| 1 | // This file is part of HFS - Copyright 2021-2023, Massimo Melina <a@rejetto.com> - License https://www.gnu.org/licenses/gpl-3.0.txt |
| 2 | |
| 3 | import { Transform, TransformCallback } from 'stream' |
| 4 | import { TokenBucket } from 'limiter' |
| 5 | |
| 6 | // throttled stream |
| 7 | export class ThrottledStream extends Transform { |
| 8 | |
| 9 | private sent: number = 0 |
| 10 | private lastSpeed: number = 0 |
| 11 | private lastSpeedTime = Date.now() |
| 12 | private totalSent: number = 0 // total sent over connection, since connection can be re-used for multiple requests |
| 13 | |
| 14 | constructor(private group: ThrottleGroup, copyStats?: ThrottledStream) { |
| 15 | super() |
| 16 | if (!copyStats) return |
| 17 | this.sent = copyStats.sent |
| 18 | this.totalSent = copyStats.totalSent |
| 19 | this.lastSpeedTime = copyStats.lastSpeedTime |
| 20 | this.lastSpeed = copyStats.lastSpeed |
| 21 | } |
| 22 | |
| 23 | async _transform(chunk: any, encoding: BufferEncoding, done: TransformCallback) { |
| 24 | let pos = 0 |
| 25 | while (1) { |
| 26 | let n = this.group.suggestChunkSize() |
| 27 | const slice = chunk.slice(pos, pos + n) |
| 28 | n = slice.length |
| 29 | if (!n) // we're done here |
| 30 | return done() |
| 31 | try { |
| 32 | await this.group.consume(n) |
| 33 | this.push(slice) |
| 34 | this.sent += n |
| 35 | this.totalSent += n |
| 36 | pos += n |
| 37 | this.emit('sent', n) |
| 38 | } catch (e) { |
| 39 | done(e as Error) |
| 40 | return |
| 41 | } |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | // @return kBs |
| 46 | getSpeed(): number { |
| 47 | const now = Date.now() |
| 48 | const past = now - this.lastSpeedTime |
| 49 | if (past >= 1000) { // recalculate? |
| 50 | this.lastSpeedTime = now |
| 51 | this.lastSpeed = this.sent / past |
| 52 | this.sent = 0 |
| 53 | } |
| 54 | return this.lastSpeed |
| 55 | } |
| 56 | |
| 57 | getBytesSent() { |
| 58 | return this.totalSent |
| 59 | } |
| 60 | } |
| 61 | |
| 62 | export class ThrottleGroup { |
| 63 | |
| 64 | private bucket: TokenBucket |
| 65 | |
| 66 | constructor(kBs: number, private parent?: ThrottleGroup) { |
| 67 | this.bucket = this.updateLimit(kBs) // assignment is redundant and yet the best way I've found to shut up typescript |
| 68 | } |
| 69 | |
| 70 | // @return kBs |
| 71 | getLimit() { |
| 72 | return this.bucket.bucketSize / 1000 |
| 73 | } |
| 74 | |
| 75 | updateLimit(kBs: number) { |
| 76 | if (kBs < 0) |
| 77 | throw Error('invalid bytesPerSecond') |
| 78 | kBs *= 1000 |
| 79 | return this.bucket = new TokenBucket({ |
| 80 | bucketSize: kBs, |
| 81 | tokensPerInterval: kBs, |
| 82 | interval: 'second', |
| 83 | }) |
| 84 | } |
| 85 | |
| 86 | suggestChunkSize() { |
| 87 | let b: TokenBucket | undefined = this.bucket |
| 88 | b.parentBucket = this.parent?.bucket |
| 89 | let min = b.bucketSize |
| 90 | while (b = b.parentBucket) |
| 91 | min = Math.min(min, b.bucketSize) |
| 92 | return min / 10 |
| 93 | } |
| 94 | |
| 95 | consume(n: number) { |
| 96 | return this.bucket.removeTokens(n) |
| 97 | } |
| 98 | } |