no-js-helpers.js

// Alias. Worth keeping in because it's so verbose. 
var encodeWrapper = window.encodeURIComponent;

// IMPORTANT!!
// ------------------------------------------
// This is how simple it is to build the final URL:
image.src = configCollectorUrl + '?' + request;
// See below for how each piece (configCollectorUrl and request) are built...

/**
 * Builds a collector URL from a CloudFront distribution.
 * We don't bother to support custom CNAMEs because Amazon CloudFront doesn't support that for SSL.
 *
 * @param string account The account ID to build the tracker URL from
 *
 * @return string The URL on which the collector is hosted
 */
function collectorUrlFromCfDist(distSubdomain) {
	return asCollectorUrl(distSubdomain + '.cloudfront.net');
}

/**
 * Adds the protocol in front of our collector URL, and i to the end
 *
 * @param string rawUrl The collector URL without protocol
 *
 * @return string collectorUrl The tracker URL with protocol
 */
function asCollectorUrl(rawUrl) {
	return ('https:' == document.location.protocol ? 'https' : 'http') + '://' + rawUrl + '/i';               
}

// This is a kind of "expanded out" function which includes logging page
// view and the getRequest code. So you can see it all in one place.
function logPageView(customTitle) {

	// Fixup page title. We'll pass this to logPagePing too.
	var pageTitle = SnowPlow.fixupTitle(customTitle || configTitle);

	// Log page view
	var sb = requestStringBuilder();
	sb.add('e', 'pv'); // 'pv' for Page View
	sb.add('page', pageTitle);
	sb.addRaw('tid', String(Math.random()).slice(2, 8));
	sb.addRaw('vp', detectViewport());
	sb.addRaw('ds', detectDocumentSize());
	
	// Encode all these
	sb.add('p', configPlatform);		
	sb.add('tv', SnowPlow.version);
	sb.add('fp', fingerprint);
	sb.add('aid', configTrackerSiteId);
	sb.add('lang', browserLanguage);
	sb.add('cs', documentCharset);
	sb.add('tz', timezone);

	// Adds with custom conditions
	if (configAttachUserId) sb.addRaw('uid', uuid);
	if (configReferrerUrl.length) sb.add('refr', purify(configReferrerUrl));
	
	// Browser features. Cookies, color depth and resolution don't get prepended with f_ (because they're not optional features)
	for (i in browserFeatures) {
		if (Object.prototype.hasOwnProperty.call(browserFeatures, i)) {
			featurePrefix = (i === 'res' || i === 'cd' || i === 'cookie') ? '' : 'f_';
			sb.addRaw(featurePrefix + i, browserFeatures[i]);
		}
	}
	
	// Add the page URL last as it may take us over the IE limit (and we don't always need it)
	sb.add('url', purify(SnowPlow.windowAlias.location));
	var request = sb.build();
	
	return request;
}

/**
 * A helper to build a SnowPlow request string from an
 * an optional initial value plus a set of individual
 * name-value pairs, provided using the add method.
 *
 * @param string initialValue The initial querystring, ready to have additional key-value pairs added
 *
 * @return object The request string builder, with add, addRaw and build methods
 */
function requestStringBuilder(initialValue) {
	var str = initialValue || '';
	var addNvPair = function(key, value, encode) {
		if (value !== undefined && value !== '') {
			str += '&' + key + '=' + (encode ? SnowPlow.encodeWrapper(value) : value);
		}
	};
	return {
		add: function(key, value) {
			addNvPair(key, value, true);
		},
		addRaw: function(key, value) {
			addNvPair(key, value, false);
		},
		build: function() {
			return str;
		}
	}
}