feat(WebSocketManager): support gateway capabilities

packages/ws/__tests__/types/WebSocketManager.test-d.ts

@@ -1,10 +1,13 @@
 import type { AsyncEventEmitter } from '@vladfrangu/async_event_emitter';
+import type { GatewayCapabilityBits } from 'discord-api-types/v10';
 import { expectTypeOf } from 'vitest';
 import type { ManagerShardEventsMap, WebSocketShardEventsMap, WebSocketManager } from '../../src/index.js';
 
 declare const manager: WebSocketManager;
 declare const eventMap: ManagerShardEventsMap;
 
+expectTypeOf(manager.options.capabilities).toEqualTypeOf<GatewayCapabilityBits | 0>();
+
 type AugmentedShardEventsMap = {
 	[K in keyof WebSocketShardEventsMap]: [...WebSocketShardEventsMap[K], shardId: number];
 };

packages/ws/__tests__/ws/WebSocketManager.test.ts

@@ -1,5 +1,5 @@
 import type { GatewaySendPayload } from 'discord-api-types/v10';
-import { GatewayOpcodes } from 'discord-api-types/v10';
+import { GatewayCapabilityBits, GatewayOpcodes } from 'discord-api-types/v10';
 import { describe, expect, test, vi } from 'vitest';
 import { WebSocketManager, type IShardingStrategy } from '../../src/index.js';
 import { mockGatewayInformation } from '../gateway.mock.js';
@@ -121,6 +121,33 @@ test('it handles passing in both shardIds and shardCount', async () => {
 	expect(await manager.getShardIds()).toStrictEqual([2, 3]);
 });
 
+describe('gateway capabilities', () => {
+	test('defaults to none', async () => {
+		const manager = new WebSocketManager({
+			token: 'A-Very-Fake-Token',
+			intents: 0,
+			async fetchGatewayInformation() {
+				return mockGatewayInformation;
+			},
+		});
+
+		expect(manager.options.capabilities).toBe(0);
+	});
+
+	test('with a provided bitfield', async () => {
+		const manager = new WebSocketManager({
+			token: 'A-Very-Fake-Token',
+			intents: 0,
+			capabilities: GatewayCapabilityBits.ChannelObfuscation,
+			async fetchGatewayInformation() {
+				return mockGatewayInformation;
+			},
+		});
+
+		expect(manager.options.capabilities).toBe(GatewayCapabilityBits.ChannelObfuscation);
+	});
+});
+
 test('strategies', async () => {
 	class MockStrategy implements IShardingStrategy {
 		public spawn = vi.fn();

packages/ws/src/strategies/context/IContextFetchingStrategy.ts

@@ -4,6 +4,7 @@ import type { SessionInfo, WebSocketManager, WebSocketManagerOptions } from '../
 
 export interface FetchingStrategyOptions extends Pick<
 	WebSocketManagerOptions,
+	| 'capabilities'
 	| 'compression'
 	| 'encoding'
 	| 'handshakeTimeout'
@@ -38,6 +39,7 @@ export interface IContextFetchingStrategy {
 
 export async function managerToFetchingStrategyOptions(manager: WebSocketManager): Promise<FetchingStrategyOptions> {
 	return {
+		capabilities: manager.options.capabilities,
 		compression: manager.options.compression,
 		encoding: manager.options.encoding,
 		handshakeTimeout: manager.options.handshakeTimeout,

packages/ws/src/utils/constants.ts

@@ -42,6 +42,7 @@ export const DefaultWebSocketManagerOptions = {
 		return new SimpleIdentifyThrottler(info.session_start_limit.max_concurrency);
 	},
 	buildStrategy: (manager) => new SimpleShardingStrategy(manager),
+	capabilities: 0,
 	shardCount: null,
 	shardIds: null,
 	largeThreshold: null,

packages/ws/src/ws/WebSocketManager.ts

@@ -3,6 +3,7 @@ import { range, type Awaitable } from '@discordjs/util';
 import { AsyncEventEmitter } from '@vladfrangu/async_event_emitter';
 import type {
 	APIGatewayBotInfo,
+	GatewayCapabilityBits,
 	GatewayIdentifyProperties,
 	GatewayPresenceUpdateData,
 	RESTGetAPIGatewayBotResult,
@@ -101,6 +102,13 @@ export interface OptionalWebSocketManagerOptions {
 	 * ```
 	 */
 	buildStrategy(manager: WebSocketManager): IShardingStrategy;
+	/**
+	 * The gateway capabilities to opt into
+	 *
+	 * @defaultValue `0`
+	 * @see {@link https://discord.com/developers/docs/events/gateway-events#identify-gateway-capabilities}
+	 */
+	capabilities: GatewayCapabilityBits | 0;
 	/**
 	 * The transport compression method to use - mutually exclusive with `useIdentifyCompression`
 	 *

packages/ws/src/ws/WebSocketShard.ts

@@ -552,6 +552,7 @@ export class WebSocketShard extends AsyncEventEmitter<WebSocketShardEventsMap> {
 			`shard id: ${this.id.toString()}`,
 			`shard count: ${this.strategy.options.shardCount}`,
 			`intents: ${this.strategy.options.intents}`,
+			`capabilities: ${this.strategy.options.capabilities}`,
 			`compression: ${this.transportCompressionEnabled ? CompressionParameterMap[this.strategy.options.compression!] : this.identifyCompressionEnabled ? 'identify' : 'none'}`,
 		]);
 
@@ -567,6 +568,10 @@ export class WebSocketShard extends AsyncEventEmitter<WebSocketShardEventsMap> {
 			data.large_threshold = this.strategy.options.largeThreshold;
 		}
 
+		if (this.strategy.options.capabilities) {
+			data.capabilities = this.strategy.options.capabilities;
+		}
+
 		if (this.strategy.options.initialPresence) {
 			data.presence = this.strategy.options.initialPresence;
 		}