Labs/F1/Modularity/WebMod HOWTO

This HOWTO is specifically tailored to web sites that wish to be tightly integrated with Firefox functionality in the form of a Web Module (WebMod).

Architecture

A WebMod extends a well-targeted piece of browser functionality with HTML and JavaScript. WebMods have no standalone abilities to modify the user agent; they only respond to API calls from the user agent. A WebMod is made available by a provider, e.g. Twitter for link-sharing, as HTML and JavaScript served from the provider's domain. It is advertised by a Web-accessible manifest, and it can be "installed" into a user agent that supports this functionality.

The user agent and WebMods communicate over postMessage(). Effectively, a WebMod is a mechanism for a web site to expose an API to the user agent over postMessage().

Advertising a WebMod

A web site can advertise to user agents that it has WebMods available to answer certain API calls using an Open Web App manifest:

{
 "version": "1.0",
 "name": "ShareBook",
 "description": "Sharing with your Friends",
 "icons": {
   "16": "/img/icon-16.png",
   "48": "/img/icon-48.png",
   "128": "/img/icon-128.png"
 },
 "developer": {
   "name": "Share Inc.",
   "url": "http://shareacme.com"
 },
 "default_locale": "en"
 "experimental": {
    "services": {
      "link.share" : {
         "url": "/webmods/link-share",
         "name": "Share via ShareBook"
      }
    }
 }
}