Modify parsing of response for Connect unary requests

packages/connect-web-bench/README.md

@@ -10,5 +10,5 @@ it like a web server would usually do.
 
 | code generator | bundle size        | minified               | compressed           |
 |----------------|-------------------:|-----------------------:|---------------------:|
-| connect        | 112,660 b | 49,405 b | 13,203 b |
+| connect        | 112,742 b | 49,450 b | 13,229 b |
 | grpc-web       | 414,906 b    | 301,127 b    | 53,279 b |

packages/connect-web-test/src/fetch.spec.ts

@@ -0,0 +1,111 @@
+// Copyright 2021-2023 Buf Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License 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.
+
+import { TestService } from "./gen/grpc/testing/test_connect.js";
+import {
+  SimpleRequest,
+  SimpleResponse,
+} from "./gen/grpc/testing/messages_pb.js";
+import { createConnectTransport } from "@bufbuild/connect-web";
+
+describe("custom fetch", function () {
+  describe("with Connect transport", () => {
+    it("should only call Response#json with the JSON format", async function () {
+      const response = new Response(
+        new SimpleResponse({ username: "donald" }).toJsonString(),
+        {
+          headers: {
+            "Content-Type": "application/json",
+          },
+        }
+      );
+      spyOn(response, "arrayBuffer").and.callThrough();
+      spyOn(response, "json").and.callThrough();
+      const transport = createConnectTransport({
+        baseUrl: "https://example.com",
+        fetch: () => Promise.resolve(response),
+      });
+      await transport.unary(
+        TestService,
+        TestService.methods.unaryCall,
+        undefined,
+        undefined,
+        undefined,
+        new SimpleRequest()
+      );
+      expect(response.json).toHaveBeenCalledTimes(1); // eslint-disable-line @typescript-eslint/unbound-method
+      expect(response.arrayBuffer).toHaveBeenCalledTimes(0); // eslint-disable-line @typescript-eslint/unbound-method
+    });
+    it("should only call Response#arrayBuffer with the binary format on the happy path", async function () {
+      const response = new Response(
+        new SimpleResponse({ username: "donald" }).toBinary(),
+        {
+          headers: {
+            "Content-Type": "application/proto",
+          },
+        }
+      );
+      spyOn(response, "arrayBuffer").and.callThrough();
+      spyOn(response, "json").and.callThrough();
+      const transport = createConnectTransport({
+        fetch: () => Promise.resolve(response),
+        baseUrl: "https://example.com",
+        useBinaryFormat: true,
+      });
+      await transport.unary(
+        TestService,
+        TestService.methods.unaryCall,
+        undefined,
+        undefined,
+        undefined,
+        new SimpleRequest()
+      );
+      expect(response.json).toHaveBeenCalledTimes(0); // eslint-disable-line @typescript-eslint/unbound-method
+      expect(response.arrayBuffer).toHaveBeenCalledTimes(1); // eslint-disable-line @typescript-eslint/unbound-method
+    });
+    it("should call Response#json with the binary format for an error response", async function () {
+      const response = new Response(
+        JSON.stringify({
+          code: "permission_denied",
+          message: "foobar",
+        }),
+        {
+          status: 403,
+          headers: {
+            "Content-Type": "application/json",
+          },
+        }
+      );
+      spyOn(response, "arrayBuffer").and.callThrough();
+      spyOn(response, "json").and.callThrough();
+      const transport = createConnectTransport({
+        fetch: () => Promise.resolve(response),
+        baseUrl: "https://example.com",
+        useBinaryFormat: true,
+      });
+      await expectAsync(
+        transport.unary(
+          TestService,
+          TestService.methods.unaryCall,
+          undefined,
+          undefined,
+          undefined,
+          new SimpleRequest()
+        )
+      ).toBeRejectedWithError(/\[permission_denied] foobar/);
+      expect(response.json).toHaveBeenCalledTimes(1); // eslint-disable-line @typescript-eslint/unbound-method
+      expect(response.arrayBuffer).toHaveBeenCalledTimes(0); // eslint-disable-line @typescript-eslint/unbound-method
+    });
+  });
+});

packages/connect-web/src/connect-transport.ts

@@ -204,7 +204,12 @@ export function createConnectTransport(
             service,
             method,
             header: demuxedHeader,
-            message: parse(new Uint8Array(await response.arrayBuffer())),
+            message: useBinaryFormat
+              ? parse(new Uint8Array(await response.arrayBuffer()))
+              : method.O.fromJson(
+                  (await response.json()) as JsonValue,
+                  options.jsonOptions
+                ),
             trailer: demuxedTrailer,
           };
         },