Optimizely

Runs optimizely experiments in node using either jsdom (node-0.10 only, full-featured, resource-hungry) or cheerio+node-vm (0.10 and 0.12, simple, lightweight)

Install

npm install optimizely --save

Usage

1. Load processing environment

// jsdom
var optimizely = require('optimizely')('jsdom');

// node vm
var optimizely = require('optimizely')('node_vm');

2. Attach Optimizely code library

optimizely.setOptimizely(optimizelyCode);

3. Process html page

// req - http request
// callback – return path out of this middleware

var originalHtml = getFinalHtmlBeforeResponse();

optimizely(req, originalHtml, function(err, modifiedHtml, extras)
{
  // only pass error if html isn't returned
  if (err && !html)
  {
    return callback(err);
  }

  // extras.images – array of image-src;
  // extras.cookies – cookie object;

  // return modified html
  callback(null, html);  
});

Notes

jQuery

In jsdom processor trimmed version of jQuery is used, which is provided by optimizely itself and bundled with the module. In turn node_vm processor is relying on augmented cheerio module.

Cookies

Module oven is used for cookie handling and it's cookie jar instance is returned in callback. Method extras.cookies.getCookieHeader() could be used to get cookie header formated string and extras.cookies.getCookies() to get list of cookie objects.

Images

Along with creating new cookies, optimizely adds images to track performed experiments, to make it slim and less opinionated, list of images passed to callback (extras.images) instead of modifying html in place.

TODO

• More tests
• Autoload of optimizely code