README

Handling dates and date spans in a immutable way, using a beautiful API.

Build status

Installation

stubbles/date is distributed as Composer package. To install it as a dependency of your package use the following command:

composer require "stubbles/date": "^9.0"

Requirements

stubbles/date requires at least PHP 8.2.

Introduction

The origin of the classes in this library are from the days when PHP's object- oriented date/time handling classes were not immutable. In the meantime immutable versions of them have been added to PHP, but we like the API of the classes here more, as they lead to a better grammar in the code in which they are used.

The underlaying implementation makes use of PHP's object-oriented date/time handling classes, but abstracts them such that the stubbles/date instances are immutable. Every change to a date will result in a new instance. Although the date class exposes the underlaying handle, the user will only receive a clone of that, so modifying such a handle will not mutate the date instance from which the handle was obtained.

stubbles\date\Date

Please note that this class not only covers a date, but an exact point in time. Each instance also has a time part. If you are interested in a concrete day only please use stubbles\date\span\Day (see below).

Create a new instance

When creating a new date instance there are different ways to set the actual date:

• integer, interpreted as timestamp: new Date(1187872547)
• string, parsed into a date: new Date('2007-01-01 01:00:00 Europe/Berlin')
• \DateTime object, will be used as is: new Date(new \DateTime())
• no argument,creates a date representing the current time: new Date(), equivalent to Date::now()

The second argument to the constructor is an optional timezone. Timezone assignment works through these rules:

• If the time is given as string and contains a parseable timezone identifier that one is used.
• If no timezone could be determined, the timezone given by the second constructor parameter is used.
• If no timezone has been given as second parameter, the default timezone of the system is used.

Liberal type hinting

If you have a method which accepts an instance of stubbles\date\Date you can choose to be liberal in what you accept. Instead of type hinting against the concrete type your method can cast the provided value into an instance:

/**
 * does something cool
 *
 * @param  int|string|stubbles\date\Date  $date
 */
function doSomething($date)
{
    $date = Date::castFrom($date);
    // now do something with $date, which is an instance of stubbles\date\Date
}

The Date::castFrom(); accepts four different value types:

• integer, interpreted as unix timestamp: Date:castFrom(1187872547)
• string, parsed into a date: Date:castFrom('2007-01-01 01:00:00 Europe/Berlin')
• \DateTime object: Date:castFrom(new \DateTime())
• instances of stubbles\date\Date itself

An instance of stubbles\date\Date will always be returned as is, the other allowed values will result in the creation of a stubbles\date\Date instance. Passing any other value will result in a \InvalidArgumentException.

Change a date

To change a date the Date::change() method can be called. This will return an instance of stubbles\date\DateModifier which provides several different methods to change the date and/or time. All changes will result in a new stubbles\date\Date instance, the instance on which Date::change() is originally called remains unchanged:

$currentDate = Date::now();
// create new date with current time but 48 hours ago, this will not change $currentDate
$newDate = $currentDate->change()->byHours(-48);

Here's a list of methods offered by stubbles\date\DateModifier:

• to($target): change date by relative format accepted by strtotime()
• timeTo($time): keep date, i.e. day, month and year, but change time to given value, must be in format HH:mm:ss
• createDateWithNewTime($hour, $minute, $second): same as above, but with separate parameters for all values
• timeToStartOfDay(): alias for timeTo('00:00:00')
• timeToEndOfDay(): alias for timeTo('23:59:59')
• hourTo($hour); keep day, month, year, minutes and seconds, but change hour to given value
• byHours($hours): add given amount of hours to current date and time. A negative value will subtract the hours
• minuteTo($minute): keep day, month, year, hours and seconds, but change minutes to given value
• byMinutes($minutes): add given amount of minutes to current date and time. A negative value will subtract the minutes.
• secondTo($second): keep day, month, year, hours and minutes, but change seconds to given value
• bySeconds($seconds): add given amount of seconds to current date and time. A negative value will subtract the seconds.
• dateTo($date): change date but keep time, given date must be in format YYYY-MM-DD
• yearTo($year): keep day, month, hours, minutes and seconds, but change year to given value
• byYears($years): add given amount of years to current date and time. A negative value will subtract the years.
• monthTo($month): keep day, year, hours, minutes and seconds, but change month to given value
• byMonths($months): add given amount of months to current date and time. A negative value will subtract the months.
• dayTo($day): keep month, year, hours, minutes and seconds, but change day to given value
• byDays($days): add given amount of days to current date and time. A negative value will subtract the days.

Comparing dates

Instances of stubbles\date\Date can be compared with each other:

$date = Date::now();
if ($date->isBefore('2017-01-01 00:00:00')) {
    // execute when current date is before 2017
}

$date = Date::now();
if ($date->isAfter('2017-01-01 00:00:00')) {
    // execute when current date is after beginning of 2017
}

Comparison is done based on the unix timestamp.

Both isBefore() and isAfter() accept all values that are accepted by Date::castFrom(), see above.

Date formatting

The date can be displayed as a string by formatting:

echo 'Current date and time in system timezone: ' . Date::now()->format('Y-m-d H:i:s') . PHP_EOL;
echo 'Current date and time in timezone Europe/Berlin: ' . Date::now()->format('Y-m-d H:i:s', new TimeZone('Europe/Berlin')) . PHP_EOL;

When an instances is casted to a string, the output format will be Y-m-d H:i:sO.

Date spans

Sometimes it is necessary to not cover a specific date only, but a span between two points in time. Most notably these are things like a single day, months, weeks or even a year. As it is impractical to always carry the starting and ending point of such a span, stubbles/date provides the stubbles\date\span\Datespan interface and various implementations.

Default methods of each date span

• start(): returns the exact starting point of the span
• startsBefore($date): checks if the date span starts before the given point
• startsAfter($date): checks if the date span starts after the given point
• end(): returns exact ending point of the span
• endsBefore($date): checks if date span ends before the given point
• endsAfter($date): checks if date span ends after the given point
• formatStart($format, TimeZone $timeZone = null): format start point in given format
• formatEnd($format, TimeZone $timeZone = null): format end point in given format
• amountOfDays(): returns amount of days that are covered by the date span
• days(): returns an iterator which allows to iterate over each single day within this date span
• isInFuture(): checks whether date span is completely in the future based on current date and time
• containsDate($date): checks if given date and time are contained in the date span

All methods which have a $date parameter accept all values that are accepted by Date::castFrom(), see above.

List of provided date span implementations

stubbles\dates\span\Day

Covers a whole day, starting at 00:00:00 and ending at 23:59:59.

// create without argument always points to current day
$today = new Day();

// create with given date
$another = new Day('2016-06-27');

// create day from given stubbles\date\Date instance
$oneMore = new Day(new Date('2013-05-28'));

// creates a new instance representing tomorrow
$tomorrow = Day::tomorrow();

// creates a new instance representing yesterday
$yesterday = Day::yesterday();

Additional methods:

• next(): creates a new instance with the day after the represented day
• before(): create a new instance with the day before the represented day
• isToday(): checks if the day represents the current day

stubbles\dates\span\Week

Covers a whole week, starting on the given date at 00:00:00 and ending at seven days later at 23:59:59.

// create a week starting today
$week1 = new Week(Date::now());

// create a week which starts tomorrow
$week2 = new Week('tomorrow');

// create a week which represents the 5th calender week of 2016
$week3 = Week::fromString('2016-W05')

Additional methods:

• number(): returns the week number

stubbles\dates\span\Month

Covers a month, starting at the first of the month at 00:00:00 and ending at the last day of the month at 23:59:59.

// creates instance representing the current month
$currentMonth = new Month();

// creates instance with current month but in the year 2014-05
$currentMonthIn2015 = new Month(2015);

// create instance representing June 2016
$exactMonth = new Month(2016, 6);

// create instance representing month given as string, format must be YYYY-MM
$otherMonth = Month::fromString('2016-07');

// creates instance representing the month before current month
$lastMonth = Month::last();

// creates instance for current month execpt when today is the first day of a
// month, the the instance represents the month before
// ideally suited when creating reports, as most often the report created on the
// first month of a day should be for the last month instead of for the current
// month
$reportingMonth = Month::currentOrLastWhenFirstDay()

Additional methods:

• next(): creates instance with month after the currently represented month
• before(): creates instance with month before the currently represented month
• year(): returns the year in which the month is
• isCurrentMonth(): checks whether month instance represents the current month

stubbles\dates\span\Year

Covers a year, starting at January 01 00:00:00 and ending at December 31 23:59:59.

// create instance representing the current year
$currentYear = new Year();

// creates instance representing the year 2015
$year2015 = new Year(2015);

Additional methods:

• months(): returns an iterator which contains all instances of stubbles\dates\span\Month for the year
• isLeapYear(): checks whether year is a leap year
• isCurrentYear(): checks whether year represents the current year

stubbles\dates\span\CustomDatespan

Covers a custom date span starting at the given date at 00:00:00 and ending at the given date at 23:59:59.

// create a span from 2006-04-04 00:00:00 to 2006-04-20 23:59:59
$custom = new CustomDatespan('2006-04-04', '2006-04-20');

Constructor parameters accept all values that are accepted by Date::castFrom(), see above. Please note that the time for the start is always set to 00:00:00 and for the end is always set to 23:59:59. It is not possible to change this to another time.

Integration with bovigo/assert

In case you want to unit test your code and need to test for date equality you can use bovigo/assert for the assertions. stubbles/date provides the predicate stubbles\date\assert\equalsDate() which can be used to check for equality of dates. It can take any argument that stubbles\date\Date accepts, and compares the unix timestamp with the actual value. In case they don't refer to the same point in time the error message will contain a diff with both dates in human readable form.