GoogleResumableUpload::getLocationForResumableUpload

protected function getLocationForResumableUpload()
{
	if(!$this->checkRequiredInputParams($this->fileData->toArray(), array(
		'name', 'mimeType', 'size',
	)))
	{
		return null;
	}

	$fileName = $this->fileData->getName();
	$fileName = $this->convertToUtf8($fileName);

	$http = new HttpClient(array(
		'redirect' => false,
		'socketTimeout' => 10,
		'streamTimeout' => 30,
		'version' => HttpClient::HTTP_1_1,
	));
	$this->setBearer($http);
	$http->setHeader('Content-Type', 'application/json; charset=UTF-8');
	$http->setHeader('X-Upload-Content-Type', $this->fileData->getMimeType());
	$http->setHeader('X-Upload-Content-Length', $this->fileData->getSize());

	$postFields = "{"name":"{$fileName}"}";
	if($this->fileData->isNeededToConvert())
	{
		$googleMimeType = GoogleHandler::getInternalMimeTypeByExtension(getFileExtension($this->fileData->getName()));
		$postFields = "{"name":"{$fileName}", "mimeType": "{$googleMimeType}"}";
	}
	if($http->post(GoogleHandler::API_URL_UPLOAD_V3 . '/files?uploadType=resumable&fields=id,webViewLink,version,createdTime,modifiedTime', $postFields) === false)
	{
		$errorString = implode('; ', array_keys($http->getError()));
		$this->errorCollection[] = new Error(
			$errorString, self::ERROR_HTTP_GET_LOCATION_FOR_UPLOAD
		);
		return null;
	}

	if(!$this->documentHandler->checkHttpResponse($http))
	{
		return null;
	}

	return $http->getHeaders()->get('Location');
}