Fix httpHeader and httpPrefixHeaders protocol tests

Author: joewyz

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

@@ -33,10 +33,6 @@ public class RestJson1ProtocolTests {
     private static final String EMPTY_BODY = "";
 
     @HttpClientRequestTests
-    @ProtocolTestFilter(
-            skipTests = {
-                    "RestJsonHttpEmptyPrefixHeadersRequestClient" //FIXME https://github.com/smithy-lang/smithy-java/issues/647
-            })
     public void requestTest(DataStream expected, DataStream actual) {
         assertThat(expected.hasKnownLength())
                 .isTrue()

aws/client/aws-client-restxml/src/it/java/software/amazon/smithy/java/aws/client/restxml/RestXmlProtocolTests.java

@@ -38,7 +38,6 @@ public class RestXmlProtocolTests {
             skipTests = {
                     "SDKAppliedContentEncoding_restXml",
                     "SDKAppendedGzipAfterProvidedEncoding_restXml",
-                    "HttpEmptyPrefixHeadersRequestClient" //FIXME https://github.com/smithy-lang/smithy-java/issues/647
             })
     public void requestTest(DataStream expected, DataStream actual) {
         if (expected.contentLength() != 0) {

aws/server/aws-server-restjson/src/it/java/software/amazon/smithy/java/aws/server/restjson/AwsRestJson1ProtocolTests.java

@@ -45,7 +45,6 @@ public class AwsRestJson1ProtocolTests {
 
                     // Header splitting needs work.
                     "RestJsonInputAndOutputWithQuotedStringHeaders",
-                    "RestJsonHttpEmptyPrefixHeadersRequestServer" //FIXME https://github.com/smithy-lang/smithy-java/issues/647
             },
             skipOperations = {
                     "aws.protocoltests.restjson#DocumentType",
@@ -80,8 +79,6 @@ public void requestTest(Runnable test) {
                     "RestJsonEmptyComplexErrorWithNoMessage",
                     //TODO this breaks because of Validation and errorCorrection doesn't handle that.
                     "RestJsonServerPopulatesNestedDefaultValuesWhenMissingInInResponseParams",
-                    "RestJsonHttpEmptyPrefixHeadersResponseServer" //FIXME https://github.com/smithy-lang/smithy-java/issues/647
-
             })
     public void responseTest(DataStream expected, DataStream actual) {
         assertThat(expected.hasKnownLength())

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

@@ -7,9 +7,11 @@
 
 import java.io.ByteArrayOutputStream;
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.StringJoiner;
 import java.util.TreeMap;
 import java.util.concurrent.Flow;
@@ -57,6 +59,7 @@ final class HttpBindingSerializer extends SpecificShapeSerializer implements Sha
     private final Map<String, String> labels = new LinkedHashMap<>();
     private final Map<String, List<String>> headers = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
     private final QueryStringBuilder queryStringParams = new QueryStringBuilder();
+    private final Set<String> namesFromHttpHeader = new HashSet<>();
 
     private ShapeSerializer shapeBodySerializer;
     private ByteArrayOutputStream shapeBodyOutput;
@@ -98,6 +101,13 @@ public void writeStruct(Schema schema, SerializableStruct struct) {
             responseStatus = bindingMatcher.responseStatus();
         }
 
+        // Prescanning names from @httpHeader for @httpPrefixHeaders
+        for (var member : schema.members()) {
+            if (member.hasTrait(TraitKey.HTTP_HEADER_TRAIT)) {
+                namesFromHttpHeader.add(member.expectTrait(TraitKey.HTTP_HEADER_TRAIT).getValue());
+            }
+        }
+
         if (allowEmptyStructPayload || bindingMatcher.writeBody(omitEmptyPayload)) {
             shapeBodyOutput = new ByteArrayOutputStream();
             shapeBodySerializer = payloadCodec.createSerializer(shapeBodyOutput);
@@ -236,7 +246,8 @@ protected ShapeSerializer before(Schema schema) {
                 case STATUS -> new ResponseStatusSerializer(i -> serializer.responseStatus = i);
                 case PREFIX_HEADERS -> new HttpPrefixHeadersSerializer(
                         schema.expectTrait(TraitKey.HTTP_PREFIX_HEADERS_TRAIT).getValue(),
-                        serializer.headerConsumer);
+                        serializer.headerConsumer,
+                        serializer.namesFromHttpHeader);
                 case QUERY_PARAMS -> new HttpQueryParamsSerializer(serializer.queryStringParams::add);
                 case BODY -> ShapeSerializer.nullSerializer(); // handled in HttpBindingSerializer#writeStruct.
                 case PAYLOAD -> {

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

@@ -32,7 +32,9 @@ public <T> void readStringMap(Schema schema, T state, MapMemberConsumer<String,
         var prefix = trait.getValue().toLowerCase(Locale.ENGLISH);
         for (var entry : headers) {
             var name = entry.getKey();
-            if (PrefixConstants.OMITTED_HEADER_NAMES.contains(name) || !name.startsWith(prefix)) {
+            var lowerCaseName = name.toLowerCase(Locale.ENGLISH);
+            if (PrefixConstants.OMITTED_HEADER_NAMES.contains(lowerCaseName)
+                    || !lowerCaseName.startsWith(prefix)) {
                 continue;
             }
             consumer.accept(state, name.substring(prefix.length()), new HeaderValueDeserializer(name));

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

@@ -5,6 +5,7 @@
 
 package software.amazon.smithy.java.http.binding;
 
+import java.util.Set;
 import java.util.function.BiConsumer;
 import software.amazon.smithy.java.core.schema.Schema;
 import software.amazon.smithy.java.core.serde.MapSerializer;
@@ -21,17 +22,23 @@ final class HttpPrefixHeadersSerializer extends SpecificShapeSerializer {
 
     private final PrefixHeadersMapSerializer prefixHeadersMapSerializer;
 
-    HttpPrefixHeadersSerializer(String prefix, BiConsumer<String, String> headerConsumer) {
-        prefixHeadersMapSerializer = new PrefixHeadersMapSerializer(prefix, headerConsumer);
+    HttpPrefixHeadersSerializer(
+            String prefix,
+            BiConsumer<String, String> headerConsumer,
+            Set<String> namesFromHttpHeader
+    ) {
+        prefixHeadersMapSerializer = new PrefixHeadersMapSerializer(prefix, headerConsumer, namesFromHttpHeader);
     }
 
     @Override
     public <T> void writeMap(Schema schema, T mapState, int size, BiConsumer<T, MapSerializer> consumer) {
         consumer.accept(mapState, prefixHeadersMapSerializer);
     }
 
-    private record PrefixHeadersMapSerializer(String prefix, BiConsumer<String, String> headerConsumer) implements
-            MapSerializer {
+    private record PrefixHeadersMapSerializer(
+            String prefix,
+            BiConsumer<String, String> headerConsumer,
+            Set<String> namesFromHttpHeader) implements MapSerializer {
         @Override
         public <K> void writeEntry(
                 Schema keySchema,
@@ -42,7 +49,12 @@ public <K> void writeEntry(
             valueSerializer.accept(keyState, new SpecificShapeSerializer() {
                 @Override
                 public void writeString(Schema schema, String value) {
-                    headerConsumer.accept(prefix + key, value);
+                    var headerName = prefix + key;
+                    // HttpHeader takes precedence if prefixHeader's value is empty.
+                    // Smithy's validator will complain if prefixHeader's value is not empty and duplicate found
+                    if (!namesFromHttpHeader.contains(headerName)) {
+                        headerConsumer.accept(headerName, value);
+                    }
                 }
             });
         }