From 51fa5fa703811a11b1171c8a6b6738dff77406ef Mon Sep 17 00:00:00 2001
From: Ronny Birkeli <ronny.birkeli@digdir.no>
Date: Sun, 6 Nov 2022 22:36:32 +0100
Subject: [PATCH] Null detection and improved error handling

---
 .../Controllers/EventsReceiverController.cs              | 9 ++++++++-
 .../Internal/Events/EventHandlerResolver.cs              | 5 +++++
 .../Internal/Events/UnhandledEventHandler.cs             | 2 +-
 .../Controllers/EventsReceiverControllerTests.cs         | 2 +-
 4 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/Altinn.App.Api/Controllers/EventsReceiverController.cs b/src/Altinn.App.Api/Controllers/EventsReceiverController.cs
index 049f94868..1a9aee535 100644
--- a/src/Altinn.App.Api/Controllers/EventsReceiverController.cs
+++ b/src/Altinn.App.Api/Controllers/EventsReceiverController.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Text.Json;
 using System.Threading.Tasks;
 using Altinn.App.Core.Configuration;
 using Altinn.App.Core.Features;
@@ -49,7 +50,13 @@ public async Task<ActionResult> Post([FromQuery] string code, [FromBody] CloudEv
             {
                 return Unauthorized();
             }
-            
+
+            if (cloudEventEnvelope.CloudEvent == null)
+            {
+                _logger.LogError("CloudEvent is null, unable to process event! Data received: {data}", JsonSerializer.Serialize(cloudEventEnvelope));
+                return BadRequest();
+            }
+
             CloudEvent cloudEvent = cloudEventEnvelope.CloudEvent;
 
             IEventHandler eventHandler = _eventHandlerResolver.ResolveEventHandler(cloudEvent.Type);
diff --git a/src/Altinn.App.Core/Internal/Events/EventHandlerResolver.cs b/src/Altinn.App.Core/Internal/Events/EventHandlerResolver.cs
index d53aa2894..b123dd4fe 100644
--- a/src/Altinn.App.Core/Internal/Events/EventHandlerResolver.cs
+++ b/src/Altinn.App.Core/Internal/Events/EventHandlerResolver.cs
@@ -16,6 +16,11 @@ public EventHandlerResolver(IEnumerable<IEventHandler> eventHandlers)
         /// <inheritDoc/>
         public IEventHandler ResolveEventHandler(string eventType)
         {
+            if (eventType == null)
+            {
+                return new UnhandledEventHandler();
+            }
+
             foreach (var handler in _eventHandlers)
             {
                 if (handler.EventType.ToLower() != eventType.ToLower())
diff --git a/src/Altinn.App.Core/Internal/Events/UnhandledEventHandler.cs b/src/Altinn.App.Core/Internal/Events/UnhandledEventHandler.cs
index 228e80e0a..ecde429a0 100644
--- a/src/Altinn.App.Core/Internal/Events/UnhandledEventHandler.cs
+++ b/src/Altinn.App.Core/Internal/Events/UnhandledEventHandler.cs
@@ -15,7 +15,7 @@ public class UnhandledEventHandler : IEventHandler
         /// <inheritdoc/>
         public Task<bool> ProcessEvent(CloudEvent cloudEvent)
         {
-            throw new NotImplementedException($"Received unhandled event {cloudEvent.Type} with the following data: {JsonSerializer.Serialize(cloudEvent)}");
+            throw new NotImplementedException($"Received unhandled event {cloudEvent?.Type} with the following data: {JsonSerializer.Serialize(cloudEvent)}");
         }
     }
 }
\ No newline at end of file
diff --git a/test/Altinn.App.Api.Tests/Controllers/EventsReceiverControllerTests.cs b/test/Altinn.App.Api.Tests/Controllers/EventsReceiverControllerTests.cs
index d992d31b5..0a2e456b2 100644
--- a/test/Altinn.App.Api.Tests/Controllers/EventsReceiverControllerTests.cs
+++ b/test/Altinn.App.Api.Tests/Controllers/EventsReceiverControllerTests.cs
@@ -71,7 +71,7 @@ public async Task Post_NonValidEventType_ShouldReturnBadRequest()
                 Time = DateTime.Parse("2022-10-13T09:33:46.6330634Z"),
                 AlternativeSubject = "/person/17858296439"
             };
-            CloudEventEnvelope envelope = new() { CloudEvent = cloudEvent };
+            CloudEventEnvelope envelope = new() { CloudEvent = null };
 
             var org = "ttd";
             var app = "non-existing-app";