84 lines
2.5 KiB
JavaScript
84 lines
2.5 KiB
JavaScript
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"use strict";
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const util = require("util");
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const Base = require("../structures/Base");
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/**
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* Ratelimit requests and release in sequence
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* TODO: add latencyref
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* @prop {Number} limit How many tokens the bucket can consume in the current interval
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* @prop {Boolean} processing Whether the queue is being processed
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* @prop {Number} remaining How many tokens the bucket has left in the current interval
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* @prop {Number} reset Timestamp of next reset
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*/
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class SequentialBucket {
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/**
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* Construct a SequentialBucket
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* @arg {Number} limit The max number of tokens the bucket can consume per interval
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* @arg {Object} [latencyRef] An object
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* @arg {Number} latencyRef.latency Interval between consuming tokens
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*/
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constructor(limit, latencyRef = {latency: 0}) {
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this.limit = this.remaining = limit;
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this.reset = 0;
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this.processing = false;
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this.latencyRef = latencyRef;
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this._queue = [];
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}
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check(override) {
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if(this._queue.length === 0) {
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if(this.processing) {
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clearTimeout(this.processing);
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this.processing = false;
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}
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return;
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}
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if(this.processing && !override) {
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return;
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}
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const now = Date.now();
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const offset = this.latencyRef.latency;
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if(!this.reset || this.reset < now - offset) {
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this.reset = now - offset;
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this.remaining = this.limit;
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}
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this.last = now;
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if(this.remaining <= 0) {
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this.processing = setTimeout(() => {
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this.processing = false;
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this.check(true);
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}, Math.max(0, (this.reset || 0) - now + offset) + 1);
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return;
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}
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--this.remaining;
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this.processing = true;
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this._queue.shift()(() => {
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if(this._queue.length > 0) {
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this.check(true);
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} else {
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this.processing = false;
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}
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});
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}
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/**
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* Queue something in the SequentialBucket
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* @arg {Function} func A function to call when a token can be consumed. The function will be passed a callback argument, which must be called to allow the bucket to continue to work
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*/
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queue(func, short) {
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if(short) {
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this._queue.unshift(func);
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} else {
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this._queue.push(func);
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}
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this.check();
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}
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[util.inspect.custom]() {
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return Base.prototype[util.inspect.custom].call(this);
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}
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}
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module.exports = SequentialBucket;
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