index.js

'use strict'

const path = require('path')
const co = require('co')
const pify = require('promise.ify')
const fs = pify.all(require('fs-extra'))
const _ = require('lodash')
const parser = require('./lib/parser.js')
const LocalUtil = require('./lib/util.js')

const FILE_TOO_SMALL = 'file too small'

/**
 * get ID3 info
 */

module.exports = co.wrap(function*(fd) {
  if (typeof fd !== 'number') {
    const filename = path.resolve(fd)
    fd = yield fs.openAsync(filename, 'r')
  }

  const stat = yield fs.fstatAsync(fd)
  if (stat.size < 10) {
    throw new Error(FILE_TOO_SMALL)
  }

  const buf = Buffer.alloc(4)
  yield fs.readAsync(
    fd, buf,
    0, buf.length, 6 // offset, length, position
  )
  const minSize = LocalUtil.getID3TotalSize(buf)
  if (stat.size <= minSize) {
    throw new Error(FILE_TOO_SMALL)
  }

  const stream = fs.createReadStream('', {
    fd,
  })
  const p = parser.create()
  process.nextTick(() => {
    stream.pipe(p)
  })

  const info = yield new Promise(resolve => {
    p.on('readable', function() {
      resolve(p.read())
    })
  })

  const ret = {}

  let singer = _.find(info.ID3, ['id', 'TPE1'])
  let title = _.find(info.ID3, ['id', 'TIT2'])
  let album = _.find(info.ID3, ['id', 'TALB'])
  singer = singer.content
  title = title.content
  album = album.content

  return {
    singer,
    title,
    album,
    raw: info,
  }
})