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/*!

    \example network/fortuneserver

    \title Fortune Server Example

    The Fortune Server example shows how to create a server for a simple

    network service. It is intended to be run alongside the

    \l{network/fortuneclient}{Fortune Client} example or the

    \l{network/blockingfortuneclient}{Blocking Fortune Client} example.

    \image fortuneserver-example.png Screenshot of the Fortune Server example

    This example uses QTcpServer to accept incoming TCP connections, and a

    simple QDataStream based data transfer protocol to write a fortune to the

    connecting client (from the \l{network/fortuneclient}{Fortune Client}

    example), before closing the connection.

    \snippet examples/network/fortuneserver/server.h 0

    The server is implemented using a simple class with only one slot, for

    handling incoming connections.

    \snippet examples/network/fortuneserver/server.cpp 1

    In its constructor, our Server object calls QTcpServer::listen() to set up

    a QTcpServer to listen on all addresses, on an arbitrary port. In then

    displays the port QTcpServer picked in a label, so that user knows which

    port the fortune client should connect to.

    \snippet examples/network/fortuneserver/server.cpp 2

    Our server generates a list of random fortunes that is can send to

    connecting clients.

    \snippet examples/network/fortuneserver/server.cpp 3

    When a client connects to our server, QTcpServer will emit

    QTcpServer::newConnection(). In turn, this will invoke our

    sendFortune() slot:

    \snippet examples/network/fortuneserver/server.cpp 4

    The purpose of this slot is to select a random line from our list of

    fortunes, encode it into a QByteArray using QDataStream, and then write it

    to the connecting socket. This is a common way to transfer binary data

    using QTcpSocket. First we create a QByteArray and a QDataStream object,

    passing the bytearray to QDataStream's constructor. We then explicitly set

    the protocol version of QDataStream to QDataStream::Qt_4_0 to ensure that

    we can communicate with clients from future versions of Qt. (See

    QDataStream::setVersion().)

    \snippet examples/network/fortuneserver/server.cpp 6

    At the start of our QByteArray, we reserve space for a 16 bit integer that

    will contain the total size of the data block we are sending. We continue

    by streaming in a random fortune. Then we seek back to the beginning of

    the QByteArray, and overwrite the reserved 16 bit integer value with the

    total size of the array. By doing this, we provide a way for clients to

    verify how much data they can expect before reading the whole packet.

    \snippet examples/network/fortuneserver/server.cpp 7

    We then call QTcpServer::newPendingConnection(), which returns the

    QTcpSocket representing the server side of the connection. By connecting

    QTcpSocket::disconnected() to QObject::deleteLater(), we ensure that the

    socket will be deleted after disconnecting.

    \snippet examples/network/fortuneserver/server.cpp 8

    The encoded fortune is written using QTcpSocket::write(), and we finally

    call QTcpSocket::disconnectFromHost(), which will close the connection

    after QTcpSocket has finished writing the fortune to the network. Because

    QTcpSocket works asynchronously, the data will be written after this

    function returns, and control goes back to Qt's event loop. The socket

    will then close, which in turn will cause QObject::deleteLater() to delete

    it.

    \sa {Fortune Client Example}, {Threaded Fortune Server Example}

 */