browser-launcher

Part of HTTP Toolkit: powerful tools for building, testing & debugging HTTP(S)

Detect the browser versions available on your system and launch them in an isolated profile for automation & testing purposes.

You can launch browsers headlessly (using Xvfb or with PhantomJS) and set the proxy configuration on the fly.

This project is the latest in a long series, each forked from the last:

• substack/browser-launcher
• browser-launcher2.
• james-proxy/james-browser-launcher

Each previous versions seems to now be unmaintained, and this is a core component of HTTP Toolkit, so it's been forked here to ensure it can continue healthy into the future.

Supported browsers

The goal for this module is to support all major browsers on every desktop platform.

At the moment, browser-launcher supports following browsers on Windows, Unix and OS X:

• Chrome
• Chromium
• Firefox
• IE (Windows only)
• Chromium-based Edge
• Brave
• Opera
• Safari (Mac only)
• PhantomJS
• Arc (experimental, Mac only)

Setup

Quick usage

> npx @httptoolkit/browser-launcher # Scans for browsers
[
    {
        "name": "chrome",
        "version": "...",
        # ...
    },
    # ...
]

> npx @httptoolkit/browser-launcher firefox # Launches a browser
firefox launched with PID: XXXXXX

If the package is already installed locally, you can use browser-launcher to launch it directly instead, either from the node_modules/.bin directly, or as binary name with npx.

Install

npm install @httptoolkit/browser-launcher

Example

Browser launch

const launcher = require('@httptoolkit/browser-launcher');

launcher(function(err, launch) {
	if (err) {
		return console.error(err);
	}

	launch('http://httptoolkit.com/', 'chrome', function(err, instance) {
		if (err) {
			return console.error(err);
		}

		console.log('Instance started with PID:', instance.pid);

		instance.on('stop', function(code) {
			console.log('Instance stopped with exit code:', code);
		});
	});
});

Outputs:

$ node example/launch.js
Instance started with PID: 12345
Instance stopped with exit code: 0

Browser launch with options

var launcher = require('@httptoolkit/browser-launcher');

launcher(function(err, launch) {
	// ...
	launch(
		'http://httptoolkit.com/',
		{
			browser: 'chrome',
			noProxy: [ '127.0.0.1', 'localhost' ],
			options: [
				'--disable-web-security',
				'--disable-extensions'
			]
		},
		function(err, instance) {
			// ...
		}
	);
});

Browser detection

var launcher = require('@httptoolkit/browser-launcher');

launcher.detect(function(available) {
	console.log('Available browsers:');
	console.dir(available);
});

Outputs:

$ node example/detect.js
Available browsers:
[ { name: 'chrome',
		version: '36.0.1985.125',
		type: 'chrome',
		command: 'google-chrome' },
	{ name: 'chromium',
		version: '36.0.1985.125',
		type: 'chrome',
		command: 'chromium-browser' },
	{ name: 'firefox',
		version: '31.0',
		type: 'firefox',
		command: 'firefox' },
	{ name: 'phantomjs',
		version: '1.9.7',
		type: 'phantom',
		command: 'phantomjs' },
	{ name: 'opera',
		version: '12.16',
		type: 'opera',
		command: 'opera' } ]

Detaching the launched browser process from your script

If you want the opened browser to remain open after killing your script, first, you need to set options.detached to true (see the API). By default, killing your script will kill the opened browsers.

Then, if you want your script to immediately return control to the shell, you may additionally call unref on the instance object in the callback:

var launcher = require('@httptoolkit/browser-launcher');
launcher(function (err, launch) {
	launch('http://example.org/', {
		browser: 'chrome',
		detached: true
    }, function(err, instance) {
		if (err) {
			return console.error(err);
		}

		instance.process.unref();
		instance.process.stdin.unref();
		instance.process.stdout.unref();
		instance.process.stderr.unref();
	});
});

API

var launcher = require('@httptoolkit/browser-launcher');

launcher([configPath], callback)

Detect available browsers and pass launch function to the callback.

Parameters:

• String configPath - path to a browser configuration file (Optional)
• Function callback(err, launch) - function called with launch function and errors (if any)

launch(uri, options, callback)

Open given URI in a browser and return an instance of it.

Parameters:

• String uri - URI to open in a newly started browser
• Object|String options - configuration options or name of a browser to launch
• String options.browser - name of a browser to launch
• String options.version - version of a browser to launch, if none was given, the highest available version will be launched
• String options.proxy - URI of the proxy server
• Array options.options - additional command line options
• Boolean options.skipDefaults - don't supply any default options to browser
• Boolean options.detached - if true, then killing your script will not kill the opened browser
• Array|String options.noProxy - An array of strings, containing proxy routes to skip over
• Boolean options.headless - run a browser in a headless mode (only if Xvfb available)
• String|null options.profile - path to a directory to use for the browser profile, overriding the default. Use null to force use of the default system profile (supported for Firefox & Chromium-based browsers only). Note that configuration options like proxy & prefs can't be used in Firefox with the default system profile.
• Function callback(err, instance) - function fired when started a browser instance or an error occurred

launch.browsers

This property contains an array of all known and available browsers.

instance

Browser instance object.

Properties:

• String command - command used to start the instance
• Array args - array of command line arguments used while starting the instance
• String image - instance's image name
• String processName - instance's process name
• Object process - reference to instance's process started with Node's child_process.spawn API
• Number pid - instance's process PID
• Stream stdout - instance's process STDOUT stream
• Stream stderr - instance's process STDERR stream

Events:

• stop - fired when instance stops

Methods:

• stop(callback) - stop the instance and fire the callback once stopped

launcher.detect(callback)

Detects all browsers available.

Parameters:

• Function callback(available) - function called with array of all recognized browsers

Each browser contains following properties:

• name - name of a browser
• version - browser's version
• type - type of a browser i.e. browser's family
• command - command used to launch a browser

launcher.update([configFile], callback)

Updates the browsers cache file (~/.config/browser-launcher/config.json is no configFile was given) and creates new profiles for found browsers.

Parameters:

• String configFile - path to the configuration file Optional
• Function callback(err, browsers) - function called with found browsers and errors (if any)

Known Issues

• IE8: after several starts and stops, if you manually open IE it will come up with a pop-up asking if we want to restore tabs (#21)
• Chrome @ OSX: it's not possible to launch multiple instances of Chrome at once

License

MIT