add first version of divviup client

package.json

@@ -7,6 +7,7 @@
     "./packages/vdaf",
     "./packages/prio3",
     "./packages/dap",
+    "./packages/divviup",
     "./packages/interop-test-client"
   ],
   "scripts": {

packages/dap/src/index.ts

@@ -1,3 +1,10 @@
-export { DAPClient, DAPClient as default } from "./client";
+export {
+  DAPClient,
+  DAPClient as default,
+  KnownVdafSpec,
+  VdafMeasurement,
+} from "./client";
 export { DAPError } from "./errors";
 export type { ReportOptions } from "./client";
+export { TaskId } from "./taskId";
+export { HpkeConfig, HpkeConfigList } from "./hpkeConfig";

packages/divviup/package.json

@@ -0,0 +1,31 @@
+{
+  "name": "divviup",
+  "version": "0.1.0",
+  "description": "",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "source": "src/index.ts",
+  "module": "dist/module.js",
+  "browser": "dist/browser.js",
+  "type": "module",
+  "license": "MPL-2.0",
+  "scripts": {
+    "clean": "rm -rf dist/*",
+    "build:clean": "npm run clean && npm run build",
+    "build": "npm run build:web && npm run build:node",
+    "build:web": "esbuild browser=src/index.ts --bundle --loader:.wasm=binary --format=esm --outdir=dist --sourcemap --minify",
+    "build:node": "tsc -p ./tsconfig.json",
+    "docs": "typedoc src",
+    "test": "mocha \"src/**/*.spec.ts\"",
+    "lint": "eslint src --ext .ts && prettier -c src",
+    "format": "prettier -w src",
+    "check": "tsc --noEmit -p ./tsconfig.json",
+    "test:coverage": "c8 npm test"
+  },
+  "dependencies": {
+    "@divviup/dap": "^0.1.0"
+  },
+  "devDependencies": {
+    "hpke": "^0.5.0"
+  }
+}

packages/divviup/src/index.spec.ts

@@ -0,0 +1,189 @@
+import assert from "assert";
+import { inspect } from "node:util";
+import { DivviupClient, sendMeasurement } from ".";
+import { HpkeConfigList, HpkeConfig, TaskId } from "@divviup/dap";
+import * as hpke from "hpke";
+
+describe("DivviupClient", () => {
+  it("fetches task from an id", async () => {
+    const taskId = TaskId.random().toString();
+    const client = new DivviupClient(taskId);
+    const fetch = mockFetch({
+      ...dapMocks(taskId),
+      [`https://api.staging.divviup.org/tasks/${taskId}`]: [
+        {
+          status: 200,
+          body: JSON.stringify(task(taskId)),
+          contentType: "application/json",
+        },
+      ],
+    });
+    client.fetch = fetch;
+    await client.sendMeasurement(10);
+    assert.equal(fetch.calls.length, 4);
+    assert.deepEqual(fetch.callStrings(), [
+      `GET https://api.staging.divviup.org/tasks/${taskId}`,
+      `GET https://a.example.com/v1/hpke_config?task_id=${taskId}`,
+      `GET https://b.example.com/dap/hpke_config?task_id=${taskId}`,
+      `PUT https://a.example.com/v1/tasks/${taskId}/reports`,
+    ]);
+  });
+
+  it("fetches task from a task url", async () => {
+    const taskId = TaskId.random().toString();
+    const client = new DivviupClient(
+      `https://production.divvi.up/v3/different-url/${taskId}.json`,
+    );
+    const fetch = mockFetch({
+      ...dapMocks(taskId),
+      [`https://production.divvi.up/v3/different-url/${taskId}.json`]: [
+        {
+          status: 200,
+          body: JSON.stringify(task(taskId)),
+          contentType: "application/json",
+        },
+      ],
+    });
+    client.fetch = fetch;
+    await client.sendMeasurement(10);
+    assert.equal(fetch.calls.length, 4);
+    assert.deepEqual(fetch.callStrings(), [
+      `GET https://production.divvi.up/v3/different-url/${taskId}.json`,
+      `GET https://a.example.com/v1/hpke_config?task_id=${taskId}`,
+      `GET https://b.example.com/dap/hpke_config?task_id=${taskId}`,
+      `PUT https://a.example.com/v1/tasks/${taskId}/reports`,
+    ]);
+  });
+});
+
+describe("sendMeasurement", () => {
+  it("fetches task from an id", async () => {
+    const taskId = TaskId.random().toString();
+    const fetch = mockFetch({
+      ...dapMocks(taskId),
+      [`https://api.staging.divviup.org/tasks/${taskId}`]: [
+        {
+          status: 200,
+          body: JSON.stringify(task(taskId)),
+          contentType: "application/json",
+        },
+      ],
+    });
+
+    await sendMeasurement(taskId, 10, fetch);
+
+    assert.equal(fetch.calls.length, 4);
+    assert.deepEqual(fetch.callStrings(), [
+      `GET https://api.staging.divviup.org/tasks/${taskId}`,
+      `GET https://a.example.com/v1/hpke_config?task_id=${taskId}`,
+      `GET https://b.example.com/dap/hpke_config?task_id=${taskId}`,
+      `PUT https://a.example.com/v1/tasks/${taskId}/reports`,
+    ]);
+  });
+});
+
+function dapMocks(taskId: string) {
+  return {
+    [`https://a.example.com/v1/hpke_config?task_id=${taskId}`]: [
+      hpkeConfigResponse(),
+    ],
+
+    [`https://b.example.com/dap/hpke_config?task_id=${taskId}`]: [
+      hpkeConfigResponse(),
+    ],
+
+    [`https://api.staging.divviup.org/tasks/${taskId}`]: [
+      {
+        status: 200,
+        body: JSON.stringify(task(taskId)),
+        contentType: "application/json",
+      },
+    ],
+    [`https://a.example.com/v1/tasks/${taskId}/reports`]: [{ status: 201 }],
+  };
+}
+
+interface Fetch {
+  (input: RequestInfo, init?: RequestInit | undefined): Promise<Response>;
+  calls: [RequestInfo, RequestInit | undefined][];
+  callStrings(): string[];
+}
+
+interface ResponseSpec {
+  body?: Buffer | Uint8Array | number[] | string;
+  contentType?: string;
+  status?: number;
+}
+
+function mockFetch(mocks: { [url: string]: ResponseSpec[] }): Fetch {
+  function fakeFetch(
+    input: RequestInfo,
+    init?: RequestInit | undefined,
+  ): Promise<Response> {
+    fakeFetch.calls.push([input, init]);
+    const responseSpec = mocks[input.toString()];
+    const response = responseSpec?.shift();
+
+    if (!response) {
+      throw new Error(
+        `received unhandled request.\n\nurl: ${input.toString()}.\n\nmocks: ${inspect(
+          mocks,
+        ).slice(1, -1)}`,
+      );
+    }
+
+    return Promise.resolve(
+      new Response(Buffer.from(response.body || ""), {
+        status: response.status || 200,
+        headers: { "Content-Type": response.contentType || "text/plain" },
+      }),
+    );
+  }
+
+  fakeFetch.calls = [] as [RequestInfo, RequestInit | undefined][];
+  fakeFetch.callStrings = function () {
+    return this.calls.map((x) => `${x[1]?.method || "GET"} ${x[0].toString()}`);
+  };
+  return fakeFetch;
+}
+
+function task(taskId: string): {
+  vdaf: {
+    type: "sum";
+    bits: number;
+  };
+  helper: string;
+  leader: string;
+  id: string;
+  time_precision_seconds: number;
+} {
+  return {
+    vdaf: {
+      type: "sum",
+      bits: 16,
+    },
+    leader: "https://a.example.com/v1",
+    helper: "https://b.example.com/dap/",
+    id: taskId,
+    time_precision_seconds: 1,
+  };
+}
+
+function hpkeConfigResponse(config = buildHpkeConfigList()): ResponseSpec {
+  return {
+    body: config.encode(),
+    contentType: "application/dap-hpke-config-list",
+  };
+}
+
+function buildHpkeConfigList(): HpkeConfigList {
+  return new HpkeConfigList([
+    new HpkeConfig(
+      Math.floor(Math.random() * 255),
+      hpke.Kem.DhP256HkdfSha256,
+      hpke.Kdf.Sha256,
+      hpke.Aead.AesGcm128,
+      Buffer.from(new hpke.Keypair(hpke.Kem.DhP256HkdfSha256).public_key),
+    ),
+  ]);
+}

packages/divviup/src/index.ts

@@ -0,0 +1,78 @@
+import { DAPClient } from "@divviup/dap";
+import { KnownVdafSpec } from "@divviup/dap/dist/client";
+
+type Fetch = (
+  input: RequestInfo,
+  init?: RequestInit | undefined,
+) => Promise<Response>;
+
+interface PublicTask {
+  id: string;
+  vdaf: KnownVdafSpec;
+  leader: string;
+  helper: string;
+  time_precision_seconds: number;
+}
+
+type AnyMeasurement = number | bigint | boolean;
+type GenericDAPClient = DAPClient<KnownVdafSpec, AnyMeasurement>;
+
+export class DivviupClient {
+  #baseUrl = new URL("https://api.staging.divviup.org/tasks");
+  #fetch: Fetch = globalThis.fetch.bind(globalThis);
+  #dapClient: null | GenericDAPClient = null;
+  #taskUrl: URL;
+
+  /** @internal */
+  set fetch(fetch: Fetch) {
+    this.#fetch = fetch;
+    if (this.#dapClient) this.#dapClient.fetch = fetch;
+  }
+
+  constructor(urlOrTaskId: string | URL) {
+    if (typeof urlOrTaskId === "string") {
+      try {
+        this.#taskUrl = new URL(urlOrTaskId);
+      } catch (e) {
+        this.#taskUrl = new URL(`${this.#baseUrl.toString()}/${urlOrTaskId}`);
+      }
+    } else {
+      this.#taskUrl = urlOrTaskId;
+    }
+  }
+
+  private async taskClient(): Promise<GenericDAPClient> {
+    if (this.#dapClient) return this.#dapClient;
+    const response = await this.#fetch(this.#taskUrl.toString());
+    const task = (await response.json()) as PublicTask;
+    const { leader, helper, vdaf, id, time_precision_seconds } = task;
+    const client = new DAPClient({
+      taskId: id,
+      leader,
+      helper,
+      id,
+      timePrecisionSeconds: time_precision_seconds,
+      ...vdaf,
+    });
+    client.fetch = this.#fetch;
+    this.#dapClient = client;
+    return client;
+  }
+
+  async sendMeasurement(measurement: AnyMeasurement) {
+    const client = await this.taskClient();
+    return client.sendMeasurement(measurement);
+  }
+}
+
+export default DivviupClient;
+
+export async function sendMeasurement(
+  urlOrTaskId: string | URL,
+  measurement: AnyMeasurement,
+  fetch?: Fetch,
+) {
+  const client = new DivviupClient(urlOrTaskId);
+  if (fetch) client.fetch = fetch;
+  return client.sendMeasurement(measurement);
+}

packages/divviup/tsconfig.json

@@ -0,0 +1,8 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "dist"
+  },
+  "include": ["./src/*.ts"]
+}

packages/divviup/typedoc.json

@@ -0,0 +1,5 @@
+{
+  "extends": ["../../typedoc.base.json"],
+  "entryPointStrategy": "expand",
+  "entryPoints": ["src/index.ts"]
+}