Eu tenho tido alguns problemas tentando fazer upload de arquivos para um servidor usando QNetworkRequest. Eu tenho usado este link (http://qt-project.org/forums/viewthread/11361) principalmente como um modelo, mas ainda estou recebendo erros de POST (203 para ser específico). Aqui está o que eu tenho até agora.

void MainWindow::processFile(){

    QByteArray postData;
    //Look below for buildUploadString() function
    postData = mReport->buildUploadString();

    QUrl mResultsURL = QUrl("http://" + VariableManager::getInstance()->getServerIP() +  "/uploadFile.php");
    QNetworkAccessManager* mNetworkManager = new QNetworkAccessManager(this);


    QString bound="margin"; //name of the boundary

    QNetworkRequest request(mResultsURL); //our server with php-script
    request.setRawHeader(QString("Content-Type").toAscii(),QString("multipart/form-data; boundary=" + bound).toAscii());
    request.setRawHeader(QString("Content-Length").toAscii(), QString::number(postData.length()).toAscii());


    connect(mNetworkManager, SIGNAL(finished(QNetworkReply*)), this, SLOT(printScriptReply(QNetworkReply*))); //This slot is used to debug the output of the server script
    mNetworkManager->post(request,postData);
}


QByteArray ReportParser::buildUploadString()
{
    QString path = VariableManager::getInstance()->getReportDirectory();
    path.append("\\\\");
    path.append(getReportFileName());


    QString bound="margin";
    QByteArray data(QString("--" + bound + "\r\n").toAscii());
    data.append("Content-Disposition: form-data; name=\"action\"\r\n\r\n");
    data.append("uploadFile.php\r\n");   
    data.append(QString("--" + bound + "\r\n").toAscii());   
    data.append("Content-Disposition: form-data; name=\"uploaded\"; filename=\"");
    data.append(getReportFileName());
    data.append("\"\r\n");  
    data.append("Content-Type: text/xml\r\n\r\n"); //data type

    QFile file(path);
        if (!file.open(QIODevice::ReadOnly)){
            qDebug() << "QFile Error: File not found!";
            return data;
        } else { qDebug() << "File found, proceed as planned"; }

    data.append(file.readAll());           
    data.append("\r\n");
    data.append("--" + bound + "--\r\n");  //closing boundary according to rfc 1867


    file.close();

    return data;
}

Aqui está o script no servidor para processar o arquivo:

<?php

       $uploaded_type = $_FILES['uploaded']['type'];

    $target = "/var/www/webpage/results/";
    $target = $target . basename( $_FILES['uploaded']['name']) ;
    $ok=1;

    echo "target: ";
    echo $target;

    //This is our limit file type condition
    if ($uploaded_type =="text/xml"){
            echo "We have an xml file!\r\n";
    }

    //Here we check that $ok was not set to 0 by an error
    //If everything is ok we try to upload it
    if ($ok==0){

            echo "Sorry your file was not uploaded";

    } else {

            echo "Looking good!";

            if(move_uploaded_file($_FILES['uploaded']['tmp_name'], $target)){
                    echo "The file successfully ". basename( $_FILES['uploadedfile']['name']). " has been uploaded";
            } else {
                    echo "Sorry, there was a problem uploading your file.";
            }
    }
?>

Eu sei que o script funciona, pois ele manipulará o arquivo corretamente ao usar um formulário HTML básico. No entanto, o lado Qt das coisas continua retornando os erros do POST.