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Tuesday, May 6th 2008, 10:46am
redirecting sockets
Hi everybody,
I have a server application that connects an IP video camera and redirects any data from this camera to a client's socket, as shown below:
The problems are:
I have a server application that connects an IP video camera and redirects any data from this camera to a client's socket, as shown below:
|
Source code |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 |
// _pIOClient is a QIODevice* object wrapping the client's socket
qint64 n64, m64;
QByteArray bytes;
QTcpSocket sckt;
// connect sckt to another server
sckt.connectToHost(...);
// ...
_pIOClient->write("test 1");
// ask the server to start the streaming
sckt.write("PLAY ...");
// ...
_pIOClient->write("test 2");
while (_pIOClient->isOpen()) {
if (sckt.waitForReadyRead(3000)) {
bytes = sckt.readAll();
m64 = bytes.size();
qDebug("%ld bytes to write", m64);
if (m64!=0) {
n64 = _pIOClient->write(bytes.data(), m64);
qDebug("written %ld of %ld bytes", n64, m64);
}
}
}
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The problems are:
- The data sent in line 11 ("test 1") are received by the client, but data in line 17 (just after camera has started the streaming) and line 25 are not received by client for some reason.
- Application never exits the loop at line 19, even when _pIOClient is not opened (because client has closed the socket).
- Application console output is:
[/list=1]
Quoted 1296 bytes to write
written 1296 of 0 bytes
4 bytes to write
written 4 of 0 bytes
1296 bytes to write
written 1296 of 0 bytes
4 bytes to write
written 4 of 0 bytes
...
And my questions are the following:
- Is the network module busy with camera's streaming? is that why client socket does not work? how can I fix it?
- Why does application think that _pIOClient is always opened?
- Why is m64 set to zero?[/list=1]
- Is the network module busy with camera's streaming? is that why client socket does not work? how can I fix it?
Tuesday, May 6th 2008, 2:54pm
RE: redirecting sockets
how and where is your loop implemented?
seems me your loop is blocking
EDIT:
better than waitForReadyRead would be to use
- the signal QIODevice::readyRead() for the camera's device
- the signal QAbstractSocket::error( QAbstractSocket:
ocketError ) for the client's socket
seems me your loop is blocking
EDIT:
better than waitForReadyRead would be to use
- the signal QIODevice::readyRead() for the camera's device
- the signal QAbstractSocket::error( QAbstractSocket:
ocketError ) for the client's socket
Nicolas
This post has been edited 4 times, last edit by "Nicolas SOUCHON" (May 6th 2008, 3:05pm)
Wednesday, May 7th 2008, 8:32am
RE: redirecting sockets
I don't know about #1 but for #2 the reason the application thinks that _pIOClient is always opened is because I don't see where you close it
Remember that my application is a server. This _pIOClient object is a socket opened by a client. When client closes this socket, the server does not exit the loop.
how and where is your loop implemented?
seems me your loop is blocking
I have a class that inherits QTcpServer. For every incoming connection (every time the client opens a socket), a thread is launched. This thread runs the sample code explained in the first post. Maybe the problem is that this thread can manage the camera socket but not the client's one, isn't it?
better than waitForReadyRead would be to use
- the signal QIODevice::readyRead() for the camera's device
- the signal QAbstractSocket::error( QAbstractSocket:
Can I implement this kind of behaviour in every single thread? or should I have to use several threads redirect one camera to a client?