CopperSpice API  1.7.2
QTcpServer Class Reference

Provides a TCP-based server. More...

Inheritance diagram for QTcpServer:
QObject

Public Signals

void acceptError (QAbstractSocket::SocketError socketError)
 
void newConnection ()
 
- Public Signals inherited from QObject
void destroyed (QObject *obj=nullptr)
 
void objectNameChanged (const QString &objectName)
 

Public Methods

 QTcpServer (QObject *parent=nullptr)
 
virtual ~QTcpServer ()
 
void close ()
 
QString errorString () const
 
virtual bool hasPendingConnections () const
 
bool isListening () const
 
bool listen (const QHostAddress &address=QHostAddress::Any, quint16 port=0)
 
int maxPendingConnections () const
 
virtual QTcpSocketnextPendingConnection ()
 
void pauseAccepting ()
 
QNetworkProxy proxy () const
 
void resumeAccepting ()
 
QHostAddress serverAddress () const
 
QAbstractSocket::SocketError serverError () const
 
quint16 serverPort () const
 
void setMaxPendingConnections (int numConnections)
 
void setProxy (const QNetworkProxy &networkProxy)
 
bool setSocketDescriptor (qintptr socketDescriptor)
 
qintptr socketDescriptor () const
 
bool waitForNewConnection (int msec=0, bool *timedOut=nullptr)
 
- Public Methods inherited from QObject
 QObject (QObject *parent=nullptr)
 
 ~QObject ()
 
bool blockSignals (bool block)
 
const QList< QObject * > & children () const
 
bool connect (const QObject *sender, const QString &signalMethod, const QString &location, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)
 
bool connect (const QObject *sender, const QString &signalMethod, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)
 
bool disconnect (const QObject *receiver, const QString &slotMethod=QString ()) const
 
bool disconnect (const QString &signalMethod, const QString &location, const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const
 
bool disconnect (const QString &signalMethod=QString (), const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const
 
void dumpObjectInfo ()
 
void dumpObjectTree ()
 
QList< QStringdynamicPropertyNames () const
 
virtual bool event (QEvent *event)
 
virtual bool eventFilter (QObject *watched, QEvent *event)
 
template<typename T >
findChild (const QString &childName=QString ()) const
 
template<class T >
QList< T > findChildren (const QRegularExpression &regExp, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 
template<class T >
QList< T > findChildren (const QString &objName=QString (), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
 
bool inherits (const QString &className) const
 
void installEventFilter (QObject *filterObj)
 
bool isWidgetType () const
 
bool isWindowType () const
 
void killTimer (int id)
 
const QMetaObjectmetaObject () const
 
void moveToThread (QThread *targetThread)
 
QString objectName () const
 
QObject * parent () const
 
template<class T = QVariant>
property (const QString &name) const
 
void removeEventFilter (QObject *obj)
 
void setObjectName (const QString &name)
 
void setParent (QObject *parent)
 
bool setProperty (const QString &name, const QVariant &value)
 
bool signalsBlocked () const
 
int startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
 
QThreadthread () const
 

Protected Methods

void addPendingConnection (QTcpSocket *socket)
 
virtual void incomingConnection (qintptr socketDescriptor)
 
- Protected Methods inherited from QObject
virtual void childEvent (QChildEvent *event)
 
virtual void connectNotify (const QMetaMethod &signalMethod) const
 
virtual void customEvent (QEvent *event)
 
virtual void disconnectNotify (const QMetaMethod &signalMethod) const
 
bool isSignalConnected (const QMetaMethod &signalMethod) const
 
int receivers (const QString &signal) const
 
QObject * sender () const
 
int senderSignalIndex () const
 
virtual void timerEvent (QTimerEvent *event)
 

Additional Inherited Members

- Public Slots inherited from QObject
void deleteLater ()
 
- Static Public Methods inherited from QObject
static bool connect (const QObject *sender, const QMetaMethod &signalMethod, const QObject *receiver, const QMetaMethod &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)
 
static bool connect (const QObject *sender, const QString &signalMethod, const QObject *receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection, const QString &location=QString ())
 
static bool connect (const QObject *sender, const QString &signalMethod, const QString &location, const QObject *receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)
 
template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool connect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, SlotReturn (SlotClass::*slotMethod)(SlotArgs...), Qt::ConnectionType type=Qt::AutoConnection)
 
template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool connect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, T slotLambda, Qt::ConnectionType type=Qt::AutoConnection)
 
static bool disconnect (const QObject *sender, const QMetaMethod &signalMethod, const QObject *receiver, const QMetaMethod &slotMethod)
 
static bool disconnect (const QObject *sender, const QString &signalMethod, const QObject *receiver, const QString &slotMethod)
 
static bool disconnect (const QObject *sender, const QString &signalMethod, const QString &location, const QObject *receiver, const QString &slotMethod)
 
template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool disconnect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, SlotReturn (SlotClass::*slotMethod)(SlotArgs...))
 
template<class Sender , class SignalClass , class... SignalArgs, class Receiver >
static bool disconnect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, std::nullptr_t slotMethod=nullptr)
 
template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool disconnect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, T slotMethod)
 
static QMetaObjectstaticMetaObject ()
 
static QString tr (const char *text, const char *comment=nullptr, std::optional< int > numArg=std::optional< int >())
 
- Properties inherited from QObject
 objectName
 

Detailed Description

The QTcpServer class provides a TCP-based server. This class makes it possible to accept incoming TCP connections. You can specify the port or have QTcpServer pick one automatically. You can listen on a specific address or on all the machine's addresses.

Call listen() to have the server listen for incoming connections. The newConnection() signal is then emitted each time a client connects to the server.

Call nextPendingConnection() to accept the pending connection as a connected QTcpSocket. The function returns a pointer to a QTcpSocket in QAbstractSocket::ConnectedState that you can use for communicating with the client.

If an error occurs, serverError() returns the type of error, and errorString() can be called to get a human readable description of what happened. When listening for connections, the address and port on which the server is listening are available as serverAddress() and serverPort().

Calling close() makes QTcpServer stop listening for incoming connections.

Although QTcpServer is mostly designed for use with an event loop, it is possible to use it without one. In that case, you must use waitForNewConnection(), which blocks until either a connection is available or a timeout expires.

See also
QTcpSocket

Constructor & Destructor Documentation

QTcpServer::QTcpServer ( QObject parent = nullptr)
explicit

Constructs a QTcpServer object using the given parent.

See also
listen(), setSocketDescriptor()
QTcpServer::~QTcpServer ( )
virtual

Destroys the QTcpServer object.

If the server is listening for connections, the socket is automatically closed. Any client QTcpSockets that are still connected must either disconnect or be reparented before the server is deleted.

See also
close()

Method Documentation

void QTcpServer::acceptError ( QAbstractSocket::SocketError  socketError)
signal

This signal is emitted when accepting a new connection results in an error. The socketError parameter describes the type of error that occurred.

See also
pauseAccepting(), resumeAccepting()
void QTcpServer::addPendingConnection ( QTcpSocket socket)
protected

This method is called by QTcpServer::incomingConnection() to add the socket to the list of pending incoming connections.

Note
Do not forget to call this member from reimplemented incomingConnection() if you do not want to break the Pending Connections mechanism.
See also
incomingConnection()
void QTcpServer::close ( )

Closes the server. The server will no longer listen for incoming connections.

See also
listen()
QString QTcpServer::errorString ( ) const

Returns a human readable description of the last error that occurred.

See also
serverError()
bool QTcpServer::hasPendingConnections ( ) const
virtual

Returns true if the server has a pending connection, otherwise returns false.

See also
nextPendingConnection(), setMaxPendingConnections()
void QTcpServer::incomingConnection ( qintptr  socketDescriptor)
protectedvirtual

This method is called by QTcpServer when a new connection is available. The socketDescriptor argument is the native socket descriptor for the accepted connection.

The base implementation creates a QTcpSocket, sets the socket descriptor and then stores the QTcpSocket in an internal list of pending connections. Finally newConnection() is emitted. Reimplement this function to alter the server's behavior when a connection is available.

If this server is using QNetworkProxy then the socketDescriptor may not be usable with native socket functions, and should only be used with QTcpSocket::setSocketDescriptor().

Note
If you want to handle an incoming connection as a new QTcpSocket object in another thread you have to pass the socketDescriptor to the other thread and create the QTcpSocket object there and use its setSocketDescriptor() method.
See also
newConnection(), nextPendingConnection(), addPendingConnection()
bool QTcpServer::isListening ( ) const

Returns true if the server is currently listening for incoming connections, otherwise returns false.

See also
listen()
bool QTcpServer::listen ( const QHostAddress address = QHostAddress::Any,
quint16  port = 0 
)

Tells the server to listen for incoming connections on address address and port port. If port is 0, a port is chosen automatically. If address is QHostAddress::Any, the server will listen on all network interfaces.

Returns true on success, otherwise returns false.

See also
isListening()
int QTcpServer::maxPendingConnections ( ) const

Returns the maximum number of pending accepted connections. The default is 30.

See also
setMaxPendingConnections(), hasPendingConnections()
void QTcpServer::newConnection ( )
signal

This signal is emitted every time a new connection is available.

See also
hasPendingConnections(), nextPendingConnection()
QTcpSocket * QTcpServer::nextPendingConnection ( )
virtual

Returns the next pending connection as a connected QTcpSocket object. If there are no pending connection nullptr is returned.

The socket is created as a child of the server, which means that it is automatically deleted when the QTcpServer object is destroyed. It is still a good idea to delete the object explicitly when you are done with it, to avoid wasting memory.

Note
The returned QTcpSocket object can not be used from another thread. If you want to use an incoming connection from another thread, you need to override incomingConnection().
See also
hasPendingConnections()
void QTcpServer::pauseAccepting ( )

Pauses accepting new connections. Queued connections will remain in queue.

See also
resumeAccepting()
QNetworkProxy QTcpServer::proxy ( ) const

Returns the network proxy for this socket. By default QNetworkProxy::DefaultProxy is used.

See also
setProxy(), QNetworkProxy
void QTcpServer::resumeAccepting ( )

Resumes accepting new connections.

See also
pauseAccepting()
QHostAddress QTcpServer::serverAddress ( ) const

Returns the server's address if the server is listening for connections, otherwise returns QHostAddress::Null.

See also
serverPort(), listen()
QAbstractSocket::SocketError QTcpServer::serverError ( ) const

Returns an error code for the last error that occurred.

See also
errorString()
quint16 QTcpServer::serverPort ( ) const

Returns the server's port if the server is listening for connections, otherwise returns 0.

See also
serverAddress(), listen()
void QTcpServer::setMaxPendingConnections ( int  numConnections)

Sets the maximum number of pending accepted connections to numConnections. QTcpServer will accept no more than numConnections incoming connections before nextPendingConnection() is called. By default, the limit is 30 pending connections.

Clients may still able to connect after the server has reached its maximum number of pending connections (i.e., QTcpSocket can still emit the connected() signal). QTcpServer will stop accepting the new connections, but the operating system may still keep them in queue.

See also
maxPendingConnections(), hasPendingConnections()
void QTcpServer::setProxy ( const QNetworkProxy networkProxy)

Sets the explicit network proxy for this socket to networkProxy. To disable the use of a proxy for this socket use the QNetworkProxy::NoProxy proxy type.

server->setProxy(QNetworkProxy::NoProxy);
See also
proxy(), QNetworkProxy
bool QTcpServer::setSocketDescriptor ( qintptr  socketDescriptor)

Sets the socket descriptor this server should use when listening for incoming connections to socketDescriptor. Returns true if the socket is set successfully, otherwise returns false.

The socket is assumed to be in listening state.

See also
socketDescriptor(), isListening()
qintptr QTcpServer::socketDescriptor ( ) const

Returns the native socket descriptor the server uses to listen for incoming instructions, or -1 if the server is not listening. If the server is using QNetworkProxy, the returned descriptor may not be usable with native socket functions.

See also
setSocketDescriptor(), isListening()
bool QTcpServer::waitForNewConnection ( int  msec = 0,
bool *  timedOut = nullptr 
)

Waits for at most msec milliseconds or until an incoming connection is available. Returns true if a connection is available, otherwise returns false. If the operation timed out and timedOut is not 0, timedOut will be set to true. If msec is -1, this function will not time out.

This is a blocking function call. Its use is disadvised in a single-threaded GUI application, since the whole application will stop responding until the function returns. waitForNewConnection() is mostly useful when there is no event loop available.

The non-blocking alternative is to connect to the newConnection() signal.

See also
hasPendingConnections(), nextPendingConnection()