diff --git a/package.json b/package.json index a3bb867..6253763 100644 --- a/package.json +++ b/package.json @@ -1,6 +1,6 @@ { "name": "wms-core", - "version": "0.2.7", + "version": "0.2.8", "description": "Node web framework", "repository": "git@gitlab.com:ArisuOngaku/wms-core.git", "author": "Alice Gaudon ", diff --git a/src/HttpError.ts b/src/HttpError.ts index de03928..0b8c232 100644 --- a/src/HttpError.ts +++ b/src/HttpError.ts @@ -58,6 +58,21 @@ export class NotFoundHttpError extends BadRequestError { } } +export class TooManyRequestsHttpError extends BadRequestError { + constructor(cause?: Error) { + super( + `You're making too many requests!`, + `We need some rest.`, + '', + cause + ); + } + + get errorCode(): number { + return 404; + } +} + export class ServerError extends HttpError { constructor(message: string, cause?: Error) { super(message, `Maybe you should contact us; see instructions below.`, cause); diff --git a/src/Throttler.ts b/src/Throttler.ts new file mode 100644 index 0000000..0619faf --- /dev/null +++ b/src/Throttler.ts @@ -0,0 +1,82 @@ +import {TooManyRequestsHttpError} from "./HttpError"; + +export default class Throttler { + private static readonly throttles: { [throttleName: string]: Throttle } = {}; + + /** + * Throttle function; will throw a TooManyRequestsHttpError when the threshold is reached. + * + * This throttle is adaptive: it will slowly decrease (linear) until it reaches 0 after {@param resetPeriod} ms. + * Threshold will hold for {@param holdPeriod} ms. + * + * @param action a unique action name (can be used multiple times, but it'll account for a single action). + * @param max how many times this action can be triggered per id. + * @param resetPeriod after how much time in ms the throttle will reach 0. + * @param id an identifier of who triggered the action. + * @param holdPeriod time in ms after each call before the threshold begins to decrease. + * @param jailPeriod time in ms for which the throttle will throw when it is triggered. + */ + public static throttle(action: string, max: number, resetPeriod: number, id: string, holdPeriod: number = 100, jailPeriod: number = 30 * 1000) { + let throttle = this.throttles[action]; + if (!throttle) throttle = this.throttles[action] = new Throttle(max, resetPeriod, holdPeriod, jailPeriod); + throttle.trigger(id); + } + + private constructor() { + } +} + +class Throttle { + private readonly max: number; + private readonly resetPeriod: number; + private readonly holdPeriod: number; + private readonly jailPeriod: number; + private readonly triggers: { + [id: string]: { + count: number, + lastTrigger?: number, + jailed?: number; + } + } = {}; + + constructor(max: number, resetPeriod: number, holdPeriod: number, jailPeriod: number) { + this.max = max; + this.resetPeriod = resetPeriod; + this.holdPeriod = holdPeriod; + this.jailPeriod = jailPeriod; + } + + + public trigger(id: string) { + let trigger = this.triggers[id]; + if (!trigger) trigger = this.triggers[id] = {count: 0}; + + let currentDate = new Date().getTime(); + + if (trigger.jailed && currentDate - trigger.jailed > 0) { + this.throw(); + return; + } + + if (trigger.lastTrigger) { + let timeDiff = currentDate - trigger.lastTrigger; + if (timeDiff > this.holdPeriod) { + timeDiff -= this.holdPeriod; + trigger.count = Math.floor(Math.min(trigger.count, this.max * (1 - timeDiff / this.resetPeriod))); + } + } + + trigger.count++; + trigger.lastTrigger = currentDate; + + if (trigger.count > this.max) { + trigger.jailed = currentDate; + this.throw(); + return; + } + } + + private throw() { + throw new TooManyRequestsHttpError(); + } +} \ No newline at end of file