Box.com upload API using Qt

gistfile1.txt

#pragma once

#include <QNetworkAccessManager>
#include <QNetworkRequest>
#include <QNetworkReply>
#include <QHttpMultiPart>
#include <QHttpPart>
#include <QFile>

namespace BoxCloud
{
	bool uploadFile( QString filename, QString accessToken, QString folderID = "871822902" )
	{
		QFile *fileUpload = new QFile(filename);
		fileUpload->open(QIODevice::ReadOnly);

		QHttpMultiPart * multiPart = new QHttpMultiPart(QHttpMultiPart::FormDataType);

		QByteArray boundary("56354654654654321768987465413574634354658");
		multiPart->setBoundary(boundary);

		QHttpPart folderPart;
		folderPart.setHeader(QNetworkRequest::ContentDispositionHeader, QVariant("form-data; name=\"folder_id\""));
		folderPart.setBody("871822902"); // folder at Box

		QString fileExt = filename.split(".").takeLast();
		QString mimeType = "application/unknown";
		QString fileName = filename.split("/").takeLast();

		QHttpPart textPart;
		textPart.setHeader(QNetworkRequest::ContentTypeHeader, mimeType);
		textPart.setHeader(QNetworkRequest::ContentDispositionHeader, QVariant("form-data; filename=\""+ fileName +"\"; name=\"filename\";"));
		textPart.setBodyDevice(fileUpload);

		multiPart->append(textPart);
		multiPart->append(folderPart);

		QNetworkRequest req;
		req.setUrl(QUrl("https://upload.box.com/api/2.0/files/content"));
		QByteArray ba_auth = QString("Bearer " + accessToken).toUtf8();
		req.setRawHeader("Authorization", ba_auth);

		QNetworkAccessManager * m_netmanager = new QNetworkAccessManager;
		QNetworkReply * reply = m_netmanager->post(req, multiPart);

		QEventLoop loop;
		QObject::connect(reply, SIGNAL(readyRead()), &loop, SLOT(quit()));
		loop.exec();

		// Lets print the HTTP GET response.
		qDebug( reply->readAll() );

		return true;
	}
}

This solution still works. But what aboute new API with such request
curl https://upload.box.com/api/2.0/files/content \
-H "Authorization: Bearer ACCESS_TOKEN" -X POST
-F attributes='{"name":"tigers.jpeg", "parent":{"id":"11446498"}}'
-F file=@myfile.jpg
I've spend so much time trying to find solution but it was useless...