Danny Tuppeny
7a6352a9b1
Changes to support DAP in DDS introduced a subtle bug where we could send the `InitializedEvent` before the response to the `Initialize` request because `sendResponse` used a `Completer` and would delay adding the response to the stream until the next iteration of the task queue. Although there were comments stating this order must be preserved, there were no tests that verified this and it breaks VS Code (https://github.com/dart-lang/sdk/issues/52222). I've added tests for this, and changed how this works slightly so instead of using a `Completer` we pass in a "responseWriter" function that must write the response to the stream synchronously. Since the DDS path isn't using events yet and it would require a little more refactoring, I've used a Completer there and added a TODO. Fixes https://github.com/dart-lang/sdk/issues/52222. Change-Id: I1832126f5015b466c721dbda192da4b8a5d83b62 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/300601 Reviewed-by: Ben Konyi <bkonyi@google.com> Commit-Queue: Ben Konyi <bkonyi@google.com>
A package used to spawn the Dart Developer Service (DDS), which is used to communicate with a Dart VM Service instance and provide extended functionality to the core VM Service Protocol.
Functionality
Existing VM Service clients can issue both HTTP, websocket, and SSE requests to a running DDS instance as if it were an instance of the VM Service itself. If a request corresponds to an RPC defined in the VM Service Protocol, DDS will forward the request and return the response from the VM Service. Requests corresponding to an RPC defined in the DDS Protocol will be handled directly by the DDS instance.
SSE Support
For certain web clients it may be preferable or required to communicate with DDS using server-sent events (SSE). DDS has an SSE handler listening for requests on /$debugHandler.
SSE and package:vm_service example
import 'package:sse/sse.dart';
import 'package:vm_service/vm_service.dart';
void main() {
// Establish connection with DDS using SSE.
final ddsChannel = SseClient('${ddsUri}\$debugHandler');
// Wait for ddsChannel to be established
await ddsChannel.onOpen.first;
// Initialize VmService using the sink and stream from ddsChannel.
final vmService = VmService(
ddsChannel.stream,
(e) => ddsChannel.sink.add(e),
);
// You're ready to query DDS and the VM service!
print(await vmService.getVersion());
}