Install.js

This page is part of the extension development documentation project.

Ask your questions in MozillaZine Forums. Also try browsing example code.

Note: development documentation is in process of being moved to Mozilla Development Center (MDC).

To make your extension install in Mozilla Suite, SeaMonkey, Mozilla Firefox pre-0.9 and Mozilla Thunderbird pre-0.7, you need to have an install.js file in the root of your XPI file. If you want your extension install in Firefox 0.9 and later and/or Thunderbird 0.7 and later only, you don't need install.js, you need an install.rdf instead.

See also [1] from XulPlanet's Main Tutorial.

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There is a different sample install.js template located at http://downloads.mozdev.org/xsidebar/mods/. This version has been developed as part of the effort to port Firefox extensions to SeaMonkey from the xSidebar Project.

Pros: This version consolidates all the changable information at the top of the file. And it also knows how to install packaged components, search engines and default preferences.

Cons: Code is bloated since it has to cater for several different ways an extension author can package the .JAR file contained in the .XPI file.

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XPI file structure

You can use the code below (taken from Pike's extensions [2]). It assumes the following structure of your XPI file:

sampleext.xpi
  chrome\
    sampleext.jar
      content\
        sampleext\
      locale\  (optional)
        en-US\
          sampleext\
        ...
      skin\    (optional)
        classic\
          sampleext\
        ...
  install.js
  install.rdf (optional -- see above)

Code

// install.js
// XpiInstaller
// By Pike (Heavily inspired by code from Henrik Gemal and Stephen Clavering)

var XpiInstaller = {
	// --- Editable items begin ---
	extFullName: 'Sample Extension', // The name displayed to the user (don't include the version)
	extShortName: 'sampleext', // The leafname of the JAR file (without the .jar part)
	extVersion: '1.0',
	extAuthor: 'Insert-your-name-here',
	extLocaleNames: null, // e.g. ['en-US', 'en-GB']
	extSkinNames: null, // e.g. ['classic', 'modern']
	extPostInstallMessage: null, // Set to null for no post-install message
	// --- Editable items end ---
	
	profileInstall: true,
	silentInstall: false,
	
	install: function()
	{
		var jarName = this.extShortName + '.jar';
		var profileDir = Install.getFolder('Profile', 'chrome');
		
		// Parse HTTP arguments
		this.parseArguments();
		
		// Check if extension is already installed in profile
		if (File.exists(Install.getFolder(profileDir, jarName)))
		{
			if (!this.silentInstall)
			{
				Install.alert('Updating existing Profile install of ' + this.extFullName + ' to version ' + this.extVersion + '.');
			}
			this.profileInstall = true;
		}
		else if (!this.silentInstall)
		{
			// Ask user for install location, profile or browser dir?
			this.profileInstall = Install.confirm('Install ' + this.extFullName + ' ' + this.extVersion + ' to your Profile directory (OK) or your Browser directory (Cancel)?');
		}
		
		// Init install
		var dispName = this.extFullName + ' ' + this.extVersion;
		var regName = '/' + this.extAuthor + '/' + this.extShortName;
		Install.initInstall(dispName, regName, this.extVersion);
		
		// Find directory to install into
		var installPath;
		if (this.profileInstall) installPath = profileDir;
		else installPath = Install.getFolder('chrome');
		
		// Add JAR file
		Install.addFile(null, 'chrome/' + jarName, installPath, null);
		
		// Register chrome
		var jarPath = Install.getFolder(installPath, jarName);
		var installType = this.profileInstall ? Install.PROFILE_CHROME : Install.DELAYED_CHROME;
		
		// Register content
		Install.registerChrome(Install.CONTENT | installType, jarPath, 'content/' + this.extShortName + '/');
		
		// Register locales
		for (var locale in this.extLocaleNames)
		{
			var regPath = 'locale/' + this.extLocaleNames[locale] + '/' + this.extShortName + '/';
			Install.registerChrome(Install.LOCALE | installType, jarPath, regPath);
		}
		
		// Register skins
		for (var skin in this.extSkinNames)
		{
			var regPath = 'skin/' + this.extSkinNames[skin] + '/' + this.extShortName + '/';
			Install.registerChrome(Install.SKIN | installType, jarPath, regPath);
		}
		
		// Perform install
		var err = Install.performInstall();
		if (err == Install.SUCCESS || err == Install.REBOOT_NEEDED)
		{
			if (!this.silentInstall && this.extPostInstallMessage)
			{
				Install.alert(this.extPostInstallMessage);
			}
		}
		else
		{
			this.handleError(err);
			return;
		}
	},
	
	parseArguments: function()
	{
		// Can't use string handling in install, so use if statement instead
		var args = Install.arguments;
		if (args == 'p=0')
		{
			this.profileInstall = false;
			this.silentInstall = true;
		}
		else if (args == 'p=1')
		{
			this.profileInstall = true;
			this.silentInstall = true;
		}
	},
	
	handleError: function(err)
	{
		if (!this.silentInstall)
		{
			Install.alert('Error: Could not install ' + this.extFullName + ' ' + this.extVersion + ' (Error code: ' + err + ')');
		}
		Install.cancelInstall(err);
	}
};

XpiInstaller.install();