feat: async adapter

packages/rsocket-adapter-async/jest.config.ts

@@ -0,0 +1,20 @@
+import type { Config } from "@jest/types";
+import { pathsToModuleNameMapper } from "ts-jest/utils";
+import { compilerOptions } from "../../tsconfig.json";
+
+const config: Config.InitialOptions = {
+  preset: "ts-jest",
+  testRegex: "(\\/__tests__\\/.*|\\.(test|spec))\\.(ts)$",
+  moduleNameMapper: pathsToModuleNameMapper(compilerOptions.paths, {
+    // This has to match the baseUrl defined in tsconfig.json.
+    prefix: "<rootDir>/../../",
+  }),
+  modulePathIgnorePatterns: [
+    "<rootDir>/__tests__/test-utils",
+    "<rootDir>/__tests__/*.d.ts",
+  ],
+  collectCoverage: true,
+  collectCoverageFrom: ["<rootDir>/src/**/*.ts", "!**/node_modules/**"],
+};
+
+export default config;

packages/rsocket-adapter-async/package.json

@@ -0,0 +1,28 @@
+{
+  "name": "rsocket-adapter-async",
+  "version": "1.0.0",
+  "main": "dist/index",
+  "types": "dist/index",
+  "files": [
+    "dist"
+  ],
+  "scripts": {
+    "build": "yarn run clean && yarn run compile",
+    "clean": "rimraf -rf ./dist",
+    "compile": "tsc -p tsconfig.build.json",
+    "prepublishOnly": "yarn run build",
+    "test": "jest"
+  },
+  "dependencies": {
+    "rsocket-composite-metadata": "^1.0.0-alpha.3",
+    "rsocket-core": "^1.0.0-alpha.3",
+    "rsocket-messaging": "^1.0.0-alpha.3",
+    "rsocket-adapter-rxjs": "^1.0.0-alpha.3",
+    "rxjs": "^7.4.0",
+    "rxjs-for-await": "^1.0.0"
+  },
+  "devDependencies": {
+    "rimraf": "~3.0.2",
+    "typescript": "~4.5.2"
+  }
+}

packages/rsocket-adapter-async/src/__tests__/BufferingForwardingSubscriber.spec.ts

@@ -0,0 +1,95 @@
+import SubscribingAsyncIterator from "../lib/SubscribingAsyncIterator";
+import { mock } from "jest-mock-extended";
+import {
+  OnExtensionSubscriber,
+  OnNextSubscriber,
+  OnTerminalSubscriber,
+  Requestable,
+} from "rsocket-core";
+import { Codec } from "rsocket-messaging";
+import BufferingForwardingSubscriber from "../lib/BufferingForwardingSubscriber";
+import { Buffer } from "buffer";
+
+jest.useFakeTimers();
+
+describe("BufferingForwardingSubscriber", function () {
+  it("forwards all received onNext calls when received before subscription", async function () {
+    const mockSubscriber = mock<
+      OnNextSubscriber & OnTerminalSubscriber & OnExtensionSubscriber
+    >();
+    const testObj = new BufferingForwardingSubscriber();
+
+    testObj.onNext({ data: Buffer.from("1") }, false);
+    testObj.onNext({ data: Buffer.from("2") }, false);
+    testObj.onNext({ data: Buffer.from("3") }, true);
+
+    testObj.subscribe(mockSubscriber);
+
+    expect(mockSubscriber.onNext).toBeCalledWith(
+      { data: Buffer.from("1") },
+      false
+    );
+    expect(mockSubscriber.onNext).toBeCalledWith(
+      { data: Buffer.from("2") },
+      false
+    );
+    expect(mockSubscriber.onNext).toBeCalledWith(
+      { data: Buffer.from("3") },
+      true
+    );
+  });
+
+  it("forwards all received onNext calls when received after subscription", async function () {
+    const mockSubscriber = mock<
+      OnNextSubscriber & OnTerminalSubscriber & OnExtensionSubscriber
+    >();
+    const testObj = new BufferingForwardingSubscriber();
+
+    testObj.subscribe(mockSubscriber);
+
+    testObj.onNext({ data: Buffer.from("1") }, false);
+    testObj.onNext({ data: Buffer.from("2") }, false);
+    testObj.onNext({ data: Buffer.from("3") }, true);
+
+    expect(mockSubscriber.onNext).toBeCalledWith(
+      { data: Buffer.from("1") },
+      false
+    );
+    expect(mockSubscriber.onNext).toBeCalledWith(
+      { data: Buffer.from("2") },
+      false
+    );
+    expect(mockSubscriber.onNext).toBeCalledWith(
+      { data: Buffer.from("3") },
+      true
+    );
+  });
+
+  it("forwards all received onNext calls before forwarding subsequent onComplete", async function () {
+    const mockSubscriber = mock<
+      OnNextSubscriber & OnTerminalSubscriber & OnExtensionSubscriber
+    >();
+    const testObj = new BufferingForwardingSubscriber();
+
+    testObj.subscribe(mockSubscriber);
+
+    testObj.onNext({ data: Buffer.from("1") }, false);
+    testObj.onNext({ data: Buffer.from("2") }, false);
+    testObj.onNext({ data: Buffer.from("3") }, false);
+    testObj.onComplete();
+
+    expect(mockSubscriber.onNext).toBeCalledWith(
+      { data: Buffer.from("1") },
+      false
+    );
+    expect(mockSubscriber.onNext).toBeCalledWith(
+      { data: Buffer.from("2") },
+      false
+    );
+    expect(mockSubscriber.onNext).toBeCalledWith(
+      { data: Buffer.from("3") },
+      false
+    );
+    expect(mockSubscriber.onComplete).toBeCalledWith();
+  });
+});

packages/rsocket-adapter-async/src/__tests__/SubscribingAsyncIterator.spec.ts

@@ -0,0 +1,233 @@
+import SubscribingAsyncIterator from "../lib/SubscribingAsyncIterator";
+import { mock } from "jest-mock-extended";
+import { Cancellable, Requestable } from "rsocket-core";
+import { Codec } from "rsocket-messaging";
+
+jest.useFakeTimers();
+
+class StringCodec implements Codec<string> {
+  readonly mimeType: string = "text/plain";
+
+  decode(buffer: Buffer): string {
+    return buffer.toString();
+  }
+
+  encode(entity: string): Buffer {
+    return Buffer.from(entity);
+  }
+}
+
+describe("SubscribingAsyncIterator", function () {
+  it("iterates over emitted values", async function () {
+    let subscriber;
+    const subscription = mock<Requestable & Cancellable>({
+      request(requestN: number) {
+        for (let i = 0; i < requestN; i++) {
+          setTimeout(() => {
+            subscriber.onNext(
+              {
+                data: Buffer.from(`${i}`),
+                metadata: undefined,
+              },
+              i === requestN - 1
+            );
+          });
+        }
+      },
+    });
+    const requestSpy = jest.spyOn(subscription, "request");
+
+    const initialRequestN = 3;
+    subscriber = new SubscribingAsyncIterator(
+      subscription,
+      initialRequestN * 2,
+      new StringCodec()
+    );
+    subscription.request(initialRequestN);
+
+    jest.runAllTimers();
+
+    const values = [];
+    for await (const value of subscriber) {
+      jest.runAllTimers();
+      values.push(value);
+    }
+
+    expect(values).toStrictEqual(["0", "1", "2"]);
+    expect(requestSpy).toBeCalledTimes(1);
+  });
+
+  it("iterates over emitted values until onComplete", async function () {
+    let subscriber;
+    const subscription = mock<Requestable & Cancellable>({
+      request(requestN: number) {
+        for (let i = 0; i < requestN; i++) {
+          setTimeout(() => {
+            if (i === requestN - 1) {
+              subscriber.onComplete();
+            } else {
+              subscriber.onNext(
+                {
+                  data: Buffer.from(`${i}`),
+                  metadata: undefined,
+                },
+                false
+              );
+            }
+          });
+        }
+      },
+    });
+    const requestSpy = jest.spyOn(subscription, "request");
+
+    const initialRequestN = 3;
+    subscriber = new SubscribingAsyncIterator(
+      subscription,
+      initialRequestN * 2,
+      new StringCodec()
+    );
+    subscription.request(initialRequestN);
+
+    jest.runAllTimers();
+
+    const values = [];
+    for await (const value of subscriber) {
+      jest.runAllTimers();
+      values.push(value);
+    }
+
+    expect(values).toStrictEqual(["0", "1"]);
+    expect(requestSpy).toBeCalledTimes(1);
+  });
+
+  it("cancels when break statement reached", async function () {
+    let subscriber;
+    const subscription = mock<Requestable & Cancellable>({
+      request(requestN: number) {
+        for (let i = 0; i < requestN; i++) {
+          setTimeout(() => {
+            subscriber.onNext(
+              {
+                data: Buffer.from(`${i}`),
+                metadata: undefined,
+              },
+              i === requestN - 1
+            );
+          });
+        }
+      },
+    });
+    const requestSpy = jest.spyOn(subscription, "request");
+    const cancelSpy = jest.spyOn(subscription, "cancel");
+
+    const initialRequestN = 10;
+    subscriber = new SubscribingAsyncIterator(
+      subscription,
+      initialRequestN * 2,
+      new StringCodec()
+    );
+    subscription.request(initialRequestN);
+
+    jest.runAllTimers();
+
+    const values = [];
+    for await (const value of subscriber) {
+      if (values.length == 2) {
+        break;
+      }
+      jest.runAllTimers();
+      values.push(value);
+    }
+
+    expect(values).toStrictEqual(["0", "1"]);
+    expect(requestSpy).toBeCalledTimes(1);
+    expect(requestSpy).toBeCalledWith(10);
+    expect(cancelSpy).toBeCalledTimes(1);
+  });
+
+  it("ends and throws with emitted exception", async function () {
+    let subscriber;
+    const expectedError = new Error("test error");
+    const subscription = mock<Requestable & Cancellable>({
+      request(requestN: number) {
+        setTimeout(() => {
+          subscriber.onError(expectedError);
+        });
+      },
+    });
+    const requestSpy = jest.spyOn(subscription, "request");
+
+    const initialRequestN = 10;
+    subscriber = new SubscribingAsyncIterator(
+      subscription,
+      initialRequestN * 2,
+      new StringCodec()
+    );
+    subscription.request(initialRequestN);
+
+    jest.runAllTimers();
+
+    const values = [];
+
+    let capturedError;
+    try {
+      for await (const value of subscriber) {
+        jest.runAllTimers();
+        values.push(value);
+      }
+    } catch (error) {
+      capturedError = error;
+    }
+
+    expect(capturedError).toBe(expectedError);
+    expect(values).toStrictEqual([]);
+    expect(requestSpy).toBeCalledWith(10);
+  });
+
+  it("cancels on exception processing emitted value", async function () {
+    let subscriber;
+    const subscription = mock<Requestable & Cancellable>({
+      request(requestN: number) {
+        for (let i = 0; i < requestN; i++) {
+          setTimeout(() => {
+            subscriber.onNext(
+              {
+                data: Buffer.from(`${i}`),
+                metadata: undefined,
+              },
+              i === requestN - 1
+            );
+          });
+        }
+      },
+    });
+    const requestSpy = jest.spyOn(subscription, "request");
+    const cancelSpy = jest.spyOn(subscription, "cancel");
+
+    const initialRequestN = 10;
+    subscriber = new SubscribingAsyncIterator(
+      subscription,
+      initialRequestN * 2,
+      new StringCodec()
+    );
+    subscription.request(initialRequestN);
+
+    jest.runAllTimers();
+
+    const values = [];
+    try {
+      for await (const value of subscriber) {
+        if (values.length == 2) {
+          throw new Error("test error");
+        }
+        values.push(value);
+        jest.runAllTimers();
+      }
+    } catch (e) {}
+
+    expect(values).toStrictEqual(["0", "1"]);
+    expect(requestSpy).toBeCalledTimes(1);
+    expect(requestSpy).toBeCalledWith(10);
+    expect(cancelSpy).toBeCalledTimes(1);
+  });
+});