feat: rest hash and handler sweeping (#7255)

Co-authored-by: SpaceEEC <spaceeec@yahoo.com>
Co-authored-by: Antonio Román <kyradiscord@gmail.com>
Co-authored-by: Vlad Frangu <kingdgrizzle@gmail.com>

packages/rest/src/lib/REST.ts

@@ -4,6 +4,9 @@ import { InternalRequest, RequestData, RequestManager, RequestMethod, RouteLike
 import { DefaultRestOptions, RESTEvents } from './utils/constants';
 import type { AgentOptions } from 'node:https';
 import type { RequestInit, Response } from 'node-fetch';
+import type { HashData } from './RequestManager';
+import type Collection from '@discordjs/collection';
+import type { IHandler } from './handlers/IHandler';
 
 /**
  * Options to be passed when creating the REST instance
@@ -74,6 +77,21 @@ export interface RESTOptions {
 	 * @default '9'
 	 */
 	version: string;
+	/**
+	 * The amount of time in milliseconds that passes between each hash sweep. (defaults to 4h)
+	 * @default 14_400_000
+	 */
+	hashSweepInterval: number;
+	/**
+	 * The maximum amount of time a hash can exist in milliseconds without being hit with a request (defaults to 24h)
+	 * @default 86_400_000
+	 */
+	hashLifetime: number;
+	/**
+	 * The amount of time in milliseconds that passes between each hash sweep. (defaults to 1h)
+	 * @default 3_600_000
+	 */
+	handlerSweepInterval: number;
 }
 
 /**
@@ -168,6 +186,8 @@ export interface RestEvents {
 	response: [request: APIRequest, response: Response];
 	newListener: [name: string, listener: (...args: any) => void];
 	removeListener: [name: string, listener: (...args: any) => void];
+	hashSweep: [sweptHashes: Collection<string, HashData>];
+	handlerSweep: [sweptHandlers: Collection<string, IHandler>];
 }
 
 export interface REST {
@@ -197,7 +217,8 @@ export class REST extends EventEmitter {
 		this.requestManager = new RequestManager(options)
 			.on(RESTEvents.Debug, this.emit.bind(this, RESTEvents.Debug))
 			.on(RESTEvents.RateLimited, this.emit.bind(this, RESTEvents.RateLimited))
-			.on(RESTEvents.InvalidRequestWarning, this.emit.bind(this, RESTEvents.InvalidRequestWarning));
+			.on(RESTEvents.InvalidRequestWarning, this.emit.bind(this, RESTEvents.InvalidRequestWarning))
+			.on(RESTEvents.HashSweep, this.emit.bind(this, RESTEvents.HashSweep));
 
 		this.on('newListener', (name, listener) => {
 			if (name === RESTEvents.Request || name === RESTEvents.Response) this.requestManager.on(name, listener);

packages/rest/src/lib/RequestManager.ts

@@ -7,7 +7,7 @@ import type { RequestInit, BodyInit } from 'node-fetch';
 import type { IHandler } from './handlers/IHandler';
 import { SequentialHandler } from './handlers/SequentialHandler';
 import type { RESTOptions, RestEvents } from './REST';
-import { DefaultRestOptions, DefaultUserAgent } from './utils/constants';
+import { DefaultRestOptions, DefaultUserAgent, RESTEvents } from './utils/constants';
 
 let agent: Agent | null = null;
 
@@ -125,6 +125,16 @@ export interface RouteData {
 	original: RouteLike;
 }
 
+/**
+ * Represents a hash and its associated fields
+ *
+ * @internal
+ */
+export interface HashData {
+	value: string;
+	lastAccess: number;
+}
+
 export interface RequestManager {
 	on: (<K extends keyof RestEvents>(event: K, listener: (...args: RestEvents[K]) => void) => this) &
 		(<S extends string | symbol>(event: Exclude<S, keyof RestEvents>, listener: (...args: any[]) => void) => this);
@@ -164,7 +174,7 @@ export class RequestManager extends EventEmitter {
 	/**
 	 * API bucket hashes that are cached from provided routes
 	 */
-	public readonly hashes = new Collection<string, string>();
+	public readonly hashes = new Collection<string, HashData>();
 
 	/**
 	 * Request handlers created from the bucket hash and the major parameters
@@ -174,6 +184,9 @@ export class RequestManager extends EventEmitter {
 	// eslint-disable-next-line @typescript-eslint/explicit-member-accessibility
 	#token: string | null = null;
 
+	private hashTimer!: NodeJS.Timer;
+	private handlerTimer!: NodeJS.Timer;
+
 	public readonly options: RESTOptions;
 
 	public constructor(options: Partial<RESTOptions>) {
@@ -181,6 +194,71 @@ export class RequestManager extends EventEmitter {
 		this.options = { ...DefaultRestOptions, ...options };
 		this.options.offset = Math.max(0, this.options.offset);
 		this.globalRemaining = this.options.globalRequestsPerSecond;
+
+		// Start sweepers
+		this.setupSweepers();
+	}
+
+	private setupSweepers() {
+		const validateMaxInterval = (interval: number) => {
+			if (interval > 14_400_000) {
+				throw new Error('Cannot set an interval greater than 4 hours');
+			}
+		};
+
+		if (this.options.hashSweepInterval !== 0 && this.options.hashSweepInterval !== Infinity) {
+			validateMaxInterval(this.options.hashSweepInterval);
+			this.hashTimer = setInterval(() => {
+				const sweptHashes = new Collection<string, HashData>();
+				const currentDate = Date.now();
+
+				// Begin sweeping hash based on lifetimes
+				this.hashes.sweep((v, k) => {
+					// `-1` indicates a global hash
+					if (v.lastAccess === -1) return false;
+
+					// Check if lifetime has been exceeded
+					const shouldSweep = Math.floor(currentDate - v.lastAccess) > this.options.hashLifetime;
+
+					// Add hash to collection of swept hashes
+					if (shouldSweep) {
+						// Add to swept hashes
+						sweptHashes.set(k, v);
+					}
+
+					// Emit debug information
+					this.emit(RESTEvents.Debug, `Hash ${v.value} for ${k} swept due to lifetime being exceeded`);
+
+					return shouldSweep;
+				});
+
+				// Fire event
+				this.emit(RESTEvents.HashSweep, sweptHashes);
+			}, this.options.hashSweepInterval).unref();
+		}
+
+		if (this.options.handlerSweepInterval !== 0 && this.options.handlerSweepInterval !== Infinity) {
+			validateMaxInterval(this.options.handlerSweepInterval);
+			this.handlerTimer = setInterval(() => {
+				const sweptHandlers = new Collection<string, IHandler>();
+
+				// Begin sweeping handlers based on activity
+				this.handlers.sweep((v, k) => {
+					const { inactive } = v;
+
+					// Collect inactive handlers
+					if (inactive) {
+						sweptHandlers.set(k, v);
+					}
+
+					this.emit(RESTEvents.Debug, `Handler ${v.id} for ${k} swept due to being inactive`);
+					return inactive;
+				});
+
+				// Fire event
+				this.emit(RESTEvents.HandlerSweep, sweptHandlers);
+			}, this.options.handlerSweepInterval).unref();
+		}
 	}
 
 	/**
@@ -201,12 +279,15 @@ export class RequestManager extends EventEmitter {
 		// Generalize the endpoint to its route data
 		const routeId = RequestManager.generateRouteData(request.fullRoute, request.method);
 		// Get the bucket hash for the generic route, or point to a global route otherwise
-		const hash =
+		const hash = this.hashes.get(`${request.method}:${routeId.bucketRoute}`) ?? {
-			this.hashes.get(`${request.method}:${routeId.bucketRoute}`) ?? `Global(${request.method}:${routeId.bucketRoute})`;
+			value: `Global(${request.method}:${routeId.bucketRoute})`,
+			lastAccess: -1,
+		};
 
 		// Get the request handler for the obtained hash, with its major parameter
 		const handler =
-			this.handlers.get(`${hash}:${routeId.majorParameter}`) ?? this.createHandler(hash, routeId.majorParameter);
+			this.handlers.get(`${hash.value}:${routeId.majorParameter}`) ??
+			this.createHandler(hash.value, routeId.majorParameter);
 
 		// Resolve the request into usable fetch/node-fetch options
 		const { url, fetchOptions } = this.resolveRequest(request);
@@ -323,6 +404,20 @@ export class RequestManager extends EventEmitter {
 		return { url, fetchOptions };
 	}
 
+	/**
+	 * Stops the hash sweeping interval
+	 */
+	public clearHashSweeper() {
+		clearInterval(this.hashTimer);
+	}
+
+	/**
+	 * Stops the request handler sweeping interval
+	 */
+	public clearHandlerSweeper() {
+		clearInterval(this.handlerTimer);
+	}
+
 	/**
 	 * Generates route data for an endpoint:method
 	 * @param endpoint The raw endpoint to generalize

packages/rest/src/lib/handlers/IHandler.ts

@@ -8,4 +8,6 @@ export interface IHandler {
 		options: RequestInit,
 		bodyData: Pick<InternalRequest, 'files' | 'body'>,
 	) => Promise<unknown>;
+	readonly inactive: boolean;
+	readonly id: string;
 }

packages/rest/src/lib/handlers/SequentialHandler.ts

@@ -355,7 +355,16 @@ export class SequentialHandler {
 			// Let library users know when rate limit buckets have been updated
 			this.debug(['Received bucket hash update', `  Old Hash  : ${this.hash}`, `  New Hash  : ${hash}`].join('\n'));
 			// This queue will eventually be eliminated via attrition
-			this.manager.hashes.set(`${method}:${routeId.bucketRoute}`, hash);
+			this.manager.hashes.set(`${method}:${routeId.bucketRoute}`, { value: hash, lastAccess: Date.now() });
+		} else if (hash) {
+			// Handle the case where hash value doesn't change
+			// Fetch the hash data from the manager
+			const hashData = this.manager.hashes.get(`${method}:${routeId.bucketRoute}`);
+
+			// When fetched, update the last access of the hash
+			if (hashData) {
+				hashData.lastAccess = Date.now();
+			}
 		}
 
 		// Handle retryAfter, which means we have actually hit a rate limit

packages/rest/src/lib/utils/constants.ts

@@ -19,6 +19,9 @@ export const DefaultRestOptions: Required<RESTOptions> = {
 	timeout: 15_000,
 	userAgentAppendix: `Node.js ${process.version}`,
 	version: APIVersion,
+	hashSweepInterval: 14_400_000, // 4 Hours
+	hashLifetime: 86_400_000, // 24 Hours
+	handlerSweepInterval: 3_600_000, // 1 Hour
 };
 
 /**
@@ -30,6 +33,8 @@ export const enum RESTEvents {
 	RateLimited = 'rateLimited',
 	Request = 'request',
 	Response = 'response',
+	HashSweep = 'hashSweep',
+	HandlerSweep = 'handlerSweep',
 }
 
 export const ALLOWED_EXTENSIONS = ['webp', 'png', 'jpg', 'jpeg', 'gif'] as const;