Enabling Global Chrome/Web Extension Shortcuts

While debugging an issue with Bookee (keyboard shorcuts not working), I noticed that a friend of mine had an extension installed that allowed her to define a Global Shortcut.

At first, I had no clue what a Global Shortcut was (but I was curious). Upon researching more, I realized that a Global Shortcut allows users to initiate an extension command even when they're not in Chrome!

I thought this was ideal for Bookee, since I often want to go to a bookmarked URL even when I'm not using Chrome. Here are a few things I noticed/ran into:

• Extension shortcuts can be accessed here: chrome://extensions/shortcuts (for security reasons, this link will likely not work)
• This page allows users to override/define Chrome/Web Extension shortcuts, different from what the developer(s) may have defined.
• These settings cannot be changed or defined programmatically; they can only be changed or defined by users.
• A Chrome scope for a shortcut defines the keyboard combination that can be pressed while the Chrome window is the focus
• A Global scope for a shortcut defines the keyboard combination that can be be pressed regardless of what operating-system level application is in focus
• Not all extensions will be able to define a Global shortcut (for example, initially Bookee couldn't).
• In order to allow a user to change the keyboard combination from a Chrome-level shortcut to a Global-level shortcut, changes may need to be made to the manifest.json file for the extension (see below).

---

Manifest changes requireed to allow for Global shortcuts

While exploring the manifest.json file for the Pocket Chrome Extension, I noticed that they define their shortcut combination differently. This is what I had for Bookee before:

"commands": {
    "_execute_action": {
        "suggested_key": {
            "default": "Ctrl+Shift+K"
        },
        "description": "Show Bookee"
    }
}

This is what I changed it to:

"commands": {
    "toggle-bookee-command": {
        "suggested_key": {
            "default": "Ctrl+Shift+K"
        },
        "description": "Toggle Bookee"
    }
}

Then, I naturally had to change the code/logic in the background script (or worker script if you're using version 3 of Chrome's manifest) to listen for that event.

By doing this, it made it possible for users (specifically, me) to change the scope of the keyboard shortcut to Global. Now, I can trigger Chrome to spring into action from any window on my computer.

For a little more context, the _execute_action property for the manifest.json file is kind of like a "default" property. Defining it will make a specific browser-action event available (which you can listen to using chrome.action.onClicked.addListener). But this has limitations: it's scope cannot be changed to Global, which means the keyboard combination will only be available within Chrome.

By defining the keyboard combination through it's own unique key (in this case toggle-bookee-command), the keyboard shortcut can be bound to the operating system (via the Global scope value).

Hope you find this helpful :)

---

Updates

• It turns out that these commands can be defined programmatically by developers, but there are limitations: commands can have a global property defined with a possible value of true or false, but only for commands that follow the following combination format: Ctrl+Shift+[0..9]