index.js

var request = require('request')
var mkdir = require('mkdirp')
var once = require('once')

var http = require('http')
var path = require('path')
var fs
try {
  fs = require('graceful-fs')
} catch (ex) {
  fs = require('fs')
}

module.exports = fetch

function fetch(remote, local, options, cb) {
  if (typeof cb !== "function") cb = options, options = {}
  cb = once(cb)
  mkdir(path.dirname(local), function (err) {
    if (err) return cb(err)
    fetch_(remote, local, options || {}, cb)
  })
}

function fetch_(remote, local, options, cb) {
  var mode = options.mode || 0666; //npm.modes.file
  var fstr = fs.createWriteStream(local, { mode : mode })
  var response = null

  fstr.on("error", function (err) {
    cb(err)
    fstr.close()
  })

  if (typeof remote === 'string') remote = {uri: remote}
  var req = request(remote)
  req.on("error", function (err) {
    cb(err)
    fstr.close()
  })
  req.pipe(fstr)

  req.on("response", function (res) {
    response = res
    response.resume()

    // Work around bug in node v0.10.0 where the CryptoStream
    // gets stuck and never starts reading again.
    if (process.version === "v0.10.0") {
      response.resume = (function (orig) {
        return function() {
          var ret = orig.apply(response, arguments)
          if (response.socket.encrypted)
            response.socket.encrypted.read(0)
          return ret
        }
      }(response.resume))
    }
  })

  fstr.on("close", function () {
    var err = null
    if (response && response.statusCode && response.statusCode >= 400) {
      err = new Error(response.statusCode + ' ' + http.STATUS_CODES[response.statusCode])
    }
    cb(err, response)
  })
}