POST-Request with JSON Data over HTTPS Connection with Qt5 - json

Question

I'm trying to send a POST request over an HTTPS-Connection via Qt5 to a Web-API, but I keep getting the following error-message:
Failure "Error downloading https://.../login - server replied: BAD REQUEST"
Reply:"{"error_tag": "ARGUMENT_MISSING", "error_code": 19, "error_extra": {"argument": "email"}, "error": "Required argument is missing"}"
It seems like the HTTPS Connection works, but the POST request is faulty...
void connection::sendLoginData(){
QUrl url = QString("https://.../login");
QNetworkRequest req(url);
//Creating the JSON-Data
QJsonDocument json;
QJsonObject data;
data["email"] = QString("a#g.com");
data["password"] = QString("---");
json.setObject(data);
QByteArray jsonPost = QJsonDocument(data).toJson();
req.setHeader(QNetworkRequest::ContentTypeHeader,QVariant("application/json; charset=utf-8"));
req.setHeader(QNetworkRequest::ContentLengthHeader, QByteArray::number(jsonPost.size()));
//Sending the Request
QNetworkReply *reply = manager->post(req,jsonPost);
// Connection via HTTPS
QFile certFile(SSLCERTIFICATE);
certFile.open(QIODevice::ReadOnly);
QSslCertificate cert(&certFile, QSsl::Pem);
QSslSocket * sslSocket = new QSslSocket(this);
sslSocket->addCaCertificate(cert);
QSslConfiguration configuration = sslSocket->sslConfiguration();
configuration.setProtocol(QSsl::TlsV1_2);
sslSocket->setSslConfiguration(configuration);
reply->setSslConfiguration(configuration);
}
this is the Slot which is called when QNetworkReply gets a reply:
void connection::onFinished(QNetworkReply *reply){
if (reply->error() == QNetworkReply::NoError) {
//success
qDebug() << "Success" <<reply->readAll();
delete reply;
}
else {
//failure
qDebug() << "Failure" <<reply->errorString();
qDebug() << "Reply: " << reply->readAll();
delete reply;
}
}
The Signal "finished" of QNetworkReply is of course connected to the "onFinished"-Slot
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
manager = new QNetworkAccessManager;
ui->setupUi(this);
Connector = new connection(ui,manager);
connect(manager,SIGNAL(finished(QNetworkReply*)),Connector,SLOT(onFinished(QNetworkReply*)));
}
Maybe someone of you could tell me what's wrong with the POST-Request? Looking at the Reply of the Server it seems like the JSON-Data is never sent, or somehow formatted in a wrong way...

Answer 1

As you didn't provide the exact URL, I'd suggest you to try to check url.isValid() and url.errorString().
I just had an issue, the code worked fine in Qt 4.8, but in Qt 5.4 all my POST requests got 400 Bad Request reply.
I looked into the TCP dump via Wireshark and found out that the URL was wrong.
In my case url.setPath("api/register"); was the line that caused the problem. It should have been url.setPath("/api/register");
Hope it helps.