Updates for HTTP serde correctness and safety

This commit includes updates to Http ProtocolGenerator components for
correctness and safety.

1. It fixes generation issues for the @httpPrefixHeaders trait in
the HttpBindingProtocolGenerator.
2. It updates SerdeContext to use an import alias for safety.
3. It only generates a local parsedOutput if it will be consumed.
4. It adds the Error type to the list of Typescript reserved words.

Author: kstich

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

@@ -305,7 +305,7 @@ protected final void generateDeserFunction(
         writer.addImport(symbol, symbol.getName());
         writer.openBlock("const $L = (\n"
                        + "  output: any,\n"
-                       + "  context: SerdeContext\n"
+                       + "  context: __SerdeContext\n"
                        + "): $T => {", "}", methodName, symbol, () -> functionBody.accept(context, shape));
         writer.write("");
     }

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/integration/DocumentShapeSerVisitor.java

@@ -300,7 +300,7 @@ private void generateSerFunction(
         writer.addImport(symbol, symbol.getName());
         writer.openBlock("const $L = (\n"
                        + "  input: $T,\n"
-                       + "  context: SerdeContext\n"
+                       + "  context: __SerdeContext\n"
                        + "): any => {", "}", methodName, symbol, () -> functionBody.accept(context, shape));
         writer.write("");
     }

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

@@ -36,6 +36,7 @@
 import software.amazon.smithy.model.shapes.DocumentShape;
 import software.amazon.smithy.model.shapes.DoubleShape;
 import software.amazon.smithy.model.shapes.FloatShape;
+import software.amazon.smithy.model.shapes.MapShape;
 import software.amazon.smithy.model.shapes.MemberShape;
 import software.amazon.smithy.model.shapes.NumberShape;
 import software.amazon.smithy.model.shapes.OperationShape;
@@ -169,7 +170,7 @@ private void generateOperationSerializer(
 
         // Ensure that the request type is imported.
         writer.addUseImports(requestType);
-        writer.addImport("SerdeContext", "SerdeContext", "@aws-sdk/types");
+        writer.addImport("SerdeContext", "__SerdeContext", "@aws-sdk/types");
         writer.addImport("Endpoint", "__Endpoint", "@aws-sdk/types");
         // e.g., serializeAws_restJson1_1ExecuteStatement
         String methodName = ProtocolGenerator.getSerFunctionName(symbol, getName());
@@ -178,7 +179,7 @@ private void generateOperationSerializer(
 
         writer.openBlock("export async function $L(\n"
                        + "  input: $T,\n"
-                       + "  context: SerdeContext\n"
+                       + "  context: __SerdeContext\n"
                        + "): Promise<$T> {", "}", methodName, inputType, requestType, () -> {
             List<HttpBinding> labelBindings = writeRequestLabels(context, operation, bindingIndex, trait);
             List<HttpBinding> queryBindings = writeRequestQueryString(context, operation, bindingIndex);
@@ -303,11 +304,13 @@ private void writeHeaders(
             for (HttpBinding binding : bindingIndex.getRequestBindings(operation, Location.PREFIX_HEADERS)) {
                 String memberName = symbolProvider.toMemberName(binding.getMember());
                 writer.openBlock("if (input.$L !== undefined) {", "}", memberName, () -> {
-                    Shape target = index.getShape(binding.getMember().getTarget()).get();
+                    MapShape prefixMap = index.getShape(binding.getMember().getTarget()).get().asMapShape().get();
+                    Shape target = index.getShape(prefixMap.getValue().getTarget()).get();
                     // Iterate through each entry in the member.
-                    writer.openBlock("Object.keys(input.$L).forEach(suffix -> {", "});", memberName, () -> {
+                    writer.openBlock("Object.keys(input.$L).forEach(suffix => {", "});", memberName, () -> {
+                        // Use a ! since we already validated the input member is defined above.
                         String headerValue = getInputValue(context, binding.getLocation(),
-                                "input." + memberName + "[suffix]", binding.getMember(), target);
+                                "input." + memberName + "![suffix]", binding.getMember(), target);
                         // Append the suffix to the defined prefix and serialize the value in to that key.
                         writer.write("headers[$S + suffix] = $L;", binding.getLocationName(), headerValue);
                     });
@@ -529,7 +532,7 @@ private void generateOperationDeserializer(
 
         // Ensure that the response type is imported.
         writer.addUseImports(responseType);
-        writer.addImport("SerdeContext", "SerdeContext", "@aws-sdk/types");
+        writer.addImport("SerdeContext", "__SerdeContext", "@aws-sdk/types");
         // e.g., deserializeAws_restJson1_1ExecuteStatement
         String methodName = ProtocolGenerator.getDeserFunctionName(symbol, getName());
         String errorMethodName = methodName + "Error";
@@ -539,7 +542,7 @@ private void generateOperationDeserializer(
         // Handle the general response.
         writer.openBlock("export async function $L(\n"
                        + "  output: $T,\n"
-                       + "  context: SerdeContext\n"
+                       + "  context: __SerdeContext\n"
                        + "): Promise<$T> {", "}", methodName, responseType, outputType, () -> {
             // Redirect error deserialization to the dispatcher
             writer.openBlock("if (output.statusCode !== $L) {", "}", trait.getCode(), () -> {
@@ -588,7 +591,7 @@ private void generateErrorDeserializer(GenerationContext context, StructureShape
 
         writer.openBlock("const $L = (\n"
                        + "  output: any,\n"
-                       + "  context: SerdeContext\n"
+                       + "  context: __SerdeContext\n"
                        + "): $T => {", "};", errorDeserMethodName, errorSymbol, () -> {
             writer.write("const data: any = output.body;");
 
@@ -638,23 +641,24 @@ private void readHeaders(
                 bindingIndex.getResponseBindings(operationOrError, Location.PREFIX_HEADERS);
         if (!prefixHeaderBindings.isEmpty()) {
             // Run through the headers one time, matching any prefix groups.
-            writer.openBlock("Object.keys(output.headers).forEach(header -> {", "});", () -> {
+            writer.openBlock("Object.keys(output.headers).forEach(header => {", "});", () -> {
                 for (HttpBinding binding : prefixHeaderBindings) {
                     // Generate a single block for each group of prefix headers.
-                    writer.openBlock("if (header.startsWith($L)) {", binding.getLocationName(), "}", () -> {
+                    writer.openBlock("if (header.startsWith($S)) {", "}", binding.getLocationName(), () -> {
                         String memberName = symbolProvider.toMemberName(binding.getMember());
-                        Shape target = context.getModel().getShapeIndex()
-                                .getShape(binding.getMember().getTarget()).get();
+                        MapShape prefixMap = index.getShape(binding.getMember().getTarget()).get().asMapShape().get();
+                        Shape target = index.getShape(prefixMap.getValue().getTarget()).get();
                         String headerValue = getOutputValue(context, binding.getLocation(),
                                 "output.headers[header]", binding.getMember(), target);
 
                         // Prepare a grab bag for these headers if necessary
                         writer.openBlock("if (contents.$L === undefined) {", "}", memberName, () -> {
-                            writer.write("contents.$L: any = {};", memberName);
+                            writer.write("contents.$L = {};", memberName);
                         });
 
                         // Extract the non-prefix portion as the key.
-                        writer.write("contents.$L[header.substring(header.length)] = $L;", memberName, headerValue);
+                        writer.write("contents.$L[header.substring($L)] = $L;",
+                                memberName, binding.getLocationName().length(), headerValue);
                     });
                 }
             });

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

@@ -135,14 +135,17 @@ static Set<StructureShape> generateErrorDispatcher(
 
         writer.openBlock("async function $L(\n"
                        + "  output: $T,\n"
-                       + "  context: SerdeContext,\n"
+                       + "  context: __SerdeContext,\n"
                        + "): Promise<$T> {", "}", errorMethodName, responseType, outputType, () -> {
             writer.write("const data: any = await parseBody(output.body, context);");
-            // Create a holding object since we have already parsed the body, but retain the rest of the output.
-            writer.openBlock("const parsedOutput: any = {", "};", () -> {
-                writer.write("...output,");
-                writer.write("body: data,");
-            });
+            // We only consume the parsedOutput if we're dispatching, so only generate if we will.
+            if (!operation.getErrors().isEmpty()) {
+                // Create a holding object since we have already parsed the body, but retain the rest of the output.
+                writer.openBlock("const parsedOutput: any = {", "};", () -> {
+                    writer.write("...output,");
+                    writer.write("body: data,");
+                });
+            }
             writer.write("let response: any;");
             writer.write("let errorCode: String;");
             errorCodeGenerator.accept(context);

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

@@ -110,17 +110,17 @@ private void generateOperationSerializer(GenerationContext context, OperationSha
 
         // Ensure that the request type is imported.
         writer.addUseImports(requestType);
-        writer.addImport("SerdeContext", "SerdeContext", "@aws-sdk/types");
+        writer.addImport("SerdeContext", "__SerdeContext", "@aws-sdk/types");
         writer.addImport("Endpoint", "__Endpoint", "@aws-sdk/types");
         // e.g., serializeAws_restJson1_1ExecuteStatement
         String methodName = ProtocolGenerator.getSerFunctionName(symbol, getName());
         // Add the normalized input type.
         Symbol inputType = symbol.expectProperty("inputType", Symbol.class);
 
         writer.openBlock("export async function $L(\n"
-                                 + "  input: $T,\n"
-                                 + "  context: SerdeContext\n"
-                                 + "): Promise<$T> {", "}", methodName, inputType, requestType, () -> {
+                       + "  input: $T,\n"
+                       + "  context: __SerdeContext\n"
+                       + "): Promise<$T> {", "}", methodName, inputType, requestType, () -> {
             writeRequestHeaders(context, operation);
             boolean hasRequestBody = writeRequestBody(context, operation);
 
@@ -220,7 +220,7 @@ private void generateOperationDeserializer(GenerationContext context, OperationS
 
         // Ensure that the response type is imported.
         writer.addUseImports(responseType);
-        writer.addImport("SerdeContext", "SerdeContext", "@aws-sdk/types");
+        writer.addImport("SerdeContext", "__SerdeContext", "@aws-sdk/types");
         // e.g., deserializeAws_restJson1_1ExecuteStatement
         String methodName = ProtocolGenerator.getDeserFunctionName(symbol, getName());
         String errorMethodName = methodName + "Error";
@@ -230,7 +230,7 @@ private void generateOperationDeserializer(GenerationContext context, OperationS
         // Handle the general response.
         writer.openBlock("export async function $L(\n"
                        + "  output: $T,\n"
-                       + "  context: SerdeContext\n"
+                       + "  context: __SerdeContext\n"
                        + "): Promise<$T> {", "}", methodName, responseType, outputType, () -> {
             // Redirect error deserialization to the dispatcher
             writer.openBlock("if (output.statusCode >= 400) {", "}", () -> {
@@ -272,7 +272,7 @@ private void generateErrorDeserializer(GenerationContext context, StructureShape
 
         writer.openBlock("const $L = (\n"
                        + "  output: any,\n"
-                       + "  context: SerdeContext\n"
+                       + "  context: __SerdeContext\n"
                        + "): $T => {", "};", errorDeserMethodName, errorSymbol, () -> {
             // First deserialize the body properly.
             writer.write("const deserialized: any = $L(output.body, context);",

smithy-typescript-codegen/src/main/resources/software/amazon/smithy/typescript/codegen/reserved-words.txt

@@ -92,6 +92,7 @@ Blob
 Boolean
 ConstructorParameters
 Date
+Error
 Exclude
 Extract
 Infinity