Userscript that adds iCal links to the De Oosterpoort website

deoosterpoort-to-ical.user.js

// ==UserScript==
// @name          iCal links for De Oosterpoort
// @namespace     http://ikhoefgeen.nl/userscripts
// @description	  Create iCal events directly from De Oosterpoort website
// @include       http://www.de-oosterpoort.nl/programma/*
// ==/UserScript==
// Credits:
//   Base64 encode / decode
//   http://www.webtoolkit.info/
//

var DeOosterpoort = {}

DeOosterpoort.findData = function(root)
{
	var header = root.querySelector('#voorstelling h1'),
		specs = root.querySelectorAll("#voorstelling .detail-info li > span"),
		event = new iCal.Event;

	if (!header || specs.size == 0)
		return null;

	event.name = header.firstChild.data.trim();

	for (var i = 0; i < specs.length; ++i)
	{
		if (!specs[i].firstChild || !specs[i].nextSibling)
			continue;
		
		var label = specs[i].firstChild.data.trim(),
			value = specs[i].nextSibling.data.trim();
		
		if (label == "Datum") {
			if (!DeOosterpoort.parseDatum(value, event))
				return null;
		}
		else if (label == "Tijdstip") {
			if (!DeOosterpoort.parseTijdstip(value, event))
				return null;
		}
		else if (label == "Locatie") {
			event.location = value;
		}
	}

	return event;
};

DeOosterpoort.parseDatum = function(datum, event)
{
	var parts = datum.match(/^\w+\ (\d+) (\w+) (\d+)$/);

	if (!parts)
		return false;

	var month = [
		'januari', 'februari', 'maart',
		'april', 'mei', 'juni',
		'juli', 'augustus', 'september',
		'oktober', 'november', 'december'
	].indexOf(parts[2]);

	['from', 'till'].forEach(function(range) {
		event[range].setYear(parts[3]);
		event[range].setMonth(month);
		event[range].setDate(parts[1]);
	});

	return true;
};

DeOosterpoort.parseTijdstip = function(tijdstip, event)
{
	var parts = tijdstip.match(/^(\d{1,2}):(\d\d)(?:\s+tot (\d{1,2}):(\d\d))?$/);
	
	if (!parts)
		return false;
	
	event.from.setHours(parts[1]);
	event.from.setMinutes(parts[2]);

	if (typeof parts[3] !== 'undefined' && typeof parts[4] !== 'undefined')
	{
		event.till.setHours(parts[3]);
		event.till.setMinutes(parts[4]);
	}
	else
	{
		event.till.setHours(parseInt(parts[1]) + 1);
		event.till.setMinutes(parts[2]);
	}

	return true;
}

function base64_encode(input)
{
	var _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
	var output = "";
	var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
	var i = 0;

	while (i < input.length)
	{
		chr1 = input.charCodeAt(i++) & 0xFF;
		chr2 = input.charCodeAt(i++) & 0xFF;
		chr3 = input.charCodeAt(i++) & 0xFF;

		enc1 = chr1 >> 2;
		enc2 = ((chr1 &  3) << 4) | (chr2 >> 4);
		enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
		enc4 = chr3 & 63;

		if (isNaN(chr2))
			enc3 = enc4 = 64;
		else if (isNaN(chr3))
			enc4 = 64;

		output += _keyStr.charAt(enc1) + _keyStr.charAt(enc2) +
			_keyStr.charAt(enc3) + _keyStr.charAt(enc4);

	}

	return output;
}

function align(length, filler, value)
{
	value = "" + value; // now it is a string for sure! :P
	return repeat(filler, length - value.length) + value;
}

function repeat(character, times)
{
	var output = '';

	while (times-- > 0)
		output += character;
	
	return output;
}


var iCal = {};

iCal.Event = function() {
	this.from = new Date;
	this.till = new Date;
	this.name = '[name]';
	this.location = '[location]';
	this.link = document.location.href;
}

iCal.Event.prototype.toDataURI = function()
{
	var ical_format = 'Ymd\THis\Z';

	var timezone = [
		'CALSCALE:GREGORIAN',
		'BEGIN:VTIMEZONE',
		'TZID:Europe/Amsterdam',
		'BEGIN:DAYLIGHT',
		'TZOFFSETFROM:+0100',
		'RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU',
		'DTSTART:19810329T020000',
		'TZNAME:CEST',
		'TZOFFSETTO:+0200',
		'END:DAYLIGHT',
		'BEGIN:STANDARD',
		'TZOFFSETFROM:+0200',
		'RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU',
		'DTSTART:19961027T030000',
		'TZNAME:CET',
		'TZOFFSETTO:+0100',
		'END:STANDARD',
		'END:VTIMEZONE'
	].join("\n");

	var data = [
		'BEGIN:VCALENDAR',
		'VERSION:2.0',
		'PRODID:-//hacksw/handcal//NONSGML v1.0//EN',
		timezone,
		'BEGIN:VEVENT',
		'CREATED:' + iCal.formatDate(ical_format, new Date),
		'DTSTAMP:' + iCal.formatDate(ical_format, new Date),
		'DTSTART;TZID=Europe/Amsterdam:' + iCal.formatDate(ical_format, this.from),
		'DTEND;TZID=Europe/Amsterdam:' + iCal.formatDate(ical_format, this.till),
		'TRANSP:OPAQUE',
		'SUMMARY:' + iCal.escapeData(this.name),
		'LOCATION:' + iCal.escapeData(this.location),
		'URL;VALUE=URI:' + this.link,
		'END:VEVENT',
		'END:VCALENDAR'
	].join("\n");

	return 'data:text/calendar;base64,' + base64_encode(data);
}

iCal.escapeData = function(data)
{
	return data
		.replace(/\\/, "\\\\")
		.replace(/,/,"\\,")
		.replace(/\n/, "\\n");
}

iCal.formatDate = function(format, date)
{
	var output = '';

	for (var i = 0; i < format.length; ++i)
	{
		switch (format[i])
		{
			case '\\':
				output += format[++i];
				break;
			
			case 'Y':
				output += date.getUTCFullYear();
				break;
			
			case 'm':
				output += align(2, '0', date.getUTCMonth() + 1);
				break;
			
			case 'd':
				output += align(2, '0', date.getUTCDate());
				break;
			
			case 'H':
				output += align(2, '0', date.getUTCHours());
				break;
			
			case 'i':
				output += align(2, '0', date.getUTCMinutes());
				break;
			
			case 's':
				output += align(2, '0', date.getUTCSeconds());
				break;
			
			default:
				output += format[i];
				break;
		}
	}

	return output;
}

function main()
{
	var event = DeOosterpoort.findData(document);

	if (!event)
		return;
	
	var link = document.createElement('a');
	link.href = event.toDataURI();
	link.appendChild(document.createTextNode('iCal'));

	document.querySelector('#voorstelling .detail-info li').appendChild(link);
}

main();