvent.ReferenceId))
+            {
+                // Ignore for self-hosted, OR, where there is no ReferenceId
+                return;
+            }
+            try
+            {
+                var message = JsonConvert.SerializeObject(referenceEvent, _jsonSerializerSettings);
+                await _queueClient.SendMessageAsync(message);
+            }
+            catch
+            {
+                // Ignore failure
+            }
+        }
+    }
+}