ISML Parsing Bench

isml_bench.js

var _ = require('lodash');
var Promise = require('bluebird');
var sax = require('sax');
var manifest = require("raw!./manifest.xml");

function domParser() {
  function parseStreamIndex(el) {
    var index = [];
    if (!el) { return; }
    var cdren = el.children;
    if (!cdren) { return; }
    for (var i = 0; i < cdren.length; i++) {
      index.push({ d: +cdren[i].getAttribute('d'), c: +cdren[i].getAttribute('c') });
    }
    return index;
  }

  var xml = new DOMParser().parseFromString(manifest, 'application/xml');
  var sidx = xml.getElementsByTagName('StreamIndex');
  var indexes = [];
  for (var i = 0; i < sidx.length; i++) {
    indexes.push(parseStreamIndex(sidx[i]));
  }

  return indexes;
}

function lodParser() {
  var xml = new DOMParser().parseFromString(manifest, "application/xml");
  return _.map(xml.getElementsByTagName('StreamIndex'), function(el) {
    return _.map(el.children, (c) => ({ d: +c.getAttribute('d'), c: +c.getAttribute('c')}));
  });
}

function saxParser() {
  return new Promise(function(done, fail) {
    var parser = sax.parser(true /* strict */);
    var indexes = [];
    var index;
    parser.onopentag = (node) => {
      if (node.name === 'StreamIndex') {
        index = [];
      } else if (node.name === 'c') {
        index.push(node.attributes);
      }
    };
    parser.onclosetag = (node) => {
      if (node === 'StreamIndex') {
        indexes.push(index);
      }
    };
    parser.onerror = (err) => fail(err);
    parser.onend = () => done(indexes);
    parser.write(manifest).close();
  });
}

function xhrParser() {
  return new Promise(function(done) {
    var xhr = new XMLHttpRequest();
    var url = "http://mediacenter.apps.canallabs.fr/live/hss/canalplus-hd.isml/manifest";
    xhr.open('GET', url);
    xhr.setRequestHeader('X-Requested-With', 'hss-live-m1-l3.canal-plus.com');
    xhr.onload = (e) => {
      var xml = e.target.responseXML;
      done(_.map(xml.getElementsByTagName('StreamIndex'), (el) => {
        return _.map(el.children, (c) => ({ d: +c.getAttribute('d'), c: +c.getAttribute('c') }));
      }));
    };
    xhr.send();
  });
}

function bench(name, fn, num) {
  var now = Date.now();
  return Promise.reduce(_.range(0, num), fn, 0).then(() => {
    var tot = Date.now() - now;
    document.body.innerHTML += `<p>${name} (${num}): ${tot / num}</p>`;
    return 1;
  });
}

document.body.style.marginLeft      = "100px";
document.body.style.backgroundColor = "red";
document.body.style.fontFamily      = "courier";
document.body.style.fontSize        = "50px";

Promise.resolve()
  .then(() => bench('dom', domParser, 100)).delay(500)
  .then(() => bench('lod', lodParser, 100)).delay(500)
  .then(() => bench('sax', saxParser, 100)).delay(500)
  .then(() => bench('xhr', xhrParser, 10)).delay(500);

// Bench (in ms)
// +-------------------------------------------+
// |        | chrome | stb (tvhd) | stb (notv) |
// | dom    |  148.1 |     19,239 |     10,657 |
// | lodash |  128.4 |     18,432 |     10,186 |
// | sax    |  603.6 |    121,911 |     55,968 |
// |        |        |            |            |
// | xhr    |  4,183 |     22,132 |     12,350 |
// +-------------------------------------------+