checkdate - PHP code example

The php Function Checkdate - Validating Dates and Times in Your Applications

Dates and times are the fundamental element in every web application. Dealing with them is one of the most common tasks for PHP programmers, from formatting to adjusting to local time zones and more. They are also prone to errors when handled incorrectly.

In this article, we will explore the php function checkdate and how it can help with data validation in your applications. Whether you are validating user input or using external data, understanding the checkdate function will ensure that your applications work properly.

PHP has inbuilt functions that simplify working with dates and time data types. These dates and times can be manipulated in many different ways, from displaying the date an article was published to recording the last time a specific data was updated. These dates are stored as a timestamp, which is the number of seconds that have elapsed since 1st January 1970 00:00:00 GMT. The timestamp is formatted in a human-readable format (i.e YYYY-MM-DD hh:mm:ss).

The mktime function creates a timestamp from a date and a timezone. You can specify the timezone using a constant or an argument. You can also use the optional isdst parameter to indicate whether or not daylight savings time is in effect.

The checkdate function validates a Gregorian date and returns TRUE if the date is valid and FALSE otherwise. For more complex date formats and validation, it is recommended that you use a library such as Carbon, which extends the DateTime class to include functionality such as checking for leap years.

checkdate example

class DateValidator extends ConstraintValidator
{
    public const PATTERN = '/^(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})$/';

    /** * Checks whether a date is valid. * * @internal */
    public static function checkDate(int $year, int $month, int $day): bool
    {
        return checkdate($month, $day, $year);
    }

    /** * @return void */
    public function validate(mixed $value, Constraint $constraint)
    {
        if (!$constraint instanceof Date) {
            throw new UnexpectedTypeException($constraint, Date::class);
        }

try {
            $dateTime = new \DateTime($rfc3339);
        } catch (\Exception $e) {
            throw new TransformationFailedException($e->getMessage(), $e->getCode(), $e);
        }

        if ($this->inputTimezone !== $dateTime->getTimezone()->getName()) {
            $dateTime->setTimezone(new \DateTimeZone($this->inputTimezone));
        }

        if (!checkdate($matches[2], $matches[3], $matches[1])) {
            throw new TransformationFailedException(sprintf('The date "%s-%s-%s" is not a valid date.', $matches[1], $matches[2], $matches[3]));
        }

        return $dateTime;
    }
}

  public static function checkArray($array) {
    $valid_date = FALSE;
    $valid_time = TRUE;
    // Check for a valid date using checkdate(). Only values that     // meet that test are valid. An empty value, either a string or a 0, is not     // a valid value.     if (!empty($array['year']) && !empty($array['month']) && !empty($array['day'])) {
      $valid_date = checkdate($array['month'], $array['day'], $array['year']);
    }
    // Testing for valid time is reversed. Missing time is OK,     // but incorrect values are not.     foreach (['hour', 'minute', 'second'] as $key) {
      if (array_key_exists($key, $array)) {
        $value = $array[$key];
        switch ($key) {
          case 'hour':
            if (!preg_match('/^([1-2][0-3]|[01]?[0-9])$/', $value)) {
              $valid_time = FALSE;
            }

throw new TransformationFailedException('This month is invalid.');
        }

        if (isset($value['day']) && !ctype_digit((string) $value['day'])) {
            throw new TransformationFailedException('This day is invalid.');
        }

        if (isset($value['year']) && !ctype_digit((string) $value['year'])) {
            throw new TransformationFailedException('This year is invalid.');
        }

        if (!empty($value['month']) && !empty($value['day']) && !empty($value['year']) && false === checkdate($value['month'], $value['day'], $value['year'])) {
            throw new TransformationFailedException('This is an invalid date.');
        }

        if (isset($value['hour']) && !ctype_digit((string) $value['hour'])) {
            throw new TransformationFailedException('This hour is invalid.');
        }

        if (isset($value['minute']) && !ctype_digit((string) $value['minute'])) {
            throw new TransformationFailedException('This minute is invalid.');
        }

try {
            $dateTime = new \DateTime($dateTimeLocal, new \DateTimeZone($this->outputTimezone));
        } catch (\Exception $e) {
            throw new TransformationFailedException($e->getMessage(), $e->getCode(), $e);
        }

        if ($this->inputTimezone !== $dateTime->getTimezone()->getName()) {
            $dateTime->setTimezone(new \DateTimeZone($this->inputTimezone));
        }

        if (!checkdate($matches[2], $matches[3], $matches[1])) {
            throw new TransformationFailedException(sprintf('The date "%s-%s-%s" is not a valid date.', $matches[1], $matches[2], $matches[3]));
        }

        return $dateTime;
    }
}

    protected function formatSearchValue($value, array $field, $expression = null)
    {
        switch ($field['type']) {
            case 'boolean':
                break;
            case 'date':
            case 'datetime':
                // validates the date value. If the value is no date value, return                 $date = date_parse($value);

                if ($date['error_count'] > 0 || !checkdate((int) $date['month'], (int) $date['day'], (int) $date['year'])) {
                    $value = '%' . $value . '%';
                    break;
                }
                $date = new DateTime($value);
                $value = $date->format('Y-m-d');
                if (!$this->isSearchExpression($expression)) {
                    return $value;
                }

                // search values for date time should added the % wildcards to search for time values.                 if ($field['type'] === 'datetime') {

        } else {
            if (!preg_match('/^\d{4}-\d{2}-\d{2}$/', $value)) {
                $this->_format = 'yyyy-MM-dd';
                $this->_error(self::FALSEFORMAT);
                $this->_format = null;
                return false;
            }

            list($year, $month, $day) = sscanf($value, '%d-%d-%d');

            if (!checkdate($month, $day, $year)) {
                $this->_error(self::INVALID_DATE);
                return false;
            }
        }

        return true;
    }

    /** * Check if the given date fits the given format * * @param string $value Date to check * @return boolean False when date does not fit the format */

function wp_checkdate( $month, $day, $year, $source_date ) {
/** * Filters whether the given date is valid for the Gregorian calendar. * * @since 3.5.0 * * @param bool $checkdate Whether the given date is valid. * @param string $source_date Date to check. */
return apply_filters( 'wp_checkdate', checkdate( $month, $day, $year ), $source_date );
}

/** * Loads the auth check for monitoring whether the user is still logged in. * * Can be disabled with remove_action( 'admin_enqueue_scripts', 'wp_auth_check_load' ); * * This is disabled for certain screens where a login screen could cause an * inconvenient interruption. A filter called {@see 'wp_auth_check_load'} can be used * for fine-grained control. * * @since 3.6.0 */