No, wysota, that was a different problem. He wanted to handle multiple requests at the same time, while I want to have one request at a time and in a blocking fashion -- the event loop should wait until the request is finished.
As I said, QAbstractSocket::waitFor*() functions do not work. marcel suggested me to use QHttp::requestFinished() instead of QThread::wait(), but it currently crashes my program. See the code is my previous post.