fix: Improve string payload handling for RestJson protocol services

Author: dscpinheiro

generator/.DevConfigs/16525a24-d518-4b1a-9bc2-6cdb3955b0f9.json

@@ -0,0 +1,18 @@
+{
+    "core": {
+        "changeLogMessages": [
+            "Updated `restJson1` protocol services to use `text/plain` as `Content-Type` (instead of `application/json`) for string payloads"
+        ],
+        "type": "Patch",
+        "updateMinimum": false
+    },
+    "services": [
+        {
+            "serviceName": "DataExchange",
+            "type": "Patch",
+            "changeLogMessages": [
+                "Updated `SendApiAsset` operation to set correct `Content-Type` header"
+            ]
+        }
+    ]
+}

generator/ProtocolTestsGenerator/smithy-dotnet-codegen/src/main/java/software/amazon/smithy/dotnet/codegen/customizations/ProtocolTestCustomizations.java

@@ -100,7 +100,6 @@ private ProtocolTestCustomizations() {
     );
     public static final List<String> VNextTests = Arrays.asList(
             //These are the tests that are failing in v4 after updating to 1.54.0 and artifacts 1.0.3004.0. Each one needs to be investigated.
-            "RestJsonStringPayloadRequest",
             "RestJsonNullAndEmptyHeaders",
             "RestJsonSerializesSparseNullMapValues",
             "NullAndEmptyHeaders"

generator/ServiceClientGeneratorLib/Generators/Marshallers/JsonRPCRequestMarshaller.cs

@@ -49,6 +49,8 @@ namespace <#=this.Config.Namespace #>.Model.Internal.MarshallTransformations
 			request.Headers["X-Amz-Target"] = target;
 <#
 	}
+
+	var payload = this.Operation.RequestPayloadMember;
 	if (this.Operation.HttpMethod != "GET" && this.Operation.HttpMethod != "DELETE")
 	{
 
@@ -62,6 +64,12 @@ namespace <#=this.Config.Namespace #>.Model.Internal.MarshallTransformations
 		{
 #>
 			request.Headers["Content-Type"] = "application/x-amz-json-<#=this.Config.ServiceModel.JsonVersion #>";
+<#
+		}
+		else if (payload?.Shape.IsString == true)
+		{
+#>
+			request.Headers["Content-Type"] = "text/plain";
 <#
 		}
 		else if (this.Operation.RequestHasBodyMembers || this.Operation.RequestPayloadMember != null)
@@ -90,7 +98,6 @@ namespace <#=this.Config.Namespace #>.Model.Internal.MarshallTransformations
 			request.ResourcePath = "<#=this.Operation.RequestUri #>";
 <#  
 
-    var payload = this.Operation.RequestPayloadMember;
     var shouldMarshallPayload = (payload != null && !payload.IsMemoryStream && !payload.Shape.IsString);
 	// Process any members which are marshalled as part of the request body
 	if (this.Operation.RequestHasBodyMembers || shouldMarshallPayload)
@@ -143,9 +150,6 @@ namespace <#=this.Config.Namespace #>.Model.Internal.MarshallTransformations
 	{
 #>
 			request.Content = System.Text.Encoding.UTF8.GetBytes(publicRequest.<#= payload.PropertyName #>);
-<# if (payload.Shape.IsEnum) { #>
-			request.Headers["Content-Type"] = "text/plain";
-<# } #>
 <#
 	}
     else if (payload?.IsMemoryStream == true)

generator/ServiceClientGeneratorLib/Generators/Marshallers/JsonRPCRequestMarshaller.tt

@@ -59,7 +59,7 @@ public IRequest Marshall(AmazonWebServiceRequest input)
         public IRequest Marshall(SendApiAssetRequest publicRequest)
         {
             IRequest request = new DefaultRequest(publicRequest, "Amazon.DataExchange");
-            request.Headers["Content-Type"] = "application/json";
+            request.Headers["Content-Type"] = "text/plain";
             request.Headers[Amazon.Util.HeaderKeys.XAmzApiVersion] = "2017-07-25";
             request.HttpMethod = "POST";
 

sdk/src/Services/DataExchange/Generated/Model/Internal/MarshallTransformations/SendApiAssetRequestMarshaller.cs

@@ -40,12 +40,6 @@ namespace AWSSDK.ProtocolTests.RestJson
     [TestClass]
     public class HttpStringPayload
     {
-        /*
-        * This test either requires a breaking change and will be addressed
-        * in V4, or has a backlog item to be fixed in the future. Please
-        * refer to the VNextTests list to see which it is.
-        * */
-        [Ignore]
         [TestMethod]
         [TestCategory("ProtocolTest")]
         [TestCategory("RequestTest")]

sdk/test/ProtocolTests/Generated/RestJsonProtocol/dotnet-protocol-test-codegen/HttpStringPayload.cs

@@ -59,13 +59,12 @@ public IRequest Marshall(AmazonWebServiceRequest input)
         public IRequest Marshall(HttpEnumPayloadRequest publicRequest)
         {
             IRequest request = new DefaultRequest(publicRequest, "Amazon.RestJsonProtocol");
-            request.Headers["Content-Type"] = "application/json";
+            request.Headers["Content-Type"] = "text/plain";
             request.Headers[Amazon.Util.HeaderKeys.XAmzApiVersion] = "2019-12-16";
             request.HttpMethod = "POST";
 
             request.ResourcePath = "/EnumPayload";
             request.Content = System.Text.Encoding.UTF8.GetBytes(publicRequest.Payload);
-            request.Headers["Content-Type"] = "text/plain";
 
             return request;
         }

sdk/test/Services/RestJsonProtocol/Generated/Model/Internal/MarshallTransformations/HttpEnumPayloadRequestMarshaller.cs

@@ -59,7 +59,7 @@ public IRequest Marshall(AmazonWebServiceRequest input)
         public IRequest Marshall(HttpStringPayloadRequest publicRequest)
         {
             IRequest request = new DefaultRequest(publicRequest, "Amazon.RestJsonProtocol");
-            request.Headers["Content-Type"] = "application/json";
+            request.Headers["Content-Type"] = "text/plain";
             request.Headers[Amazon.Util.HeaderKeys.XAmzApiVersion] = "2019-12-16";
             request.HttpMethod = "POST";