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<?php
/**
* Zend Framework (http://framework.zend.com/)
*
* @link http://github.com/zendframework/zf2 for the canonical source repository
* @copyright Copyright (c) 2005-2015 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
namespace Zend\Http\Header;
/**
* @throws Exception\InvalidArgumentException
* @see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9
*/
class CacheControl implements HeaderInterface
{
/**
* @var string
*/
protected $value;
/**
* Array of Cache-Control directives
*
* @var array
*/
protected $directives = array();
/**
* Creates a CacheControl object from a headerLine
*
* @param string $headerLine
* @throws Exception\InvalidArgumentException
* @return CacheControl
*/
public static function fromString($headerLine)
{
list($name, $value) = GenericHeader::splitHeaderLine($headerLine);
// check to ensure proper header type for this factory
if (strtolower($name) !== 'cache-control') {
throw new Exception\InvalidArgumentException(sprintf(
'Invalid header line for Cache-Control string: ""',
$name
));
}
HeaderValue::assertValid($value);
$directives = static::parseValue($value);
// @todo implementation details
$header = new static();
foreach ($directives as $key => $value) {
$header->addDirective($key, $value);
}
return $header;
}
/**
* Required from HeaderDescription interface
*
* @return string
*/
public function getFieldName()
{
return 'Cache-Control';
}
/**
* Checks if the internal directives array is empty
*
* @return bool
*/
public function isEmpty()
{
return empty($this->directives);
}
/**
* Add a directive
* For directives like 'max-age=60', $value = '60'
* For directives like 'private', use the default $value = true
*
* @param string $key
* @param string|bool $value
* @return CacheControl - provides the fluent interface
*/
public function addDirective($key, $value = true)
{
HeaderValue::assertValid($key);
if (! is_bool($value)) {
HeaderValue::assertValid($value);
}
$this->directives[$key] = $value;
return $this;
}
/**
* Check the internal directives array for a directive
*
* @param string $key
* @return bool
*/
public function hasDirective($key)
{
return array_key_exists($key, $this->directives);
}
/**
* Fetch the value of a directive from the internal directive array
*
* @param string $key
* @return string|null
*/
public function getDirective($key)
{
return array_key_exists($key, $this->directives) ? $this->directives[$key] : null;
}
/**
* Remove a directive
*
* @param string $key
* @return CacheControl - provides the fluent interface
*/
public function removeDirective($key)
{
unset($this->directives[$key]);
return $this;
}
/**
* Assembles the directives into a comma-delimited string
*
* @return string
*/
public function getFieldValue()
{
$parts = array();
ksort($this->directives);
foreach ($this->directives as $key => $value) {
if (true === $value) {
$parts[] = $key;
} else {
if (preg_match('#[^a-zA-Z0-9._-]#', $value)) {
$value = '"' . $value.'"';
}
$parts[] = "$key=$value";
}
}
return implode(', ', $parts);
}
/**
* Returns a string representation of the HTTP Cache-Control header
*
* @return string
*/
public function toString()
{
return 'Cache-Control: ' . $this->getFieldValue();
}
/**
* Internal function for parsing the value part of a
* HTTP Cache-Control header
*
* @param string $value
* @throws Exception\InvalidArgumentException
* @return array
*/
protected static function parseValue($value)
{
$value = trim($value);
$directives = array();
// handle empty string early so we don't need a separate start state
if ($value == '') {
return $directives;
}
$lastMatch = null;
state_directive:
switch (static::match(array('[a-zA-Z][a-zA-Z_-]*'), $value, $lastMatch)) {
case 0:
$directive = $lastMatch;
goto state_value;
// intentional fall-through
default:
throw new Exception\InvalidArgumentException('expected DIRECTIVE');
}
state_value:
switch (static::match(array('="[^"]*"', '=[^",\s;]*'), $value, $lastMatch)) {
case 0:
$directives[$directive] = substr($lastMatch, 2, -1);
goto state_separator;
// intentional fall-through
case 1:
$directives[$directive] = rtrim(substr($lastMatch, 1));
goto state_separator;
// intentional fall-through
default:
$directives[$directive] = true;
goto state_separator;
}
state_separator:
switch (static::match(array('\s*,\s*', '$'), $value, $lastMatch)) {
case 0:
goto state_directive;
// intentional fall-through
case 1:
return $directives;
default:
throw new Exception\InvalidArgumentException('expected SEPARATOR or END');
}
}
/**
* Internal function used by parseValue to match tokens
*
* @param array $tokens
* @param string $string
* @param string $lastMatch
* @return int
*/
protected static function match($tokens, &$string, &$lastMatch)
{
// Ensure we have a string
$value = (string) $string;
foreach ($tokens as $i => $token) {
if (preg_match('/^' . $token . '/', $value, $matches)) {
$lastMatch = $matches[0];
$string = substr($value, strlen($matches[0]));
return $i;
}
}
return -1;
}
}
|
