Register encoding options when adding the service to the service collection

Libraries/src/Amazon.Lambda.AspNetCoreServer.Hosting/EncodingOptions.cs

@@ -0,0 +1,20 @@
+namespace Amazon.Lambda.AspNetCoreServer.Hosting
+{
+    /// <summary>
+    /// Options for configuring AWS Lambda content type transformation
+    /// </summary>
+    public class EncodingOptions : IEncodingOptions
+    {
+        /// <summary>
+        /// Defines a mapping from registered content types to the response encoding format 
+        /// which dictates what transformations should be applied before returning response content
+        /// </summary>
+        public Dictionary<string, ResponseContentEncoding>? ResponseContentEncodingForContentType { get; set ; }
+
+        /// <summary>
+        /// Defines a mapping from registered content encodings to the response encoding format
+        /// which dictates what transformations should be applied before returning response content
+        /// </summary>
+        public Dictionary<string, ResponseContentEncoding>? ResponseContentEncodingForContentEncoding { get; set; }
+    }
+}

Libraries/src/Amazon.Lambda.AspNetCoreServer.Hosting/HostingOptions.cs

@@ -12,4 +12,10 @@ public class HostingOptions
     /// back to JSON to return to Lambda.
     /// </summary>
     public ILambdaSerializer Serializer { get; set; }
+
+    /// <summary>
+    /// The encoding response options sent from the Lambda to the API Gateway.
+    /// Used to adjust what content types are sent to the API Gatway as binary data
+    /// </summary>
+    public IEncodingOptions EncodingOptions { get; set; }
 }

Libraries/src/Amazon.Lambda.AspNetCoreServer.Hosting/IEncodingOptions.cs

@@ -0,0 +1,8 @@
+namespace Amazon.Lambda.AspNetCoreServer.Hosting
+{
+    public interface IEncodingOptions
+    {
+        public Dictionary<string, ResponseContentEncoding>? ResponseContentEncodingForContentType { get; set; }
+        public Dictionary<string, ResponseContentEncoding>? ResponseContentEncodingForContentEncoding { get; set; }
+    }
+}

Libraries/src/Amazon.Lambda.AspNetCoreServer.Hosting/Internal/LambdaRuntimeSupportServer.cs

@@ -1,9 +1,7 @@
 using Amazon.Lambda.AspNetCoreServer.Internal;
 using Amazon.Lambda.Core;
 using Amazon.Lambda.RuntimeSupport;
-using Amazon.Lambda.Serialization.SystemTextJson;
 using Microsoft.AspNetCore.Hosting.Server;
-using Microsoft.AspNetCore.Mvc.ApplicationParts;
 using Microsoft.Extensions.DependencyInjection;
 
 namespace Amazon.Lambda.AspNetCoreServer.Hosting.Internal
@@ -18,6 +16,7 @@ public abstract class LambdaRuntimeSupportServer : LambdaServer
     {
         IServiceProvider _serviceProvider;
         internal ILambdaSerializer Serializer;
+        internal IEncodingOptions EncodingOptions;
 
         /// <summary>
         /// Creates an instance on the LambdaRuntimeSupportServer
@@ -27,6 +26,7 @@ public LambdaRuntimeSupportServer(IServiceProvider serviceProvider)
         {
             _serviceProvider = serviceProvider;
             Serializer = serviceProvider.GetRequiredService<ILambdaSerializer>();
+            EncodingOptions = serviceProvider.GetRequiredService<IEncodingOptions>();
         }
 
         /// <summary>
@@ -51,6 +51,34 @@ public override Task StartAsync<TContext>(IHttpApplication<TContext> application
         /// <param name="serviceProvider"></param>
         /// <returns></returns>
         protected abstract HandlerWrapper CreateHandlerWrapper(IServiceProvider serviceProvider);
+
+        /// <summary>
+        /// Registers encoding options for the given <see cref="AbstractAspNetCoreFunction{TREQUEST, TRESPONSE}"/>
+        /// </summary>
+        /// <typeparam name="TREQUEST"></typeparam>
+        /// <typeparam name="TRESPONSE"></typeparam>
+        /// <param name="aspNetCoreFunction"></param>
+        protected void RegisterEncodingOptions<TREQUEST, TRESPONSE>(AbstractAspNetCoreFunction<TREQUEST, TRESPONSE> aspNetCoreFunction)
+        {
+            if (EncodingOptions != null)
+            {
+                if (EncodingOptions.ResponseContentEncodingForContentType != null)
+                {
+                    foreach (var responseContentEncodingForContentType in EncodingOptions.ResponseContentEncodingForContentType)
+                    {
+                        aspNetCoreFunction.RegisterResponseContentEncodingForContentType(responseContentEncodingForContentType.Key, responseContentEncodingForContentType.Value);
+                    }
+                }
+
+                if (EncodingOptions.ResponseContentEncodingForContentEncoding != null)
+                {
+                    foreach (var responseContentEncodingForContentEncoding in EncodingOptions.ResponseContentEncodingForContentEncoding)
+                    {
+                        aspNetCoreFunction.RegisterResponseContentEncodingForContentEncoding(responseContentEncodingForContentEncoding.Key, responseContentEncodingForContentEncoding.Value);
+                    }
+                }
+            }
+        }
     }
 
     /// <summary>
@@ -74,7 +102,9 @@ public APIGatewayHttpApiV2LambdaRuntimeSupportServer(IServiceProvider servicePro
         /// <returns></returns>
         protected override HandlerWrapper CreateHandlerWrapper(IServiceProvider serviceProvider)
         {
-            var handler = new APIGatewayHttpApiV2MinimalApi(serviceProvider).FunctionHandlerAsync;
+            var apiGatewayHttpApiV2MinimalApi = new APIGatewayHttpApiV2MinimalApi(serviceProvider);
+            RegisterEncodingOptions(apiGatewayHttpApiV2MinimalApi);
+            var handler = apiGatewayHttpApiV2MinimalApi.FunctionHandlerAsync;
             return HandlerWrapper.GetHandlerWrapper(handler, this.Serializer);
         }
 
@@ -115,7 +145,9 @@ public APIGatewayRestApiLambdaRuntimeSupportServer(IServiceProvider serviceProvi
         /// <returns></returns>
         protected override HandlerWrapper CreateHandlerWrapper(IServiceProvider serviceProvider)
         {
-            var handler = new APIGatewayRestApiMinimalApi(serviceProvider).FunctionHandlerAsync;
+            var apiGatewayRestApiMinimalApi = new APIGatewayRestApiMinimalApi(serviceProvider);
+            RegisterEncodingOptions(apiGatewayRestApiMinimalApi);
+            var handler = apiGatewayRestApiMinimalApi.FunctionHandlerAsync;
             return HandlerWrapper.GetHandlerWrapper(handler, this.Serializer);
         }
 
@@ -156,7 +188,9 @@ public ApplicationLoadBalancerLambdaRuntimeSupportServer(IServiceProvider servic
         /// <returns></returns>
         protected override HandlerWrapper CreateHandlerWrapper(IServiceProvider serviceProvider)
         {
-            var handler = new ApplicationLoadBalancerMinimalApi(serviceProvider).FunctionHandlerAsync;
+            var applicationLoadBalancerMinimalApi = new ApplicationLoadBalancerMinimalApi(serviceProvider);
+            RegisterEncodingOptions(applicationLoadBalancerMinimalApi);
+            var handler = applicationLoadBalancerMinimalApi.FunctionHandlerAsync;
             return HandlerWrapper.GetHandlerWrapper(handler, this.Serializer);
         }
 

Libraries/src/Amazon.Lambda.AspNetCoreServer.Hosting/ServiceCollectionExtensions.cs

@@ -1,6 +1,6 @@
 using Amazon.Lambda.AspNetCoreServer.Hosting;
-using Amazon.Lambda.AspNetCoreServer.Internal;
 using Amazon.Lambda.AspNetCoreServer.Hosting.Internal;
+using Amazon.Lambda.AspNetCoreServer.Internal;
 using Amazon.Lambda.Core;
 using Amazon.Lambda.Serialization.SystemTextJson;
 using Microsoft.Extensions.DependencyInjection.Extensions;
@@ -66,6 +66,7 @@ public static IServiceCollection AddAWSLambdaHosting(this IServiceCollection ser
                 configure.Invoke(hostingOptions);
 
             services.TryAddSingleton<ILambdaSerializer>(hostingOptions.Serializer ?? new DefaultLambdaJsonSerializer());
+            services.TryAddSingleton<IEncodingOptions>(hostingOptions.EncodingOptions);
 
             var serverType = eventSource switch
             {