silverstripe-framework/src/Control/HTTPStreamResponse.php

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2017-05-12 05:17:38 +02:00
<?php
namespace SilverStripe\Control;
use BadMethodCallException;
/**
* A response which contains a streamable data source.
*
* @package framework
* @subpackage control
*/
class HTTPStreamResponse extends HTTPResponse
{
/**
* Stream source for this response
*
* @var resource
*/
protected $stream = null;
/**
* Set to true if this stream has been consumed.
* A consumed non-seekable stream will not be re-consumable
*
* @var bool
*/
protected $consumed = false;
/**
* HTTPStreamResponse constructor.
* @param resource $stream Data stream
* @param int $contentLength size of the stream in bytes
* @param int $statusCode The numeric status code - 200, 404, etc
* @param string $statusDescription The text to be given alongside the status code.
*/
public function __construct($stream, $contentLength, $statusCode = null, $statusDescription = null)
{
parent::__construct(null, $statusCode, $statusDescription);
$this->setStream($stream);
if ($contentLength) {
$this->addHeader('Content-Length', $contentLength);
}
}
/**
* Determine if a stream is seekable
*
* @return bool
*/
protected function isSeekable()
{
$stream = $this->getStream();
if (!$stream) {
return false;
}
$metadata = stream_get_meta_data($stream);
return $metadata['seekable'];
}
/**
* @return resource
*/
public function getStream()
{
return $this->stream;
}
/**
* @param resource $stream
* @return $this
*/
public function setStream($stream)
{
$this->setBody(null);
$this->stream = $stream;
return $this;
}
/**
* Get body prior to stream traversal
*
* @return string
*/
public function getSavedBody()
{
return parent::getBody();
}
public function getBody()
{
$body = $this->getSavedBody();
if (isset($body)) {
return $body;
}
// Consume stream into string
$body = $this->consumeStream(function ($stream) {
$body = stream_get_contents($stream);
// If this stream isn't seekable, we'll need to save the body
// in case of subsequent requests.
if (!$this->isSeekable()) {
$this->setBody($body);
}
return $body;
});
return $body;
}
/**
* Safely consume the stream
*
* @param callable $callback Callback which will perform the consumable action on the stream
* @return mixed Result of $callback($stream) or null if no stream available
* @throws BadMethodCallException Throws exception if stream can't be re-consumed
*/
protected function consumeStream($callback)
{
// Load from stream
$stream = $this->getStream();
if (!$stream) {
return null;
}
// Check if stream must be rewound
if ($this->consumed) {
if (!$this->isSeekable()) {
throw new BadMethodCallException(
"Unseekable stream has already been consumed"
);
}
rewind($stream);
}
// Consume
$this->consumed = true;
return $callback($stream);
}
/**
* Output body of this response to the browser
*/
protected function outputBody()
{
// If the output has been overwritten, or the stream is irreversable and has
// already been consumed, return the cached body.
$body = $this->getSavedBody();
if ($body) {
echo $body;
return;
}
// Stream to output
if ($this->getStream()) {
$this->consumeStream(function ($stream) {
fpassthru($stream);
});
return;
}
// Fail over
parent::outputBody();
}
}