Ability to read offsets

[mikeal]

In order to do video playback properly I need to be able to seek through parts of a file.

So, what I basically need is a version of ipfs.cat that has offset support. Something like:

ipfs.seek(hash, offset, length, (err, exporter) => {
  if (err) throw err
  exporter.pipe(destinationStream)
})

[mikeal]

It could also be called "range" if you want to match the http terminology.

[dignifiedquire]

I agree this would be really nice to have. There is some ground work to be done in the code, but it's very much possible to do (go-ipfs already supports this on the gateway, but not exposed through the api)

[daviddias]

@dignifiedquire it is exposed on the Files API (ipfs files read --offset), but that requires moving the file to mfs, like:

> ipfs add file.txt
QmHash
> ipfs files cp /ipfs/QmHash /file.txt
> ipfs files read /file.txt --offset=200

This is related with the convergence of Files with the basic unixfs commands ipfs/specs#98 (comment)

[daviddias]

This now exists thanks to @achingbrain \o/ Check https://github.com/ipfs/interface-ipfs-core/blob/master/SPEC/FILES.md#filescat for details