incommingConnection not called by QTcpServer

[toufic.dbouk]

Hi all,
i have this Server but whenever i try to connect to it from the client side
the incommingConnection is not being executed
can anyone help me to know the reason and how to fix it ?
Thanks in advance.

Server:

#include "server.h"
#include "ui_server.h"
#include <myclient.h>
#include <QtCore>
#include <QtGui>
#include <QTcpServer>
#include <QTcpSocket>
 
server::server(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::server)
{
    ui->setupUi(this);
 
    mServer=new QTcpServer(this);
 
    QString rPath="whateverpath";
    UserModel= new QFileSystemModel(this);
    UserModel = new QFileSystemModel(this);
    UserModel->setRootPath(rPath);
    QModelIndex index= UserModel->index(rPath);
    ui->UserListView->setModel(UserModel);
    ui->UserListView->setRootIndex(index);
 
    UserFileModel = new QFileSystemModel(this);
    UserFileModel->setFilter(QDir::NoDotAndDotDot | QDir::Files | QDir::AllDirs);
    ui->UserFilesTableView->setModel(UserFileModel);
    ui->UserFilesTableView->resizeColumnsToContents();
    ui->UserFilesTableView->setColumnWidth(3,266);
}
 
server::~server()
{
    delete ui;
}
 
void server::on_StartPushButton_2_clicked()
{
    // starting up the server on port number 1234
 
    if(mServer->isListening())
    {
        QMessageBox::information(this,"Start Up","The Server is already running");
        return;
    }
    if(mServer->listen(QHostAddress::Any,1234))
    {
 
        QMessageBox::information(this,"Start Up","The Server Has Started");
    }
    else
    {
 
       QMessageBox::information(this,"Start Up","The Server failed to Start up");
    }
 
}
 
void server::on_shutdownPushButton_8_clicked()
{
    //shutting down the server
    if(!mServer->isListening())
    { QMessageBox::information(this,"Shutdown","The Server is Already Turned Off");
      return;
    }
     mServer->close();
     QMessageBox::information(this,"Shutdown","The Server is Turned Off");
 
}
 
void server::incomingConnection(int handle) //-----> this is never executed , i add a qDebug but it never shows
{
    //when there is an incomming connection it is set to a client
    myClient *mClient = new myClient(this);
    mClient->SetSocket(handle);
}

#include "server.h"
#include "ui_server.h"
#include <myclient.h>
#include <QtCore>
#include <QtGui>
#include <QTcpServer>
#include <QTcpSocket>

server::server(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::server)
{
    ui->setupUi(this);
    
    mServer=new QTcpServer(this);
    
    QString rPath="whateverpath";
    UserModel= new QFileSystemModel(this);
    UserModel = new QFileSystemModel(this);
    UserModel->setRootPath(rPath);
    QModelIndex index= UserModel->index(rPath);
    ui->UserListView->setModel(UserModel);
    ui->UserListView->setRootIndex(index);

    UserFileModel = new QFileSystemModel(this);
    UserFileModel->setFilter(QDir::NoDotAndDotDot | QDir::Files | QDir::AllDirs);
    ui->UserFilesTableView->setModel(UserFileModel);
    ui->UserFilesTableView->resizeColumnsToContents();
    ui->UserFilesTableView->setColumnWidth(3,266);
}

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

void server::on_StartPushButton_2_clicked()
{
    // starting up the server on port number 1234

    if(mServer->isListening())
    {
        QMessageBox::information(this,"Start Up","The Server is already running");
        return;
    }
    if(mServer->listen(QHostAddress::Any,1234))
    {

        QMessageBox::information(this,"Start Up","The Server Has Started");
    }
    else
    {

       QMessageBox::information(this,"Start Up","The Server failed to Start up");
    }

}

void server::on_shutdownPushButton_8_clicked()
{
    //shutting down the server
    if(!mServer->isListening())
    { QMessageBox::information(this,"Shutdown","The Server is Already Turned Off");
      return;
    }
     mServer->close();
     QMessageBox::information(this,"Shutdown","The Server is Turned Off");

}

void server::incomingConnection(int handle) //-----> this is never executed , i add a qDebug but it never shows
{
    //when there is an incomming connection it is set to a client
    myClient *mClient = new myClient(this);
    mClient->SetSocket(handle);
}

To copy to clipboard, switch view to plain text mode 

Client:

#include "myclient.h"
#include "mytask.h"
#include <QtCore>
 
myClient::myClient(QObject *parent) :
    QObject(parent)
{
}
 
void myClient::SetSocket(int Descriptor)
{
    socket = new QTcpSocket(this);
 
    connect(socket,SIGNAL(connected()),this,SLOT(connected()));
    connect(socket,SIGNAL(disconnected()),this,SLOT(disconnected()));
    connect(socket,SIGNAL(readyRead()),this,SLOT(readyRead()));
    socket->setSocketDescriptor(Descriptor);
    qDebug() << "client connected";
 
}
 
void myClient::connected()
{
    qDebug() << "client connected event";
}
 
void myClient::disconnected()
{
    qDebug() << "client disconnected";
}
 
void myClient::readyRead()
{
    //do something
}

#include "myclient.h"
#include "mytask.h"
#include <QtCore>

myClient::myClient(QObject *parent) :
    QObject(parent)
{
}

void myClient::SetSocket(int Descriptor)
{
    socket = new QTcpSocket(this);

    connect(socket,SIGNAL(connected()),this,SLOT(connected()));
    connect(socket,SIGNAL(disconnected()),this,SLOT(disconnected()));
    connect(socket,SIGNAL(readyRead()),this,SLOT(readyRead()));
    socket->setSocketDescriptor(Descriptor);
    qDebug() << "client connected";

}

void myClient::connected()
{
    qDebug() << "client connected event";
}

void myClient::disconnected()
{
    qDebug() << "client disconnected";
}

void myClient::readyRead()
{
    //do something
}

To copy to clipboard, switch view to plain text mode 

[Santosh Reddy]

Server is listening, but where is it accepting new connection?

You should have something like this

connect(mServer, SIGNAL(newConnection()), ....);
or
if(mServer->hasPendingConnections())
{
    QTcpSocket * clientSocket = mServer->nextPendingConnection ();
    clientSocket->readAll();
...
}

connect(mServer, SIGNAL(newConnection()), ....);
or
if(mServer->hasPendingConnections())
{
    QTcpSocket * clientSocket = mServer->nextPendingConnection ();
    clientSocket->readAll();
...
}

To copy to clipboard, switch view to plain text mode 

[toufic.dbouk]

thanks for your reply
but isnt the incommingConnection function should accept the incomming connections and queue them ?

---

Added after 21 minutes:

i added a newConnection() public slot to the server class
implemented it as such

void Server::newConnection()
{   
      qDebug() << "new connection ";
     if(mServer->hasPendingConnections())
{
      QTcpSocket *socket = mServer->nextPendingConnection();
       qDebug() << "connected"l 
}
 
}

void Server::newConnection()
{   
      qDebug() << "new connection ";
     if(mServer->hasPendingConnections())
{
      QTcpSocket *socket = mServer->nextPendingConnection();
       qDebug() << "connected"l 
}

}

To copy to clipboard, switch view to plain text mode 

then in my constructor :
i added

connect(mServer,SIGNAL(newConnection()),this,SLOT(newConnection());

connect(mServer,SIGNAL(newConnection()),this,SLOT(newConnection());

To copy to clipboard, switch view to plain text mode 

but again non of the qDebugs were executed...
i rly need some help here
Best regards.

[boudie]

I think you better have a look here:
http://qt-project.org/doc/qt-4.8/examples-network.html

[toufic.dbouk]

well i fixed the problem
but now on the server side
when the file is being uploaded by the client to the server
the whole GUI just freezes
i know its from the

while(Socket.waitForReadyRead())
{
    //read from socket 
    // append to QByteArray
}

while(Socket.waitForReadyRead())
{
    //read from socket 
    // append to QByteArray
}

To copy to clipboard, switch view to plain text mode 

so does anyone have a solution to this ?
any other way to not freeze the GUI ?
i was actually thinking of send the file size before the data
read it separately then doing the while loop as such :
loop until the block size is equal to the file size sent
if anyone have tried this , may you hint me how to send the file size alone before the data ?
thanks is advance.

[toufic.dbouk]

Non of you guys or admins want to reply?
i need some help here.
thanks

[wysota]

I can only suggest to use signals and slots instead of waitFor* calls.

[toufic.dbouk]

well in other words how can i transfer that waitForreadyRead() loop into signals and slots ?
im not able to get the point of what you are saying
a sample code or pseudo code would be helpfull if not at least some logic...
thanks.

[elmasmalo1]

well i fixed the problem
but now on the server side
when the file is being uploaded by the client to the server
the whole GUI just freezes...

Hi there!

The solution to your problem will be adding a thread to your fuction thus when you receive data, it just simply goes in background doing its job while in the meanwhile you can still use other portions of your program. I think this is so far the best solution available to you =D

You can find more about QThread HERE With latest Qt-5.0.0 Support =D Head over "Detailed Description" so you can see whats happening in there

[toufic.dbouk]

threads... thanks ill give it a try
but i have a question
at the server side i create a QTcpSocket for ever client that connects in a class
now how can i move this exact same socket to the thread so that i does the job right ?
like if i created a new tcpsocket at the thread class it would be in an unconnected state ?
thanks for your fast respons.

[wysota]

well in other words how can i transfer that waitForreadyRead() loop into signals and slots ?

Yes. handle readyRead() and all will be fine.

a sample code or pseudo code would be helpfull if not at least some logic...

Sample code is in Qt docs.

threads... thanks ill give it a try

No, please don't give threads a try. That's a wrong approach here.

[elmasmalo1]

For moving that specific socket into the thread will be to make your QTcpSocket in your QThread Class and make it to listen for incoming connections and then serialize that Socket in order to identify it and there you have it. That QThread Class will be the one in charge of Receiving Incomming Connections and handling them over the program as you desire.

I should call a practical Trial & Error sample where you make few threads and each of them you assign your Incomming Connections function... and test with different settings...

If you need more reference I can suggest this series of video tutorials that could come handy in your project:

C++ Qt 28 - QThread Part #1: Creating a Thread
C++ Qt 29 - QThread Part #2: The Priority
C++ Qt 30 - QThread Part #3: The QMutex Class (This is what you will be needing in order to Serialize Objects in this case your Socket)
C++ Qt 31 - QThread Part 4: Threads and GUI (This will teach you how to organize threads and use them normally in a GUI Form)
C++ Qt 33 - QThread Part 5: The Waiting Thread Member
C++ Qt 35 - QThread Part 6: Threading done correctly in Qt

I suggest you to get a good grip over the concepts of Threading in Qt with these tutorials and later on deploying the techniques learned here into your project, only then you will have a vast knowledge on how to over control your program =D

Hope I helped in something.

[toufic.dbouk]

well i can figure out what u mean by handle the readyRead
i was just reading the Qthreads documentation and trying to solve my problem
basicly if a thread handles the readyRead() singnal then my problem would be solved
because then the thread will wait for the data to be written and block while my main thread which is my GUI
would be working fine
right ?
im confused now
im u just give me more hints on your approach ill be greatfull
Thanks.

[wysota]

basicly if a thread handles the readyRead() singnal then my problem would be solved

You don't need an extra thread to handle readyRead(). The main thread will do that just fine. Just connect the socket's readyRead() signal to a slot and read data from the socket from within that slot. Then when you receive the signal again, read data from the socket again, etc.

Using threads for reading socket data is just stupid. Sure you can do it, you can even start 20 threads for each client if your operating system lets you but what's the point?

[anda_skoa]

but isnt the incommingConnection function should accept the incomming connections and queue them ?

QTcpServer::incomingConnection will be called for each accepted connection.
The problem in your original code is that you are expecting server::incomingConnection to be called, but server is a subclass of QMainWindow.

Cheers,
_

[toufic.dbouk]

QTcpServer::incomingConnection will be called for each accepted connection.
The problem in your original code is that you are expecting server::incomingConnection to be called, but server is a subclass of QMainWindow.

Cheers,
_

and thats exactly what i want , i want the QTcpServer::incommingConnection to be called when a connection is established after which ill handle it the way i want.
well server in my class is an instance of QTcpServer class , hence i guess , for sure it will signal the QTcpServer::incommingConnection when a connection is accepted even if i subclassed from QMainWindow, i still have that QTcpServer object with its incommingConnection
so i still cant see the problem , why isnt it being invoked ?
if im wrong , correct my information.
thanks.

---

Added after 20 minutes:

You don't need an extra thread to handle readyRead(). The main thread will do that just fine. Just connect the socket's readyRead() signal to a slot and read data from the socket from within that slot. Then when you receive the signal again, read data from the socket again, etc.
Using threads for reading socket data is just stupid. Sure you can do it, you can even start 20 threads for each client if your operating system lets you but what's the point?

well the whole point of using threads in my case is that i want a thread other than the main thread of my application to handle the readyRead singal so that when data is being written to the server , the servers GUI wont block or freeze. Thats all my need from a thread.
i already linked the readyRead signal to a slot to take care of the reading and writing data to the sever but still it is managed by the main thread resulting in blocking my GUI
because i used waitforReadyRead as a loop to write the whole data to server.
if threads is a stupid thing to do in my case, im sorry for doing it because i dont actually know how to make it non block method , even though i tried several times.
i have already posted my code at the first post , so if u could fix it to a non blocking way by a sample code , id be waaaay too greatfull.
thanks for your understanding and best regards.

[wysota]

well the whole point of using threads in my case is that i want a thread other than the main thread of my application to handle the readyRead singal so that when data is being written to the server , the servers GUI wont block or freeze. Thats all my need from a thread.

And how much data is it? 100GB/s? 1GB/s? 1MB/s? 10kB/s? Do you also create a new thread if you want to write 10kB to a file? You don't because it takes mili if not microseconds to do it so your GUI will not even notice that. It's exactly the same with sockets -- your application only stores data in a system buffer for the socket and returns immediately. The rest is taken care of by the OS and hardware outside the scope of your application. Thus there is no need to create threads when reading or writing data from/to a socket. Without threads you end up with much cleaner, safer and quicker code.

i already linked the readyRead signal to a slot to take care of the reading and writing data to the sever but still it is managed by the main thread resulting in blocking my GUI
because i used waitforReadyRead as a loop to write the whole data to server.

If you use waitForReadyRead() then there is no point in connecting to the readyRead() signal. You only need to do the latter -- connect to readyRead() and read the available data in the socket when the slot is called.

if threads is a stupid thing to do in my case, im sorry for doing it because i dont actually know how to make it non block method , even though i tried several times.

No, you haven't, because all the time you end up calling waitForReadyRead() despite being told not to do it.

i have already posted my code at the first post , so if u could fix it to a non blocking way by a sample code , id be waaaay too greatfull.

void myClient::readyRead() {
  QByteArray ba = socket->readAll();
  doSomethingWithData(ba);
}

void myClient::readyRead() {
  QByteArray ba = socket->readAll();
  doSomethingWithData(ba);
}

To copy to clipboard, switch view to plain text mode 

[toufic.dbouk]

now thats a well and good explained reply.
thank you for your patience.
but trust me i did try and more than once to not use the waitforReadyRead loop
and when i dont, the file sent just is not fully received
thats why i was insisting on using it just to solve my problem ( it caused another problem , blocking the GUI , so i was trying to solve my other problem)
my GUI freezes at a 7 MB file , even a 2 MB file lead to a half a sec or so of freezing , thats why it is really annoying and cant overlook it. a 1GB file would block it forever until it is fully saved on the server.
anyway i will try to not use the waitforRedayRead() again and see how it goes another time, maybe i had a silly hidden mistake or something.
again Iam really thankful for your concern.

[wysota]

and when i dont, the file sent just is not fully received

How many times was readyRead() called for your file? What did you do with the data after receiving it? Show your code please. And while you're at it, fix the thing anda_skoa mentioned.

[toufic.dbouk]

void myClient::readyRead()
{
    QString fPath("C:\\Users\\Ali\\Desktop\\music");
    QByteArray block;
 
    block=socket->readAll();
    socket->flush();
    qDebug()<< "block: " << block;
    socket->waitForReadyRead();
 
    QString fName= QString(block);
    QFile sentFile(fPath +QDir::separator() + fName);
    block.clear();
 
    if(!sentFile.exists())
    {
        sentFile.open(QFile::WriteOnly);
        while(socket->waitForReadyRead())
        {
        QByteArray block= socket->readAll();
        qDebug()<< "read:  " << block.size();
        sentFile.write(block);
        block.clear();
        }
        sentFile.close();
    }
}

void myClient::readyRead()
{
    QString fPath("C:\\Users\\Ali\\Desktop\\music");
    QByteArray block;

    block=socket->readAll();
    socket->flush();
    qDebug()<< "block: " << block;
    socket->waitForReadyRead();

    QString fName= QString(block);
    QFile sentFile(fPath +QDir::separator() + fName);
    block.clear();

    if(!sentFile.exists())
    {
        sentFile.open(QFile::WriteOnly);
        while(socket->waitForReadyRead())
        {
        QByteArray block= socket->readAll();
        qDebug()<< "read:  " << block.size();
        sentFile.write(block);
        block.clear();
        }
        sentFile.close();
    }
}

To copy to clipboard, switch view to plain text mode 

thats how iam saving the data.
this readyRead slot is connected to the sockets readyRead Signal

now when this loop is removed while(socket->waitForReadyRead())
the file wont be fully saved, it will be corrupted. If its a picture , the first couple of pixels will be saved.

i replied to anda_skoa but he havnt replied back , i need him to reply to my question first to understand whats going on.
for now i connected the newConnection to another slot that will handle the work.