Unsure of how to configure QHttpMultiPart for Google Drive upload - Error 400

cjrennie

I am trying to upload a file to Google Drive using a multi part upload as described here https://developers.google.com/drive/api/v3/multipart-upload while following the Qt Documentation for QHttpMultiPart. I believe the error may be due to the headers. The API documentation states:

Add the following top-level HTTP headers:
Content-Type. Set to multipart/related, and include the boundary string you're using to identify the different parts of the request. For example: Content-Type: multipart/related; boundary=foo_bar_baz
Content-Length. Set to the total number of bytes in the request body.

Since QHttpMultiPart only supports Content-Type as a header Included these in my QNetworkRequest but I receive a 400 error that my request is not formatted properly. Is there some other way I should be setting my headers up? Or did I miss something when setting up QHttpMultiPart? Thanks.

   //get MIME type of file
QMimeDatabase mimeDB; //contains a database of all MIME types
QMimeType mime = mimeDB.mimeTypeForFile(filePath);
QByteArray mimeType = mime.name().toUtf8();

multiPart = new QHttpMultiPart(); //contains our multipart upload

//part 1 - metadata
QHttpPart metaData; 
metaData.setRawHeader("Content-Type", "application/json; charset=UTF-8");
QJsonObject metaBody; //body containing metadata
QJsonValue JName(fileCopyHandler::extractName(filePath));
QJsonValue JMime(mime.name());
metaBody.insert("name", JName);
metaBody.insert("mimeType", JMime);
metaBody.insert("Description", "Uploaded by AutoBackup.");
QByteArray metaBodyJson(QJsonDocument(metaBody).toJson());
metaData.setBody(metaBodyJson);

//part 2 - media data
QHttpPart mediaData; 
mediaData.setRawHeader("Content-Type", mimeType);
QFile *file = new QFile(filePath);
file->open(QIODevice::ReadOnly);
mediaData.setBodyDevice(file);
file->setParent(multiPart); //delete file when multiPart is deleted

multiPart->append(metaData);
multiPart->append(mediaData);
QByteArray bodySize;
bodySize.setNum(file->size() + metaBodyJson.size()); //number of bytes in entire request body

//setup rest of the request
QUrl uploadURL("https://www.googleapis.com/upload/drive/v3/files?uploadType=multipart");
QNetworkRequest request(uploadURL);
request.setRawHeader("Authorization", "Bearer " + authToken.toUtf8()); //convert authToken to QByteArray when we set header;
request.setRawHeader("Content-Type", "multipart/related; boundary=" + multiPart->boundary());
request.setRawHeader("Content-Length", bodySize);

networkReply = networkManager->post(request, multiPart);

QObject::connect(networkReply, SIGNAL(metaDataChanged()), this, SLOT(testSlot1()));

SGaist

Hi,

One thing you can do is use something like Fiddler to check what you are sending to the google Drive API.

cjrennie

So I tried fiddler and wireshark and I am unable to see my POST request. I can see the request for receiving authentication however.

SGaist

Do you mean it's not sent ?