ipv6.js

/*
 * Copyright (c) 2011, Yahoo! Inc.  All rights reserved.
 * Copyrights licensed under the BSD License. See the accompanying LICENSE.txt file for terms.
 */

/**
\file ipv6.js
Plugin to measure various ipv6 related metrics.
This plugin tries to do a few things:
- Check if the client can connect to an ipv6 address
- Check if the client can resolve DNS that points to an ipv6 address
- Check latency of connecting to an ipv6 address
- Check avg latency of doing dns lookup to an ipv6 address (not worstcase)

You'll need a server that has an ipv6 address, and a DNS name to point to it.
Additionally, this server needs to be configured to serve content requested
from the IPv6 address and should not require a virtual host name.  This means
that you probably cannot use shared hosting that puts multiple hosts on the
same IP address.

All beacon parameters are prefixed with ipv6_

Beacon parameters:
- ipv6_latency: Latency in milliseconds of getting data from an ipv6 host when
		connecting to the IP.  Set to NA if the client cannot connect
		to the ipv6 host.
- ipv6_lookup:  Latency of getting data from a hostname that resolves to an
		ipv6 address.  Set to NA if the client cannot resolve or connect
		to the ipv6 host.
*/

(function(w) {

BOOMR = BOOMR || {};
BOOMR.plugins = BOOMR.plugins || {};

/*
Algorithm:

1. Try to load a sizeless image from an IPv6 host
   - onerror, flag no IPv6 connect support and end
   - onload, measure load time
2. Try to load a sizeless image from a hostname that resolves to an IPv6 address
   - onerror, flag no IPv6 DNS resolver and end
   - onload, measure load time
*/
var impl = {
	complete: false,
	ipv6_url: "",
	host_url: "",
	timeout: 1200,

	timers: {
		ipv6: { start: null, end: null },
		host: { start: null, end: null }
	},

	start: function() {
		this.load_img('ipv6', 'host');
	},

	load_img: function() {
		var img,
			rnd = "?t=" + (new Date().getTime()) + Math.random(),
			timer=0, error = null,
			that = this,
			which = Array.prototype.shift.call(arguments),
			a = arguments;

		// Terminate if we've reached end of test list
		if(!which || !(which in this.timers)) {
			this.done();
			return false;
		}

		// Skip if URL wasn't set for this test
		if(!this[which + '_url']) {
			return this.load_img.apply(this, a);
		}

		img = new Image();

		img.onload = function() {
			that.timers[which].end = new Date().getTime();
			clearTimeout(timer);
			img.onload = img.onerror = null;
			img = null;

			that.load_img.apply(that, a);
			that = a = null;
		};

		error = function() {
			that.timers[which].supported = false;
			clearTimeout(timer);
			img.onload = img.onerror = null;
			img = null;

			that.done();
			that = a = null;
		};

		img.onerror = error;
		timer = setTimeout(error, this.timeout);
		this.timers[which].start = new Date().getTime();
		img.src = this[which + '_url'] + rnd;

		return true;
	},

	done: function() {
		if(this.complete) {
			return;
		}

		BOOMR.removeVar('ipv6_latency', 'ipv6_lookup');
		if(this.timers.ipv6.end !== null) {
			BOOMR.addVar('ipv6_latency', this.timers.ipv6.end - this.timers.ipv6.start);
		}
		else {
			BOOMR.addVar('ipv6_latency', 'NA');
		}

		if(this.timers.host.end !== null) {
			BOOMR.addVar('ipv6_lookup', this.timers.host.end - this.timers.host.start);
		}
		else {
			BOOMR.addVar('ipv6_lookup', 'NA');
		}

		this.complete = true;
		BOOMR.sendBeacon();
	}
};

BOOMR.plugins.IPv6 = {
	init: function(config) {
		BOOMR.utils.pluginConfig(impl, config, "IPv6", ["ipv6_url", "host_url", "timeout"]);

		if(!impl.ipv6_url) {
			BOOMR.warn("IPv6.ipv6_url is not set.  Cannot run IPv6 test.", "ipv6");
			impl.complete = true;	// set to true so that is_complete doesn't
						// block other plugins
			return this;
		}

		if(!impl.host_url) {
			BOOMR.warn("IPv6.host_url is not set.  Will skip hostname test.", "ipv6");
		}

		// make sure that test images use the same protocol as the host page
		if(w.location.protocol === 'https:') {
			impl.ipv6_url = impl.ipv6_url.replace(/^http:/, 'https:');
			impl.host_url = impl.host_url.replace(/^http:/, 'https:');
		}
		else {
			impl.ipv6_url = impl.ipv6_url.replace(/^https:/, 'http:');
			impl.host_url = impl.host_url.replace(/^https:/, 'http:');
		}

		BOOMR.subscribe("page_ready", impl.start, null, impl);

		return this;
	},

	is_complete: function() {
		return impl.complete;
	}
};

}(window));