<?php
/**
* Zend Framework (http://framework.zend.com/)
*
* @see http://github.com/zendframework/zend-diactoros for the canonical source repository
* @copyright Copyright (c) 2015-2016 Zend Technologies USA Inc. (http://www.zend.com)
* @license https://github.com/zendframework/zend-diactoros/blob/master/LICENSE.md New BSD License
*/
namespace Zend\Diactoros;
use InvalidArgumentException;
use Psr\Http\Message\StreamInterface;
use RuntimeException;
use function array_key_exists;
use const SEEK_SET;
/**
* Implementation of PSR HTTP streams
*/
class CallbackStream implements StreamInterface
{
/**
* @var callable|null
*/
protected $callback;
/**
* @param callable $callback
* @throws InvalidArgumentException
*/
public function __construct(callable $callback)
{
$this->attach($callback);
}
/**
* {@inheritdoc}
*/
public function __toString()
{
return $this->getContents();
}
/**
* {@inheritdoc}
*/
public function close()
{
$this->callback = null;
}
/**
* {@inheritdoc}
*/
public function detach()
{
$callback = $this->callback;
$this->callback = null;
return $callback;
}
/**
* Attach a new callback to the instance.
*
* @param callable $callback
* @throws InvalidArgumentException for callable callback
*/
public function attach(callable $callback)
{
$this->callback = $callback;
}
/**
* {@inheritdoc}
*/
public function getSize()
{
}
/**
* {@inheritdoc}
*/
public function tell()
{
throw new RuntimeException('Callback streams cannot tell position');
}
/**
* {@inheritdoc}
*/
public function eof()
{
return empty($this->callback);
}
/**
* {@inheritdoc}
*/
public function isSeekable()
{
return false;
}
/**
* {@inheritdoc}
*/
public function seek($offset, $whence = SEEK_SET)
{
throw new RuntimeException('Callback streams cannot seek position');
}
/**
* {@inheritdoc}
*/
public function rewind()
{
throw new RuntimeException('Callback streams cannot rewind position');
}
/**
* {@inheritdoc}
*/
public function isWritable()
{
return false;
}
/**
* {@inheritdoc}
*/
public function write($string)
{
throw new RuntimeException('Callback streams cannot write');
}
/**
* {@inheritdoc}
*/
public function isReadable()
{
return false;
}
/**
* {@inheritdoc}
*/
public function read($length)
{
throw new RuntimeException('Callback streams cannot read');
}
/**
* {@inheritdoc}
*/
public function getContents()
{
$callback = $this->detach();
return $callback ? $callback() : '';
}
/**
* {@inheritdoc}
*/
public function getMetadata($key = null)
{
$metadata = [
'eof' => $this->eof(),
'stream_type' => 'callback',
'seekable' => false
];
if (null === $key) {
return $metadata;
}
if (! array_key_exists($key, $metadata)) {
return null;
}
return $metadata[$key];
}
}