Harnessing the Mozilla Platform

Brian King

Independent Consultant / mozdev.org / Mozdev Group, Inc.

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Introduction

• Web Applications are becoming widely deployed.
• Lines being blurred between Client and Server (Web) applications.
• Mozilla:
  • Uses proven Web technologies
  • Runtime interpretation of non-compiled languages such as XUL, JavaScript and CSS
  • (D)HTML falls short in the UI space (e.g. context menus, tabs, ...)
  • Cross-platform rich client application development
  • Viable alternative to the more costly development cycle of traditional software development

Development Platform

• XPFE - Cross-Platform Front End
  • Widget Toolkit (XUL/XBL)
  • Style (CSS) and Implementation (JavaScript, RDF)
• Component Architecture - XPCOM
  2,000+ of XPCOM interfaces available:
  • Image handling
  • Security
  • File System
  • Plugins
  • Much more ...
• Cross Platform - "Write once, run anywhere"
• Win, Max OS 9/OS X, Linux, HP UX, FreeBSD, OS/2 ...(see ports page)

XPFE Layer Model

XUL - Benefits

• Of Language:
  • Separation of content, functionality and style
  • Cross-platform
  • l10n enabled - Easily localisable
• To Developers:
  • Uses technologies that are familiar
  • No compilation
  • Quick Prototyping / Faster development time
  • Promotes Customisability - themes, locales

XUL Features

• Widgets and Controls
• Box Model - boxes, grids, stacks
• Window, Dialog, Page, Wizard
• Buttons, Menus, Tabs, ...
• Tabular data - Tree, Listbox
• Content widgets - (tab)browser, iframe and editor
• Templates
• Hierarchal structures displaying data collected from RDF datasources
• Overlays
  • Modularisation of code in separate files
  • *New* Dynamic Overlays pulled in after document load.
    document.loadOverlay(file, observer);

XBL

• Extensible Bindings Language
• 'Bind/Attach' content, layout and behaviour to new widget
• New widgets + extending existing ones
• Still in development - 2.0 spec currently being written.

XBL Example

  <binding id="mySidebarTabs"
           extends="chrome://global/content/bindings/tabbox.xml#tabs">
    <content>
      <xul:hbox aID="row1">
        <children includes="tabupper" />
      </xul:hbox>
      <xul:hbox aID="row2">
        <children includes="tablower" />
      </xul:hbox>
    </content>
    <implementation>
      // Method and properties go here
    </implementation>
  </binding>

XBL Model

Accompanying Technologies

• JavaScript
• CSS
• XUL Overlays
• RDF
• XUL Templates

XPCOM

• Cross-Platform Component Object Model
• Components in theoretically any language - currently implementations in JavaScript, C++, and Python (PyXPCOM)
• XPConnect - "Scriptable" IDL interfaces

Localisation

• Infrastructure for multiple-locale applications
• DTD Entities (.dtd) and String Bundles (.properties)
• Menu items, buttons, statusbar, Help files, ... anything that is visible
• Language Packs for UI customisation
• Language switching via global preferences:
  
  general.useragent.locale

Web Services and More...

• Web Services
  • XMLHttpRequest
  • XML-RPC
  • SOAP (sketchy)
• Extras
  • Database support (PostgreSQL, MySQL)
  • XSLT
  • XPath
  • MathML
  • SVG and Canvas, using Cairo libraries
  • "Web ready"

Mozilla Architecture Diagram

(Click for larger version)

Software Installation

• XPInstall
  • XPI file format
  • One click install
  • APIs for writing installation scripts in JavaScript
  • Handles installation, registration ...
  • Used for language packs, software add-ons, toolbars ...
• Extension Manager
  • RDF install file (install.rdf)
  • Built-in UI
  • Functionality - Uninstall, Disable
  • Access to extension Options
  • Version control and built-in Update system
• Custom Installer

Deployment

• Extensions:
  • Browser/Mail add-ons, Themes, Language packs
  • Require an install script (install.js, install.rdf)
  • Auto Update built into the EM
• Distributions:
  • Building from source required
  • Packaged with installer
  • Which Branch Tag to use?
    • Stable releases are the best for production
    • Use trunk for latest features and bug fixes

XULRunner 1 (1.9)

• Bootstrap XPCOM+XUL applications - GRE (Gecko Runtime Environment)
• Customisable executable name, icons, profile directory, and more
• Uses the latest toolkit
• Built-in Installer (eventually)
• Still in early development stages, but maturing all the time. Only stable developer releases.

XULRunner 2

Getting the GRE Runtime

2 Options:

1. Download and build from source
2. Download a nightly (trunk) build

XULRunner 3

Application Structure

XULRunner 4

Entry Point

• The application has to know where to start...
• Options
  1. In Preferences
     pref("toolkit.defaultChromeURI", "chrome://openkiosk/content/go.xul");
  2. Override the default command line handler with your own.

XULRunner 5

application.ini

The application will not install without this file which containes meta information.

[App]
Vendor=My Company
Name=mycoolapp
Version=1.0
BuildID=20051123
Copyright=Copyright (c) 2005 My Company

[Gecko]
MinVersion=1.8
MaxVersion=1.9a1

XULRunner 6

Registering the GRE

xulrunner -register-global

This updates the registry on Windows (HKLM\Software\mozilla.org\GRE), and writes to /etc/gre.d on Linux.

XULRunner 7

Deployment 1 - Launching from Flat Structure

xulrunner /path/to/my/application/application.ini

This will launch the application directly from where it is unpacked on the system.

Linux : ./xulrunner -install-app /path/to/my/application.xpi
    Installed to /usr/lib/<vendor>/<appname>/

Mac : /Library/Frameworks/XUL.framework/xulrunner-bin -install-app /path/to/my/application.xpi
    Installed to /Applications/<vendor>/<Appname>

Windows : xulrunner.exe -install-app /path/to/my/application.xpi
    Installed to c:\Program Files\<vendor>\<appname>\