Expose LiveObjects as a plugin

Base code, tests and build setup for new LiveObjects plugin. Adds a new
`.liveObjects` property for RealtimeChannel.

Plugin setup is based on Web Push plugin PR [1], and CDN setup for Push
plugin PR [2].

Resolves DTP-947

[1] #1775
[2] #1861

Gruntfile.js

@@ -73,7 +73,14 @@ module.exports = function (grunt) {
     });
   });
 
-  grunt.registerTask('build', ['checkGitSubmodules', 'webpack:all', 'build:browser', 'build:node', 'build:push']);
+  grunt.registerTask('build', [
+    'checkGitSubmodules',
+    'webpack:all',
+    'build:browser',
+    'build:node',
+    'build:push',
+    'build:liveobjects',
+  ]);
 
   grunt.registerTask('all', ['build', 'requirejs']);
 
@@ -138,9 +145,26 @@ module.exports = function (grunt) {
       });
   });
 
+  grunt.registerTask('build:liveobjects', function () {
+    var done = this.async();
+
+    Promise.all([
+      esbuild.build(esbuildConfig.liveObjectsPluginConfig),
+      esbuild.build(esbuildConfig.liveObjectsPluginCdnConfig),
+      esbuild.build(esbuildConfig.minifiedLiveObjectsPluginCdnConfig),
+    ])
+      .then(() => {
+        done(true);
+      })
+      .catch((err) => {
+        done(err);
+      });
+  });
+
   grunt.registerTask('test:webserver', 'Launch the Mocha test web server on http://localhost:3000/', [
     'build:browser',
     'build:push',
+    'build:liveobjects',
     'checkGitSubmodules',
     'mocha:webserver',
   ]);

README.md

@@ -586,6 +586,41 @@ The Push plugin is developed as part of the Ably client library, so it is availa
 
 For more information on publishing push notifcations over Ably, see the [Ably push documentation](https://ably.com/docs/push).
 
+### Live Objects functionality
+
+Live Objects functionality is supported for Realtime clients via the LiveObjects plugin. In order to use Live Objects, you must pass in the plugin via client options.
+
+```javascript
+import * as Ably from 'ably';
+import LiveObjects from 'ably/liveobjects';
+
+const client = new Ably.Realtime({
+  ...options,
+  plugins: { LiveObjects },
+});
+```
+
+LiveObjects plugin also works with the [Modular variant](#modular-tree-shakable-variant) of the library.
+
+Alternatively, you can load the LiveObjects plugin directly in your HTML using `script` tag (in case you can't use a package manager):
+
+```html
+<script src="https://cdn.ably.com/lib/liveobjects.umd.min-2.js"></script>
+```
+
+When loaded this way, the LiveObjects plugin will be available on the global object via the `AblyLiveObjectsPlugin` property, so you will need to pass it to the Ably instance as follows:
+
+```javascript
+const client = new Ably.Realtime({
+  ...options,
+  plugins: { LiveObjects: AblyLiveObjectsPlugin },
+});
+```
+
+The LiveObjects plugin is developed as part of the Ably client library, so it is available for the same versions as the Ably client library itself. It also means that it follows the same semantic versioning rules as they were defined for [the Ably client library](#for-browsers). For example, to lock into a major or minor version of the LiveObjects plugin, you can specify a specific version number such as https://cdn.ably.com/lib/liveobjects.umd.min-2.js for all v2._ versions, or https://cdn.ably.com/lib/liveobjects.umd.min-2.4.js for all v2.4._ versions, or you can lock into a single release with https://cdn.ably.com/lib/liveobjects.umd.min-2.4.0.js. Note you can load the non-minified version by omitting `.min` from the URL such as https://cdn.ably.com/lib/liveobjects.umd-2.js.
+
+For more information about Live Objects product, see the [Ably Live Objects documentation](https://ably.com/docs/products/liveobjects).
+
 ## Delta Plugin
 
 From version 1.2 this client library supports subscription to a stream of Vcdiff formatted delta messages from the Ably service. For certain applications this can bring significant data efficiency savings.

ably.d.ts

@@ -623,6 +623,11 @@ export interface CorePlugins {
    * A plugin which allows the client to be the target of push notifications.
    */
   Push?: unknown;
+
+  /**
+   * A plugin which allows the client to use LiveObjects functionality at {@link RealtimeChannel.liveObjects}.
+   */
+  LiveObjects?: unknown;
 }
 
 /**
@@ -2010,6 +2015,11 @@ export declare interface PushChannel {
   listSubscriptions(params?: Record<string, string>): Promise<PaginatedResult<PushChannelSubscription>>;
 }
 
+/**
+ * Enables the LiveObjects state to be subscribed to for a channel.
+ */
+export declare interface LiveObjects {}
+
 /**
  * Enables messages to be published and historic messages to be retrieved for a channel.
  */
@@ -2139,6 +2149,10 @@ export declare interface RealtimeChannel extends EventEmitter<channelEventCallba
    * A {@link RealtimePresence} object.
    */
   presence: RealtimePresence;
+  /**
+   * A {@link LiveObjects} object.
+   */
+  liveObjects: LiveObjects;
   /**
    * Attach to this channel ensuring the channel is created in the Ably system and all messages published on the channel are received by any channel listeners registered using {@link RealtimeChannel.subscribe | `subscribe()`}. Any resulting channel state change will be emitted to any listeners registered using the {@link EventEmitter.on | `on()`} or {@link EventEmitter.once | `once()`} methods. As a convenience, `attach()` is called implicitly if {@link RealtimeChannel.subscribe | `subscribe()`} for the channel is called, or {@link RealtimePresence.enter | `enter()`} or {@link RealtimePresence.subscribe | `subscribe()`} are called on the {@link RealtimePresence} object for this channel.
    *

grunt/esbuild/build.js

@@ -77,6 +77,28 @@ const minifiedPushPluginCdnConfig = {
   minify: true,
 };
 
+const liveObjectsPluginConfig = {
+  ...createBaseConfig(),
+  entryPoints: ['src/plugins/liveobjects/index.ts'],
+  plugins: [umdWrapper.default({ libraryName: 'AblyLiveObjectsPlugin', amdNamedModule: false })],
+  outfile: 'build/liveobjects.js',
+};
+
+const liveObjectsPluginCdnConfig = {
+  ...createBaseConfig(),
+  entryPoints: ['src/plugins/liveobjects/index.ts'],
+  plugins: [umdWrapper.default({ libraryName: 'AblyLiveObjectsPlugin', amdNamedModule: false })],
+  outfile: 'build/liveobjects.umd.js',
+};
+
+const minifiedLiveObjectsPluginCdnConfig = {
+  ...createBaseConfig(),
+  entryPoints: ['src/plugins/liveobjects/index.ts'],
+  plugins: [umdWrapper.default({ libraryName: 'AblyLiveObjectsPlugin', amdNamedModule: false })],
+  outfile: 'build/liveobjects.umd.min.js',
+  minify: true,
+};
+
 module.exports = {
   webConfig,
   minifiedWebConfig,
@@ -85,4 +107,7 @@ module.exports = {
   pushPluginConfig,
   pushPluginCdnConfig,
   minifiedPushPluginCdnConfig,
+  liveObjectsPluginConfig,
+  liveObjectsPluginCdnConfig,
+  minifiedLiveObjectsPluginCdnConfig,
 };

liveobjects.d.ts

@@ -0,0 +1,28 @@
+// The ESLint warning is triggered because we only use these types in a documentation comment.
+/* eslint-disable no-unused-vars, @typescript-eslint/no-unused-vars */
+import { RealtimeClient } from './ably';
+import { BaseRealtime } from './modular';
+/* eslint-enable no-unused-vars, @typescript-eslint/no-unused-vars */
+
+/**
+ * Provides a {@link RealtimeClient} instance with the ability to use LiveObjects functionality.
+ *
+ * To create a client that includes this plugin, include it in the client options that you pass to the {@link RealtimeClient.constructor}:
+ *
+ * ```javascript
+ * import { Realtime } from 'ably';
+ * import LiveObjects from 'ably/liveobjects';
+ * const realtime = new Realtime({ ...options, plugins: { LiveObjects } });
+ * ```
+ *
+ * The LiveObjects plugin can also be used with a {@link BaseRealtime} client
+ *
+ * ```javascript
+ * import { BaseRealtime, WebSocketTransport, FetchRequest } from 'ably/modular';
+ * import LiveObjects from 'ably/liveobjects';
+ * const realtime = new BaseRealtime({ ...options, plugins: { WebSocketTransport, FetchRequest, LiveObjects } });
+ * ```
+ */
+declare const LiveObjects: any;
+
+export = LiveObjects;

package.json

@@ -29,13 +29,18 @@
     "./push": {
       "types": "./push.d.ts",
       "import": "./build/push.js"
+    },
+    "./liveobjects": {
+      "types": "./liveobjects.d.ts",
+      "import": "./build/liveobjects.js"
     }
   },
   "files": [
     "build/**",
     "ably.d.ts",
-    "push.d.ts",
+    "liveobjects.d.ts",
     "modular.d.ts",
+    "push.d.ts",
     "resources/**",
     "src/**",
     "react/**"
@@ -138,7 +143,7 @@
     "start:react": "npx vite serve",
     "grunt": "grunt",
     "test": "npm run test:node",
-    "test:node": "npm run build:node && npm run build:push && mocha",
+    "test:node": "npm run build:node && npm run build:push && npm run build:liveobjects && mocha",
     "test:node:skip-build": "mocha",
     "test:webserver": "grunt test:webserver",
     "test:playwright": "node test/support/runPlaywrightTests.js",
@@ -152,6 +157,7 @@
     "build:react:mjs": "tsc --project src/platform/react-hooks/tsconfig.mjs.json && cp src/platform/react-hooks/res/package.mjs.json react/mjs/package.json",
     "build:react:cjs": "tsc --project src/platform/react-hooks/tsconfig.cjs.json && cp src/platform/react-hooks/res/package.cjs.json react/cjs/package.json",
     "build:push": "grunt build:push",
+    "build:liveobjects": "grunt build:liveobjects",
     "requirejs": "grunt requirejs",
     "lint": "eslint .",
     "lint:fix": "eslint --fix .",

scripts/cdn_deploy.js

@@ -21,7 +21,7 @@ async function run() {
     // Comma separated directories (relative to `path`) to exclude from upload
     excludeDirs: 'node_modules,.git',
     // Regex to match files against for upload
-    fileRegex: '^(ably|push\\.umd)?(\\.min)?\\.js$',
+    fileRegex: '^(ably|push\\.umd|liveobjects\\.umd)?(\\.min)?\\.js$',
     ...argv,
   };
 

scripts/moduleReport.ts

@@ -6,7 +6,7 @@ import { gzip } from 'zlib';
 import Table from 'cli-table';
 
 // The maximum size we allow for a minimal useful Realtime bundle (i.e. one that can subscribe to a channel)
-const minimalUsefulRealtimeBundleSizeThresholdsKiB = { raw: 98, gzip: 30 };
+const minimalUsefulRealtimeBundleSizeThresholdsKiB = { raw: 99, gzip: 30 };
 
 const baseClientNames = ['BaseRest', 'BaseRealtime'];
 
@@ -183,22 +183,30 @@ async function calculateAndCheckFunctionSizes(): Promise<Output> {
   return output;
 }
 
-async function calculatePushPluginSize(): Promise<Output> {
+async function calculatePluginSize(options: { path: string; description: string }): Promise<Output> {
   const output: Output = { tableRows: [], errors: [] };
-  const pushPluginBundleInfo = getBundleInfo('./build/push.js');
+  const pluginBundleInfo = getBundleInfo(options.path);
   const sizes = {
-    rawByteSize: pushPluginBundleInfo.byteSize,
-    gzipEncodedByteSize: (await promisify(gzip)(pushPluginBundleInfo.code)).byteLength,
+    rawByteSize: pluginBundleInfo.byteSize,
+    gzipEncodedByteSize: (await promisify(gzip)(pluginBundleInfo.code)).byteLength,
   };
 
   output.tableRows.push({
-    description: 'Push',
+    description: options.description,
     sizes: sizes,
   });
 
   return output;
 }
 
+async function calculatePushPluginSize(): Promise<Output> {
+  return calculatePluginSize({ path: './build/push.js', description: 'Push' });
+}
+
+async function calculateLiveObjectsPluginSize(): Promise<Output> {
+  return calculatePluginSize({ path: './build/liveobjects.js', description: 'LiveObjects' });
+}
+
 async function calculateAndCheckMinimalUsefulRealtimeBundleSize(): Promise<Output> {
   const output: Output = { tableRows: [], errors: [] };
 
@@ -296,6 +304,15 @@ async function checkPushPluginFiles() {
   return checkBundleFiles(pushPluginBundleInfo, allowedFiles, 100);
 }
 
+async function checkLiveObjectsPluginFiles() {
+  const pluginBundleInfo = getBundleInfo('./build/liveobjects.js');
+
+  // These are the files that are allowed to contribute >= `threshold` bytes to the LiveObjects bundle.
+  const allowedFiles = new Set(['src/plugins/liveobjects/index.ts']);
+
+  return checkBundleFiles(pluginBundleInfo, allowedFiles, 100);
+}
+
 async function checkBundleFiles(bundleInfo: BundleInfo, allowedFiles: Set<string>, thresholdBytes: number) {
   const exploreResult = await runSourceMapExplorer(bundleInfo);
 
@@ -347,6 +364,7 @@ async function checkBundleFiles(bundleInfo: BundleInfo, allowedFiles: Set<string
       calculateAndCheckExportSizes(),
       calculateAndCheckFunctionSizes(),
       calculatePushPluginSize(),
+      calculateLiveObjectsPluginSize(),
     ])
   ).reduce((accum, current) => ({
     tableRows: [...accum.tableRows, ...current.tableRows],
@@ -355,6 +373,7 @@ async function checkBundleFiles(bundleInfo: BundleInfo, allowedFiles: Set<string
 
   output.errors.push(...(await checkBaseRealtimeFiles()));
   output.errors.push(...(await checkPushPluginFiles()));
+  output.errors.push(...(await checkLiveObjectsPluginFiles()));
 
   const table = new Table({
     style: { head: ['green'] },

src/common/lib/client/modularplugins.ts

@@ -11,6 +11,7 @@ import {
 } from '../types/presencemessage';
 import { TransportCtor } from '../transport/transport';
 import * as PushPlugin from 'plugins/push';
+import * as LiveObjectsPlugin from 'plugins/liveobjects';
 
 export interface PresenceMessagePlugin {
   presenceMessageFromValues: typeof presenceMessageFromValues;
@@ -32,6 +33,7 @@ export interface ModularPlugins {
   FetchRequest?: typeof fetchRequest;
   MessageInteractions?: typeof FilteredSubscriptions;
   Push?: typeof PushPlugin;
+  LiveObjects?: typeof LiveObjectsPlugin;
 }
 
 export const allCommonModularPlugins: ModularPlugins = { Rest };

src/common/lib/client/realtimechannel.ts

@@ -29,6 +29,7 @@ import { ChannelOptions } from '../../types/channel';
 import { normaliseChannelOptions } from '../util/defaults';
 import { PaginatedResult } from './paginatedresource';
 import type { PushChannel } from 'plugins/push';
+import type { LiveObjects } from 'plugins/liveobjects';
 
 interface RealtimeHistoryParams {
   start?: number;
@@ -99,6 +100,7 @@ class RealtimeChannel extends EventEmitter {
   retryTimer?: number | NodeJS.Timeout | null;
   retryCount: number = 0;
   _push?: PushChannel;
+  _liveObjects?: LiveObjects;
 
   constructor(client: BaseRealtime, name: string, options?: API.ChannelOptions) {
     super(client.logger);
@@ -137,6 +139,10 @@ class RealtimeChannel extends EventEmitter {
     if (client.options.plugins?.Push) {
       this._push = new client.options.plugins.Push.PushChannel(this);
     }
+
+    if (client.options.plugins?.LiveObjects) {
+      this._liveObjects = new client.options.plugins.LiveObjects.LiveObjects(this);
+    }
   }
 
   get push() {
@@ -146,6 +152,13 @@ class RealtimeChannel extends EventEmitter {
     return this._push;
   }
 
+  get liveObjects() {
+    if (!this._liveObjects) {
+      Utils.throwMissingPluginError('LiveObjects');
+    }
+    return this._liveObjects;
+  }
+
   invalidStateError(): ErrorInfo {
     return new ErrorInfo(
       'Channel operation failed as channel state is ' + this.state,

src/plugins/index.d.ts

@@ -1,5 +1,7 @@
+import LiveObjects from './liveobjects';
 import Push from './push';
 
 export interface StandardPlugins {
+  LiveObjects?: typeof LiveObjects;
   Push?: typeof Push;
 }

src/plugins/liveobjects/index.ts

@@ -0,0 +1,7 @@
+import { LiveObjects } from './liveobjects';
+
+export { LiveObjects };
+
+export default {
+  LiveObjects,
+};

src/plugins/liveobjects/liveobjects.ts

@@ -0,0 +1,12 @@
+import type BaseClient from 'common/lib/client/baseclient';
+import type RealtimeChannel from 'common/lib/client/realtimechannel';
+
+export class LiveObjects {
+  private _client: BaseClient;
+  private _channel: RealtimeChannel;
+
+  constructor(channel: RealtimeChannel) {
+    this._channel = channel;
+    this._client = channel.client;
+  }
+}