With QNetworkReply how can I post a file and then receive a converted file back from the server?

1
votes

I can post a file in Qt using QNetworkReply, QNetworkAccessManager, QNetworkRequest, etc. to a server. This server converts the file and spits it back. How do I get that spitted-back file? Do I need to find the url of the file coming back from the headers somehow and then have QNetworkAccessManager make a get request for it? Or can I somehow get it from the existingQNetworkReply signals and write it to file?

1
c++qtqnetworkaccessmanagerqnetworkreply

1 Answers

2
votes

If the server returns the file in response to the request then you can read the file directly from the returned reply :

QNetworkAccessManager nam;

QUrl url(QString("http://www.example.com"));
url.addQueryItem("parameter", "value");

QNetworkRequest request(url);

QNetworkReply *reply = nam.get(request);

QEventLoop eventloop;
connect(reply,SIGNAL(finished()),&eventloop,SLOT(quit()));
eventloop.exec();

if (reply->error() == QNetworkReply::NoError)
{
    QByteArray bts = reply->readAll();

    QFile file("path/to/file");
    file.open(QIODevice::WriteOnly);
    file.write(bts);
    file.close();
}

You can also do it in an asynchronous way by connecting the finished signal of the QNetworkAccessManager to a slot and write the file there :

connect(&nam,SIGNAL(finished(QNetworkReply*)),this,SLOT(onFinished(QNetworkReply*)));

void onFinished(QNetworkReply* reply)
{

   if (reply->error() == QNetworkReply::NoError)
   {
       QByteArray bts = reply->readAll();

       QFile file("path/to/file");
       file.open(QIODevice::WriteOnly);
       file.write(bts);
       file.close();
   }
}