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- <?php
- //--------------------------------------------------------------------------------------------------
- // Utilities for our event-fetching scripts.
- //
- // Requires PHP 5.2.0 or higher.
- //--------------------------------------------------------------------------------------------------
- // PHP will fatal error if we attempt to use the DateTime class without this being set.
- date_default_timezone_set('UTC');
- class Event {
- // Tests whether the given ISO8601 string has a time-of-day or not
- const ALL_DAY_REGEX = '/^\d{4}-\d\d-\d\d$/'; // matches strings like "2013-12-29"
- public $title;
- public $allDay; // a boolean
- public $start; // a DateTime
- public $end; // a DateTime, or null
- public $properties = array(); // an array of other misc properties
- // Constructs an Event object from the given array of key=>values.
- // You can optionally force the timezone of the parsed dates.
- public function __construct($array, $timezone=null) {
- $this->title = $array['title'];
- if (isset($array['allDay'])) {
- // allDay has been explicitly specified
- $this->allDay = (bool)$array['allDay'];
- }
- else {
- // Guess allDay based off of ISO8601 date strings
- $this->allDay = preg_match(self::ALL_DAY_REGEX, $array['start']) &&
- (!isset($array['end']) || preg_match(self::ALL_DAY_REGEX, $array['end']));
- }
- if ($this->allDay) {
- // If dates are allDay, we want to parse them in UTC to avoid DST issues.
- $timezone = null;
- }
- // Parse dates
- $this->start = parseDateTime($array['start'], $timezone);
- $this->end = isset($array['end']) ? parseDateTime($array['end'], $timezone) : null;
- // Record misc properties
- foreach ($array as $name => $value) {
- if (!in_array($name, array('title', 'allDay', 'start', 'end'))) {
- $this->properties[$name] = $value;
- }
- }
- }
- // Returns whether the date range of our event intersects with the given all-day range.
- // $rangeStart and $rangeEnd are assumed to be dates in UTC with 00:00:00 time.
- public function isWithinDayRange($rangeStart, $rangeEnd) {
- // Normalize our event's dates for comparison with the all-day range.
- $eventStart = stripTime($this->start);
- if (isset($this->end)) {
- $eventEnd = stripTime($this->end); // normalize
- }
- else {
- $eventEnd = $eventStart; // consider this a zero-duration event
- }
- // Check if the two whole-day ranges intersect.
- return $eventStart < $rangeEnd && $eventEnd >= $rangeStart;
- }
- // Converts this Event object back to a plain data array, to be used for generating JSON
- public function toArray() {
- // Start with the misc properties (don't worry, PHP won't affect the original array)
- $array = $this->properties;
- $array['title'] = $this->title;
- // Figure out the date format. This essentially encodes allDay into the date string.
- if ($this->allDay) {
- $format = 'Y-m-d'; // output like "2013-12-29"
- }
- else {
- $format = 'c'; // full ISO8601 output, like "2013-12-29T09:00:00+08:00"
- }
- // Serialize dates into strings
- $array['start'] = $this->start->format($format);
- if (isset($this->end)) {
- $array['end'] = $this->end->format($format);
- }
- return $array;
- }
- }
- // Date Utilities
- //----------------------------------------------------------------------------------------------
- // Parses a string into a DateTime object, optionally forced into the given timezone.
- function parseDateTime($string, $timezone=null) {
- $date = new DateTime(
- $string,
- $timezone ? $timezone : new DateTimeZone('UTC')
- // Used only when the string is ambiguous.
- // Ignored if string has a timezone offset in it.
- );
- if ($timezone) {
- // If our timezone was ignored above, force it.
- $date->setTimezone($timezone);
- }
- return $date;
- }
- // Takes the year/month/date values of the given DateTime and converts them to a new DateTime,
- // but in UTC.
- function stripTime($datetime) {
- return new DateTime($datetime->format('Y-m-d'));
- }
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