Building Browser Extensions: Create Modern Extensions for Chrome, Safari, Firefox, and Edge

Table of Contents
About the Author
About the Technical Reviewer
Acknowledgments
Foreword
Introduction
Chapter 1: What Are Browser Extensions?
	History of Browser Extensions
		Customizing Software with Plugins
		History of Web Browsers
		Native Browser Plugins
		From Browser Add-ons to Extensions
	The Browser Extension Landscape
		Comparing Mobile Apps and Browser Extensions
		Browser Extension Stores
		Types of Browser Extensions
			Ad and Tracking Blockers
			Password Managers
			Smart Writing Management Tools
			Accessibility Tools
			Content and Link Aggregators
			Tab Management Tools
			Screen Recording Tools
			Integrations for Software Platforms
			Digital Currency Wallets
			Developer Tools
	Summary
	Credits
Chapter 2: Fundamental Elements of Browser Extensions
	The Browser Model
		Browser Tabs
		Same-Origin Policy
	The Browser Extension Model
		Independent JavaScript Pages and Runtimes
		Native APIs and User Interfaces
		Tab and Domain Access
		Observing and Intercepting Network Requests
	Elements of Browser Extensions
		Extension Manifest
			Manifest v2 and v3
		Background Scripts
		The Popup Page
		The Options Page
		Content Scripts
		Devtools Panels and Sidebars
	Extension Elements in Action
		Honey
		LastPass
		Grammarly
		React Developer Tools
	Summary
Chapter 3: Browser Extension Crash Course
	Creating the Manifest
	Minimum Viable Extension
	Installing Your Extension
	Reloading Your Extension
	Adding a Background Script
	Adding a Popup Page
	Adding an Options Page
	Adding a Content Script
	Working with Multiple Tabs
	Adding a Devtools Panel
	Summary
Untitled
Chapter 4: Browser Extension Architecture
	Architecture Overview
	Plurality, Lifecycles, and Updates
		Background Service Worker
		Popup and Options Pages
		Devtools Pages
		Content Scripts
	Browser Extension File Server
	Sandboxed Pages
	Summary
Chapter 5: The Extension Manifest
	The Manifest File
	Supporting Different Locales
	Match Patterns and Globs
		File Path Match Patterns
		URL Match Patterns
		URL Globs
	Manifest Properties
		action
			default_icon
			default_popup
			default_title
			browser_style
			theme_icons
		author
		automation
		background
			Manifest v2 background scripts
			Manifest v2 background page
			Manifest v2 persistent pages and event pages
			Manifest v3 service worker
		browser_action
		browser_specific_settings
		chrome_settings_overrides
			Custom Homepage
			Custom Search Engine
			Custom Startup Page
		chrome_url_overrides
		commands
			Command Syntax
			Defining Key Shortcuts
			Multi-browser Support
			Reserved Commands
			Custom Commands
			Global Commands
		content_capabilities
		content_scripts
		content_security_policy
			Manifest v2 content security policy
			Manifest v3 content security policy
		converted_from_user_script
		cross_origin_embedder_policy
		cross_origin_opener_policy
		declarative_net_request
		default_locale
		description
		developer
		devtools_page
		differential_fingerprint
		event_rules
		externally_connectable
		file_browser_handlers
		file_system_provider_capabilities
		homepage_url
		host_permissions
		icons
		incognito
		key
		manifest_version
		minimum_chrome_version
		nacl_modules
		name
		oauth2
		offline_enabled
		omnibox
		optional_host_permissions
		optional_permissions
		options_page
		options_ui
			browser_style
			open_in_tab
		page_action
		permissions
		platforms
		replacement_web_app
		requirements
		sandbox
		short_name
		storage
		system_indicator
		tts_engine
		update_url
		version
		version_name
		web_accessible_resources
			Manifest v2
			Manifest v3
	Summary
Chapter 6: Understanding the Implications of Manifest V3
	Motivation for Manifest V3
		Security
		Performance
			Migration to DeclarativeNetRequest
			Migration to Service Workers
		Privacy and Transparency
		Revenue
	Implications of Background Service Workers
		DOM
		XMLHttpRequest
		Timer API
		Event Handlers
		Service Worker Persistence
		Global State and Storage
		Audio and Video
	Implications of Content Security Policy Restrictions
	Implications of DeclarativeNetRequest
	Summary
Chapter 7: Background Scripts
	Web Page Service Workers vs. Extension Service Workers
		Similarities
			Single Occupancy
			Installation and Lifecycle
			Top-Level Event Handling
			Async Messaging
		Differences
			Registration
			Purpose
	Manifest v2 vs. Manifest v3
		Scripts vs. Service Workers
		JavaScript Imports
		No Access to DOM and Limited Global APIs
		Nonpersistent
		No Shutdown Event
		No Programmatic Background Access
	Working with Background Scripts
		Inspecting Background Service Workers
		Service Worker Errors
		Service Worker Termination
	Common Patterns
		Event Handler
		Secret Management and Authentication
		Message Hub
		Storage Manager
		Injecting Scripts
		Sniffing Web Traffic
		Installed/Updated Events
		Opening Tabs
	Forcing Service Worker Persistence
		Implementation
		Drawbacks and Limitations
	Summary
Chapter 8: Popup and Options Pages
	Popup Pages
		Popup Page Properties
		Opening and Closing Popup Pages
		Changing the Popup Page
		Detecting Popup State
		Suggested Use
	Options Pages
		Options Page Properties
		Opening and Closing Options Pages
		Detecting Options Pages
		Suggested Use
		Content Script Restrictions
	Summary
Chapter 9: Content Scripts
	Introduction to Content Scripts
		Injecting CSS
		Content Script Isolation
		Page Automation
		Logging and Errors
	Extension API Access
	Modules and Code Splitting
	Bundling
		Dynamic Imports
		Dynamic Script Tags
	Specialized Content Script Properties
	Programmatic Injection
	Summary
Chapter 10: Devtools Pages
	Introduction to Devtools Pages
		Creating a devtools Page
		Adding panels and sidebars
			Adding a Panel
			Adding a Sidebar
	The Devtools API
	Sniffing network traffic
	Inspecting the Page
	Content Scripts and Devtools Messaging
	Other Devtools API Features
	Summary
Chapter 11: Extension and Browser APIs
	Global API Namespace
	Promises vs. Callbacks
	Error Handling
	Context-restricted APIs
	Events API
		Format
		Event Filtering
	WebExtensions API Quick Reference
		Permissions
		Messaging
			One-off Messages
			Opening Message Ports
			Messaging Native Applications
			Messaging Other Extensions
		Storage
		Authentication
	Network Requests
		Internationalization
		Browser and System Control
			Power
			Omnibox
			Action
			Notifications
			Context Menu
		Page and Screen Capture
		Proxy
		Browser State Management
			Font Settings
			Content Settings
			Cookies
			Bookmarks
			History
			Downloads
			Top Sites
			Browsing Data
			Sessions
		Tabs and Windows
		Debugger
		Search
		Alarms
		Scripting
		DOM
		Text to Speech
		Privacy
		Idle
		Devtools
		Extension Introspection
		Extension Management
		System State
		Enterprise Only
		Firefox Only
		Chrome OS Only
		Deprecated
	Summary
Chapter 12: Permissions
	Permissions Basics
	Checking Permissions
	Using Optional Permissions
		Granting Permissions Declaratively vs. Imperatively
		Permission Request Idempotence
	Host Permissions
		Permissions Lifetime
	Permissions Warnings
		Testing Permissions Warnings
	Considerations for Published Extensions
		Triggering the Slow Review Queue
	Auto-Disable Updates
	Permissions List
		activeTab
		alarms
		background
		bookmarks
		browserSettings
		browsingData
		captivePortal
		certificateProvider
		clipboardRead
		clipboardWrite
		contentSettings
		contextMenus
		contextualIdentities
		cookies
		debugger
		declarativeContent
		declarativeNetRequest
		declarativeNetRequestFeedback
		declarativeWebRequest
		desktopCapture
		Devtools page
		dns
		documentScan
		downloads
		downloads.open
		enterprise.deviceAttributes
		enterprise.hardwarePlatform
		enterprise.networkingAttributes
		enterprise.platformKeys
		experimental
		fileBrowserHandler
		fileSystemProvider
		find
		fontSettings
		gcm
		geolocation
		history
		Host Permissions
			Global Host Permission
			Partial Host Permission
		identity
		idle
		loginState
		management
		menus
		menus.overrideContext
		nativeMessaging
		notifications
		pageCapture
		pkcs11
		platformKeys
		power
		printerProvider
		printing
		printingMetrics
		privacy
		processes
		proxy
		scripting
		search
		sessions
		signedInDevices
		storage
		system.cpu
		system.display
		system.memory
		system.storage
		tabCapture
		tabGroups
		tabHide
		tabs
		theme
		topSites
		tts
		ttsEngine
		unlimitedStorage
		vpnProvider
		wallpaper
		webNavigation
		webRequest
		webRequestBlocking
	Summary
Untitled
Chapter 13: Networking
	Comparing Websites and Extensions
	Networking Architecture
		Options Pages
		Popup and Devtools Pages
		Content Scripts
		Background Scripts
	Pinning an Extension ID
	Authentication Styles
		No Authentication
		Content Script Spoofing
		Cookie Authentication
		Json Web Token Authentication
		OAuth and OpenID
	OAuth, OpenID, and the Identity API
		OAuth API Methods
		OAuth Redirect URLs
		Configuring the Authorization Platform
		Additional Help
	OAuth and OpenID Examples
		Google OAuth with getAuthToken()
		Google OpenID with launchWebAuthFlow( )
		Manual Github OAuth with launchWebAuthFlow()
	Networking APIs
		The webNavigation API
		The webRequest API
			Modifying Requests
			Fragmentation
		The declarativeNetRequest API
			Permissions
			Rule and Ruleset Structure
			Static Rulesets
			Dynamic Rules
	Summary
Chapter 14: Extension Development and Deployment
	Local Development
		Inspecting Your Extension
			Inspecting an Extension View
			Inspecting a Background Service Worker
			Inspecting a Content Script
		File Changes
		Error Monitoring
		Extension Reloads
	Automated Extension Tests
		Unit Tests
		Integration Tests
		Additional Reading
	Publishing Extensions
		Store Listing
		Privacy Practices
	Review Process
	Updating Extensions
		Update Considerations
			Update Delays
			Auto-Disabling
		Cancelling Updates
		Automated Update Publishing
	Tracking User Activity
		Dashboard Metrics
		Analytics Libraries
		Setting Up Google Analytics
			Set Up ga.js
		Install and Uninstall Events
	Summary
Chapter 15: Cross-Browser Extensions
	Introduction to Cross-Browser Support
	Browser Coverage Tradeoffs
		Browser Share
		Chromium Browser Extension Sharing
	Adapting Your Codebase
		API Probing
		Differential Manifests
		Manifest v2/v3
	Extension Marketplaces
		Marketplace Similarities
		Marketplace Differences
		Chrome Web Store
		Add-ons for Firefox
		Microsoft Edge Add-ons
		Safari Extensions App Store
		Opera Addons
	Mobile Extensions
		Mobile Extension User Interfaces
		Kiwi Browser
		Firefox Mobile
		iOS Safari
	Automated Deployment
	WebExtensions API Support
	Safari Extension Development
		Prerequisites
		Architecture
		Creating an Extension Project
		Writing the App
		Testing on macOS
		Testing on iOS
		Deploying to the App Store
		Converting an Existing Extension
	Firefox Idiosyncrasies
		Manifest Versions
		Sidebars
		API Additions
	Summary
Chapter 16: Tooling and Frameworks
	Building Extensions with React
		Single Entrypoint React Extensions
		Multiple Entrypoint React Extensions
		Reactive State Management
		Routing
			Extension Views and HashRouter
			Content Scripts and MemoryRouter
	Mozilla Tools
		web-ext
		webextension-polyfill
	Bundlers and CLI Tools
		Parcel
		Webpack
	Plasmo
		High-level Overview
		JavaScript Frameworks
		Documentation and Examples
		Differential Build Outputs
		Automatic Manifest Generation
		Icon Generation
		Bundling Remote Code
		Environment Variables
		Content Script Mounting
		Extension-friendly Hot Module Replacement
		Automated Deployment with Browser Platform Publish
	Useful Sites
	Summary
Index