Merge pull request modelcontextprotocol#560 from daidi/main

fix: Ensure _meta object is not lost when onprogress option is passed

Author: ihrpr

src/shared/protocol.test.ts

@@ -27,9 +27,11 @@ class MockTransport implements Transport {
 describe("protocol tests", () => {
  let protocol: Protocol<Request, Notification, Result>;
  let transport: MockTransport;
+ let sendSpy: jest.SpyInstance;
 
  beforeEach(() => {
  transport = new MockTransport();
+ sendSpy = jest.spyOn(transport, 'send');
  protocol = new (class extends Protocol<Request, Notification, Result> {
  protected assertCapabilityForMethod(): void {}
  protected assertNotificationCapability(): void {}
@@ -63,6 +65,130 @@ describe("protocol tests", () => {
  expect(oncloseMock).toHaveBeenCalled();
  });
 
+ describe("_meta preservation with onprogress", () => {
+ test("should preserve existing _meta when adding progressToken", async () => {
+ await protocol.connect(transport);
+ const request = { 
+ method: "example", 
+ params: {
+ data: "test",
+ _meta: {
+ customField: "customValue",
+ anotherField: 123
+ }
+ }
+ };
+ const mockSchema: ZodType<{ result: string }> = z.object({
+ result: z.string(),
+ });
+ const onProgressMock = jest.fn();
+ 
+ protocol.request(request, mockSchema, {
+ onprogress: onProgressMock,
+ });
+ 
+ expect(sendSpy).toHaveBeenCalledWith(expect.objectContaining({
+ method: "example",
+ params: {
+ data: "test",
+ _meta: {
+ customField: "customValue",
+ anotherField: 123,
+ progressToken: expect.any(Number)
+ }
+ },
+ jsonrpc: "2.0",
+ id: expect.any(Number)
+ }), expect.any(Object));
+ });
+
+ test("should create _meta with progressToken when no _meta exists", async () => {
+ await protocol.connect(transport);
+ const request = { 
+ method: "example", 
+ params: {
+ data: "test"
+ }
+ };
+ const mockSchema: ZodType<{ result: string }> = z.object({
+ result: z.string(),
+ });
+ const onProgressMock = jest.fn();
+ 
+ protocol.request(request, mockSchema, {
+ onprogress: onProgressMock,
+ });
+ 
+ expect(sendSpy).toHaveBeenCalledWith(expect.objectContaining({
+ method: "example",
+ params: {
+ data: "test",
+ _meta: {
+ progressToken: expect.any(Number)
+ }
+ },
+ jsonrpc: "2.0",
+ id: expect.any(Number)
+ }), expect.any(Object));
+ });
+
+ test("should not modify _meta when onprogress is not provided", async () => {
+ await protocol.connect(transport);
+ const request = { 
+ method: "example", 
+ params: {
+ data: "test",
+ _meta: {
+ customField: "customValue"
+ }
+ }
+ };
+ const mockSchema: ZodType<{ result: string }> = z.object({
+ result: z.string(),
+ });
+ 
+ protocol.request(request, mockSchema);
+ 
+ expect(sendSpy).toHaveBeenCalledWith(expect.objectContaining({
+ method: "example",
+ params: {
+ data: "test",
+ _meta: {
+ customField: "customValue"
+ }
+ },
+ jsonrpc: "2.0",
+ id: expect.any(Number)
+ }), expect.any(Object));
+ });
+
+ test("should handle params being undefined with onprogress", async () => {
+ await protocol.connect(transport);
+ const request = { 
+ method: "example"
+ };
+ const mockSchema: ZodType<{ result: string }> = z.object({
+ result: z.string(),
+ });
+ const onProgressMock = jest.fn();
+ 
+ protocol.request(request, mockSchema, {
+ onprogress: onProgressMock,
+ });
+ 
+ expect(sendSpy).toHaveBeenCalledWith(expect.objectContaining({
+ method: "example",
+ params: {
+ _meta: {
+ progressToken: expect.any(Number)
+ }
+ },
+ jsonrpc: "2.0",
+ id: expect.any(Number)
+ }), expect.any(Object));
+ });
+ });
+
  describe("progress notification timeout behavior", () => {
  beforeEach(() => {
  jest.useFakeTimers();

src/shared/protocol.ts

@@ -541,7 +541,10 @@ export abstract class Protocol<
  this._progressHandlers.set(messageId, options.onprogress);
  jsonrpcRequest.params = {
  ...request.params,
- _meta: { progressToken: messageId },
+ _meta: {
+ ...(request.params?._meta || {}),
+ progressToken: messageId
+ },
  };
  }