feat: Handle invalid Base64 body

Author: xavibel

src/Voxel.MiddyNet.HttpJsonBodyParserMiddleware/HttpJsonBodyParserMiddleware.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Text;
 using Amazon.Lambda.APIGatewayEvents;
 using Newtonsoft.Json;
 using System.Threading.Tasks;
@@ -9,27 +10,32 @@ public class HttpJsonBodyParserMiddleware<T> : ILambdaMiddleware<APIGatewayProxy
     {
         public Task Before(APIGatewayProxyRequest lambdaEvent, MiddyNetContext context)
         {
-            if (!HasJSONContentHeaders(lambdaEvent))
+            if (!HasJsonContentHeaders(lambdaEvent))
             {
                 context.AdditionalContext.Add("Body", lambdaEvent.Body);
                 return Task.CompletedTask;
             }
 
+            if (lambdaEvent.IsBase64Encoded)
+            {
+                lambdaEvent.Body = Encoding.UTF8.GetString(Convert.FromBase64String(lambdaEvent.Body));
+            }
+           
             T source;
             try
             {
                 source = JsonConvert.DeserializeObject<T>(lambdaEvent.Body);
             }
             catch (JsonReaderException)
             {
-                throw new Exception($"Error parsing \"{lambdaEvent.Body}\" to type {typeof(T)}");
+                throw new Exception("Content type defined as JSON but an invalid JSON was provided");
             }
 
             context.AdditionalContext.Add("Body", source);
             return Task.CompletedTask;
         }
 
-        private static bool HasJSONContentHeaders(APIGatewayProxyRequest lambdaEvent)
+        private static bool HasJsonContentHeaders(APIGatewayProxyRequest lambdaEvent)
         {
             return lambdaEvent.Headers != null &&
                    (lambdaEvent.Headers.ContainsKey("Content-Type") &&

test/Voxel.MiddyNet.HttpJsonBodyParserMiddleware.Tests/HttpJsonBodyParserMiddlewareShould.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Text;
 using System.Threading.Tasks;
 using Amazon.Lambda.APIGatewayEvents;
 using Amazon.Lambda.Core;
@@ -41,7 +42,7 @@ public async Task ProcessTheJsonRequest()
         [Fact]
         public async Task ErrorWhenJsonNotMapsToObject()
         {
-            var source = "Not Mapped object" + serializedExpectation;
+            var source = "Make it broken" + serializedExpectation;
             var request = new APIGatewayProxyRequest()
             {
                 Headers = new Dictionary<string, string> { { "Content-Type", "application/json" } },
@@ -50,7 +51,7 @@ public async Task ErrorWhenJsonNotMapsToObject()
             var middleware = new HttpJsonBodyParserMiddleware<TestObject>();
             Action action = () => middleware.Before(request, context);
 
-            action.Should().Throw<Exception>().WithMessage($"Error parsing \"{source}\" to type {typeof(TestObject)}");
+            action.Should().Throw<Exception>().WithMessage("Content type defined as JSON but an invalid JSON was provided");
         }
 
         [Fact]
@@ -66,5 +67,43 @@ public async Task NotProcessTheBodyIfNoHeaderIsPassed()
             context.AdditionalContext.ContainsKey("Body").Should().BeTrue();
             context.AdditionalContext["Body"].Should().Be(serializedExpectation);
         }
+
+        [Fact]
+        public async Task HandleABase64Body()
+        {
+            string base64Serialized = Convert.ToBase64String(Encoding.UTF8.GetBytes(serializedExpectation));
+            
+            var request = new APIGatewayProxyRequest()
+            {
+                Headers = new Dictionary<string, string> { { "Content-Type", "application/json" } },
+                IsBase64Encoded = true,
+                Body = base64Serialized
+            };
+
+            var middleware = new HttpJsonBodyParserMiddleware<TestObject>();
+            await middleware.Before(request, context);
+
+            context.AdditionalContext.ContainsKey("Body").Should().BeTrue();
+            context.AdditionalContext["Body"].Should().BeEquivalentTo(expectation);
+        }
+
+        [Fact]
+        public async Task HandleInvalidBase64Body()
+        {
+            var source = "Make it broken" + serializedExpectation;
+            string base64Serialized = Convert.ToBase64String(Encoding.UTF8.GetBytes(source));
+
+            var request = new APIGatewayProxyRequest()
+            {
+                Headers = new Dictionary<string, string> { { "Content-Type", "application/json" } },
+                IsBase64Encoded = true,
+                Body = base64Serialized
+            };
+
+            var middleware = new HttpJsonBodyParserMiddleware<TestObject>();
+            Action action = () => middleware.Before(request, context);
+
+            action.Should().Throw<Exception>().WithMessage("Content type defined as JSON but an invalid JSON was provided");
+        }
     }
 }