Setting offset in catReadableStream results in incorrect stream length

[jhiesey]

@achingbrain

The following example doesn't give the expected result:

const Ipfs = require('ipfs')
const videoCid = 'QmcPZGXSyaQSnDVEtJrgtp2EyxhENiBdpGa8pfs5rMBCWr' // sintel.mp4
const fs = require('fs')

const offset = 48

const ipfs = new Ipfs()
ipfs.on('ready', () => {
	let numDone = 0
	const s1Data = []
	const s2Data = []
	const s1 = ipfs.files.catReadableStream(videoCid, {
		offset: 0
	})

	s1.on('data', (buf) => {
		s1Data.push(buf)
	})

	s1.on('end', () => {
		if (++numDone === 2) {
			checkResult()
		}
	})

	const s2 = ipfs.files.catReadableStream(videoCid, {
		offset: offset
	})

	s2.on('data', (buf) => {
		s2Data.push(buf)
	})

	s2.on('end', () => {
		if (++numDone === 2) {
			checkResult()
		}
	})

	function checkResult () {
		const b1 = Buffer.concat(s1Data).slice(offset)
		const b2 = Buffer.concat(s2Data)
		const eq = b1.equals(b2)

		console.log('length 1', b1.length)
		console.log('length 2', b2.length)
		console.log('equal?', eq)
		process.exit(eq ? 0 : 1)
	}
})

[achingbrain]

Great catch, thanks for pointing this out! The fix has been released in v0.32.7.

[jhiesey]

Thanks for the quick fix!