Firefox Add-ons Workshop

CMRIT | 29th July, 2017

Santosh Viswanatham

Work at Infosys Ltd

Mozilla Tech Speaker

Mozilla Rep

Web Developer

@isantoshv | viswanathamsantosh.github.io |viswanathamsantosh@gmail.com

Hi.

We’re Mozilla, the proudly non-profit champions of the Internet, helping to keep it healthy, open and accessible to all.

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Local groups of students with a passion for technology working together to build the open web on University and College campuses worldwide.

A global Community of Volunteers

  • Browser Add-ons
  • WebExtensions
  • Anatomy of WebExtensions
  • Building your first Add-on

Agenda

Browser Add-ons extend and modify the functionality of the browser.

Browser Add-ons?

Firefox is the most customizable browser!

1 Million+ addons downloaded everyday

70+ Add-ons published everyday

250 million+ Add-ons used everyday

2000+ users signup everyday

WebExtensions

A cross-browser system for developing browser add-ons

  • Uses standard HTML, CSS and JS
  • e10s compatible (multiprocess)
  • Few changes and you can run it on Chrome, Edge and Opera
  • Documentations from multiple resources.

Why WebExtensions?

http://arewewebextensionsyet.com

Few WebExtension API's

Anatomy/Architecture of WebExtensions

manifest.json

{
  "manifest_version": 2,
  "name": "inShorts in dark",
  "version": "2.0.1",
  "homepage_url": "https://github.com/viswanathamsantosh/inshorts",
  "description": "Read your favourite news on inShorts by dimming the light right away on your browser.",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "permissions": [
    "activeTab",
    "tabs"
  ],
  "browser_action": {
  "browser_style": true,
  "default_icon": {
    "19": "icons/icon-19.png",
    "38": "icons/icon-38.png"
  },
  "default_title": "Turn on or off"
  },
  "background": {
    "scripts": ["background.js"]
  }
}

Background scripts

  • Loaded as soon as the extension is loaded

  • Stay loaded until the extension is disabled or uninstalled

  • You can use any of the WebExtension APIs in the script

"background": {
  "scripts": ["background-script.js"]
}

Content Scripts

  • Similar to loading normal scripts in the page

  • Can access DOM structure and use a small subset of the WebExtension APIs

  • Make cross-domain XHR requests

  • Exchange messages with their background scripts and can in this way indirectly access all the WebExtension APIs

"content_scripts": [
  {
    "matches": ["*://*.mozilla.org/*"],
    "js": ["jquery.js", "content-script.js"]
  }
]

Browser action

  • Used to add button to browser toolbar
  • Use this when your add-on's features are applicable to all websites else use Page action instead.
"browser_action": {
  "default_icon": {
    "19": "button/geo-19.png",
    "38": "button/geo-38.png"
  },
  "default_title": "Whereami?",
  "default_popup": "popup/choose_beast.html"
}
browser.browserAction.onClicked.addListener(handleClick);

Page action

  • Used to add button to address toolbar
  • Use this when your add-on's features are specific to a particular website.
"page_action": {
  "default_icon": {
    "19": "button/geo-19.png",
    "38": "button/geo-38.png"
  },
  "default_title": "Whereami?",
  "default_popup": "popup/choose_beast.html"
}
browser.pageAction.onClicked.addListener(handleClick);

Web-accessible resources

Resources such as images, HTML, CSS, and JavaScript that you include in the extension.

Developing your first browser add-on

  • Adding a browser action
  • Adding a page action
  • Accessing DOM from content scripts
  • Using a couple of WebExtension API's
  • Debugging your add-on

Debugging your add-on

Links:

  • https://developer.mozilla.org/en-US/Add-ons/WebExtensions
  • https://developer.chrome.com/extensions
  • https://github.com/mdn/webextensions-examples
  • https://wiki.mozilla.org/WebExtensions

Need help?

IRC Channels: #webextensions, #extdev, #addons

Mailing List: https://mail.mozilla.org/listinfo/dev-addons

Telegram: @addonschat

Questions?

Santosh Viswanatham | @isantoshv | viswanathamsantosh@gmail.com

Slides: https://slides.com/isantoshv/fx-addons-workshop

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