fix: Updates the grpc-web example to avoid dart:html

CHANGELOG.md

@@ -6,6 +6,7 @@
   the connection, as defined in the gRPC spec.
 * Upgrade to `package:lints` version 5.0.0 and Dart SDK version 3.5.0.
 * Upgrade `example/grpc-web` code.
+* Update xhr transport to migrate off legacy JS/HTML apis.
 
 ## 4.0.1
 

example/grpc-web/lib/app.dart

@@ -14,8 +14,7 @@
 // limitations under the License.
 
 import 'dart:async';
-import 'dart:html';
-
+import 'package:web/web.dart';
 import 'src/generated/echo.pbgrpc.dart';
 
 class EchoApp {
@@ -56,13 +55,23 @@ class EchoApp {
   }
 
   void _addMessage(String message, String cssClass) {
-    final classes = cssClass.split(' ');
-    querySelector('#first')!.after(DivElement()
-      ..classes.add('row')
-      ..append(Element.tag('h2')
-        ..append(SpanElement()
-          ..classes.add('label')
-          ..classes.addAll(classes)
+    document.querySelector('#first')!.after(HTMLDivElement()
+      ..classList.add('row')
+      ..append(HTMLHeadingElement.h2()
+        ..append(HTMLSpanElement()
+          ..classList.add('label')
+          ..classList.addAll(cssClass)
           ..text = message)));
   }
 }
+
+// The documentation of DOMTokenList.add implies it can handle multiple classes,
+// but in Chrome at least it does not.
+extension AddAll on DOMTokenList {
+  void addAll(String cssClass) {
+    final classes = cssClass.split(' ');
+    for (final c in classes) {
+      add(c);
+    }
+  }
+}

example/grpc-web/pubspec.yaml

@@ -9,6 +9,7 @@ dependencies:
   grpc:
     path: ../../
   protobuf: ^3.0.0
+  web: ^1.1.0
 
 dev_dependencies:
   build_runner: ^2.4.13

example/grpc-web/web/main.dart

@@ -12,21 +12,20 @@
 // 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 'dart:html';
-
 import 'package:grpc/grpc_web.dart';
 import 'package:grpc_web/app.dart';
 import 'package:grpc_web/src/generated/echo.pbgrpc.dart';
+import 'package:web/web.dart';
 
 void main() {
   final channel = GrpcWebClientChannel.xhr(Uri.parse('http://localhost:8080'));
   final service = EchoServiceClient(channel);
   final app = EchoApp(service);
 
-  final button = querySelector('#send') as ButtonElement;
+  final button = document.querySelector('#send') as HTMLButtonElement;
   button.onClick.listen((e) async {
-    final msg = querySelector('#msg') as TextInputElement;
-    final value = msg.value!.trim();
+    final msg = document.querySelector('#msg') as HTMLInputElement;
+    final value = msg.value.trim();
     msg.value = '';
 
     if (value.isEmpty) return;

lib/grpc_or_grpcweb.dart

@@ -14,7 +14,7 @@
 // limitations under the License.
 
 import 'src/client/grpc_or_grpcweb_channel_grpc.dart'
-    if (dart.library.html) 'src/client/grpc_or_grpcweb_channel_web.dart';
+    if (dart.library.js_interop) 'src/client/grpc_or_grpcweb_channel_web.dart';
 import 'src/client/http2_channel.dart';
 import 'src/client/options.dart';
 

lib/src/client/transport/xhr_transport.dart

@@ -14,10 +14,11 @@
 // limitations under the License.
 
 import 'dart:async';
-import 'dart:html';
+import 'dart:js_interop';
 import 'dart:typed_data';
 
 import 'package:meta/meta.dart';
+import 'package:web/web.dart';
 
 import '../../client/call.dart';
 import '../../shared/message.dart';
@@ -30,7 +31,7 @@ import 'web_streams.dart';
 const _contentTypeKey = 'Content-Type';
 
 class XhrTransportStream implements GrpcTransportStream {
-  final HttpRequest _request;
+  final XMLHttpRequest _request;
   final ErrorHandler _onError;
   final Function(XhrTransportStream stream) _onDone;
   bool _headersReceived = false;
@@ -49,19 +50,20 @@ class XhrTransportStream implements GrpcTransportStream {
       {required ErrorHandler onError, required onDone})
       : _onError = onError,
         _onDone = onDone {
-    _outgoingMessages.stream
-        .map(frame)
-        .listen((data) => _request.send(data), cancelOnError: true);
+    _outgoingMessages.stream.map(frame).listen(
+        (data) => _request.send(Uint8List.fromList(data).toJS),
+        cancelOnError: true,
+        onError: _onError);
 
-    _request.onReadyStateChange.listen((data) {
+    _request.onReadyStateChange.listen((_) {
       if (_incomingProcessor.isClosed) {
         return;
       }
       switch (_request.readyState) {
-        case HttpRequest.HEADERS_RECEIVED:
+        case XMLHttpRequest.HEADERS_RECEIVED:
           _onHeadersReceived();
           break;
-        case HttpRequest.DONE:
+        case XMLHttpRequest.DONE:
           _onRequestDone();
           _close();
           break;
@@ -81,13 +83,11 @@ class XhrTransportStream implements GrpcTransportStream {
       if (_incomingProcessor.isClosed) {
         return;
       }
-      // Use response over responseText as most browsers don't support
-      // using responseText during an onProgress event.
-      final responseString = _request.response as String;
+      final responseText = _request.responseText;
       final bytes = Uint8List.fromList(
-              responseString.substring(_requestBytesRead).codeUnits)
+              responseText.substring(_requestBytesRead).codeUnits)
           .buffer;
-      _requestBytesRead = responseString.length;
+      _requestBytesRead = responseText.length;
       _incomingProcessor.add(bytes);
     });
 
@@ -122,9 +122,11 @@ class XhrTransportStream implements GrpcTransportStream {
     if (!_headersReceived && !_validateResponseState()) {
       return;
     }
-    if (_request.response == null) {
+    if (_request.status != 200) {
       _onError(
-          GrpcError.unavailable('XhrConnection request null response', null,
+          GrpcError.unavailable(
+              'Request failed with status: ${_request.status}',
+              null,
               _request.responseText),
           StackTrace.current);
       return;
@@ -153,20 +155,20 @@ class XhrClientConnection implements ClientConnection {
 
   @override
   String get authority => uri.authority;
+
   @override
   String get scheme => uri.scheme;
 
-  void _initializeRequest(HttpRequest request, Map<String, String> metadata) {
-    for (final header in metadata.keys) {
-      request.setRequestHeader(header, metadata[header]!);
-    }
+  void _initializeRequest(
+      XMLHttpRequest request, Map<String, String> metadata) {
+    metadata.forEach(request.setRequestHeader);
     // Overriding the mimetype allows us to stream and parse the data
     request.overrideMimeType('text/plain; charset=x-user-defined');
     request.responseType = 'text';
   }
 
   @visibleForTesting
-  HttpRequest createHttpRequest() => HttpRequest();
+  XMLHttpRequest createHttpRequest() => XMLHttpRequest();
 
   @override
   GrpcTransportStream makeRequest(String path, Duration? timeout,

pubspec.yaml

@@ -17,6 +17,7 @@ dependencies:
   http2: ^2.2.0
   protobuf: '>=2.0.0 <4.0.0'
   clock: ^1.1.1
+  web: ^1.1.0
 
 dev_dependencies:
   build_runner: ^2.0.0