feat(27254): implement new remote-feature-flag-controller

packages/remote-feature-flag-controller/CHANGELOG.md

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+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [0.1.0]
+
+### Added
+
+- Initial release
+
+[Unreleased]: https://github.com/MetaMask/core/

packages/remote-feature-flag-controller/LICENSE

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+MIT License
+
+Copyright (c) 2024 MetaMask
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

packages/remote-feature-flag-controller/README.md

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+# `@metamask/example-controllers`
+
+This package is designed to illustrate best practices for controller packages and controller files, including tests.
+
+## Installation
+
+`yarn add @metamask/example-controllers`
+
+or
+
+`npm install @metamask/example-controllers`
+
+## Contributing
+
+This package is part of a monorepo. Instructions for contributing can be found in the [monorepo README](https://github.com/MetaMask/core#readme).

packages/remote-feature-flag-controller/jest.config.js

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+/*
+ * For a detailed explanation regarding each configuration property and type check, visit:
+ * https://jestjs.io/docs/configuration
+ */
+
+const merge = require('deepmerge');
+const path = require('path');
+
+const baseConfig = require('../../jest.config.packages');
+
+const displayName = path.basename(__dirname);
+
+module.exports = merge(baseConfig, {
+  // The display name when running multiple projects
+  displayName,
+
+  // An object that configures minimum threshold enforcement for coverage results
+  coverageThreshold: {
+    global: {
+      branches: 100,
+      functions: 100,
+      lines: 100,
+      statements: 100,
+    },
+  },
+});

packages/remote-feature-flag-controller/package.json

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+{
+  "name": "@metamask/remote-feature-flag-controller",
+  "version": "0.0.1",
+  "private": true,
+  "description": "Controller with caching, fallback, and privacy for managing feature flags via ClientConfigAPI",
+  "keywords": [
+    "MetaMask",
+    "Ethereum"
+  ],
+  "homepage": "https://github.com/MetaMask/core/tree/main/packages/remote-feature-flag-controller#readme",
+  "bugs": {
+    "url": "https://github.com/MetaMask/core/issues"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/MetaMask/core.git"
+  },
+  "license": "MIT",
+  "sideEffects": false,
+  "exports": {
+    ".": {
+      "import": {
+        "types": "./dist/index.d.mts",
+        "default": "./dist/index.mjs"
+      },
+      "require": {
+        "types": "./dist/index.d.cts",
+        "default": "./dist/index.cjs"
+      }
+    },
+    "./package.json": "./package.json"
+  },
+  "main": "./dist/index.cjs",
+  "types": "./dist/index.d.cts",
+  "files": [
+    "dist/"
+  ],
+  "scripts": {
+    "build": "ts-bridge --project tsconfig.build.json --verbose --clean --no-references",
+    "build:docs": "typedoc",
+    "changelog:update": "../../scripts/update-changelog.sh @metamask/remote-feature-flag-controllers",
+    "changelog:validate": "../../scripts/validate-changelog.sh @metamask/remote-feature-flag-controllers",
+    "publish:preview": "yarn npm publish --tag preview",
+    "since-latest-release": "../../scripts/since-latest-release.sh",
+    "test": "NODE_OPTIONS=--experimental-vm-modules jest --reporters=jest-silent-reporter",
+    "test:clean": "NODE_OPTIONS=--experimental-vm-modules jest --clearCache",
+    "test:verbose": "NODE_OPTIONS=--experimental-vm-modules jest --verbose",
+    "test:watch": "NODE_OPTIONS=--experimental-vm-modules jest --watch"
+  },
+  "dependencies": {
+    "@lavamoat/allow-scripts": "^3.3.0",
+    "@metamask/base-controller": "^7.0.2",
+    "@metamask/utils": "^10.0.0"
+  },
+  "devDependencies": {
+    "@metamask/auto-changelog": "^3.4.4",
+    "@metamask/controller-utils": "^11.4.3",
+    "@types/jest": "^27.4.1",
+    "deepmerge": "^4.2.2",
+    "jest": "^27.5.1",
+    "nock": "^13.3.1",
+    "ts-jest": "^27.1.4",
+    "typedoc": "^0.24.8",
+    "typedoc-plugin-missing-exports": "^2.0.0",
+    "typescript": "~5.2.2"
+  },
+  "engines": {
+    "node": "^18.18 || >=20"
+  },
+  "publishConfig": {
+    "access": "public",
+    "registry": "https://registry.npmjs.org/"
+  }
+}

packages/remote-feature-flag-controller/src/client-config-api-service/abstract-client-config-api-service.ts

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+import type { PublicInterface } from '@metamask/utils';
+
+import type { ClientConfigApiService } from './client-config-api-service';
+
+/**
+ * A service object responsible for fetching feature flags.
+ */
+export type AbstractClientConfigApiService =
+  PublicInterface<ClientConfigApiService>;

packages/remote-feature-flag-controller/src/client-config-api-service/client-config-api-service.test.ts

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+import type { FeatureFlags } from '../remote-feature-flag-controller-types';
+import {
+  ClientType,
+  DistributionType,
+  EnvironmentType,
+} from '../remote-feature-flag-controller-types';
+import { ClientConfigApiService } from './client-config-api-service';
+
+const BASE_URL = 'https://client-config.api.cx.metamask.io/v1';
+
+describe('ClientConfigApiService', () => {
+  let originalConsoleError: typeof console.error;
+  let clientConfigApiService: ClientConfigApiService;
+  let mockFetch: jest.Mock;
+
+  const mockFeatureFlags: FeatureFlags = {
+    feature1: false,
+    feature2: { chrome: '<109' },
+  };
+
+  const networkError = new Error('Network error');
+  Object.assign(networkError, {
+    response: {
+      status: 503,
+      statusText: 'Service Unavailable',
+    },
+  });
+
+  beforeEach(() => {
+    mockFetch = jest.fn();
+    clientConfigApiService = new ClientConfigApiService({ fetch: mockFetch });
+  });
+
+  beforeAll(() => {
+    originalConsoleError = console.error;
+    console.error = jest
+      .spyOn(console, 'error')
+      .mockImplementation() as unknown as typeof console.error;
+  });
+
+  afterAll(() => {
+    console.error = originalConsoleError;
+  });
+
+  describe('fetchFlags', () => {
+    it('should successfully fetch and return feature flags', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        status: 200,
+        statusText: 'OK',
+        json: async () => mockFeatureFlags,
+      });
+
+      const result = await clientConfigApiService.fetchFlags(
+        ClientType.Extension,
+        DistributionType.Main,
+        EnvironmentType.Production,
+      );
+
+      expect(mockFetch).toHaveBeenCalledWith(
+        `${BASE_URL}/flags?client=extension&distribution=main&environment=prod`,
+        { cache: 'no-cache' },
+      );
+
+      expect(result).toStrictEqual({
+        error: false,
+        message: 'Success',
+        statusCode: '200',
+        statusText: 'OK',
+        cachedData: mockFeatureFlags,
+        cacheTimestamp: expect.any(Number),
+      });
+    });
+
+    it('should return cached data when API request fails and cached data is available', async () => {
+      const cachedData = { feature3: true };
+      const cacheTimestamp = Date.now();
+
+      mockFetch.mockRejectedValueOnce(networkError);
+
+      const result = await clientConfigApiService.fetchFlags(
+        ClientType.Extension,
+        DistributionType.Main,
+        EnvironmentType.Production,
+        cachedData,
+        cacheTimestamp,
+      );
+
+      expect(result).toStrictEqual({
+        error: true,
+        message: 'Network error',
+        statusCode: '503',
+        statusText: 'Service Unavailable',
+        cachedData,
+        cacheTimestamp,
+      });
+    });
+
+    it('should return empty object when API request fails and cached data is not available', async () => {
+      mockFetch.mockRejectedValueOnce(networkError);
+      const result = await clientConfigApiService.fetchFlags(
+        ClientType.Extension,
+        DistributionType.Main,
+        EnvironmentType.Production,
+      );
+      const currentTime = Date.now();
+      expect(result).toStrictEqual({
+        error: true,
+        message: 'Network error',
+        statusCode: '503',
+        statusText: 'Service Unavailable',
+        cachedData: {},
+        cacheTimestamp: currentTime,
+      });
+    });
+
+    it('should handle non-200 responses without cache data', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: false,
+        status: 404,
+        statusText: 'Not Found',
+      });
+
+      const result = await clientConfigApiService.fetchFlags(
+        ClientType.Extension,
+        DistributionType.Main,
+        EnvironmentType.Production,
+      );
+      const currentTime = Date.now();
+      expect(result).toStrictEqual({
+        error: true,
+        message: 'Failed to fetch flags',
+        statusCode: '404',
+        statusText: 'Not Found',
+        cachedData: {},
+        cacheTimestamp: currentTime,
+      });
+    });
+
+    it('should handle non-200 responses with cache data', async () => {
+      const cachedData = { feature3: true };
+      const cacheTimestamp = Date.now();
+      mockFetch.mockResolvedValueOnce({
+        ok: false,
+        status: 404,
+        statusText: 'Not Found',
+      });
+
+      const result = await clientConfigApiService.fetchFlags(
+        ClientType.Extension,
+        DistributionType.Main,
+        EnvironmentType.Production,
+        cachedData,
+        cacheTimestamp,
+      );
+      const currentTime = Date.now();
+      expect(result).toStrictEqual({
+        error: true,
+        message: 'Failed to fetch flags',
+        statusCode: '404',
+        statusText: 'Not Found',
+        cachedData,
+        cacheTimestamp: currentTime,
+      });
+    });
+
+    it('should handle invalid API responses', async () => {
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        status: 200,
+        statusText: 'OK',
+        json: async () => null, // Invalid response
+      });
+
+      const result = await clientConfigApiService.fetchFlags(
+        ClientType.Extension,
+        DistributionType.Main,
+        EnvironmentType.Production,
+      );
+
+      const currentTime = Date.now();
+      expect(result).toStrictEqual({
+        error: true,
+        message: 'Invalid API response',
+        statusCode: null,
+        statusText: null,
+        cachedData: {},
+        cacheTimestamp: currentTime,
+      });
+    });
+  });
+});