feat(codegen): add Smithy RPCv2 CBOR protocol as an option

Author: kuhe

codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/AddProtocols.java

@@ -18,7 +18,6 @@
 import java.util.List;
 import software.amazon.smithy.typescript.codegen.integration.ProtocolGenerator;
 import software.amazon.smithy.typescript.codegen.integration.TypeScriptIntegration;
-import software.amazon.smithy.typescript.codegen.protocols.cbor.SmithyRpcV2Cbor;
 import software.amazon.smithy.utils.ListUtils;
 import software.amazon.smithy.utils.SmithyInternalApi;
 
@@ -28,13 +27,20 @@
 @SmithyInternalApi
 public class AddProtocols implements TypeScriptIntegration {
 
+    /**
+     * This order differs from the base protocol selection specification
+     * in that for JavaScript runtimes, JSON-based protocols have higher default priority than CBOR-based.
+     * This behavior may be fine-tuned at the service level in a case-by-case basis.
+     *
+     * @return a list of ProtocolGenerators in the default priority order, highest first.
+     */
     @Override
     public List<ProtocolGenerator> getProtocolGenerators() {
         return ListUtils.of(
-            new SmithyRpcV2Cbor(),
             new AwsJsonRpc1_0(),
             new AwsJsonRpc1_1(),
             new AwsRestJson1(),
+            new AwsSmithyRpcV2Cbor(),
             new AwsRestXml(),
             new AwsQuery(),
             new AwsEc2()

codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/AwsSmithyRpcV2Cbor.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package software.amazon.smithy.aws.typescript.codegen;
+
+import software.amazon.smithy.aws.traits.protocols.AwsQueryCompatibleTrait;
+import software.amazon.smithy.typescript.codegen.TypeScriptDependency;
+import software.amazon.smithy.typescript.codegen.TypeScriptWriter;
+import software.amazon.smithy.typescript.codegen.protocols.cbor.SmithyRpcV2Cbor;
+
+/**
+ * Extension of the Smithy RPCv2 CBOR protocol generator, adding
+ * AWSQuery compatibility.
+ */
+public final class AwsSmithyRpcV2Cbor extends SmithyRpcV2Cbor {
+    @Override
+    public void generateSharedComponents(GenerationContext context) {
+        super.generateSharedComponents(context);
+        if (context.getService().hasTrait(AwsQueryCompatibleTrait.class)) {
+            TypeScriptWriter writer = context.getWriter();
+            writer.addImport("HeaderBag", "__HeaderBag", TypeScriptDependency.SMITHY_TYPES);
+            writer.write("""
+                const populateBodyWithQueryCompatibility = (parsedOutput: any, headers: __HeaderBag) => {
+                  const queryErrorHeader = headers["x-amzn-query-error"];
+                  if (parsedOutput.body !== undefined && queryErrorHeader != null) {
+                    const codeAndType = queryErrorHeader.split(";");
+                    parsedOutput.body.Code = codeAndType[0];
+                    parsedOutput.body.Type = codeAndType[1];
+                  }
+                };
+                """);
+        }
+    }
+
+    @Override
+    protected void writeErrorCodeParser(GenerationContext generationContext) {
+        super.writeErrorCodeParser(generationContext);
+        TypeScriptWriter writer = generationContext.getWriter();
+
+        if (generationContext.getService().hasTrait(AwsQueryCompatibleTrait.class)) {
+            // Populate parsedOutput.body with 'Code' and 'Type' fields
+            // "x-amzn-query-error" header is available when AwsQueryCompatibleTrait is applied to a service
+            // The header value contains query error Code and Type joined by ';'
+            // E.g. "MalformedInput;Sender" or "InternalFailure;Receiver"
+            writer.write("populateBodyWithQueryCompatibility(parsedOutput, output.headers);");
+        }
+    }
+}