qt QNetworkAccesManager

Plik main.cpp:
#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();

    return a.exec();
}

Plik mainwindow.h:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QString>
#include <QtNetwork/QNetworkAccessManager>
#include <memory>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

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

private slots:
    void urlConnect();
    void urlRead();
    void urlFinished();
    void urlSend();
    void sendFinished(QNetworkReply *r);

private:
    std::unique_ptr<Ui::MainWindow> ui;
    QNetworkAccessManager *manager;
    QNetworkReply *reply;
    QString text;
    QString notify;
    QByteArray buffer;
};

#endif // MAINWINDOW_H

Plik mainwindow.cpp:
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtNetwork/QNetworkRequest>
#include <QtNetwork/QNetworkReply>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    manager = new QNetworkAccessManager;

    connect(ui->pushButton, SIGNAL(clicked()), this, SLOT(urlConnect()));
    connect(ui->pushButton_2, SIGNAL(clicked()), this, SLOT(urlSend()));
}

MainWindow::~MainWindow()
{
    delete manager;
}

void MainWindow::urlConnect()
{
    notify = QString("");
    QUrl url = ui->lineEdit->text();
    QNetworkRequest req(url);
    notify.append(QString("host: ") + req.url().host() + QString("\n"));
    notify.append(QString("path: ") + req.url().path() + QString("\n"));
    notify.append(QString("user: ") + req.url().userName() + QString("\n"));
    notify.append(QString("user: ") + req.url().userInfo() + QString("\n"));
    notify.append(QString("url: ") + req.url().url() + QString("\n"));
    notify.append(QString("str: ") + req.url().toString() + QString("\n"));
    notify.append(QString("file: ") + req.url().toLocalFile() + QString("\n"));

    reply = manager->get(req);
    text = QString("czytanie danych");
    ui->label_2->setText(text);
    connect(reply, SIGNAL(readyRead()), this, SLOT(urlRead()));
    connect(reply, SIGNAL(finished()), this, SLOT(urlFinished()));

    ui->textBrowser->setText(notify);
}

void MainWindow::urlRead()
{
    text.append(".");
    if (text.length() > 25) text = QString("czytanie danych");
    ui->label_2->setText(text);
    buffer += reply->readAll();
}

void MainWindow::urlFinished()
{
    text = QString("wczytano dane");
    ui->label_2->setText(text);
    QString a(buffer);
    notify.append(QString("dane: ") + a);
    ui->textBrowser->setText(notify);
}

void MainWindow::urlSend()
{
    QString txt = ui->textEdit->toPlainText();
    QByteArray postData;
    postData.append(txt);
    QNetworkRequest request = QNetworkRequest(QUrl(ui->lineEdit->text()));
    request.setRawHeader("Content-Type", "application/x-www-form-urlencoded");
    manager->post(request, postData);
    connect(manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(sendFinished(QNetworkReply*)));
}

void MainWindow::sendFinished(QNetworkReply *r)
{
    disconnect(manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(sendFinished(QNetworkReply*)));
    if(r->error() == QNetworkReply::NoError)
        ui->textBrowser_2->setText("wysyłanie zakończone bez błędu");
    else
        ui->textBrowser_2->setText(QString("Błąd przy wysyłaniu: ") + r->errorString());
}