root/branch/twedit/DataSocketCommunicators.py

from PyQt4.QtCore import *
from PyQt4.QtGui import *
from PyQt4.QtNetwork import *
from  PyQt4 import *
from Messaging import stdMsg, dbgMsg, errMsg, setDebugging

#This clazs does not use Qt event loop so we have to use blocking statements waitForConnected and waitForDisconnected to make sure 
# data was delivered succesfully within given time frame - we give it 3 sec waiting time
class FileNameSender:
    def __init__(self,_fileName):
  
        self.tcpSocket = QtNetwork.QTcpSocket()
        self.fileName=_fileName
        
    def send(self):
    
        self.tcpSocket.abort()
        self.tcpSocket.connectToHost(QHostAddress.LocalHost,47405)
        if self.tcpSocket.waitForConnected(3000):           
            self.tcpSocket.writeData(self.fileName)
        else:
            dbgMsg("Connection timed out")
            
        # wait here for tcp server to read fileName
        if self.tcpSocket.waitForDisconnected(3000):
            pass
        else:
            dbgMsg("server busy - did not respond within 3 secs")

# this class runs inside Qt event loop we can use slots and signals to handle communication   
         
class FileNameReceiver(QObject):    

    newlyReadFileName = QtCore.pyqtSignal( ('char*',))
    
    def __init__(self, parent=None):
        super(FileNameReceiver, self).__init__(parent)

        self.tcpServer = QTcpServer(self)
        self.clientSocket=None
        
        if not self.tcpServer.listen(QHostAddress.LocalHost,47405):
            QtGui.QMessageBox.critical(self, "FileNameReceiverr",
                    "Unable to start the server: %s." % self.tcpServer.errorString())
            # self.close()
            return


        self.tcpServer.newConnection.connect(self.acceptConnection)


        
    def acceptConnection(self):
        dbgMsg("ACCEPTING NEW CONNECTION")
        self.clientSocket = self.tcpServer.nextPendingConnection() # this is connecting tcp socket from the client
        self.clientSocket.disconnected.connect(self.clientSocket.deleteLater)
        self.clientSocket.readyRead.connect(self.readFileName)
        
    def readFileName(self):

        # # clientSocket = self.tcpServer.nextPendingConnection() # this is connecting tcp socket from the client
        # # clientSocket.disconnected.connect(clientSocket.deleteLater)

        # # clientSocket.write(block)
        # dbgMsg("clientSocket.bytesAvailable()=",self.clientSocket.bytesAvailable())
        fileName=self.clientSocket.readData(self.clientSocket.bytesAvailable())
        dbgMsg("THIS IS FILENAME READ FROM CLIENT=",fileName)
        self.clientSocket.disconnectFromHost()
        self.newlyReadFileName.emit(fileName)