<?php
/**
* Zend Framework (http://framework.zend.com/)
*
* @link http://github.com/zendframework/zf2 for the canonical source repository
* @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
namespace Zend\Http\Header;
use DateTime;
use DateTimeZone;
/**
* Abstract Date/Time Header
* Supports headers that have date/time as value
*
* @see Zend\Http\Header\Date
* @see Zend\Http\Header\Expires
* @see Zend\Http\Header\IfModifiedSince
* @see Zend\Http\Header\IfUnmodifiedSince
* @see Zend\Http\Header\LastModified
*
* Note for 'Location' header:
* While RFC 1945 requires an absolute URI, most of the browsers also support relative URI
* This class allows relative URIs, and let user retrieve URI instance if strict validation needed
*/
abstract class AbstractDate implements HeaderInterface
{
/**
* Date formats according to RFC 2616
* @link http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.3
*/
const DATE_RFC1123 = 0;
const DATE_RFC1036 = 1;
const DATE_ANSIC = 2;
/**
* Date instance for this header
*
* @var DateTime
*/
protected $date = null;
/**
* Date output format
*
* @var string
*/
protected static $dateFormat = 'D, d M Y H:i:s \G\M\T';
/**
* Date formats defined by RFC 2616. RFC 1123 date is required
* RFC 1036 and ANSI C formats are provided for compatibility with old servers/clients
* @link http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.3
*
* @var array
*/
protected static $dateFormats = array(
self::DATE_RFC1123 => 'D, d M Y H:i:s \G\M\T',
self::DATE_RFC1036 => 'D, d M y H:i:s \G\M\T',
self::DATE_ANSIC => 'D M j H:i:s Y',
);
/**
* Create date-based header from string
*
* @param string $headerLine
* @return AbstractDate
* @throws Exception\InvalidArgumentException
*/
public static function fromString($headerLine)
{
$dateHeader = new static();
list($name, $date) = GenericHeader::splitHeaderLine($headerLine);
// check to ensure proper header type for this factory
if (strtolower($name) !== strtolower($dateHeader->getFieldName())) {
throw new Exception\InvalidArgumentException(
'Invalid header line for "' . $dateHeader->getFieldName() . '" header string'
);
}
$dateHeader->setDate($date);
return $dateHeader;
}
/**
* Set date output format
*
* @param int $format
* @throws Exception\InvalidArgumentException
*/
public static function setDateFormat($format)
{
if (!isset(static::$dateFormats[$format])) {
throw new Exception\InvalidArgumentException(
"No constant defined for provided date format: {$format}"
);
}
static::$dateFormat = static::$dateFormats[$format];
}
/**
* Return current date output format
*
* @return string
*/
public static function getDateFormat()
{
return static::$dateFormat;
}
/**
* Set the date for this header, this can be a string or an instance of \DateTime
*
* @param string|DateTime $date
* @return AbstractDate
* @throws Exception\InvalidArgumentException
*/
public function setDate($date)
{
if (is_string($date)) {
try {
$date = new DateTime($date, new DateTimeZone('GMT'));
} catch (\Exception $e) {
throw new Exception\InvalidArgumentException(
sprintf('Invalid date passed as string (%s)', (string) $date),
$e->getCode(),
$e
);
}
} elseif (!($date instanceof DateTime)) {
throw new Exception\InvalidArgumentException('Date must be an instance of \DateTime or a string');
}
$date->setTimezone(new DateTimeZone('GMT'));
$this->date = $date;
return $this;
}
/**
* Return date for this header
*
* @return string
*/
public function getDate()
{
return $this->date()->format(static::$dateFormat);
}
/**
* Return date for this header as an instance of \DateTime
*
* @return DateTime
*/
public function date()
{
if ($this->date === null) {
$this->date = new DateTime(null, new DateTimeZone('GMT'));
}
return $this->date;
}
/**
* Compare provided date to date for this header
* Returns < 0 if date in header is less than $date; > 0 if it's greater, and 0 if they are equal.
* @see \strcmp()
*
* @param string|DateTime $date
* @return int
* @throws Exception\InvalidArgumentException
*/
public function compareTo($date)
{
if (is_string($date)) {
try {
$date = new DateTime($date, new DateTimeZone('GMT'));
} catch (\Exception $e) {
throw new Exception\InvalidArgumentException(
sprintf('Invalid Date passed as string (%s)', (string) $date),
$e->getCode(),
$e
);
}
} elseif (!($date instanceof DateTime)) {
throw new Exception\InvalidArgumentException('Date must be an instance of \DateTime or a string');
}
$dateTimestamp = $date->getTimestamp();
$thisTimestamp = $this->date()->getTimestamp();
return ($thisTimestamp === $dateTimestamp) ? 0 : (($thisTimestamp > $dateTimestamp) ? 1 : -1);
}
/**
* Get header value as formatted date
*
* @return string
*/
public function getFieldValue()
{
return $this->getDate();
}
/**
* Return header line
*
* @return string
*/
public function toString()
{
return $this->getFieldName() . ': ' . $this->getDate();
}
/**
* Allow casting to string
*
* @return string
*/
public function __toString()
{
return $this->toString();
}
}