Analytics for OER
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CaPReT (capret)

OER reuse tracking and analytics storage

The CaPReT analytics system is a derivative of Hummingbird ( License parsing script derived from openattribute-chrome (


CaPReT provides a script that can be pasted into OER related sites which then serves a 1x1 tracking pixel to users. At the time of copy the script adds license information. In the browser's GET request it sends back tracking data generated by javascript.


  • node.js v0.2.0
  • npm v0.2.4
  • mongodb


git clone
cd capret

# Use npm to install the dependencies
npm install

# Copy the default configuration file
cp config/app.json.sample config/app.json

# To use the map, download MaxMind's GeoIP database and extract to the root directory:
gunzip GeoLiteCity.dat.gz

Running CaPReT

To start the server, run the following:

mongod &   (or start mongo some other way)
node server.js 

If you get the error:

"throw e; // process.nextTick error, or 'error' event on first tick Error: EACCES, Permission denied" 

Then you might be trying to bind to a port below 1024. By default the project is configured for production deployment. Two solutions:

  1. Run as sudo
  2. Open /config/app.json and /config/config.js and change dashboard_port in each from 80 to 8080. Be sure to change the port back when deploying to production.

By default a dashboard will be run on port 8080. You can disable it for production use in config/app.json. The dashboard is just html served out of public/; you can serve it using any webserver.


Make sure to properly secure the dashboard if you don't want outside people to see it. The dashboard httpServer's 'listen' function takes a second argument that is the interface to bind; typically you would choose "" to only allow access from localhost, or "" to listen on all interfaces. In production you should change the instances of "localhost:8000" in public/index.html to point to the server where you're hosting the dashboard.

Architecture Overview

CaPReT is organized into three parts: a node.js-based tracking server that records user activity via a tracking pixel, and a collection of javascript-based widgets that display that activity. The server records all activity in MongoDB and broadcasts it to the clients using WebSockets if possible, and falling back to Flash sockets if necessary.

The capret.WebSocket object receives websocket events from the server in the form of JSON objects. Individual widgets subscribe to a property in the JSON tree and register handler functions to be called whenever that property is present.

The capret scripts can be copied and pasted into any website. The scripts then watch for the copy event in the web page and add the appropriate attribution information.

Logging Customization

Metrics are stored in lib/metrics and auto-loaded. Each metric contains a handler function that is called every time a new user event occurs. Metrics store data in the data object property which gets emitted to clients in intervals specified by the metric. A basic example can be found in lib/metrics/total_views.js. An example of how a metric can filter based on urls is in lib/metric/sales.js.

Display Customization

CaPReT comes with some stock widgets (Counter, Logger, Graph) that demonstrate how to hook into the data provided by the node.js server. For the minimum amount required to create a widget, see public/js/widgets/logger.js. A widget is an object whose prototype extends capret.Base and implements onMessage.


Use node-inspector. More instructions here:

Start Capret: node --debug server.js

Then start the inspector: node-inspector &

Last visit:


sudo gem install jspec
jspec run --node




CaPReT (capret) is licensed under the MIT License. (See LICENSE)


CaPRéT was developed by Tatemae and the MIT Office of Educational Innovation and Technology with support from JISC CETIS.