src/downloaders.js


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54

const fs = require('fs')
const fetch = require('node-fetch')
const promisifyProcess = require('./promisify-process')
const tempy = require('tempy')
const path = require('path')
const sanitize = require('sanitize-filename')

const { spawn } = require('child_process')
const { promisify } = require('util')

const writeFile = promisify(fs.writeFile)

function makeHTTPDownloader() {
  return function(arg) {
    const dir = tempy.directory()
    const out = dir + '/' + sanitize(decodeURIComponent(path.basename(arg)))

    return fetch(arg)
      .then(response => response.buffer())
      .then(buffer => writeFile(out, buffer))
      .then(() => out)
  }
}

function makeYouTubeDownloader() {
  return function(arg) {
    const tempDir = tempy.directory()

    const opts = [
      '--quiet',
      '--extract-audio',
      '--audio-format', 'wav',
      '--output', tempDir + '/dl.%(ext)s',
      arg
    ]

    return promisifyProcess(spawn('youtube-dl', opts))
      .then(() => tempDir + '/dl.wav')
  }
}

function makeLocalDownloader() {
  return function(arg) {
    // Since we're grabbing the file from the local file system, there's no
    // need to download or copy it!
    return arg
  }
}

module.exports = {
  makeHTTPDownloader,
  makeYouTubeDownloader,
  makeLocalDownloader
}