feat: enable ctor arg passthrough for requestHandler

Author: kuhe

.changeset/three-paws-add.md

@@ -0,0 +1,6 @@
+---
+"@smithy/protocol-http": minor
+"@smithy/smithy-client": minor
+---
+
+allow constructor parameters pass-through when initializing requestHandler

packages/protocol-http/src/httpHandler.ts

@@ -1,7 +1,12 @@
-import { HttpHandlerOptions, RequestHandler } from "@smithy/types";
+import type {
+  FetchHttpHandlerOptions,
+  HttpHandlerOptions,
+  NodeHttpHandlerOptions,
+  RequestHandler,
+} from "@smithy/types";
 
-import { HttpRequest } from "./httpRequest";
-import { HttpResponse } from "./httpResponse";
+import type { HttpRequest } from "./httpRequest";
+import type { HttpResponse } from "./httpResponse";
 
 /**
  * @internal
@@ -23,3 +28,21 @@ export type HttpHandler<HttpHandlerConfig extends object = {}> = RequestHandler<
    */
   httpHandlerConfigs(): HttpHandlerConfig;
 };
+
+/**
+ * @public
+ *
+ * A type representing the accepted user inputs for the `requestHandler` field
+ * of a client's constructor object.
+ *
+ * You may provide an instance of an HttpHandler, or alternatively
+ * provide the constructor arguments as an object which will be passed
+ * to the constructor of the default request handler.
+ *
+ * The default class constructor to which your arguments will be passed
+ * varies. The Node.js default is the NodeHttpHandler and the browser/react-native
+ * default is the FetchHttpHandler. In rarer cases specific clients may be
+ * configured to use other default implementations such as Websocket or HTTP2.
+ *
+ */
+export type HttpHandlerUserInput = HttpHandler | NodeHttpHandlerOptions | FetchHttpHandlerOptions;

packages/smithy-client/src/client.ts

@@ -1,11 +1,19 @@
 import { constructStack } from "@smithy/middleware-stack";
-import { Client as IClient, Command, MetadataBearer, MiddlewareStack, RequestHandler } from "@smithy/types";
+import {
+  Client as IClient,
+  Command,
+  FetchHttpHandlerOptions,
+  MetadataBearer,
+  MiddlewareStack,
+  NodeHttpHandlerOptions,
+  RequestHandler,
+} from "@smithy/types";
 
 /**
  * @public
  */
 export interface SmithyConfiguration<HandlerOptions> {
-  requestHandler: RequestHandler<any, any, HandlerOptions>;
+  requestHandler: RequestHandler<any, any, HandlerOptions> | NodeHttpHandlerOptions | FetchHttpHandlerOptions | any;
   /**
    * The API version set internally by the SDK, and is
    * not planned to be used by customer code.
@@ -17,7 +25,10 @@ export interface SmithyConfiguration<HandlerOptions> {
 /**
  * @internal
  */
-export type SmithyResolvedConfiguration<HandlerOptions> = SmithyConfiguration<HandlerOptions>;
+export type SmithyResolvedConfiguration<HandlerOptions> = {
+  requestHandler: RequestHandler<any, any, HandlerOptions>;
+  readonly apiVersion: string;
+};
 
 /**
  * @public

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/RuntimeConfigGenerator.java

@@ -58,7 +58,7 @@ final class RuntimeConfigGenerator {
                 writer.addDependency(TypeScriptDependency.AWS_SDK_NODE_HTTP_HANDLER);
                 writer.addImport("NodeHttpHandler", "RequestHandler",
                         TypeScriptDependency.AWS_SDK_NODE_HTTP_HANDLER);
-                writer.write("new RequestHandler(defaultConfigProvider)");
+                writer.write("RequestHandler.create(config.requestHandler ?? defaultConfigProvider)");
             },
             "sha256", writer -> {
                 writer.addDependency(TypeScriptDependency.AWS_SDK_HASH_NODE);
@@ -81,7 +81,7 @@ final class RuntimeConfigGenerator {
                 writer.addDependency(TypeScriptDependency.AWS_SDK_FETCH_HTTP_HANDLER);
                 writer.addImport("FetchHttpHandler", "RequestHandler",
                         TypeScriptDependency.AWS_SDK_FETCH_HTTP_HANDLER);
-                writer.write("new RequestHandler(defaultConfigProvider)");
+                writer.write("RequestHandler.create(config.requestHandler ?? defaultConfigProvider)");
             },
             "sha256", writer -> {
                 writer.addDependency(TypeScriptDependency.AWS_CRYPTO_SHA256_BROWSER);
@@ -197,11 +197,20 @@ void generate(LanguageTarget target) {
                 }
                 int indentation = target.equals(LanguageTarget.SHARED) ? 1 : 2;
                 configs.forEach((key, value) -> {
-                    writer.indent(indentation).disableNewlines().openBlock("$1L: config?.$1L ?? ", ",\n", key,
-                        () -> {
-                            value.accept(writer);
-                        });
-                    writer.dedent(indentation);
+                    String defaultPrefix = "config?.$1L ?? ";
+                    if (key.equals("requestHandler")) {
+                        defaultPrefix = "";
+                    }
+                    writer
+                        .indent(indentation)
+                        .disableNewlines()
+                        .openBlock(
+                            "$1L: " + defaultPrefix, ",\n", key,
+                            () -> {
+                                value.accept(writer);
+                            }
+                        )
+                        .dedent(indentation);
                 });
             });
             writer.dedent();

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/ServiceBareBonesClientGenerator.java

@@ -253,11 +253,13 @@ private void generateClientDefaults() {
 
         writer.writeDocs("@public")
             .openBlock("export interface ClientDefaults\n"
-                         + "  extends Partial<__SmithyResolvedConfiguration<$T>> {", "}",
+                         + "  extends Partial<__SmithyConfiguration<$T>> {", "}",
                 applicationProtocol.getOptionsType(), () -> {
-            writer.addImport("HttpHandler", "__HttpHandler", TypeScriptDependency.PROTOCOL_HTTP);
-            writer.writeDocs("The HTTP handler to use. Fetch in browser and Https in Nodejs.");
-            writer.write("requestHandler?: __HttpHandler;\n");
+            writer.addImport("HttpHandlerUserInput", "__HttpHandlerUserInput", TypeScriptDependency.PROTOCOL_HTTP);
+            writer.writeDocs(
+                "The HTTP handler to use or its constructor options. Fetch in browser and Https in Nodejs."
+            );
+            writer.write("requestHandler?: __HttpHandlerUserInput;\n");
 
             writer.addImport("HashConstructor", "__HashConstructor", TypeScriptDependency.SMITHY_TYPES);
             writer.addImport("ChecksumConstructor", "__ChecksumConstructor", TypeScriptDependency.SMITHY_TYPES);