The Device

• Developed by Google
• Announced and went to market on July 24, 2013
• Costs only 35$
• Runs web applications, primarily built for multimedia streaming

Hardware

• Model H2G2-42
• Armada 1500-mini system on a chip
• Hardware codec decoding
• 1080p HDMI output supporting CEC
• WiFi
• 512 Mb of RAM
• 2 Gb of flash storage

Software

• "a simplified version of Chrome OS"
• Acts as a single Chrome tab
• SKD available for:
  • Android 2.3+
  • iOS 6.0+
  • Chrome 28+
• SDK went public on February 3, 2014

"Chromecast cast button icon" by Google, Inc. - https://developers.google.com/cast/docs/downloads. Licensed under Creative Commons Attribution 3.0 via Wikimedia Commons

How does it work?

• mDNS is used for device discovery
• Sender devices (i.e. Android, iOS or Chrome client) instruct receiver (Chromecast) to open specific URL where application is hosted
• Sender and receiver apps communicate using WebSockets
• These operations are abstracted with Chromecast receiver and sender APIs
• Once ran, receiver app is able to communicate over the Internet without sender

And security?

• Sender device must be in the same WiFi as the receiver
• Chromecast application is run inside the Chrome browser so all security contrains apply, just as they apply on a regular web page

Implementing the receiver

• API provides simple mechanisms for asynchronous communication
• //www.gstatic.com/cast/sdk/libs/receiver/
  /2.0.0/cast_receiver.js

• cast.receiver.CastReceiverManager

  • Singleton that manages connected senders and message buses

• cast.receiver.CastMessageBus

  • Manages messages for a specific namespace

Implementing the receiver

• cast.receiver.CastChannel

  • Manages messages for a specific sender and namespace

• cast.receiver.MediaManager

  • Used to handle media messages
  • Last class in the API!

Chrome is underneath!

• Apps are run in (almost) latest version of  Chrome browser
  • All the ugly things related to the web application development are gone!
• Debugging is easy
  • Chrome developer tools are available at Chromecast's IP at port 9222

Problems?

• It is still a new technology, there are known issues
• Chromecast is weak
  • Use native CSS animations!
• Cross-origin requests
  • Server side must implement CORS