FTPClient using QTcpSocket and signals and slots

[robsonQTnewbie]

SOCKETCONNECTION.h
@#ifndef SOCKETCONNECTION_H
#define SOCKETCONNECTION_H

#include <QMainWindow>
#include <QObject>
#include <iostream>
#include <QTcpSocket>
#include <QAbstractSocket>
#include <QString>

class socketconnection : public QObject
{
Q_OBJECT
public:
explicit socketconnection(QString url, QString login, QString password, QString port, QObject *parent = 0);
QString test();
QString komunikat, message, command;
QString url, login, password, port;
QString directoryList; //pointer to the downloaded directory listing
QString currentPath;
signals:

public slots:
void connected();
private:
QTcpSocket *socket;
QTcpSocket socketTransmit;
};

#endif // SOCKETCONNECTION_H
@

[robsonQTnewbie]

SOCKETCONNECTION.cpp
@#include "socketconnection.h"
#include "mainwindow.h"
#include <stdio.h>
socketconnection::socketconnection(QString url, QString login, QString password, QString port, QObject *parent) :
QObject(parent)
{
this->url = url;
this->login = login;
this->password = password;
this->port = port;
}
QString socketconnection::test(){
komunikat = "Status: ";
socket = new QTcpSocket(this);
connect(socket, SIGNAL(connected()), this, SLOT(connected()));
komunikat += "Łączenie do serwera FTP...\n";
socket->connectToHost((url.toUtf8().constData()), port.toShort());
if(!socket->waitForConnected(3000)){
komunikat += "Message: ";
komunikat += "Przekroczony limit czasu...\n";
}
return komunikat;
}
void socketconnection::connected()
{
QString adresIP, transfer_port;
std::string passive_connection = "";
std::string oktet[6];
int licznik = 0, portA, portB, portC;
komunikat += "Message: ";
while(message.length() == 0) message = socket->readLine();
komunikat += message;
komunikat += "Polecenie: ";
message = "";
command = "USER " + login + "\r\n";
komunikat += "Polecenie: ";
komunikat += command;
socket->write(command.toUtf8().constData());
socket->waitForBytesWritten(5000);
while(message.length() == 0) message = socket->readLine();
komunikat += "Message: ";
komunikat += message;
message = "";
command = "PASS " + password + "\r\n";
komunikat += "Polecenie: PASS <nie pokażę Ci hasła>\n";
socket->write(command.toUtf8().constData());
socket->waitForBytesWritten(5000);
while(message.length() == 0) message = socket->readLine();
komunikat += "Message: ";
komunikat += message;
message = "";
command = "OPTS UTF8 ON\r\n";
komunikat += "Polecenie: ";
komunikat += command;
socket->write(command.toUtf8().constData());
socket->waitForBytesWritten(5000);
while(message.length() == 0) message = socket->readLine();
komunikat += "Message: ";
komunikat += message;
message = "";
komunikat += "Status: Connected succesfully. Now I'm checking the directory list...\n";
command = "TYPE I\r\n";
komunikat += "Polecenie: ";
komunikat += command;
socket->write(command.toUtf8().constData());
socket->waitForBytesWritten(5000);
while(message.length() == 0) message = socket->readLine();
komunikat += "Message: ";
komunikat += message;
message = "";
command = "PWD \r\n";
komunikat += "Polecenie: ";
komunikat += command;
socket->write(command.toUtf8().constData());
socket->waitForBytesWritten(5000);
int i = 0;
while(message.length() == 0){
message = socket->readLine();
}
currentPath = message;
komunikat += "Message: ";
komunikat += message;
message = "";
command = "PASV \r\n";
komunikat += "Polecenie: ";
komunikat += command;
socket->write(command.toUtf8().constData());
socket->waitForBytesWritten(5000);
while(message.length() == 0) message = socket->readLine();
komunikat += "Message: ";
komunikat += message;
passive_connection = message.toUtf8().constData();
message = "";
for(int i = 3; i < passive_connection.length()-2; i++){
if(passive_connection[i] >= '0' && passive_connection[i] <= '9'){
oktet[licznik] += passive_connection[i];
if(passive_connection[i+1] == ',')
{
licznik++;
continue;
}
}
}
adresIP = QString::fromStdString(oktet[0]) + "." + QString::fromStdString(oktet[1]) + "." + QString::fromStdString(oktet[2])
+ "." + QString::fromStdString(oktet[3]);
portA = QString::fromStdString(oktet[4]).toInt();
portB = QString::fromStdString(oktet[5]).toInt();
portC = (portA * 256 + portB);
transfer_port.setNum(portC);
komunikat += "Tworzę połączenie na następujący adres i port: \n";
komunikat += "Adres: " + adresIP + "\n";
komunikat += "Port: " + transfer_port + "\n";

    socketTransmit.connectToHost(adresIP, portC);
    socketTransmit.waitForConnected(2000);
    komunikat += "Polecenie: ";
    command = "LIST \r\n";
    komunikat += command;
    socket->write(command.toUtf8().constData());
    socket->waitForBytesWritten(5000);              
    socketTransmit.waitForBytesWritten(5000);
    socketTransmit.waitForReadyRead(5000);
    socket->waitForBytesWritten(5000);

    socket->waitForBytesWritten(5000);
    message = socket->readLine();  //czekamy na odpowiedź kolejną z socketu poleceń
    komunikat += "Message: ";
    komunikat += message;
    message = "";

    message = socketTransmit.readAll();
    directoryList = message;    //  pobieramy do zmiennej directoryList listing plików i folderów
    if (directoryList != ""){
        komunikat += "Listing plików i folderów przesłąny z powodzeniem!!!:\n";
    }
    else
        komunikat += "Błąd! Nie udało mi się pobrać listy plików i folderów!!!\n";
    //komunikat += message;
    message = "";
    i = 0;
    while(message.length() == 0){
        i++;
        message = socket->readLine();
        if(i == 32768)
        {
            message = "Błąd podczas transmisji polecenia";
            break;
        }
    }
    komunikat += "Message: ";
    komunikat += message;
    message = "";
}

@

[robsonQTnewbie]

I know my code isn't nice but I've just started my QT experience, so I hope that you'll understand and can help me. Thanks a lot :)

[SGaist]

There are indeed several things that I don't follow:

• Why are you mixing std::string and QString ? Currently it just complicates your code without any benefits
• Why are you using pointers to QString ?

You are also creating memory leaks with your custom dialogs.

Anyway, for your original problem. You are doing everything in the connected slot, which is a bad idea. You need to refactor that and split the logic for the various commands you want to send in their own functions

[robsonQTnewbie]

I'm mixing QString with std::string because I couldn't filter the QString like a simple array, so I decided to go on the easiest way and parse it to std::string.

I need pointers to QString because I have no idea how get access to one variable from one class in another class. I think pointers are a good method to get the content from variables....

Which custom dialogs do you mean? I thinked about your advice to split to signal and slot system but I have trouble with it..... now i have something like that:
@#include "mainwindow.h"
#include "ui_mainwindow.h"

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

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

void MainWindow::on_pushButton_clicked() // connect Button
{
commandSocket = new QTcpSocket(this);

login = ui->loginValue->text();
url = ui->urlValue->text();
password = ui->passwordValue->text();
port = ui->portValue->text();
qint64 timeout = 4000;

connect(commandSocket, SIGNAL(connected()), this, SLOT(connected()));
connect(commandSocket, SIGNAL(bytesWritten(timeout)), this, SLOT(getMessage()));
qDebug() << "Connecting...";

commandSocket->connectToHost(url, port.toShort());
if(!commandSocket->waitForConnected(3000)){
    qDebug() << "Przekroczony limit czasu...\n";
}

}

void MainWindow::connected()
{
qDebug() << "In connected()...";
sendMessage("USER ", login);

}
void MainWindow::sendMessage(QString message, QString argument)
{
qDebug() << "in sendMessage...";
QString displayedArgument, command;
if(message == "PASS ")
displayedArgument = "SECRET_PASSWORD...";
else
displayedArgument = argument;
command = message + argument + "\r\n";
commandSocket->write(command.toUtf8().constData());
commandSocket->waitForBytesWritten(10000);

ui->textBrowser->setOverwriteMode(false);
ui->textBrowser->setText("Polecenie: " + message + displayedArgument + "\n");
qDebug() << "send message done...";

}
void MainWindow::getMessage()
{
qDebug() << "In getMessage()...";
QString message = "";
//while(message == "")
message = commandSocket->readLine();

qDebug() << message;
ui->textBrowser->setOverwriteMode(false);
ui->textBrowser->setText(message);

}@
and unfortunately it's not working:/
PS. I decidet to put everything in the mainwindow.cpp.

[SGaist]

What do you mean by "can't filter like a simple array" ?

You should have a look at the fortune client/server example for inspiration

[robsonQTnewbie]

I mean something like that:
@
QString someQString = "I like Qt!", outputQString = "";
for(int i = 0; i < someQString.length(); i++)
{
if(someQString[i] != " ")
outputString += someQString[i];
}
@

[SGaist]

You want to remove all white spaces in the string ?
From the top of my head:
@
someQString.replace(QRegular[removed]"\s"), "");
@

Replace QRegularExpression by QRegExp if you are on Qt 4

[robsonQTnewbie]

Thanks:) I moved forward with my project and now i need help with downloading files. The problem is that, when I download a file (first .txt) the data go on the socket but not everything. When i download a small file it works fine, but when I download a bigger file it looses data. :/ Do you have a advice form me?

P.S. I start the download from the transfer socket, when on the commandLineSocket is the command RETR succesfully transmited.

[SGaist]

Look at readyRead and the asynchronousness handling of IO devices