/**
* Scale a file with a remote "scaler", as exists on the Wikimedia Foundation
* cluster, and output it to STDOUT.
* Note: Unlike the usual thumbnail process, the web client never sees the
* cluster URL; we do the whole HTTP transaction to the scaler ourselves
* and cat the results out.
* Note: We rely on NFS to have propagated the file contents to the scaler.
* However, we do not rely on the thumbnail being created in NFS and then
* propagated back to our filesystem. Instead we take the results of the
* HTTP request instead.
* Note: No caching is being done here, although we are instructing the
* client to cache it forever.
*
* @param File $file
* @param array $params Scaling parameters ( e.g. array( width => '50' ) );
* @param int $flags Scaling flags ( see File:: constants )
* @throws MWException
* @return bool Success
*/
private function outputRemoteScaledThumb($file, $params, $flags)
{
// This option probably looks something like
// '//upload.wikimedia.org/wikipedia/test/thumb/temp'. Do not use
// trailing slash.
$scalerBaseUrl = $this->getConfig()->get('UploadStashScalerBaseUrl');
if (preg_match('/^\\/\\//', $scalerBaseUrl)) {
// this is apparently a protocol-relative URL, which makes no sense in this context,
// since this is used for communication that's internal to the application.
// default to http.
$scalerBaseUrl = wfExpandUrl($scalerBaseUrl, PROTO_CANONICAL);
}
// We need to use generateThumbName() instead of thumbName(), because
// the suffix needs to match the file name for the remote thumbnailer
// to work
$scalerThumbName = $file->generateThumbName($file->getName(), $params);
$scalerThumbUrl = $scalerBaseUrl . '/' . $file->getUrlRel() . '/' . rawurlencode($scalerThumbName);
// make a curl call to the scaler to create a thumbnail
$httpOptions = array('method' => 'GET', 'timeout' => 5);
$req = MWHttpRequest::factory($scalerThumbUrl, $httpOptions, __METHOD__);
$status = $req->execute();
if (!$status->isOK()) {
$errors = $status->getErrorsArray();
$errorStr = "Fetching thumbnail failed: " . print_r($errors, 1);
$errorStr .= "\nurl = {$scalerThumbUrl}\n";
throw new MWException($errorStr);
}
$contentType = $req->getResponseHeader("content-type");
if (!$contentType) {
throw new MWException("Missing content-type header");
}
return $this->outputContents($req->getContent(), $contentType);
}
