feat: Add support for the aws.ec2 protocol (#791)

* Add support for the aws.ec2 protocol

This commit adds support for the `aws.ec2` protocol, building on top
of the `HttpRpcProtocolGenerator`, `Xml[Member|Shape]DeserVisitor`,
and `Query[Member|Shape]SerVisitor` for document serde.

The `QueryShapeSerVisitor` has been opened up for re-use by the new
`Ec2ShapeSerVisitor` because `aws.ec2` is a specific version of the
`aws.query` protocol. Hooks have been made available to influence
the specific behavior that is updated.

This also fixes a critical bug with query list and map serialization
that would have resulted in runtime failues on serilaizing the member
target shape's contents.

* Update to empty default error code

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

@@ -28,6 +28,6 @@ public class AddProtocols implements TypeScriptIntegration {
     @Override
     public List<ProtocolGenerator> getProtocolGenerators() {
         return ListUtils.of(new AwsRestJson1_1(), new AwsJsonRpc1_0(), new AwsJsonRpc1_1(),
-                new AwsRestXml(), new AwsQuery());
+                new AwsRestXml(), new AwsQuery(), new AwsEc2());
     }
 }

codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/AwsEc2.java

@@ -0,0 +1,150 @@
+/*
+ * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.smithy.aws.typescript.codegen;
+
+import java.util.Set;
+import software.amazon.smithy.codegen.core.SymbolReference;
+import software.amazon.smithy.model.shapes.OperationShape;
+import software.amazon.smithy.model.shapes.Shape;
+import software.amazon.smithy.model.shapes.StructureShape;
+import software.amazon.smithy.model.traits.TimestampFormatTrait.Format;
+import software.amazon.smithy.typescript.codegen.TypeScriptWriter;
+import software.amazon.smithy.typescript.codegen.integration.HttpRpcProtocolGenerator;
+
+/**
+ * Handles generating the aws.ec2 protocol for services. It handles reading and
+ * writing from document bodies, including generating any functions needed for
+ * performing serde.
+ *
+ * This builds on the foundations of the {@link HttpRpcProtocolGenerator} to handle
+ * standard components of the HTTP requests and responses.
+ *
+ * @see Ec2ShapeSerVisitor
+ * @see XmlShapeDeserVisitor
+ * @see QueryMemberSerVisitor
+ * @see XmlMemberDeserVisitor
+ * @see AwsProtocolUtils
+ * @see <a href="https://awslabs.github.io/smithy/spec/xml.html">Smithy XML traits.</a>
+ * @see <a href="https://awslabs.github.io/smithy/spec/aws-core.html#ec2QueryName-trait">Smithy EC2 Query Name trait.</a>
+ */
+final class AwsEc2 extends HttpRpcProtocolGenerator {
+
+    AwsEc2() {
+        super(true);
+    }
+
+    @Override
+    protected String getOperationPath(GenerationContext context, OperationShape operationShape) {
+        return "/";
+    }
+
+    @Override
+    public String getName() {
+        return "aws.ec2";
+    }
+
+    @Override
+    protected String getDocumentContentType() {
+        return "application/x-www-form-urlencoded";
+    }
+
+    @Override
+    protected void generateDocumentBodyShapeSerializers(GenerationContext context, Set<Shape> shapes) {
+        AwsProtocolUtils.generateDocumentBodyShapeSerde(context, shapes, new Ec2ShapeSerVisitor(context));
+    }
+
+    @Override
+    protected void generateDocumentBodyShapeDeserializers(GenerationContext context, Set<Shape> shapes) {
+        AwsProtocolUtils.generateDocumentBodyShapeSerde(context, shapes, new XmlShapeDeserVisitor(context));
+    }
+
+    @Override
+    public void generateSharedComponents(GenerationContext context) {
+        super.generateSharedComponents(context);
+        AwsProtocolUtils.generateXmlParseBody(context);
+        AwsProtocolUtils.generateBuildFormUrlencodedString(context);
+
+        TypeScriptWriter writer = context.getWriter();
+
+        // Generate a function that handles the complex rules around deserializing
+        // an error code from an xml error body.
+        SymbolReference responseType = getApplicationProtocol().getResponseType();
+        writer.openBlock("const loadEc2ErrorCode = (\n"
+                       + "  output: $T,\n"
+                       + "  data: any\n"
+                       + "): string => {", "};", responseType, () -> {
+
+            // Attempt to fetch the error code from the specific location, including the wrapper.
+            writer.openBlock("if (data.Errors.Error.Code !== undefined) {", "}", () -> {
+                writer.write("return data.Errors.Error.Code;");
+            });
+
+            // Default a 404 status code to the NotFound code.
+            writer.openBlock("if (output.statusCode == 404) {", "}", () -> writer.write("return 'NotFound';"));
+
+            // Default to an empty error code so an unmodeled exception is built.
+            writer.write("return '';");
+        });
+        writer.write("");
+    }
+
+    @Override
+    protected void writeDefaultHeaders(GenerationContext context, OperationShape operation) {
+        super.writeDefaultHeaders(context, operation);
+        AwsProtocolUtils.generateUnsignedPayloadSigV4Header(context, operation);
+    }
+
+    @Override
+    protected void serializeInputDocument(
+            GenerationContext context,
+            OperationShape operation,
+            StructureShape inputStructure
+    ) {
+        TypeScriptWriter writer = context.getWriter();
+
+        // Gather all the explicit input entries.
+        writer.write("const entries = $L;",
+                inputStructure.accept(new QueryMemberSerVisitor(context, "input", Format.DATE_TIME)));
+
+        // Set the form encoded string.
+        writer.openBlock("body = buildFormUrlencodedString({", "});", () -> {
+            writer.write("...entries,");
+            // Set the protocol required values.
+            writer.write("Action: $S,", operation.getId().getName());
+            writer.write("Version: $S,", context.getService().getVersion());
+        });
+    }
+
+    @Override
+    protected void writeErrorCodeParser(GenerationContext context) {
+        TypeScriptWriter writer = context.getWriter();
+
+        // Outsource error code parsing since it's complex for this protocol.
+        writer.write("errorCode = loadEc2ErrorCode(output, parsedOutput.body);");
+    }
+
+    @Override
+    protected void deserializeOutputDocument(
+            GenerationContext context,
+            OperationShape operation,
+            StructureShape outputStructure
+    ) {
+        TypeScriptWriter writer = context.getWriter();
+
+        writer.write("contents = $L;",
+                outputStructure.accept(new XmlMemberDeserVisitor(context, "data", Format.DATE_TIME)));
+    }
+}

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

@@ -120,6 +120,23 @@ static void generateXmlParseBody(GenerationContext context) {
         writer.write("");
     }
 
+    /**
+     * Writes a form urlencoded string builder function for query based protocols.
+     * This will escape the keys and values, combine those with an '=', and combine
+     * those strings with an '&'.
+     *
+     * @param context The generation context.
+     */
+    static void generateBuildFormUrlencodedString(GenerationContext context) {
+        TypeScriptWriter writer = context.getWriter();
+
+        // Write a single function to handle combining a map in to a valid query string.
+        writer.openBlock("const buildFormUrlencodedString = (entries: any): string => {", "}", () -> {
+            writer.openBlock("return Object.keys(entries).map(", ").join(\"&\");", () ->
+                    writer.write("key => encodeURIComponent(key) + '=' + encodeURIComponent(entries[key])"));
+        });
+    }
+
     /**
      * Writes an attribute containing information about a Shape's optionally specified
      * XML namespace configuration to an attribute of the passed node name.

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

@@ -75,6 +75,7 @@ protected void generateDocumentBodyShapeDeserializers(GenerationContext context,
     public void generateSharedComponents(GenerationContext context) {
         super.generateSharedComponents(context);
         AwsProtocolUtils.generateXmlParseBody(context);
+        AwsProtocolUtils.generateBuildFormUrlencodedString(context);
 
         TypeScriptWriter writer = context.getWriter();
 
@@ -94,15 +95,10 @@ public void generateSharedComponents(GenerationContext context) {
             // Default a 404 status code to the NotFound code.
             writer.openBlock("if (output.statusCode == 404) {", "}", () -> writer.write("return 'NotFound';"));
 
-            // Default to an UnknownError code.
-            writer.write("return 'UnknownError';");
+            // Default to an empty error code so an unmodeled exception is built.
+            writer.write("return '';");
         });
         writer.write("");
-
-        // Write a single function to handle combining a map in to a valid query string.
-        writer.openBlock("const buildFormUrlencodedString = (entries: any): string => {", "}", () -> {
-            writer.write("return Object.keys(entries).map(key => key + '=' + entries[key]).join(\"&\");");
-        });
     }
 
     @Override

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

@@ -116,8 +116,8 @@ public void generateSharedComponents(GenerationContext context) {
             // Default a 404 status code to the NotFound code.
             writer.openBlock("if (output.statusCode == 404) {", "}", () -> writer.write("return 'NotFound';"));
 
-            // Default to an UnknownError code.
-            writer.write("return 'UnknownError';");
+            // Default to an empty error code so an unmodeled exception is built.
+            writer.write("return '';");
         });
         writer.write("");
     }

codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/Ec2ShapeSerVisitor.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.smithy.aws.typescript.codegen;
+
+import java.util.Optional;
+import software.amazon.smithy.aws.traits.Ec2QueryNameTrait;
+import software.amazon.smithy.codegen.core.CodegenException;
+import software.amazon.smithy.model.shapes.DocumentShape;
+import software.amazon.smithy.model.shapes.MemberShape;
+import software.amazon.smithy.model.traits.TimestampFormatTrait.Format;
+import software.amazon.smithy.model.traits.XmlNameTrait;
+import software.amazon.smithy.typescript.codegen.integration.ProtocolGenerator.GenerationContext;
+import software.amazon.smithy.utils.StringUtils;
+
+/**
+ * Visitor to generate serialization functions for shapes in form-urlencoded
+ * based document bodies specific to aws.ec2.
+ *
+ * This class uses the implementations provided by {@code QueryShapeSerVisitor} but with
+ * the following protocol specific customizations for aws.ec2:
+ *
+ * <ul>
+ *   <li>aws.ec2 flattens all lists, sets, and maps regardless of the {@code @xmlFlattened} trait.</li>
+ *   <li>aws.ec2 respects the {@code @ec2QueryName} trait, then the {@code xmlName}
+ *     trait value with the first letter capitalized.</li>
+ * </ul>
+ *
+ * Timestamps are serialized to {@link Format}.DATE_TIME by default.
+ *
+ * @see AwsEc2
+ * @see QueryShapeSerVisitor
+ * @see <a href="https://awslabs.github.io/smithy/spec/aws-core.html#ec2QueryName-trait">Smithy EC2 Query Name trait.</a>
+ */
+final class Ec2ShapeSerVisitor extends QueryShapeSerVisitor {
+
+    Ec2ShapeSerVisitor(GenerationContext context) {
+        super(context);
+    }
+
+    @Override
+    protected void serializeDocument(GenerationContext context, DocumentShape shape) {
+        throw new CodegenException(String.format(
+                "Cannot serialize Document types in the aws.ec2 protocol, shape: %s.", shape.getId()));
+    }
+
+    @Override
+    protected String getMemberSerializedLocationName(MemberShape memberShape, String defaultValue) {
+        // The serialization for aws.ec2 prioritizes the @ec2QueryName trait for serialization.
+        Optional<Ec2QueryNameTrait> trait = memberShape.getTrait(Ec2QueryNameTrait.class);
+        if (trait.isPresent()) {
+            return trait.get().getValue();
+        }
+
+        // Fall back to the capitalized @xmlName trait if present on the member,
+        // otherwise use the capitalized default value.
+        return memberShape.getTrait(XmlNameTrait.class)
+                .map(XmlNameTrait::getValue)
+                .map(StringUtils::capitalize)
+                .orElseGet(() -> StringUtils.capitalize(defaultValue));
+    }
+
+    @Override
+    protected boolean isFlattenedMember(MemberShape memberShape) {
+        // All lists, sets, and maps are flattened in aws.ec2.
+        return true;
+    }
+}