micjabbour/main.cpp

## main.cpp
//the following file demonstrates a minimal test case for a possible bug in
//QHttpMultiPart. The request hangs completely when calling
//QApplication::processEvents() from a slot connected to
//QNetworkReply::uploadProgress. Note that this happens naturally when using
//QProgressDialog::setValue from a slot connected to uploadProgress signal (as
//setValue is documented to call QApplication::processEvents internally)

#include <QtWidgets>
#include <QtNetwork>

const bool reproduceBug = true;

int main(int argc, char* argv[]) {
    QApplication a(argc, argv);
    QNetworkAccessManager nam;

    QString openFileName = QFileDialog::getOpenFileName();
    QFile source(openFileName);
    if(!source.open(QIODevice::ReadOnly)) return 1;
    QFileInfo fileInfo(openFileName);

    //upload selected file using an HTTP multipart request
    //based on http://doc.qt.io/qt-5/qhttpmultipart.html#details
    //construct QNetworkRequest
    QNetworkRequest request{QUrl("http://127.0.0.1:5000/")};
    //setting up multipart content object
    QHttpMultiPart * multiPart = new QHttpMultiPart(QHttpMultiPart::FormDataType);
    //setting up attachment file part of the above request
    QHttpPart attachmentFilePart;
    attachmentFilePart.setHeader(QNetworkRequest::ContentDispositionHeader,
                                 QVariant(QString("form-data; name=\"file\"; "
                                                  "filename=\"%1\"")
                                          .arg(fileInfo.fileName())));
    attachmentFilePart.setBodyDevice(&source);
    //add attachment part to multi part content object
    multiPart->append(attachmentFilePart);
    QNetworkReply *reply = nam.post(request, multiPart);
    multiPart->setParent(reply); //delete the multipart object with the reply

    QObject::connect(reply, &QNetworkReply::uploadProgress,
                     [] (qint64 bytesSent, qint64 bytesTotal) {
        qInfo() << "uploadProgress: " << bytesSent << " out of " << bytesTotal;
        if(reproduceBug) QApplication::processEvents();
    });

    QObject::connect(reply, &QNetworkReply::finished, [reply] {
        reply->deleteLater();
        if(reply->error() == QNetworkReply::NoError)
            qInfo().noquote() << reply->readAll();
        else
            qInfo() << "Error: " << reply->error();
        //quit when the request is finished
        qApp->quit();
    });

    return a.exec();
}

## server.py
# a minimal flask server to test HTTP multipart file upload requests
# based on http://flask.pocoo.org/docs/0.12/patterns/fileuploads/
from flask import Flask, request

app = Flask(__name__)


@app.route('/', methods=['GET', 'POST'])
def upload_file():
    if request.method == 'POST':
        # check if the post request has the file part
        if 'file' not in request.files:
            return 'no file part'
        file = request.files['file']
        # if user does not select file, browser also
        # submit a empty part without filename
        if file.filename == '':
            return 'no file selected'
        if file:
            return 'uploaded successfully'
    # GET request
    return '''
    <!doctype html>
    <title>Upload new File</title>
    <h1>Upload new File</h1>
    <form method=post enctype=multipart/form-data>
      <p><input type=file name=file>
         <input type=submit value=Upload>
    </form>
    '''
	//the following file demonstrates a minimal test case for a possible bug in
	//QHttpMultiPart. The request hangs completely when calling
	//QApplication::processEvents() from a slot connected to
	//QNetworkReply::uploadProgress. Note that this happens naturally when using
	//QProgressDialog::setValue from a slot connected to uploadProgress signal (as
	//setValue is documented to call QApplication::processEvents internally)

	#include <QtWidgets>
	#include <QtNetwork>

	const bool reproduceBug = true;

	int main(int argc, char* argv[]) {
	QApplication a(argc, argv);
	QNetworkAccessManager nam;

	QString openFileName = QFileDialog::getOpenFileName();
	QFile source(openFileName);
	if(!source.open(QIODevice::ReadOnly)) return 1;
	QFileInfo fileInfo(openFileName);

	//upload selected file using an HTTP multipart request
	//based on http://doc.qt.io/qt-5/qhttpmultipart.html#details
	//construct QNetworkRequest
	QNetworkRequest request{QUrl("http://127.0.0.1:5000/")};
	//setting up multipart content object
	QHttpMultiPart * multiPart = new QHttpMultiPart(QHttpMultiPart::FormDataType);
	//setting up attachment file part of the above request
	QHttpPart attachmentFilePart;
	attachmentFilePart.setHeader(QNetworkRequest::ContentDispositionHeader,
	QVariant(QString("form-data; name=\"file\"; "
	"filename=\"%1\"")
	.arg(fileInfo.fileName())));
	attachmentFilePart.setBodyDevice(&source);
	//add attachment part to multi part content object
	multiPart->append(attachmentFilePart);
	QNetworkReply *reply = nam.post(request, multiPart);
	multiPart->setParent(reply); //delete the multipart object with the reply

	QObject::connect(reply, &QNetworkReply::uploadProgress,
	[] (qint64 bytesSent, qint64 bytesTotal) {
	qInfo() << "uploadProgress: " << bytesSent << " out of " << bytesTotal;
	if(reproduceBug) QApplication::processEvents();
	});

	QObject::connect(reply, &QNetworkReply::finished, [reply] {
	reply->deleteLater();
	if(reply->error() == QNetworkReply::NoError)
	qInfo().noquote() << reply->readAll();
	else
	qInfo() << "Error: " << reply->error();
	//quit when the request is finished
	qApp->quit();
	});

	return a.exec();
	}
	# a minimal flask server to test HTTP multipart file upload requests
	# based on http://flask.pocoo.org/docs/0.12/patterns/fileuploads/
	from flask import Flask, request

	app = Flask(__name__)


	@app.route('/', methods=['GET', 'POST'])
	def upload_file():
	if request.method == 'POST':
	# check if the post request has the file part
	if 'file' not in request.files:
	return 'no file part'
	file = request.files['file']
	# if user does not select file, browser also
	# submit a empty part without filename
	if file.filename == '':
	return 'no file selected'
	if file:
	return 'uploaded successfully'
	# GET request
	return '''
	<!doctype html>
	<title>Upload new File</title>
	<h1>Upload new File</h1>
	<form method=post enctype=multipart/form-data>
	<p><input type=file name=file>
	<input type=submit value=Upload>
	</form>
	'''