RestXml Deserialization support

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/SmithyGoDependency.java

@@ -39,6 +39,7 @@ public final class SmithyGoDependency {
     public static final GoDependency CRYPTORAND = stdlib("crypto/rand", "cryptorand");
     public static final GoDependency TESTING = stdlib("testing");
     public static final GoDependency ERRORS = stdlib("errors");
+    public static final GoDependency XML = stdlib("encoding/xml");
 
     public static final GoDependency SMITHY = smithy(null, "smithy");
     public static final GoDependency SMITHY_HTTP_TRANSPORT = smithy("transport/http", "smithyhttp");

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/integration/DocumentShapeDeserVisitor.java

@@ -41,8 +41,8 @@
 /**
  * Visitor to generate deserialization functions for shapes in protocol document bodies.
  *
- * Visitor methods for aggregate types are final and will generate functions that dispatch
- * their loading from the body to the matching abstract method.
+ * Visitor methods for aggregate types except maps and collections are final and will
+ * generate functions that dispatch their loading from the body to the matching abstract method.
  *
  * Visitor methods for all other types will default to not generating deserialization
  * functions. This may be overwritten by downstream implementations if the protocol requires
@@ -472,7 +472,7 @@ public final Void documentShape(DocumentShape shape) {
      * @return null
      */
     @Override
-    public final Void listShape(ListShape shape) {
+    public Void listShape(ListShape shape) {
         generateDeserFunction(shape, (c, s) -> deserializeCollection(c, s.asListShape().get()));
         return null;
     }
@@ -484,7 +484,7 @@ public final Void listShape(ListShape shape) {
      * @return null
      */
     @Override
-    public final Void mapShape(MapShape shape) {
+    public Void mapShape(MapShape shape) {
         generateDeserFunction(shape, (c, s) -> deserializeMap(c, s.asMapShape().get()));
         return null;
     }
@@ -496,7 +496,7 @@ public final Void mapShape(MapShape shape) {
      * @return null
      */
     @Override
-    public final Void setShape(SetShape shape) {
+    public Void setShape(SetShape shape) {
         generateDeserFunction(shape, (c, s) -> deserializeCollection(c, s.asSetShape().get()));
         return null;
     }

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/integration/HttpBindingProtocolGenerator.java

@@ -280,6 +280,7 @@ private void generateOperationDeserializerMiddleware(GenerationContext context,
         ApplicationProtocol applicationProtocol = getApplicationProtocol();
         Symbol responseType = applicationProtocol.getResponseType();
         GoWriter goWriter = context.getWriter();
+
         String errorFunctionName = ProtocolGenerator.getOperationErrorDeserFunctionName(
                 operation, context.getProtocolName());
 

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/integration/HttpProtocolGeneratorUtils.java

@@ -45,7 +45,7 @@ private HttpProtocolGeneratorUtils() {}
      *                                  and {@code errorMessage} variables from the http response.
      * @return A set of all error structure shapes for the operation that were dispatched to.
      */
-    static Set<StructureShape> generateErrorDispatcher(
+     static Set<StructureShape> generateErrorDispatcher(
             GenerationContext context,
             OperationShape operation,
             Symbol responseType,
@@ -78,13 +78,14 @@ static Set<StructureShape> generateErrorDispatcher(
             // Dispatch to the message/code generator to try to get the specific code and message.
             errorMessageCodeGenerator.accept(context);
 
-            writer.openBlock("switch errorCode {", "}", () -> {
+            writer.openBlock("switch {", "}", () -> {
                 new TreeSet<>(operation.getErrors()).forEach(errorId -> {
                     StructureShape error = context.getModel().expectShape(errorId).asStructureShape().get();
                     errorShapes.add(error);
                     String errorDeserFunctionName = ProtocolGenerator.getErrorDeserFunctionName(
                             error, context.getProtocolName());
-                    writer.openBlock("case $S:", "", errorId.getName(), () -> {
+                    writer.addUseImports(SmithyGoDependency.STRINGS);
+                    writer.openBlock("case strings.EqualFold($S, errorCode):", "", errorId.getName(), () -> {
                         writer.write("return $L(response, errorBody)", errorDeserFunctionName);
                     });
                 });

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/integration/HttpRpcProtocolGenerator.java

@@ -120,7 +120,7 @@ private void generateOperationSerializer(GenerationContext context, OperationSha
             writer.write("request.Request.URL.Path = $S", getOperationPath(context, operation));
             writer.write("request.Request.Method = \"POST\"");
             writer.write("httpBindingEncoder, err := httpbinding.NewEncoder(request.URL.Path, "
-                    +  "request.URL.RawQuery, request.Header)");
+                    + "request.URL.RawQuery, request.Header)");
             writer.openBlock("if err != nil {", "}", () -> {
                 writer.write("return out, metadata, &smithy.SerializationError{Err: err}");
             });
@@ -160,16 +160,16 @@ private void writeRequestHeaders(GenerationContext context, OperationShape opera
      *   <li>{@code ctx: context.Context}: a type containing context and tools for type serde.</li>
      * </ul>
      *
-     * @param context The generation context.
+     * @param context   The generation context.
      * @param operation The operation being generated.
-     * @param writer The writer to use.
+     * @param writer    The writer to use.
      */
     protected void writeDefaultHeaders(GenerationContext context, OperationShape operation, GoWriter writer) {}
 
     /**
      * Provides the request path for the operation.
      *
-     * @param context The generation context.
+     * @param context   The generation context.
      * @param operation The operation being generated.
      * @return The path to send HTTP requests to.
      */
@@ -185,7 +185,7 @@ protected void writeDefaultHeaders(GenerationContext context, OperationShape ope
      *   <li>{@code ctx: context.Context}: a type containing context and tools for type serde.</li>
      * </ul>
      *
-     * @param context The generation context.
+     * @param context   The generation context.
      * @param operation The operation to serialize for.
      */
     protected abstract void serializeInputDocument(GenerationContext context, OperationShape operation);
@@ -204,7 +204,7 @@ public void generateSharedDeserializerComponents(GenerationContext context) {
      * {@code deserializeOutputDocument}.
      *
      * @param context The generation context.
-     * @param shapes The shapes to generate deserialization for.
+     * @param shapes  The shapes to generate deserialization for.
      */
     protected abstract void generateDocumentBodyShapeDeserializers(GenerationContext context, Set<Shape> shapes);
 
@@ -280,7 +280,7 @@ private void generateOperationDeserializer(GenerationContext context, OperationS
      *   <li>{@code ctx: context.Context}: a type containing context and tools for type serde.</li>
      * </ul>
      *
-     * @param context The generation context
+     * @param context   The generation context
      * @param operation The operation to deserialize for.
      */
     protected abstract void deserializeOutputDocument(GenerationContext context, OperationShape operation);
@@ -306,7 +306,7 @@ private void generateErrorDeserializer(GenerationContext context, StructureShape
      * </ul>
      *
      * @param context The generation context.
-     * @param shape The error shape.
+     * @param shape   The error shape.
      */
     protected abstract void deserializeError(GenerationContext context, StructureShape shape);
 

xml/xml_decoder.go

@@ -0,0 +1,87 @@
+package xml
+
+import (
+	"encoding/xml"
+	"fmt"
+)
+
+// NodeDecoder is a XML decoder wrapper that is responsible to decoding
+// a single XML Node element and it's nested member elements. This wrapper decoder
+// takes in the start element of the top level node being decoded.
+type NodeDecoder struct {
+	Decoder *xml.Decoder
+	StartEl xml.StartElement
+}
+
+// WrapNodeDecoder returns an initialized XMLNodeDecoder
+func WrapNodeDecoder(decoder *xml.Decoder, startEl xml.StartElement) NodeDecoder {
+	return NodeDecoder{
+		Decoder: decoder,
+		StartEl: startEl,
+	}
+}
+
+// Token on a Node Decoder returns a xml StartElement. It returns a boolean that indicates the
+// a token is the node decoder's end node token; and an error which indicates any error
+// that occurred while retrieving the start element
+func (d NodeDecoder) Token() (t xml.StartElement, done bool, err error) {
+	for {
+		token, e := d.Decoder.Token()
+		if e != nil {
+			return t, done, e
+		}
+
+		// check if we reach end of the node being decoded
+		if el, ok := token.(xml.EndElement); ok {
+			return t, el == d.StartEl.End(), err
+		}
+
+		if t, ok := token.(xml.StartElement); ok {
+			return t, false, err
+		}
+
+		// skip token if it is a comment or preamble or empty space value due to indentation
+		// or if it's a value and is not expected
+	}
+
+	return
+}
+
+// Value provides an abstraction to retrieve char data value within an xml element.
+// The method will return an error if it encounters a nested xml element instead of char data.
+// This method should only be used to retrieve simple type or blob shape values as []byte.
+func (d NodeDecoder) Value() (c []byte, done bool, err error) {
+	t, e := d.Decoder.Token()
+	if e != nil {
+		return c, done, e
+	}
+
+	// check if token is of type charData
+	if ev, ok := t.(xml.CharData); ok {
+		return ev, done, err
+	}
+
+	if ev, ok := t.(xml.EndElement); ok {
+		if ev == d.StartEl.End() {
+			return c, true, err
+		}
+	}
+
+	return c, done, fmt.Errorf("expected value for %v element, got %T type %v instead", d.StartEl.Name.Local, t, t)
+}
+
+// FetchRootElement takes in a decoder and returns the first start element within the xml body.
+// This function is useful in fetching the start element of an XML response and ignore the
+// comments and preamble
+func FetchRootElement(decoder *xml.Decoder) (startElement xml.StartElement, err error) {
+	for {
+		t, e := decoder.Token()
+		if e != nil {
+			return startElement, e
+		}
+
+		if startElement, ok := t.(xml.StartElement); ok {
+			return startElement, err
+		}
+	}
+}