Add support for Lambda Response Streaming in ASP.NET Core bridge packages

.autover/changes/f0d5a912-bcfa-4244-96cb-ac3c847f877c.json

@@ -0,0 +1,27 @@
+{
+  "Projects": [
+    {
+      "Name": "Amazon.Lambda.AspNetCoreServer",
+      "Type": "Major",
+      "ChangelogMessages": [
+        "[Breaking] Update build targets from .NET 6 and 8 to .NET 8 and 10",
+		"[Preview] Add support for Lambda Response Streaming enabled by setting the EnableResponseStreaming property from the base class AbstractAspNetCoreFunction"
+      ]
+    },
+    {
+      "Name": "Amazon.Lambda.AspNetCoreServer.Hosting",
+      "Type": "Major",
+      "ChangelogMessages": [
+        "[Breaking] Update build targets from .NET 6 and 8 to .NET 8 and 10",
+		"[Preview] Add support for Lambda Response Streaming enabled by setting the EnableResponseStreaming property on the HostingOptions object passed into the AddAWSLambdaHosting method"
+      ]
+    },
+    {
+      "Name": "Amazon.Lambda.Logging.AspNetCore",
+      "Type": "Major",
+      "ChangelogMessages": [
+        "[Breaking] Update build targets from .NET 6 and 8 to .NET 8 and 10"
+      ]
+    }	
+  ]
+}

Libraries/Libraries.sln

@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio Version 18
-VisualStudioVersion = 18.3.11512.155 d18.3
+VisualStudioVersion = 18.3.11512.155
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{AAB54E74-20B1-42ED-BC3D-CE9F7BC7FD12}"
 EndProject
@@ -153,6 +153,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TestCustomAuthorizerApp", "
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ResponseStreamingFunctionHandlers", "test\Amazon.Lambda.RuntimeSupport.Tests\ResponseStreamingFunctionHandlers\ResponseStreamingFunctionHandlers.csproj", "{E404A7AC-812B-BC03-CA76-02C0BC2BA7F9}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "AspNetCoreStreamingApiGatewayTest", "test\Amazon.Lambda.RuntimeSupport.Tests\AspNetCoreStreamingApiGatewayTest\AspNetCoreStreamingApiGatewayTest.csproj", "{0768FA72-CF49-2B59-BC4C-E4CE579E5D93}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -955,6 +957,18 @@ Global
 		{E404A7AC-812B-BC03-CA76-02C0BC2BA7F9}.Release|x64.Build.0 = Release|Any CPU
 		{E404A7AC-812B-BC03-CA76-02C0BC2BA7F9}.Release|x86.ActiveCfg = Release|Any CPU
 		{E404A7AC-812B-BC03-CA76-02C0BC2BA7F9}.Release|x86.Build.0 = Release|Any CPU
+		{0768FA72-CF49-2B59-BC4C-E4CE579E5D93}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{0768FA72-CF49-2B59-BC4C-E4CE579E5D93}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{0768FA72-CF49-2B59-BC4C-E4CE579E5D93}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{0768FA72-CF49-2B59-BC4C-E4CE579E5D93}.Debug|x64.Build.0 = Debug|Any CPU
+		{0768FA72-CF49-2B59-BC4C-E4CE579E5D93}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{0768FA72-CF49-2B59-BC4C-E4CE579E5D93}.Debug|x86.Build.0 = Debug|Any CPU
+		{0768FA72-CF49-2B59-BC4C-E4CE579E5D93}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{0768FA72-CF49-2B59-BC4C-E4CE579E5D93}.Release|Any CPU.Build.0 = Release|Any CPU
+		{0768FA72-CF49-2B59-BC4C-E4CE579E5D93}.Release|x64.ActiveCfg = Release|Any CPU
+		{0768FA72-CF49-2B59-BC4C-E4CE579E5D93}.Release|x64.Build.0 = Release|Any CPU
+		{0768FA72-CF49-2B59-BC4C-E4CE579E5D93}.Release|x86.ActiveCfg = Release|Any CPU
+		{0768FA72-CF49-2B59-BC4C-E4CE579E5D93}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -1030,6 +1044,7 @@ Global
 		{8EEDD576-7FC4-4FAC-A5A2-F58562753A53} = {1DE4EE60-45BA-4EF7-BE00-B9EB861E4C69}
 		{3BFA4B73-BA61-4578-833B-C5B3A16EDA9E} = {1DE4EE60-45BA-4EF7-BE00-B9EB861E4C69}
 		{E404A7AC-812B-BC03-CA76-02C0BC2BA7F9} = {B5BD0336-7D08-492C-8489-42C987E29B39}
+		{0768FA72-CF49-2B59-BC4C-E4CE579E5D93} = {B5BD0336-7D08-492C-8489-42C987E29B39}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {503678A4-B8D1-4486-8915-405A3E9CF0EB}

Libraries/src/Amazon.Lambda.AspNetCoreServer.Hosting/Amazon.Lambda.AspNetCoreServer.Hosting.csproj

@@ -4,7 +4,7 @@
 
   <PropertyGroup>
 	<Description>Package for running ASP.NET Core applications using the Minimal API style as a AWS Lambda function.</Description>
-    <TargetFrameworks>net6.0;net8.0</TargetFrameworks>
+    <TargetFrameworks>net8.0;net10.0</TargetFrameworks>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <Version>1.10.0</Version>

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

@@ -9,6 +9,12 @@ namespace Amazon.Lambda.AspNetCoreServer.Hosting;
 /// </summary>
 public class HostingOptions
 {
+    internal const string ParameterizedPreviewMessage =
+        "Response streaming is in preview till a new version of .NET Lambda runtime client that supports response streaming " +
+        "has been deployed to the .NET Lambda managed runtime. Till deployment has been made the feature can be used by deploying as an " +
+        "executable including the latest version of Amazon.Lambda.RuntimeSupport and setting the \"EnablePreviewFeatures\" in the Lambda " +
+        "project file to \"true\"";
+
     /// <summary>
     /// The ILambdaSerializer used by Lambda to convert the incoming event JSON into the .NET event type and serialize the .NET response type
     /// back to JSON to return to Lambda.
@@ -27,6 +33,15 @@ public class HostingOptions
     /// </summary>
     public bool IncludeUnhandledExceptionDetailInResponse { get; set; } = false;
 
+    /// <summary>
+    /// When true, the Lambda hosting server enables Lambda response streaming behavior
+    /// when invoking <c>FunctionHandlerAsync</c>. In streaming mode,
+    /// <c>FunctionHandlerAsync</c> writes directly to the Lambda response stream and
+    /// returns <c>null</c>. Requires net8.0 or later.
+    /// </summary>
+    [System.Runtime.Versioning.RequiresPreviewFeatures(ParameterizedPreviewMessage)]
+    public bool EnableResponseStreaming { get; set; } = false;
+
     /// <summary>
     /// Callback invoked after request marshalling to customize the HTTP request feature.
     /// Receives the IHttpRequestFeature, Lambda request object, and ILambdaContext.

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

@@ -5,7 +5,6 @@
 
 namespace Amazon.Lambda.AspNetCoreServer.Hosting.Internal;
 
-#if NET8_0_OR_GREATER
 /// <summary>
 /// Helper class for storing Requests for
 /// <see cref="ServiceCollectionExtensions.AddAWSLambdaBeforeSnapshotRequest"/>
@@ -14,4 +13,3 @@ internal class GetBeforeSnapshotRequestsCollector
 {
     public HttpRequestMessage? Request { get; set; }
 }
-#endif

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

@@ -78,18 +78,21 @@ public APIGatewayHttpApiV2LambdaRuntimeSupportServer(IServiceProvider servicePro
         /// <returns></returns>
         protected override HandlerWrapper CreateHandlerWrapper(IServiceProvider serviceProvider)
         {
-            var handler = new APIGatewayHttpApiV2MinimalApi(serviceProvider).FunctionHandlerAsync;
-            return HandlerWrapper.GetHandlerWrapper(handler, this.Serializer);
+            var handler = new APIGatewayHttpApiV2MinimalApi(serviceProvider);
+#pragma warning disable CA2252
+            var hostingOptions = serviceProvider.GetService<HostingOptions>();
+            handler.EnableResponseStreaming = hostingOptions?.EnableResponseStreaming ?? false;
+#pragma warning restore CA2252
+            Func<APIGatewayEvents.APIGatewayHttpApiV2ProxyRequest, ILambdaContext, Task<APIGatewayEvents.APIGatewayHttpApiV2ProxyResponse>> bufferedHandler = handler.FunctionHandlerAsync;
+            return HandlerWrapper.GetHandlerWrapper(bufferedHandler, this.Serializer);
         }
 
         /// <summary>
         /// Create the APIGatewayHttpApiV2ProxyFunction passing in the ASP.NET Core application's IServiceProvider
         /// </summary>
         public class APIGatewayHttpApiV2MinimalApi : APIGatewayHttpApiV2ProxyFunction
         {
-            #if NET8_0_OR_GREATER
             private readonly IEnumerable<GetBeforeSnapshotRequestsCollector> _beforeSnapshotRequestsCollectors;
-            #endif
             private readonly HostingOptions? _hostingOptions;
 
             /// <summary>
@@ -99,9 +102,7 @@ public class APIGatewayHttpApiV2MinimalApi : APIGatewayHttpApiV2ProxyFunction
             public APIGatewayHttpApiV2MinimalApi(IServiceProvider serviceProvider)
                 : base(serviceProvider)
             {
-                #if NET8_0_OR_GREATER
                 _beforeSnapshotRequestsCollectors = serviceProvider.GetServices<GetBeforeSnapshotRequestsCollector>();
-                #endif
 
                 // Retrieve HostingOptions from service provider (may be null for backward compatibility)
                 _hostingOptions = serviceProvider.GetService<HostingOptions>();
@@ -127,14 +128,12 @@ public APIGatewayHttpApiV2MinimalApi(IServiceProvider serviceProvider)
                 }
             }
 
-            #if NET8_0_OR_GREATER
             protected override IEnumerable<HttpRequestMessage> GetBeforeSnapshotRequests()
             {
                 foreach (var collector in _beforeSnapshotRequestsCollectors)
                     if (collector.Request != null)
                         yield return collector.Request;
             }
-            #endif
 
             protected override void PostMarshallRequestFeature(IHttpRequestFeature aspNetCoreRequestFeature, APIGatewayEvents.APIGatewayHttpApiV2ProxyRequest lambdaRequest, ILambdaContext lambdaContext)
             {
@@ -208,18 +207,21 @@ public APIGatewayRestApiLambdaRuntimeSupportServer(IServiceProvider serviceProvi
         /// <returns></returns>
         protected override HandlerWrapper CreateHandlerWrapper(IServiceProvider serviceProvider)
         {
-            var handler = new APIGatewayRestApiMinimalApi(serviceProvider).FunctionHandlerAsync;
-            return HandlerWrapper.GetHandlerWrapper(handler, this.Serializer);
+            var handler = new APIGatewayRestApiMinimalApi(serviceProvider);
+#pragma warning disable CA2252
+            var hostingOptions = serviceProvider.GetService<HostingOptions>();
+            handler.EnableResponseStreaming = hostingOptions?.EnableResponseStreaming ?? false;
+#pragma warning restore CA2252
+            Func<APIGatewayEvents.APIGatewayProxyRequest, ILambdaContext, Task<APIGatewayEvents.APIGatewayProxyResponse>> bufferedHandler = handler.FunctionHandlerAsync;
+            return HandlerWrapper.GetHandlerWrapper(bufferedHandler, this.Serializer);
         }
 
         /// <summary>
         /// Create the APIGatewayProxyFunction passing in the ASP.NET Core application's IServiceProvider
         /// </summary>
         public class APIGatewayRestApiMinimalApi : APIGatewayProxyFunction
         {
-            #if NET8_0_OR_GREATER
             private readonly IEnumerable<GetBeforeSnapshotRequestsCollector> _beforeSnapshotRequestsCollectors;
-            #endif
             private readonly HostingOptions? _hostingOptions;
 
             /// <summary>
@@ -229,9 +231,7 @@ public class APIGatewayRestApiMinimalApi : APIGatewayProxyFunction
             public APIGatewayRestApiMinimalApi(IServiceProvider serviceProvider)
                 : base(serviceProvider)
             {
-                #if NET8_0_OR_GREATER
                 _beforeSnapshotRequestsCollectors = serviceProvider.GetServices<GetBeforeSnapshotRequestsCollector>();
-                #endif
 
                 // Retrieve HostingOptions from service provider (may be null for backward compatibility)
                 _hostingOptions = serviceProvider.GetService<HostingOptions>();
@@ -257,14 +257,12 @@ public APIGatewayRestApiMinimalApi(IServiceProvider serviceProvider)
                 }
             }
 
-            #if NET8_0_OR_GREATER
             protected override IEnumerable<HttpRequestMessage> GetBeforeSnapshotRequests()
             {
                 foreach (var collector in _beforeSnapshotRequestsCollectors)
                     if (collector.Request != null)
                         yield return collector.Request;
             }
-            #endif
 
             protected override void PostMarshallRequestFeature(IHttpRequestFeature aspNetCoreRequestFeature, APIGatewayEvents.APIGatewayProxyRequest lambdaRequest, ILambdaContext lambdaContext)
             {
@@ -338,18 +336,21 @@ public ApplicationLoadBalancerLambdaRuntimeSupportServer(IServiceProvider servic
         /// <returns></returns>
         protected override HandlerWrapper CreateHandlerWrapper(IServiceProvider serviceProvider)
         {
-            var handler = new ApplicationLoadBalancerMinimalApi(serviceProvider).FunctionHandlerAsync;
-            return HandlerWrapper.GetHandlerWrapper(handler, this.Serializer);
+            var handler = new ApplicationLoadBalancerMinimalApi(serviceProvider);
+#pragma warning disable CA2252
+            var hostingOptions = serviceProvider.GetService<HostingOptions>();
+            handler.EnableResponseStreaming = hostingOptions?.EnableResponseStreaming ?? false;
+#pragma warning restore CA2252
+            Func<ApplicationLoadBalancerEvents.ApplicationLoadBalancerRequest, ILambdaContext, Task<ApplicationLoadBalancerEvents.ApplicationLoadBalancerResponse>> bufferedHandler = handler.FunctionHandlerAsync;
+            return HandlerWrapper.GetHandlerWrapper(bufferedHandler, this.Serializer);
         }
 
         /// <summary>
         /// Create the ApplicationLoadBalancerFunction passing in the ASP.NET Core application's IServiceProvider
         /// </summary>
         public class ApplicationLoadBalancerMinimalApi : ApplicationLoadBalancerFunction
         {
-            #if NET8_0_OR_GREATER
             private readonly IEnumerable<GetBeforeSnapshotRequestsCollector> _beforeSnapshotRequestsCollectors;
-            #endif
             private readonly HostingOptions? _hostingOptions;
 
             /// <summary>
@@ -359,9 +360,7 @@ public class ApplicationLoadBalancerMinimalApi : ApplicationLoadBalancerFunction
             public ApplicationLoadBalancerMinimalApi(IServiceProvider serviceProvider)
                 : base(serviceProvider)
             {
-                #if NET8_0_OR_GREATER
                 _beforeSnapshotRequestsCollectors = serviceProvider.GetServices<GetBeforeSnapshotRequestsCollector>();
-                #endif
 
                 // Retrieve HostingOptions from service provider (may be null for backward compatibility)
                 _hostingOptions = serviceProvider.GetService<HostingOptions>();
@@ -387,14 +386,12 @@ public ApplicationLoadBalancerMinimalApi(IServiceProvider serviceProvider)
                 }
             }
 
-            #if NET8_0_OR_GREATER
             protected override IEnumerable<HttpRequestMessage> GetBeforeSnapshotRequests()
             {
                 foreach (var collector in _beforeSnapshotRequestsCollectors)
                     if (collector.Request != null)
                         yield return collector.Request;
             }
-            #endif
 
             protected override void PostMarshallRequestFeature(IHttpRequestFeature aspNetCoreRequestFeature, ApplicationLoadBalancerEvents.ApplicationLoadBalancerRequest lambdaRequest, ILambdaContext lambdaContext)
             {

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

@@ -88,7 +88,6 @@ public static IServiceCollection AddAWSLambdaHosting(this IServiceCollection ser
             return services;
         }
 
-        #if NET8_0_OR_GREATER
         /// <summary>
         /// Adds a <see cref="HttpRequestMessage"/>> that will be used to invoke
         /// Routes in your lambda function in order to initialize the ASP.NET Core and Lambda pipelines
@@ -142,7 +141,6 @@ public static IServiceCollection AddAWSLambdaBeforeSnapshotRequest(this IService
 
             return services;
         }
-        #endif
 
         private static bool TryLambdaSetup(IServiceCollection services, LambdaEventSource eventSource, Action<HostingOptions>? configure, out HostingOptions? hostingOptions)
         {

Libraries/src/Amazon.Lambda.AspNetCoreServer/APIGatewayHttpApiV2ProxyFunction.cs

@@ -54,6 +54,46 @@ private protected override void InternalCustomResponseExceptionHandling(APIGatew
             apiGatewayResponse.SetHeaderValues("ErrorType", ex.GetType().Name, false);
         }
 
+#if NET8_0_OR_GREATER
+        /// <summary>
+        /// Override for HTTP API v2 to use single-value <c>headers</c> in the streaming prelude
+        /// instead of <c>multiValueHeaders</c>. API Gateway HTTP API v2 expects the <c>headers</c>
+        /// format; using <c>multiValueHeaders</c> causes a 500 Internal Server Error.
+        /// </summary>
+        [System.Runtime.Versioning.RequiresPreviewFeatures(ParameterizedPreviewMessage)]
+        protected override Amazon.Lambda.Core.ResponseStreaming.HttpResponseStreamPrelude BuildStreamingPrelude(IHttpResponseFeature responseFeature)
+        {
+            var prelude = new Amazon.Lambda.Core.ResponseStreaming.HttpResponseStreamPrelude
+            {
+                StatusCode = (System.Net.HttpStatusCode)(responseFeature.StatusCode != 0 ? responseFeature.StatusCode : 200)
+            };
+
+            foreach (var kvp in responseFeature.Headers)
+            {
+                if (string.Equals(kvp.Key, "Content-Length", StringComparison.OrdinalIgnoreCase) ||
+                    string.Equals(kvp.Key, "Transfer-Encoding", StringComparison.OrdinalIgnoreCase))
+                {
+                    continue;
+                }
+
+                if (string.Equals(kvp.Key, "Set-Cookie", StringComparison.OrdinalIgnoreCase))
+                {
+                    foreach (var value in kvp.Value)
+                    {
+                        prelude.Cookies.Add(value);
+                    }
+                }
+                else
+                {
+                    // HTTP API v2 uses single-value headers. Join multiple values with ", ".
+                    prelude.Headers[kvp.Key] = string.Join(", ", kvp.Value);
+                }
+            }
+
+            return prelude;
+        }
+#endif
+
         /// <summary>
         /// Convert the JSON document received from API Gateway into the InvokeFeatures object.
         /// InvokeFeatures is then passed into IHttpApplication to create the ASP.NET Core request objects.