chore(streams): refactor integrityStream fn

Author: claudiahdz

index.js

@@ -24,17 +24,62 @@ const SsriOpts = figgyPudding({
  strict: {default: false}
 })
 
-class Transform extends MiniPass {
+class IntegrityStream extends MiniPass {
  constructor (opts) {
  super()
  this.size = 0
- this.transform = opts.transform
+ this.opts = opts
+ // For verification
+ this.sri = opts.integrity && parse(opts.integrity, opts)
+ this.goodSri = this.sri && Object.keys(this.sri).length
+ this.algorithm = this.goodSri && this.sri.pickAlgorithm(opts)
+ this.digests = this.goodSri && this.sri[this.algorithm]
+ // Calculating stream
+ this.algorithms = Array.from(
+ new Set(opts.algorithms.concat(this.algorithm ? [this.algorithm] : []))
+ )
+ this.hashes = this.algorithms.map(crypto.createHash)
+ this.onEnd = this.onEnd.bind(this)
+ }
+ emit (ev, data) {
+ if (ev === 'end') this.onEnd()
+ return super.emit(ev, data)
  }
  write (data) {
  this.size += data.length
- this.transform(data)
+ this.hashes.forEach(h => h.update(data))
  super.write(data)
  }
+ onEnd () {
+ const optString = (this.opts.options && this.opts.options.length)
+ ? `?${this.opts.options.join('?')}`
+ : ''
+ const newSri = parse(this.hashes.map((h, i) => {
+ return `${this.algorithms[i]}-${h.digest('base64')}${optString}`
+ }).join(' '), this.opts)
+ // Integrity verification mode
+ const match = this.goodSri && newSri.match(this.sri, this.opts)
+ if (typeof this.opts.size === 'number' && this.size !== this.opts.size) {
+ const err = new Error(`stream size mismatch when checking ${this.sri}.\n Wanted: ${this.opts.size}\n Found: ${this.size}`)
+ err.code = 'EBADSIZE'
+ err.found = this.size
+ err.expected = this.opts.size
+ err.sri = this.sri
+ this.emit('error', err)
+ } else if (this.opts.integrity && !match) {
+ const err = new Error(`${this.sri} integrity checksum failed when using ${this.algorithm}: wanted ${this.digests} but got ${newSri}. (${this.size} bytes)`)
+ err.code = 'EINTEGRITY'
+ err.found = newSri
+ err.expected = this.digests
+ err.algorithm = this.algorithm
+ err.sri = this.sri
+ this.emit('error', err)
+ } else {
+ this.emit('size', this.size)
+ this.emit('integrity', newSri)
+ match && this.emit('verified', match)
+ }
+ }
 }
 
 class Hash {
@@ -303,53 +348,7 @@ function checkStream (stream, sri, opts) {
 
 module.exports.integrityStream = integrityStream
 function integrityStream (opts) {
- opts = SsriOpts(opts)
- // For verification
- const sri = opts.integrity && parse(opts.integrity, opts)
- const goodSri = sri && Object.keys(sri).length
- const algorithm = goodSri && sri.pickAlgorithm(opts)
- const digests = goodSri && sri[algorithm]
- // Calculating stream
- const algorithms = Array.from(
- new Set(opts.algorithms.concat(algorithm ? [algorithm] : []))
- )
- const hashes = algorithms.map(crypto.createHash)
- const stream = new Transform({
- transform (chunk) { hashes.forEach(h => h.update(chunk)) }
- })
-
- stream.on('end', () => {
- const optString = (opts.options && opts.options.length)
- ? `?${opts.options.join('?')}`
- : ''
- const newSri = parse(hashes.map((h, i) => {
- return `${algorithms[i]}-${h.digest('base64')}${optString}`
- }).join(' '), opts)
- // Integrity verification mode
- const match = goodSri && newSri.match(sri, opts)
- const streamSize = stream.size
- if (typeof opts.size === 'number' && streamSize !== opts.size) {
- const err = new Error(`stream size mismatch when checking ${sri}.\n Wanted: ${opts.size}\n Found: ${streamSize}`)
- err.code = 'EBADSIZE'
- err.found = streamSize
- err.expected = opts.size
- err.sri = sri
- stream.emit('error', err)
- } else if (opts.integrity && !match) {
- const err = new Error(`${sri} integrity checksum failed when using ${algorithm}: wanted ${digests} but got ${newSri}. (${streamSize} bytes)`)
- err.code = 'EINTEGRITY'
- err.found = newSri
- err.expected = digests
- err.algorithm = algorithm
- err.sri = sri
- stream.emit('error', err)
- } else {
- stream.emit('size', streamSize)
- stream.emit('integrity', newSri)
- match && stream.emit('verified', match)
- }
- })
- return stream
+ return new IntegrityStream(SsriOpts(opts))
 }
 
 module.exports.create = createIntegrity