evansiroky/gtfs-sequelize

var fs = require('fs')
var path = require('path')

var async = require('async')
var download = require('download')
var Client = require('ftp')
var parse = require('url-parse')
var rimraf = require('rimraf')

module.exports = function (gtfsUrl, downloadsDir, callback) {
  var err
  if (!gtfsUrl) {
    err = new Error('GTFS download url not specified.')
    return callback(err)
  }

  if (!downloadsDir) {
    err = Error('GTFS download directory not specified.')
    return callback(err)
  }

  try {
    fs.mkdirSync(downloadsDir)
  } catch (e) {
    if (e.code !== 'EEXIST') {
      return callback(e)
    }
  }

  // determine download protocol
  var parsed = parse(gtfsUrl)

  if (['http:', 'https:'].indexOf(parsed.protocol) > -1) {
    // download using http(s) the gtfs and save to the downloads folder
    var dlFile = downloadsDir + '/google_transit.zip'

    console.log('Downloading', gtfsUrl)
    async.auto({
      rm: function (cb) {
        rimraf(dlFile, cb)
      },
      dl: ['rm', function (results, cb) {
        download(gtfsUrl, downloadsDir, { filename: 'google_transit.zip' })
          .then(() => cb())
          .catch(cb)
      }]
    }, callback)
  } else if (parsed.protocol === 'ftp:') {
    // download using ftp
    var c = new Client()
    c.on('ready', function () {
      console.log('downloading ' + parsed.pathname)
      c.get(parsed.pathname, function (err, stream) {
        if (err) {
          callback(err)
          return
        }
        stream.once('close', function () {
          c.end()
          callback()
        })
        stream.pipe(fs.createWriteStream(path.join(downloadsDir, 'google_transit.zip')))
      })
    })
    console.log('connecting to ftp')
    // connect to ftp
    c.connect({
      host: parsed.host,
      user: parsed.username,
      password: parsed.password
    })
  } else {
    var error = new Error('unsupported download protocol')
    return callback(error)
  }
}