insomnia-node-libcurl/examples/progress-callback.js

Node bindings for libcurl. Based on the work from node-curl.

/**
 * @author Jonathan Cardoso Machado
 * @license MIT
 * @copyright 2015-2016, Jonathan Cardoso Machado
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is furnished to do
 * so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * Example that shows the use of the the progress callback.
 * The progress bar is made using the node-progress (https://github.com/visionmedia/node-progress) module.
 * You need to install the dev dependencies to make it work.
 */
var Curl = require('../lib/Curl'),
  path = require('path'),
  fs = require('fs'),
  ProgressBar = require('progress');

var curl = new Curl(),
  url = process.argv[2] || 'http://ovh.net/files/100Mio.dat',
  complete = '\u001b[42m \u001b[0m',
  incomplete = '\u001b[43m \u001b[0m',
  outputFile = path.resolve(__dirname, 'result.out'),
  lastdlnow = 0,
  speedInfo = {
    timeStart: [0, 0],
    timeSpent: 0,
    timeLast: [0, 0],
    counter: 0,
    speedAverage: 0,
  },
  bar;

if (fs.existsSync(outputFile)) {
  fs.unlinkSync(outputFile);
}

curl.setOpt('URL', url);
curl.setOpt(Curl.option.NOPROGRESS, false);

//Since we are downloading a large file, disable internal storage
// used for automatic http data/headers parsing.
//Because of that, the end event will receive null for both data/header arguments.
curl.enable(Curl.feature.NO_STORAGE);

// utility function to convert process.hrtime() call result to ms.
function hrtimeToMs(hrtimeTouple) {
  return (hrtimeTouple[0] * 1000 + hrtimeTouple[1] / 1e6) | 0;
}

// The option XFERINFOFUNCTION was introduced in curl version 7.32.0,
// versions older than that should use PROGRESSFUNCTION.
// if you don't want to mess with version numbers,
// there is the following helper method to set the progress cb.
curl.setProgressCallback(function(dltotal, dlnow /*, ultotal, ulnow*/) {
  if (dltotal === 0) {
    return 0;
  }

  if (!bar) {
    console.log();
    bar = new ProgressBar('Downloading [:bar] :percent :etas - Avg :speed Kb/s', {
      complete: complete,
      incomplete: incomplete,
      width: 20,
      total: dltotal,
    });
  }

  speedInfo.timeSpent = process.hrtime(speedInfo.timeStart);

  var now = process.hrtime();

  //update no more than 1 time per second, or if it's the last call to the callback.
  if (((hrtimeToMs(speedInfo.timeLast) / 1000) | 0) === ((hrtimeToMs(now) / 1000) | 0) && dlnow !== dltotal) {
    return 0;
  }

  speedInfo.timeLast = now;

  //average speed
  speedInfo.speedAverage = dlnow / (speedInfo.timeSpent[0] > 0 ? speedInfo.timeSpent[0] : 1);

  if (bar) {
    bar.tick(dlnow - lastdlnow, {
      speed: (speedInfo.speedAverage / 1000).toFixed(2),
    });

    lastdlnow = dlnow;
  }

  return 0;
});

// This is the same than the data event, however,
// keep in mind that here the return value is considered.
curl.setOpt(Curl.option.WRITEFUNCTION, function(chunk) {
  fs.appendFileSync(outputFile, chunk);

  return chunk.length;
});

curl.on('end', function() {
  console.log('Download ended');
  curl.close();
});

curl.on('error', function(err) {
  console.log('Failed to download file', err);
  curl.close();
});

speedInfo.timeStart = process.hrtime();
curl.perform();