Upgrading from vobject 3.x to 4.x

VObject 4 got a number of new features, as well as a few backwards compatibility changes.

While VObject 4 has a lot of improvements, the changes are mostly incremental. The upgrade from VObject 2 to 3 was much bigger overhaul, but in this release the changes we made are smaller and more localized.

This document is split up in two major segments: "New features" and "Backwards compatibility breaks". We're starting with the fun stuff.

New features

PHP 7 support

This version of VObject supports PHP 7. We also dropped support for PHP versions before 5.5. If you are running an older PHP version, we will continue to maintain vObject 3.x. But really, you should upgrade!

Support for different input encodings

By default VObject always assumed everything is UTF-8. This is a fair assumption for objects sent via CalDAV and CardDAV and is also the only valid encoding for vCard 4, jCard and jCal.

However, iCalendar 2.0, vCard 3.0 and vCard 2.1 might also be encoded using other charsets. In the case of vCard 2.1, individual lines in the vCard can even have specific encodings.

If your data uses a different encoding than UTF-8, you can now specify this. sabre/vobject will then automatically convert everything to UTF-8 during decoding.

Example:

$vcard = Sabre\VObject\Reader::read($data, 0, 'ISO-8859-1');

Currently only the following encodings are supported:

Those encodings are (so far) the only one we have seen in the wild, but if you have a different encoding you need support for, just open a ticket with a sample file.

Support for xCal / xCard

After adding support for jCal and jCard, we now also have support for xCal and xCard. These two formats are the XML representation of iCalendar and vCard.

Reading these formats is pretty simple:

$vcalendar = Sabre\VObject\Reader::readXml('<?xml version=".....'?>);

Writing works as follows:

$xml = Sabre\VObject\Writer::writeXml($vCalendar);

This feature was contributed by Ivan Enderlin.

Added a BirthdayCalendarGenerator

This new component can take a list of VCARD objects, and automatically generate a VCALENDAR with all the birthdays.

Example usage:

$vcards = []; // Imagine we have a list of vCard objects.

$generator = new Sabre\VObject\BirthdayCalendarGenerator();
$generator->setObjects($vcards);

$vcalendar = $generator->getResult();

This feature was contributed by Dominik Tobschall.

Speed improvements

We optimized a number of common access patterns in sabre/vobject, and in particular are doing less looping and better indexing of objects.

Especially manipulating objects can be up to 40% faster than before.

Added a destroy() method

sabre/vobject components are a fairly complicated data-structure, and they also contain circular references. This unfortunately means that they are often not garbage collected by PHP.

If you are completely done with a vCalendar object, you can now call the destroy() method on it. This method will remove a lot of circular references, and enough so that PHP can can easily clean up the object.

Especially if you are doing processing on large or many objects, these memory leaks can quickly grow out of control. Calling destroy() should result in massive drops in memory usage.

// Destroys many references and makes the object unusable
$vcalendar->destroy();

Full support for VAVAILABILITY

VAVAILABILITY is an upcoming standard that allows people to specify when they are available. It complements VFREEBUSY, as it allows people to specify rules such as "I'm available for meetings every weekday between 9 and 5".

VObject 4 provides a parsers for these, and the FreeBusyGenerator can now generate a VFREEBUSY object based on existing calendar events + a VAVAILABILITY specification. VAVAILABILITY is already supported by a number of calendar applications.

Added a utility for merging duplicate vCards on the command line.

If you have a large file with lots of vCard objects, you can use this tool to find duplicates and merge them together.

The tool finds duplicates solely using the FN property. This means if you have multiple contacts with the exact same name, they will be merged.

Run the command for usage instructions:

./bin/mergeduplicates.php

Smaller stuff / bugfixes.

Backwards compatibility breaks

PHP 5.5 is the minimum version

As mentioned before, the minimum PHP version has been changed from 5.3 to 5.4. If you are running unsupported PHP versions, you can still use sabre/vobject 3, which we still support.

Using DateTimeImmutable instead of DateTime.

PHP added a new object for dealing with dates and times: DateTimeImmutable. Starting from sabre/vobject 4, we now return DateTimeImmutable everywhere instead of DateTime.

This can unfortunately lead to subtle bugs, as before you might have been able to make modifications to a DateTime object you received from a function.

Non-exhaustive list of functions that now return DateTimeImmutable:

Sabre\VObject\Component\VAlarm::getEffectiveTriggerTime()
Sabre\VObject\DateTimeParser::parseDateTime()
Sabre\VObject\DateTimeParser::parseDate()
Sabre\VObject\DateTimeParser::parse()
Sabre\VObject\Property\ICalendar\DateTime::getDateTime()
Sabre\VObject\Property\ICalendar\DateTime::getDateTimes()
Sabre\VObject\Property\VCard\DateAndOrTime::getDateTime()
Sabre\VObject\Recur\EventIterator::current()
Sabre\VObject\Recur\EventIterator::getDtStart()
Sabre\VObject\Recur\EventIterator::getDtEnd()

To illustrate how this can be a problem, consider the following:

$dtStart = $vcalendar->VEVENT->DTSTART->getDateTime();
$dtStart->modify('+1 day');

In vObject 3, $dtStart was a DateTime object. Calling modify on it would mean that the $dtStart would be changed to be a day later (just in the variable, not the original DTSTART).

From vObject 4 onwards, $dtStart is a DateTimeImmutable. Calling modify on that object does not alter it's value, but it returns a new DateTimeImmutable with this new value.

Component::$children is gone

In sabre/vobject 3 every (vcard/vcalendar/vevent/etc..) component had a public $children property that contained a simple array with all the properties/components inside of the component.

The simple array made everything quite slow, and in order to optimize common operations we had to remove it.

If you're still looking for a flat list of all the children properties/components, call the children() method instead.

Effectively this changes your code from:

$children = $vevent->children;

to:

$children = $vevent->children();

More specific exceptions

A lot of the VObject functions work in two stages. There's an initial parse stage, in which we only validate the correctness of the overall syntax of the source, and a manipulation phase.

Some invalid data (such as an invalid date in DTSTART) will not throw an error during parsing, but only when you actually do something related to dates.

Before, we would often throw either InvalidArgumentException or LogicException when we hit invalid data. In vObject 4 we consistently always throw Sabre\VObject\InvalidDataException.

Note that any errors during the parsing phase will still throw Sabre\VObject\ParseException.

RecurrenceIterator now stops automatically at 3500 iterations

In case a user created a recurring event, and traversing that event results in more than 3500 instances, we'll now automatically throw Sabre\VObject\Recur\MaxInstancesExceededException. This acts as a protection against some denial of service attacks.

To change this number, change the following static property:

Sabre\VObject\Settings::$maxRecurrences = 1000;

Set it to -1 to completely disable this check.

Changes to expanding events

If you ever expanded a recurring event in a calendar, this API has now changed. The expand method no longer updates the calendar in-place, but rather returns a new copy of the calendar with the events expanded.

The expand method no longer makes changes to the calendar on which it's called on.

This means that if your code previously looked like this:

$vcalendar->expand(new DateTime('...'), new DateTime('...'));

This must be changed to:

$vcalendar = $vcalendar->expand(new DateTime('...'), new DateTime('...'));

Renamed two classes for PHP 7 support.

vObject 3 had the following two classes:

Sabre\VObject\Property\Float
Sabre\VObject\Property\Integer

In PHP 7 those are no longer valid class names. We've renamed them to:

Sabre\VObject\Property\FloatValue
Sabre\VObject\Property\IntegerValue

Sabre\VObject\RecurrenceIterator is removed

This object was already deprecated, but in version 4 it's removed. Simply use Sabre\VObject\Recur\EventIterator instead. It has an identical interface.

Sabre\VObject\Component::remove no longer returns the removed item.

The remove() function, which exists on every component used to return the removed item. In version 4 this is no longer the case.


Comments