From c74f57ed6e7b6d87577d5f7991d90260c5954e6b Mon Sep 17 00:00:00 2001
From: Stuart Ferguson <stuart_ferguson1@btinternet.com>
Date: Thu, 1 Dec 2022 21:41:43 +0000
Subject: [PATCH] Enforce event Id on event controller

---
 .../ControllerTests/ControllerTests.cs        | 71 +++++++++++++++++++
 .../Controllers/DomainEventController.cs      | 36 +++++-----
 2 files changed, 91 insertions(+), 16 deletions(-)
 create mode 100644 TransactionProcessor.Tests/ControllerTests/ControllerTests.cs

diff --git a/TransactionProcessor.Tests/ControllerTests/ControllerTests.cs b/TransactionProcessor.Tests/ControllerTests/ControllerTests.cs
new file mode 100644
index 00000000..bfeab949
--- /dev/null
+++ b/TransactionProcessor.Tests/ControllerTests/ControllerTests.cs
@@ -0,0 +1,71 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Moq;
+using Newtonsoft.Json;
+using Shared.EventStore.EventHandling;
+using Shouldly;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using TransactionProcessor.Controllers;
+using TransactionProcessor.Transaction.DomainEvents;
+using Xunit;
+
+namespace TransactionProcessor.Tests.ControllerTests
+{
+    using System.Threading;
+    using Shared.General;
+    using Shared.Logger;
+
+    public class ControllerTests
+    {
+        public ControllerTests()
+        {
+            Logger.Initialise(new NullLogger());
+        }
+        [Fact]
+        public async Task DomainEventController_EventIdNotPresentInJson_ErrorThrown()
+        {
+            Mock<IDomainEventHandlerResolver> resolver = new Mock<IDomainEventHandlerResolver>();
+            TypeMap.AddType<TransactionHasBeenCompletedEvent>("TransactionHasBeenCompletedEvent");
+            DefaultHttpContext httpContext = new DefaultHttpContext();
+            httpContext.Request.Headers["eventType"] = "TransactionHasBeenCompletedEvent";
+            DomainEventController controller = new DomainEventController(resolver.Object)
+            {
+                ControllerContext = new ControllerContext()
+                {
+                    HttpContext = httpContext
+                }
+            };
+            String json = "{\r\n  \"completedDateTime\": \"2022-11-08T15:40:07\",\r\n  \"estateId\": \"435613ac-a468-47a3-ac4f-649d89764c22\",\r\n  \"isAuthorised\": true,\r\n  \"transactionAmount\": 35.0,\r\n  \"merchantId\": \"8bc8434d-41f9-4cc3-83bc-e73f20c02e1d\",\r\n  \"responseCode\": \"0000\",\r\n  \"responseMessage\": \"SUCCESS\",\r\n  \"transactionId\": \"626644c5-bb7b-40ca-821e-cf115488867b\",\r\n}";
+            Object request = JsonConvert.DeserializeObject(json);
+            ArgumentException ex = Should.Throw<ArgumentException>(async () => {
+                await controller.PostEventAsync(request, CancellationToken.None);
+            });
+            ex.Message.ShouldBe("Domain Event must contain an Event Id");
+        }
+
+        [Fact]
+        public async Task DomainEventController_EventIdPresentInJson_NoErrorThrown()
+        {
+            Mock<IDomainEventHandlerResolver> resolver = new Mock<IDomainEventHandlerResolver>();
+            TypeMap.AddType<TransactionHasBeenCompletedEvent>("TransactionHasBeenCompletedEvent");
+            DefaultHttpContext httpContext = new DefaultHttpContext();
+            httpContext.Request.Headers["eventType"] = "TransactionHasBeenCompletedEvent";
+            DomainEventController controller = new DomainEventController(resolver.Object)
+            {
+                ControllerContext = new ControllerContext()
+                {
+                    HttpContext = httpContext
+                }
+            };
+            String json = "{\r\n  \"completedDateTime\": \"2022-11-08T15:40:07\",\r\n  \"estateId\": \"435613ac-a468-47a3-ac4f-649d89764c22\",\r\n  \"isAuthorised\": true,\r\n  \"transactionAmount\": 35.0,\r\n  \"merchantId\": \"8bc8434d-41f9-4cc3-83bc-e73f20c02e1d\",\r\n  \"responseCode\": \"0000\",\r\n  \"responseMessage\": \"SUCCESS\",\r\n  \"transactionId\": \"626644c5-bb7b-40ca-821e-cf115488867b\",\r\n  \"eventId\": \"9840045a-df9f-4ae3-879d-db205a744bf3\"\r\n}";
+            Object request = JsonConvert.DeserializeObject(json);
+            Should.NotThrow(async () => {
+                await controller.PostEventAsync(request, CancellationToken.None);
+            });
+        }
+    }
+}
diff --git a/TransactionProcessor/Controllers/DomainEventController.cs b/TransactionProcessor/Controllers/DomainEventController.cs
index 1b7759cd..42c6fc28 100644
--- a/TransactionProcessor/Controllers/DomainEventController.cs
+++ b/TransactionProcessor/Controllers/DomainEventController.cs
@@ -9,6 +9,7 @@ namespace TransactionProcessor.Controllers
     using System.Threading;
     using Microsoft.AspNetCore.Mvc;
     using Newtonsoft.Json;
+    using Newtonsoft.Json.Linq;
     using Shared.DomainDrivenDesign.EventSourcing;
     using Shared.EventStore.Aggregate;
     using Shared.EventStore.EventHandling;
@@ -94,11 +95,6 @@ public async Task<IActionResult> PostEventAsync([FromBody] Object request,
             }
         }
 
-        /// <summary>
-        /// Callbacks the specified cancellation token.
-        /// </summary>
-        /// <param name="cancellationToken">The cancellation token.</param>
-        /// <param name="eventId">The event identifier.</param>
         private void Callback(CancellationToken cancellationToken,
                               Guid eventId)
         {
@@ -109,22 +105,17 @@ private void Callback(CancellationToken cancellationToken,
             }
         }
 
-        /// <summary>
-        /// Gets the domain event.
-        /// </summary>
-        /// <param name="domainEvent">The domain event.</param>
-        /// <returns></returns>
         private async Task<IDomainEvent> GetDomainEvent(Object domainEvent)
         {
-            String eventType = this.Request.Query["eventType"].ToString();
+            String eventType = this.Request.Headers["eventType"].ToString();
 
-            var type = TypeMap.GetType(eventType);
+            Type type = TypeMap.GetType(eventType);
 
             if (type == null)
                 throw new Exception($"Failed to find a domain event with type {eventType}");
 
             JsonIgnoreAttributeIgnorerContractResolver jsonIgnoreAttributeIgnorerContractResolver = new JsonIgnoreAttributeIgnorerContractResolver();
-            var jsonSerialiserSettings = new JsonSerializerSettings
+            JsonSerializerSettings jsonSerialiserSettings = new JsonSerializerSettings
             {
                 ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
                 TypeNameHandling = TypeNameHandling.All,
@@ -135,15 +126,28 @@ private async Task<IDomainEvent> GetDomainEvent(Object domainEvent)
 
             if (type.IsSubclassOf(typeof(DomainEvent)))
             {
-                var json = JsonConvert.SerializeObject(domainEvent, jsonSerialiserSettings);
-                DomainEventFactory domainEventFactory = new();
+                String json = JsonConvert.SerializeObject(domainEvent, jsonSerialiserSettings);
 
-                return domainEventFactory.CreateDomainEvent(json, type);
+                DomainEventFactory domainEventFactory = new();
+                String validatedJson = this.ValidateEvent(json);
+                return domainEventFactory.CreateDomainEvent(validatedJson, type);
             }
 
             return null;
         }
 
+        private String ValidateEvent(String domainEventJson)
+        {
+            JObject domainEvent = JObject.Parse(domainEventJson);
+
+            if (domainEvent.ContainsKey("eventId") == false || domainEvent["eventId"].ToObject<Guid>() == Guid.Empty)
+            {
+                throw new ArgumentException("Domain Event must contain an Event Id");
+            }
+
+            return domainEventJson;
+        }
+
         #endregion
 
         #region Others