client/src/assets/player/shared/p2p-media-loader/segment-validator.ts

   1 import { basename } from 'path'
   2 import { Segment } from '@peertube/p2p-media-loader-core'
   3 import { logger } from '@root-helpers/logger'
   4 import { wait } from '@root-helpers/utils'
   5 import { removeQueryParams } from '@shared/core-utils'
   6 import { isSameOrigin } from '../common'
   7
   8 type SegmentsJSON = { [filename: string]: string | { [byterange: string]: string } }
   9
  10 const maxRetries = 10
  11
  12 function segmentValidatorFactory (options: {
  13   serverUrl: string
  14   segmentsSha256Url: string
  15   authorizationHeader: () => string
  16   requiresAuth: boolean
  17 }) {
  18   const { serverUrl, segmentsSha256Url, authorizationHeader, requiresAuth } = options
  19
  20   let segmentsJSON = fetchSha256Segments({ serverUrl, segmentsSha256Url, authorizationHeader, requiresAuth })
  21   const regex = /bytes=(\d+)-(\d+)/
  22
  23   return async function segmentValidator (segment: Segment, _method: string, _peerId: string, retry = 1) {
  24     const filename = basename(removeQueryParams(segment.url))
  25
  26     const segmentValue = (await segmentsJSON)[filename]
  27
  28     if (!segmentValue && retry > maxRetries) {
  29       throw new Error(`Unknown segment name ${filename} in segment validator`)
  30     }
  31
  32     if (!segmentValue) {
  33       logger.info(`Refetching sha segments for ${filename}`)
  34
  35       await wait(500)
  36
  37       segmentsJSON = fetchSha256Segments({ serverUrl, segmentsSha256Url, authorizationHeader, requiresAuth })
  38       await segmentValidator(segment, _method, _peerId, retry + 1)
  39
  40       return
  41     }
  42
  43     let hashShouldBe: string
  44     let range = ''
  45
  46     if (typeof segmentValue === 'string') {
  47       hashShouldBe = segmentValue
  48     } else {
  49       const captured = regex.exec(segment.range)
  50       range = captured[1] + '-' + captured[2]
  51
  52       hashShouldBe = segmentValue[range]
  53     }
  54
  55     if (hashShouldBe === undefined) {
  56       throw new Error(`Unknown segment name ${filename}/${range} in segment validator`)
  57     }
  58
  59     const calculatedSha = await sha256Hex(segment.data)
  60     if (calculatedSha !== hashShouldBe) {
  61       throw new Error(
  62         `Hashes does not correspond for segment ${filename}/${range}` +
  63         `(expected: ${hashShouldBe} instead of ${calculatedSha})`
  64       )
  65     }
  66   }
  67 }
  68
  69 // ---------------------------------------------------------------------------
  70
  71 export {
  72   segmentValidatorFactory
  73 }
  74
  75 // ---------------------------------------------------------------------------
  76
  77 function fetchSha256Segments (options: {
  78   serverUrl: string
  79   segmentsSha256Url: string
  80   authorizationHeader: () => string
  81   requiresAuth: boolean
  82 }): Promise<SegmentsJSON> {
  83   const { serverUrl, segmentsSha256Url, requiresAuth, authorizationHeader } = options
  84
  85   const headers = requiresAuth && isSameOrigin(serverUrl, segmentsSha256Url)
  86     ? { Authorization: authorizationHeader() }
  87     : {}
  88
  89   return fetch(segmentsSha256Url, { headers })
  90     .then(res => res.json() as Promise<SegmentsJSON>)
  91     .catch(err => {
  92       logger.error('Cannot get sha256 segments', err)
  93       return {}
  94     })
  95 }
  96
  97 async function sha256Hex (data?: ArrayBuffer) {
  98   if (!data) return undefined
  99
 100   if (window.crypto.subtle) {
 101     return window.crypto.subtle.digest('SHA-256', data)
 102       .then(data => bufferToHex(data))
 103   }
 104
 105   // Fallback for non HTTPS context
 106   const shaModule = (await import('sha.js') as any).default
 107   // eslint-disable-next-line new-cap
 108   return new shaModule.sha256().update(Buffer.from(data)).digest('hex')
 109 }
 110
 111 // Thanks: https://stackoverflow.com/a/53307879
 112 function bufferToHex (buffer?: ArrayBuffer) {
 113   if (!buffer) return ''
 114
 115   let s = ''
 116   const h = '0123456789abcdef'
 117   const o = new Uint8Array(buffer)
 118
 119   o.forEach((v: any) => {
 120     s += h[v >> 4] + h[v & 15]
 121   })
 122
 123   return s
 124 }