Event pages keep apps and extensions efficient by allowing them to respond to a variety of
events such as timers or navigation to a particular site, without having to remain running
persistently. But what if you need to respond to something that occurs outside of Chrome, such
as a news alert, a message sent to a user or a stock hitting a price threshold? Until now, you
had to do this by repeatedly polling a server. This process consumed bandwidth and reduced the
battery life of your users’ machines. For a more efficient solution, starting today you can
use Google Cloud
Messaging for Chrome (GCM) - across all channels of Chrome.
Request a token (channel ID) via chrome.pushMessaging.getChannelId().
Pass the returned token to your server.
Whenever you need to send a message to your app or extension, post the message along
with the token to the GCM server-side API.
Your message is then delivered in near real time to Chrome. This makes your event
page wake up (if it’s not already running), and the message is delivered to your chrome.pushMessaging.onMessage listener.
To use GCM, your users must be signed into Chrome, as the service relies on an efficient push
channel that’s only established for signed-in users. Messages are automatically delivered to
all the devices where the user has signed in and installed your app/extension.
To add GCM to your app/extension, take a look at the overview of the
service or start with some of the sample
apps—and start pushing!
Mark Scott is a Product Manager on the Google Chrome team. He works with a team in
Kirkland on features that make Chrome a great platform for building
apps.
By Mark Scott, Product Manager, Chrome