I am building a packaged chrome app (It is needed as I want to access chrome.socket). I have a website from which I would like to call my app (if installed or ask the user to install it) by clicking a link. Is this possible ? Not able to find any easy way for this workflow.
The url_handlers might be the best way to achieve this.
You can also use the externally_connectable manifest property to declare that your website can connect to your app, then call chrome.runtime.sendMessage or chrome.runtime.connect from your webpage and handle it in an chrome.runtime.onMessage handler in the app.
Which one is better suited depends on your needs. The url_handlers is an easier way, but it will permanently assign the URL on your link to your app, so you won't be able to use it for anything else if the app is installed. The externally_connectable is a harder way, but it enables a much more elaborate bidirectional communication between your website and the app.
You can even use a combination of the two approaches, if you need: launch the app using the url_handlers feature, then establish a communication channel back to the website once the app is up and running.
Apps can now (as of Chrome 31 I believe) register to handle urls by adding url_handlers in their manifest and detecting the url causing the app to launch in the chrome.app.runtime.onLaunched event. If the app doesn't launch, your hosted web site will be loaded an can present an inline installation with chrome.webstore.install.
来源：https://stackoverflow.com/questions/19519277/activate-chrome-app-from-web-page