78c0f2c7e9
It was not used nor maintained by XO devs, and was causing issues with editors. JSDoc or TypeScript should be used instead.
85 lines
2.4 KiB
JavaScript
85 lines
2.4 KiB
JavaScript
import through2 from 'through2'
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import { createHash } from 'crypto'
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import { defer, fromEvent } from 'promise-toolbox'
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import { invert } from 'lodash'
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// Format: $<algorithm>$<salt>$<encrypted>
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//
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// http://man7.org/linux/man-pages/man3/crypt.3.html#NOTES
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const ALGORITHM_TO_ID = {
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md5: '1',
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sha256: '5',
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sha512: '6',
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}
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const ID_TO_ALGORITHM = invert(ALGORITHM_TO_ID)
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// Create a through stream which computes the checksum of all data going
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// through.
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//
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// The `checksum` attribute is a promise which resolves at the end of the stream
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// with a string representation of the checksum.
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//
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// const source = ...
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// const checksumStream = source.pipe(createChecksumStream())
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// checksumStream.resume() // make the data flow without an output
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// console.log(await checksumStream.checksum)
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export const createChecksumStream = (algorithm = 'md5') => {
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const algorithmId = ALGORITHM_TO_ID[algorithm]
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if (!algorithmId) {
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throw new Error(`unknown algorithm: ${algorithm}`)
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}
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const hash = createHash(algorithm)
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const { promise, resolve, reject } = defer()
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const stream = through2(
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(chunk, enc, callback) => {
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hash.update(chunk)
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callback(null, chunk)
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},
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callback => {
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resolve(`$${algorithmId}$$${hash.digest('hex')}`)
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callback()
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}
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).once('error', reject)
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stream.checksum = promise
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return stream
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}
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// Check if the checksum of a readable stream is equals to an expected checksum.
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// The given stream is wrapped in a stream which emits an error event
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// if the computed checksum is not equals to the expected checksum.
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export const validChecksumOfReadStream = (stream, expectedChecksum) => {
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const algorithmId = expectedChecksum.slice(1, expectedChecksum.indexOf('$', 1))
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if (!algorithmId) {
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throw new Error(`unknown algorithm: ${algorithmId}`)
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}
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const hash = createHash(ID_TO_ALGORITHM[algorithmId])
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const wrapper = stream.pipe(
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through2(
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{ highWaterMark: 0 },
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(chunk, enc, callback) => {
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hash.update(chunk)
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callback(null, chunk)
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},
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callback => {
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const checksum = `$${algorithmId}$$${hash.digest('hex')}`
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callback(
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checksum !== expectedChecksum ? new Error(`Bad checksum (${checksum}), expected: ${expectedChecksum}`) : null
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)
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}
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)
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)
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stream.on('error', error => wrapper.emit('error', error))
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wrapper.checksumVerified = fromEvent(wrapper, 'end')
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return wrapper
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}
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