Add content-type header and empty body for empty structure payload in restJSON request

aws/client/aws-client-restjson/src/it/java/software/amazon/smithy/java/client/aws/restjson/RestJson1ProtocolTests.java

@@ -35,9 +35,6 @@ public class RestJson1ProtocolTests {
     @HttpClientRequestTests
     @ProtocolTestFilter(
             skipTests = {
-                    // TODO: These tests require a payload even when the httpPayload member is null. Should it?
-                    "RestJsonHttpWithHeadersButNoPayload",
-                    "RestJsonHttpWithEmptyStructurePayload",
                     "RestJsonHttpEmptyPrefixHeadersRequestClient" //FIXME https://github.com/smithy-lang/smithy-java/issues/647
             })
     public void requestTest(DataStream expected, DataStream actual) {

aws/client/aws-client-restjson/src/main/java/software/amazon/smithy/java/aws/client/restjson/RestJsonClientProtocol.java

@@ -5,6 +5,7 @@
 
 package software.amazon.smithy.java.aws.client.restjson;
 
+import java.net.URI;
 import software.amazon.smithy.aws.traits.protocols.RestJson1Trait;
 import software.amazon.smithy.java.aws.events.AwsEventDecoderFactory;
 import software.amazon.smithy.java.aws.events.AwsEventEncoderFactory;
@@ -17,14 +18,20 @@
 import software.amazon.smithy.java.client.http.binding.HttpBindingClientProtocol;
 import software.amazon.smithy.java.client.http.binding.HttpBindingErrorFactory;
 import software.amazon.smithy.java.context.Context;
+import software.amazon.smithy.java.core.schema.ApiOperation;
 import software.amazon.smithy.java.core.schema.InputEventStreamingApiOperation;
 import software.amazon.smithy.java.core.schema.OutputEventStreamingApiOperation;
+import software.amazon.smithy.java.core.schema.SerializableStruct;
+import software.amazon.smithy.java.core.schema.TraitKey;
 import software.amazon.smithy.java.core.serde.Codec;
 import software.amazon.smithy.java.core.serde.event.EventDecoderFactory;
 import software.amazon.smithy.java.core.serde.event.EventEncoderFactory;
 import software.amazon.smithy.java.core.serde.event.EventStreamingException;
+import software.amazon.smithy.java.http.api.HttpRequest;
+import software.amazon.smithy.java.http.binding.RequestSerializer;
 import software.amazon.smithy.java.json.JsonCodec;
 import software.amazon.smithy.model.shapes.ShapeId;
+import software.amazon.smithy.model.shapes.ShapeType;
 
 /**
  * Implements aws.protocols#restJson1.
@@ -55,6 +62,29 @@ public RestJsonClientProtocol(ShapeId service) {
                 .build();
     }
 
+    @Override
+    public <I extends SerializableStruct, O extends SerializableStruct> HttpRequest createRequest(
+            ApiOperation<I, O> operation,
+            I input,
+            Context context,
+            URI endpoint
+    ) {
+        RequestSerializer serializer = httpBinding().requestSerializer()
+                .operation(operation)
+                .payloadCodec(payloadCodec())
+                .payloadMediaType(payloadMediaType())
+                .shapeValue(input)
+                .endpoint(endpoint)
+                .omitEmptyPayload(omitEmptyPayload())
+                .allowEmptyStructPayload(hasStructPayload(input));
+
+        if (operation instanceof InputEventStreamingApiOperation<?, ?, ?> i) {
+            serializer.eventEncoderFactory(getEventEncoderFactory(i));
+        }
+
+        return serializer.serializeRequest();
+    }
+
     @Override
     public Codec payloadCodec() {
         return codec;
@@ -94,6 +124,17 @@ protected EventDecoderFactory<AwsEventFrame> getEventDecoderFactory(
         return AwsEventDecoderFactory.forOutputStream(outputOperation, payloadCodec(), f -> f);
     }
 
+    private <I extends SerializableStruct> boolean hasStructPayload(I input) {
+        var members = input.schema().members();
+        for (var member : members) {
+            if (member.type().equals(ShapeType.STRUCTURE)
+                    && member.hasTrait(TraitKey.HTTP_PAYLOAD_TRAIT)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     public static final class Factory implements ClientProtocolFactory<RestJson1Trait> {
         @Override
         public ShapeId id() {

http/http-binding/src/main/java/software/amazon/smithy/java/http/binding/HttpBindingSerializer.java

@@ -52,6 +52,7 @@ final class HttpBindingSerializer extends SpecificShapeSerializer implements Sha
     private final String payloadMediaType;
     private final boolean omitEmptyPayload;
     private final boolean isFailure;
+    private final boolean allowEmptyStructPayload;
 
     private final Map<String, String> labels = new LinkedHashMap<>();
     private final Map<String, List<String>> headers = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
@@ -75,7 +76,8 @@ final class HttpBindingSerializer extends SpecificShapeSerializer implements Sha
             String payloadMediaType,
             BindingMatcher bindingMatcher,
             boolean omitEmptyPayload,
-            boolean isFailure
+            boolean isFailure,
+            boolean allowEmptyStructPayload
     ) {
         uriPattern = httpTrait.getUri();
         responseStatus = httpTrait.getCode();
@@ -84,6 +86,7 @@ final class HttpBindingSerializer extends SpecificShapeSerializer implements Sha
         this.payloadMediaType = payloadMediaType;
         this.omitEmptyPayload = omitEmptyPayload;
         this.isFailure = isFailure;
+        this.allowEmptyStructPayload = allowEmptyStructPayload;
         headerSerializer = new HttpHeaderSerializer(headerConsumer);
         querySerializer = new HttpQuerySerializer(queryStringParams::add);
         labelSerializer = new HttpLabelSerializer(labels::put);
@@ -95,7 +98,7 @@ public void writeStruct(Schema schema, SerializableStruct struct) {
             responseStatus = bindingMatcher.responseStatus();
         }
 
-        if (bindingMatcher.writeBody(omitEmptyPayload)) {
+        if (allowEmptyStructPayload || bindingMatcher.writeBody(omitEmptyPayload)) {
             shapeBodyOutput = new ByteArrayOutputStream();
             shapeBodySerializer = payloadCodec.createSerializer(shapeBodyOutput);
             // Serialize only the body members to the codec.

http/http-binding/src/main/java/software/amazon/smithy/java/http/binding/RequestSerializer.java

@@ -34,6 +34,7 @@ public final class RequestSerializer {
     private SerializableShape shapeValue;
     private EventEncoderFactory<?> eventStreamEncodingFactory;
     private boolean omitEmptyPayload = false;
+    private boolean allowEmptyStructPayload = false;
     private final ConcurrentMap<Schema, BindingMatcher> bindingCache;
 
     RequestSerializer(ConcurrentMap<Schema, BindingMatcher> bindingCache) {
@@ -119,6 +120,11 @@ public RequestSerializer omitEmptyPayload(boolean omitEmptyPayload) {
         return this;
     }
 
+    public RequestSerializer allowEmptyStructPayload(boolean allowEmptyStructPayload) {
+        this.allowEmptyStructPayload = allowEmptyStructPayload;
+        return this;
+    }
+
     /**
      * Finishes setting up the serializer and creates an HTTP request.
      *
@@ -129,7 +135,6 @@ public HttpRequest serializeRequest() {
         Objects.requireNonNull(operation, "operation is not set");
         Objects.requireNonNull(payloadCodec, "payloadCodec is not set");
         Objects.requireNonNull(endpoint, "endpoint is not set");
-        Objects.requireNonNull(shapeValue, "value is not set");
         Objects.requireNonNull(payloadMediaType, "payloadMediaType is not set");
 
         var matcher = bindingCache.computeIfAbsent(operation.inputSchema(), BindingMatcher::requestMatcher);
@@ -140,7 +145,8 @@ public HttpRequest serializeRequest() {
                 payloadMediaType,
                 matcher,
                 omitEmptyPayload,
-                false);
+                false,
+                allowEmptyStructPayload);
         shapeValue.serialize(serializer);
         serializer.flush();
 

http/http-binding/src/main/java/software/amazon/smithy/java/http/binding/ResponseSerializer.java

@@ -143,7 +143,8 @@ public HttpResponse serializeResponse() {
                 payloadMediaType,
                 bindingCache.computeIfAbsent(schema, BindingMatcher::responseMatcher),
                 omitEmptyPayload,
-                isFailure);
+                isFailure,
+                false);
         shapeValue.serialize(serializer);
         serializer.flush();