Qt/C++ - Tutorial 066. Uploading files to an FTP server

Qt, QNetworkAccessManager, FTP

To work with the network in Qt 5 , the Network module is used, and for data transmission over the network, you can actively use the QNetworkAccessManager class if you do not create your own protocol for data transfer. But for working with FTP it is enough to use QNetworkAccessManager , with which we already worked when downloading a file from the site .

We will write a small program that will upload an arbitrary file to the server, which we will select on our PC using the file selection dialog. Also, the progress of the file upload to the FTP server will be shown.

To do this, there will be a button in the application window to open the file selection dialog. QLineEdit, in which the path to the file will be displayed. QLineEdit, in which we will enter the address where the file will be downloaded. A startup boot button, and a progress bar that will show the progress of the file upload to the server.

Project structure

  • UploadFile.pro - Project profile.
  • main.cpp - File of the main function.
  • widget.h - Application window header file.
  • widget.cpp - Application window implementation file.
  • widget.ui - Application window form file.

In the project profile, you need to add a network module to work with QNetworkAccessManger.

QT       += network

The main.cpp file is created by default and is not affected by the change. The graphic designer will create a window form, which was shown at the beginning of the article.

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QString>
#include <QFile>

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();

private slots:
    void on_selectFileButton_clicked();         // Slot for calling the file selection dialog
    void on_uploadButton_clicked();             // Upload slot
    void uploadFinished(QNetworkReply *reply);  // Upload finish slot
    void uploadProgress(qint64 bytesSent, qint64 bytesTotal);  // Upload progress slot

private:
    Ui::Widget *ui;
    QNetworkAccessManager *m_manager;
    QString m_fileName;
    // You must save the file on the heap
    // If you create a file object on the stack, the program will crash.
    QFile *m_file;
};

#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"

#include <QFileDialog>
#include <QUrl>
#include <QDebug>

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    m_manager = new QNetworkAccessManager(this);
    connect(m_manager, &QNetworkAccessManager::finished, this, &Widget::uploadFinished);
}

Widget::~Widget()
{
    delete ui;
}

void Widget::on_selectFileButton_clicked()
{
    m_fileName = QFileDialog::getOpenFileName(this, "Get Any File");
    ui->fileNameLineEdit->setText(m_fileName);
}

void Widget::on_uploadButton_clicked()
{
    // Создаём объект файла при запуске загрузки
    m_file = new QFile(m_fileName);

    // Next, you need information about the file name
    // The upload path to the server should look like this
    // ftp://example.com/path/to/file/filename.txt
    // That is, we specify the protocol -> ftp
    // Server -> example.com
    // The path where the file will be located -> path/to/file/
    // And the name of the file itself, which we take from QFileInfo -> filename.txt
    QFileInfo fileInfo(*m_file);
    QUrl url(ui->uploadUrlLineEdit->text() + fileInfo.fileName());
    url.setUserName("login");    // Set login
    url.setPassword("password"); // Set пароль
    url.setPort(21);             // Protocol port, which we will work on

    if (m_file->open(QIODevice::ReadOnly))
    {
        // Start upload
        QNetworkReply *reply = m_manager->put(QNetworkRequest(url), m_file);
        // And connect to the progress upload signal
        connect(reply, &QNetworkReply::uploadProgress, this, &Widget::uploadProgress);
    }

}

void Widget::uploadFinished(QNetworkReply *reply)
{
    // If the upload was successful without errors
    if (!reply->error())
    {
        // то закрываем файл
        m_file->close();
        m_file->deleteLater();  // delete object of file
        reply->deleteLater();   // delete object of reply
    }
}

void Widget::uploadProgress(qint64 bytesSent, qint64 bytesTotal)
{
    // Display the progress of the upload
    ui->progressBar->setValue(100 * bytesSent/bytesTotal);
}

Result

As a result, you will be able to download the selected file to the FTP server (although of course in the network on the forums and there are reports that not all FTP-servers work well, but these are nuances).

Also note that this program has few checks and validations, so enter the path to the server so that the line was closed by the slash. For example:

ftp://example.com/path/to/file/

Download project

Virtual hosting with 10 percent discount
Virtual hosting with 10 percent discount
EVILEG offers reliable hosting with a 10% discount for virtual hosting and 5% for VPS
Support the author Donate

Comments

Only authorized users can post comments.
Please, Log in or Sign up
Looking for a Job?
14,000.00 руб. - 40,000.00 руб.
Разработчик Qt
Annino, Moscow Oblast, Russia
5,000.00 руб. - 15,000.00 руб.
Дизайнер
Moskovskiy, Moscow, Russia
25,000.00 руб. - 30,000.00 руб.
Разработчик Qt/C++
Barnaul, Altai Krai, Russia

For registered users on the site there is a minimum amount of advertising

A
Aug. 22, 2019, 11:24 p.m.
Aleksandr73

Qt - Test 001. Signals and slots

  • Result:47points,
  • Rating points-6
Aug. 21, 2019, 10:23 a.m.
Andrej Ermoshin

C++ - Test 002. Constants

  • Result:58points,
  • Rating points-2
Aug. 21, 2019, 10:15 a.m.
Andrej Ermoshin

C++ - Test 001. The first program and data types

  • Result:86points,
  • Rating points6
Last comments
Aug. 19, 2019, 7:41 a.m.
Andrej Jankovich

это проблема дистрибутива, попробуйте установить через пакетный менеджер snap Суть проблемы: libQt5Core которая лежит в дистрибутиве требует версию glibc >= 2.25 у вас видимо …
b
Aug. 18, 2019, 6:09 a.m.
bbb116

cqtdeployer /home/aleks/CQtDeployer/bin/cqtdeployer: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.25' not found (required by /home/aleks/CQtDeployer/lib/libQt5Core.so.5) linux mint …
D
Aug. 17, 2019, 9:04 a.m.
Damir

github ChekableTView Правой групповая смена значения при перетаскивании левой как обычно.
Aug. 16, 2019, 1:03 p.m.
Evgenij Legotskoj

Потому, что в минуте 60 секунд
Aug. 16, 2019, 12:16 p.m.
Dmitrij

а почему делитель 60000, а не 1000?
Now discuss on the forum
Aug. 24, 2019, 7:21 a.m.
Evgenij Legotskoj

Не помню, давно уже с QML не работал, по-моему, обычно пишет в консоль, что не находит файл. В любом случае какую-то ошибку в консоль выкидывает. Но если честно, если у вас проект будет ак…
BG
Aug. 24, 2019, 4:27 a.m.
Brjus Gliff

Спасибо, вначале в документации было не понятно что к чему, теперь разобрался
I
Aug. 21, 2019, 8:36 a.m.
Intruder

Александр, мне не нужно перебирать. Вы говорите правильно, сначала я написал избыточный код просто не подумав. Задача такая, мне нужно просто переложить из QMap в атрибуты xml тега все, что там …
Aug. 21, 2019, 3:16 a.m.
nayk1982

Если Вы разрабатываете какую-то универсальную утилиту, которая вообще не привязана к логике, тогда как вариант: 1. Получить список таблиц через QSqlDatabase::tables 2. Для каждой табли…
EVILEG
About
Services
© EVILEG 2015-2019
Recommend hosting TIMEWEB