incommingConnection not called by QTcpServer

[wysota]

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();
    }
}

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

You didn't get my question. I asked you specifically -- how many times is readyRead() called for your file? Remove all content of the method and only put a debug statement that prints something and a call to socket->readAll(). Then run the program and see how many times the method is called for your file. Then sit down and think why it happens and how to change your code.

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.

I can tell you what is going on. There is a class A that has a virtual method x() and class B that doesn't have that method and you are implementing B::x() hoping that whatever was calling A::x() will call B::x() now. This is not the case in C++. You need to subclass A and reimplement x() for it to be called.

[toufic.dbouk]

You didn't get my question. I asked you specifically -- how many times is readyRead() called for your file? Remove all content of the method and only put a debug statement that prints something and a call to socket->readAll(). Then run the program and see how many times the method is called for your file. Then sit down and think why it happens and how to change your code.

hello Wysota,
sorry for the late reply i got busy last day
anyway i tried what u told me , the readyRead is emiited lots of time depending on the file size for sure
i was able to get rid of that waitforReadyReady loop
data is fully written on server
BUT STILL THE WHOLE GUI FREEZES!!
it freezes as long as the file is being written
so actually this didnt solve my problem...
heres the code:

void myClient::readyRead()
{    
 QString fPath("path");
    QByteArray block;
    QString fName= "test1";
    QFile sentFile(fPath +QDir::separator() + fName);
    sentFile.open(QFile::WriteOnly | QFile::Append);
    block=socket->readAll();
    socket->flush();
    qDebug()<< "block: " << block.size();
    sentFile.write(block);
}

void myClient::readyRead()
{    
 QString fPath("path");
    QByteArray block;
    QString fName= "test1";
    QFile sentFile(fPath +QDir::separator() + fName);
    sentFile.open(QFile::WriteOnly | QFile::Append);
    block=socket->readAll();
    socket->flush();
    qDebug()<< "block: " << block.size();
    sentFile.write(block);
}

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so do i use threads for this to not freeze ? or dd i do a mistake or missed something ?
please let me know ASAP
your help is really appreciated
thanks.

[wysota]

1. open the file once instead of reopening every time the method is called.
2. don't flush the socket.
3. create a QTime object at the beginning of the method, call its start() method and prints the result of its elapsed() method at the end of the readyRead() function. See how much time (in miliseconds) it takes to execute the method. It shouldn't take more than 100ms unless you are using a really low-end machine or you have problems elsewhere in your design which causes unnecessary lags and buildup in pending socket data.
4. also see how large blocks of data you receive, if you operate on the boundary of available memory, you might be getting into slowdowns caused by swapping, try to eliminate those (e.g. by not reading all data at once but instead reading it in smaller blocks that are guaranteed to fit in ram).

See if it helps.

[toufic.dbouk]

1. open the file once instead of reopening every time the method is called.
2. don't flush the socket.

do you mean that i should open the file outside the readyRead slot ?
may i ask why flushing the socket would result in such a slow or freeze of GUI ?

ill try all of what you said and let you know the result

[anda_skoa]

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.

As I said you need to create a subclass of QTcpServer for that and then reimplement/override the virtual method incomingConnection()

well server in my class is an instance of QTcpServer class

The class "server" is a QMainWindow, not a QTcpServer

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

Yes, QTcpServer works totally independent of where you put it, whether a main window or somewhere else.

so i still cant see the problem , why isnt it being invoked ?

QTcpServer::incomingConnection() is invoked.

If you want your method to be invoked instead, you have to derive from QTcpServer and reimplement/override it.

Your original code looks like you were assuming that the method of a totally different object (server::incomingConnection) would somehow magically be invoked.
C++ might look like magic from time to time but I am afraid it is not

Cheers,
_

[toufic.dbouk]

The class "server" is a QMainWindow, not a QTcpServer

what i meant here is that i have a QTcpServer instance(mServer) in my server class
so i was expecting the incommingConnection to be invoked from it

Your original code looks like you were assuming that the method of a totally different object (server::incomingConnection) would somehow magically be invoked.
C++ might look like magic from time to time but I am afraid it is not

its nice to have some sense of comedy from time to time, it removes the feeling of student-instructor at such forms:P
thanks ill give what u said a try and reply back later.

[wysota]

do you mean that i should open the file outside the readyRead slot ?

Yes, that's correct. Opening and closing the file takes some time, why waste it?

may i ask why flushing the socket would result in such a slow or freeze of GUI ?

I didn't say it does (maybe it does, maybe not). What flush does is that it forces all data pending to be written to be forced into the socket (AFAIR it sets the P(U)SH flag in TCP). Since you're not writing anything to the socket there is no point in flushing it, it's a pure waste of time. Even if you were writing something to the socket, flushing it in the part of code related to reading from the socket wouldn't make much sense too.

[toufic.dbouk]

I didn't say it does (maybe it does, maybe not). What flush does is that it forces all data pending to be written to be forced into the socket (AFAIR it sets the P(U)SH flag in TCP). Since you're not writing anything to the socket there is no point in flushing it, it's a pure waste of time. Even if you were writing something to the socket, flushing it in the part of code related to reading from the socket wouldn't make much sense too.

sure this makes sense thanks.
but how can i open the file before the readyRead slot is invoked even if the file isnt there ?
in other other words , im getting the name of the file from the readyRead slot and creating that file too when the readyRead Slot is executed ?
so how can i open the file before executing the readyRead slot ?

[wysota]

sure this makes sense thanks.
but how can i open the file before the readyRead slot is invoked even if the file isnt there ?
in other other words , im getting the name of the file from the readyRead slot and creating that file too when the readyRead Slot is executed ?
so how can i open the file before executing the readyRead slot ?

Open it when you receive the file name from the socket and then keep it open (you can create QFile on the heap or make it a member variable of your class). Note that you may receive the file name in parts, you have to take that into account when implementing the slot that handles incoming data.

[toufic.dbouk]

alright things are getting better i guess
but i need you to tell me something
if i have a block of code in a method (Readyread Slot ) which is entered everytime the readyRead Signal is emitted
in this method i want part of the code to not be executed but for the first time it enters
is there any easy way to lock such part of code so that it is not executed on the 2nd , third , fourth etc executions of the method?
i havnt slept for a while so honestly i dont know how to do it
may you help in this please?

[wysota]

if i have a block of code in a method (Readyread Slot ) which is entered everytime the readyRead Signal is emitted
in this method i want part of the code to not be executed but for the first time it enters
is there any easy way to lock such part of code so that it is not executed on the 2nd , third , fourth etc executions of the method?
i havnt slept for a while so honestly i dont know how to do it
may you help in this please?

Have a bool member variable, initialize it to something and then check its value in the method and flip it to the other value. Or simply have a QFile member variable and each time you enter the method, check if the file is open or not.

[toufic.dbouk]

i guess i cant do that cuz :

void myFucntion()
{

bool lock=false;

while(lock==false)
{
/* code that i want to block after first execution*/

bool = true;

}

// rest of the code




}

this will result in re-initialization off variable bool to false everytime the method is executed which will result in the
execution of my code

if u suggest to define in it header tell me how cuz i tried several times and each resulted in a different error.
thanks

[wysota]

I said a (class) member variable, not a local variable.

class myClient : ... {
  ...
  myClient(...) : ... {
    ...
    isInitialized = false;
  }
private:
  bool isInitialized;
};
 
void myClient::readyRead() {
  if(!isInitialized) {
    isInitialized = true;
    // executed once
  }
  // executed every time
}

class myClient : ... {
  ...
  myClient(...) : ... {
    ...
    isInitialized = false;
  }
private:
  bool isInitialized;
};

void myClient::readyRead() {
  if(!isInitialized) {
    isInitialized = true;
    // executed once
  }
  // executed every time
}

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[toufic.dbouk]

error: ISO C++ forbids initialization of member 'lock'
error: making 'lock' static
error: ISO C++ forbids in-class initialization of non-const static member 'lock'

these are the errors when i declare lock in my header as : bool lock=false;

if i make it static and const i wont be able to change it

if i make it just static : error: ISO C++ forbids in-class initialization of non-const static member 'lock'

thats what i meant by i tried several times each with an error

[wysota]

Look at the code I posted and compare it with yours.

[toufic.dbouk]

Look at the code I posted and compare it with yours.

yea sry i wrote the reply before the code appear

it is working , the readyRead SLot is almost good
its not blocking that much i guess the slight freeze might be from my laptop even though its a corei7 toshiba with 8GB of rams
but i havnt turned it off for a quite long time :P

ok so lets continue
do u have any easy idea to do authentication ?
what i mean is that when my client connects he will have to enter a user name and pass and email
i want the server to do authentication on this after he signs up
so the next time he logs in the server can authenticate
if the user name and pass are correct he will have access else he wont
can it be done without saving the data to a file on the server ?
should i encrypt the password ?

[wysota]

This is really out of scope of this forum. Although I have some knowledge regarding the topics you are asking about, I suggest you read some articles on designing protocols and services. I can only suggest that you follow standards instead of reinventing the wheel. E.g. think about using HTTP as your application protocol, maybe it suits your needs.

[toufic.dbouk]

ahhh...

may you give me your email so that you help me on this cuz its out of scop of this form? if your are willing to help me for sure

i thought you would know how to use the QAuthenticator and whether it can suit my need or not
i couldnt fine much tutorials about it but for the qt documentations

one more thing
i forgot to ask when should i close the file ?
i cant close it at that same readyRead slot , cuz then i would have done nothin
so whats the solution ?
i really appreciate your help.
thanks.

[wysota]

I will not design a protocol for you. The problem is not about Qt, it is about your understanding of how networking works. I cannot teach you that via email. This is not a task for 10 minutes, you have to do some reading and thinking. Choosing the right classes for the job is the last step that you need to do. First you need to go through a bunch of others.

[toufic.dbouk]

i ddnt ask to design a protocol for me
i simply asked for help via email thats all
i know networking, i took networking courses and do understand what you say about tcp and http and all that networking stuff
dont go to NAT cuz i havnt took that yet :P
im obliged to use what im using here and i have to use a authentication way and encrypting password
anyway if thats out of scope its fine.
but u ddnt answer me about the QAuthenticator ?