[cupertino_http] Fix a bug where content-length was not set for multipart messages (#1247)

Author: brianquinlan

pkgs/cupertino_http/CHANGELOG.md

@@ -1,6 +1,8 @@
 ## 1.5.1-wip
 
 * Allow `1000` as a `code` argument in `CupertinoWebSocket.close`.
+* Fix a bug where the `Content-Length` header would not be set under certain
+  circumstances.
 
 ## 1.5.0
 

pkgs/cupertino_http/lib/src/cupertino_client.dart

@@ -308,16 +308,18 @@ class CupertinoClient extends BaseClient {
       ..headersCommaValues = request.headers
       ..maxRedirects = request.maxRedirects;
 
-    if (profile != null && request.contentLength != null) {
-      profile.requestData.headersListValues = {
+    final urlRequest = MutableURLRequest.fromUrl(request.url)
+      ..httpMethod = request.method;
+
+    if (request.contentLength != null) {
+      profile?.requestData.headersListValues = {
         'Content-Length': ['${request.contentLength}'],
         ...profile.requestData.headers!
       };
+      urlRequest.setValueForHttpHeaderField(
+          'Content-Length', '${request.contentLength}');
     }
 
-    final urlRequest = MutableURLRequest.fromUrl(request.url)
-      ..httpMethod = request.method;
-
     if (request is Request) {
       // Optimize the (typical) `Request` case since assigning to
       // `httpBodyStream` requires a lot of expensive setup and data passing.

pkgs/http/test/html/client_conformance_test.dart

@@ -14,5 +14,6 @@ void main() {
       redirectAlwaysAllowed: true,
       canStreamRequestBody: false,
       canStreamResponseBody: false,
-      canWorkInIsolates: false);
+      canWorkInIsolates: false,
+      supportsMultipartRequest: false);
 }

pkgs/http_client_conformance_tests/lib/http_client_conformance_tests.dart

@@ -7,6 +7,7 @@ import 'package:http/http.dart';
 import 'src/close_tests.dart';
 import 'src/compressed_response_body_tests.dart';
 import 'src/isolate_test.dart';
+import 'src/multipart_tests.dart';
 import 'src/multiple_clients_tests.dart';
 import 'src/redirect_tests.dart';
 import 'src/request_body_streamed_tests.dart';
@@ -25,6 +26,7 @@ export 'src/close_tests.dart' show testClose;
 export 'src/compressed_response_body_tests.dart'
     show testCompressedResponseBody;
 export 'src/isolate_test.dart' show testIsolate;
+export 'src/multipart_tests.dart' show testMultipartRequests;
 export 'src/multiple_clients_tests.dart' show testMultipleClients;
 export 'src/redirect_tests.dart' show testRedirect;
 export 'src/request_body_streamed_tests.dart' show testRequestBodyStreamed;
@@ -67,6 +69,9 @@ export 'src/server_errors_test.dart' show testServerErrors;
 /// If [supportsFoldedHeaders] is `false` then the tests that assume that the
 /// [Client] can parse folded headers will be skipped.
 ///
+/// If [supportsMultipartRequest] is `false` then tests that assume that
+/// multipart requests can be sent will be skipped.
+///
 /// The tests are run against a series of HTTP servers that are started by the
 /// tests. If the tests are run in the browser, then the test servers are
 /// started in another process. Otherwise, the test servers are run in-process.
@@ -80,6 +85,7 @@ void testAll(
   bool supportsFoldedHeaders = true,
   bool canSendCookieHeaders = false,
   bool canReceiveSetCookieHeaders = false,
+  bool supportsMultipartRequest = true,
 }) {
   testRequestBody(clientFactory());
   testRequestBodyStreamed(clientFactory(),
@@ -97,6 +103,8 @@ void testAll(
   testServerErrors(clientFactory());
   testCompressedResponseBody(clientFactory());
   testMultipleClients(clientFactory);
+  testMultipartRequests(clientFactory(),
+      supportsMultipartRequest: supportsMultipartRequest);
   testClose(clientFactory);
   testIsolate(clientFactory, canWorkInIsolates: canWorkInIsolates);
   testRequestCookies(clientFactory(),

pkgs/http_client_conformance_tests/lib/src/multipart_server.dart

@@ -0,0 +1,48 @@
+// Copyright (c) 2024, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:stream_channel/stream_channel.dart';
+
+/// Starts an HTTP server that captures the request headers and body.
+///
+/// Channel protocol:
+///    On Startup:
+///     - send port
+///    On Request Received:
+///     - send the received headers and request body
+///    When Receive Anything:
+///     - exit
+void hybridMain(StreamChannel<Object?> channel) async {
+  late HttpServer server;
+
+  server = (await HttpServer.bind('localhost', 0))
+    ..listen((request) async {
+      request.response.headers.set('Access-Control-Allow-Origin', '*');
+      if (request.method == 'OPTIONS') {
+        // Handle a CORS preflight request:
+        // https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS#preflighted_requests
+        request.response.headers
+          ..set('Access-Control-Allow-Methods', '*')
+          ..set('Access-Control-Allow-Headers', '*');
+      } else {
+        final headers = <String, List<String>>{};
+        request.headers.forEach((field, value) {
+          headers[field] = value;
+        });
+        final body =
+            await const Utf8Decoder().bind(request).fold('', (x, y) => '$x$y');
+        channel.sink.add((headers, body));
+      }
+      unawaited(request.response.close());
+    });
+
+  channel.sink.add(server.port);
+  await channel
+      .stream.first; // Any writes indicates that the server should exit.
+  unawaited(server.close());
+}

pkgs/http_client_conformance_tests/lib/src/multipart_server_vm.dart

@@ -0,0 +1,51 @@
+// Copyright (c) 2024, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:async/async.dart';
+import 'package:http/http.dart';
+import 'package:stream_channel/stream_channel.dart';
+import 'package:test/test.dart';
+
+import 'multipart_server_vm.dart'
+    if (dart.library.js_interop) 'multipart_server_web.dart';
+
+/// Tests that the [Client] correctly sends [MultipartRequest].
+///
+/// If [supportsMultipartRequest] is `false` then tests that assume that
+/// multipart requests can be sent will be skipped.
+void testMultipartRequests(Client client,
+    {required bool supportsMultipartRequest}) async {
+  group('multipart requests', () {
+    late final String host;
+    late final StreamChannel<Object?> httpServerChannel;
+    late final StreamQueue<Object?> httpServerQueue;
+
+    setUpAll(() async {
+      httpServerChannel = await startServer();
+      httpServerQueue = StreamQueue(httpServerChannel.stream);
+      host = 'localhost:${await httpServerQueue.nextAsInt}';
+    });
+    tearDownAll(() => httpServerChannel.sink.add(null));
+
+    test('attached file', () async {
+      final request = MultipartRequest('POST', Uri.http(host, ''));
+
+      request.files.add(MultipartFile.fromString('file1', 'Hello World'));
+
+      await client.send(request);
+      final (headers, body) =
+          await httpServerQueue.next as (Map<String, List<String>>, String);
+      expect(headers['content-length']!.single, '${request.contentLength}');
+      expect(headers['content-type']!.single,
+          startsWith('multipart/form-data; boundary='));
+      expect(body, contains('''content-type: text/plain; charset=utf-8\r
+content-disposition: form-data; name="file1"\r
+\r
+Hello World'''));
+    });
+  },
+      skip: supportsMultipartRequest
+          ? false
+          : 'does not support multipart requests');
+}