GET Network program

[eleanor]

I'm curious, why doesn't this program work:

MAIN.CPP

#include <QApplication>
#include "mainwindow.h"
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
	CMainWindow window;
	window.show();
 
    //return app.exec();
}

#include <QApplication>
#include "mainwindow.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
	CMainWindow window;
	window.show();

    //return app.exec();
}

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MAINWINDOW.H

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
/**
	@author eleanor <eleanor@localhost>
*/
 
#include <QWidget>
#include <QString>
#include <QTextStream>
#include <QTcpSocket>
#include <QAbstractSocket>
#include <QLabel>
 
class CMainWindow : public QWidget {
public:
    CMainWindow(QWidget *parent=0);
 
    ~CMainWindow();
 
private:
	QTcpSocket *m_pSocket;
};
 
#endif

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

/**
	@author eleanor <eleanor@localhost>
*/

#include <QWidget>
#include <QString>
#include <QTextStream>
#include <QTcpSocket>
#include <QAbstractSocket>
#include <QLabel>

class CMainWindow : public QWidget {
public:
    CMainWindow(QWidget *parent=0);

    ~CMainWindow();

private:
	QTcpSocket *m_pSocket;
};

#endif

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MAINWINDOW.CPP

#include "mainwindow.h"
 
CMainWindow::CMainWindow(QWidget *parent) : QWidget(parent) {
	//creating a socket
	m_pSocket = new QTcpSocket(this);
 
 
	QString myHost("www.google.com");
	int myPort = 80;
 
	//this function establishes connection and returns immediately
	m_pSocket->connectToHost(myHost, myPort);
 
	QString input = "GET /index.php HTTP/1.1\n\n";
	if(m_pSocket->state() == QAbstractSocket::ConnectedState) {
		QTextStream stream(m_pSocket);
		stream << input;
	}
 
	QString text;
	while(m_pSocket->canReadLine()) {
		text += m_pSocket->readLine();
	}
 
	QTextStream output(stdout);
	QString enteredCommand = text;
	output >> text;
}
 
 
CMainWindow::~CMainWindow() {
 
}

#include "mainwindow.h"

CMainWindow::CMainWindow(QWidget *parent) : QWidget(parent) {
	//creating a socket
	m_pSocket = new QTcpSocket(this);
	

	QString myHost("www.google.com");
	int myPort = 80;

	//this function establishes connection and returns immediately
	m_pSocket->connectToHost(myHost, myPort);
	
	QString input = "GET /index.php HTTP/1.1\n\n";
	if(m_pSocket->state() == QAbstractSocket::ConnectedState) {
		QTextStream stream(m_pSocket);
		stream << input;
	}

	QString text;
	while(m_pSocket->canReadLine()) {
		text += m_pSocket->readLine();
	}

	QTextStream output(stdout);
	QString enteredCommand = text;
	output >> text;
}


CMainWindow::~CMainWindow() {

}

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I would appreciate any tips. Thanks

[wysota]

Because the socket works asynchronously to the application - it doesn't block when you write or read from it. You need to react on signals or use QHttp instead.

[eleanor]

Ok, I'm trying this way:

QString myHost("www.google.com");
	int myPort = 80;
 
	//this function establishes connection and returns immediately
	m_pSocket->connectToHost(myHost, myPort);
	connect(m_pSocket, SIGNAL(connected()), this, SLOT(connectedSlot()));

QString myHost("www.google.com");
	int myPort = 80;

	//this function establishes connection and returns immediately
	m_pSocket->connectToHost(myHost, myPort);
	connect(m_pSocket, SIGNAL(connected()), this, SLOT(connectedSlot()));

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void 	CMainWindow::connectedSlot() {
	QString input = "GET /index.php HTTP/1.1\n\n";
	if(m_pSocket->state() == QAbstractSocket::ConnectedState) {
		QTextStream stream(m_pSocket);
		stream << input;
	}
 
	QString text;
	while(m_pSocket->canReadLine()) {
		text += m_pSocket->readLine();
	}
 
	QTextStream output(stdout);
	QString enteredCommand = text;
	output >> text;
}

void 	CMainWindow::connectedSlot() {
	QString input = "GET /index.php HTTP/1.1\n\n";
	if(m_pSocket->state() == QAbstractSocket::ConnectedState) {
		QTextStream stream(m_pSocket);
		stream << input;
	}

	QString text;
	while(m_pSocket->canReadLine()) {
		text += m_pSocket->readLine();
	}

	QTextStream output(stdout);
	QString enteredCommand = text;
	output >> text;
}

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I'm calling this slot when the connecter() signal occurs, still does not work!

[wysota]

Because m_pSocket->canReadLine() will return false and break out of the loop immediately - there is no data in the socket yet. You need to make your flow event driven - for example connect to the socket's readyRead() signal - it is emited when some data becomes available in the socket.