communication.CommandThread Class Reference

QThread class used to receive commands, try to execute and respond to them. More...

Inheritance diagram for communication.CommandThread:

Public Member Functions
def	__init__ (self, socketDescriptor, parent)
	Initialization method for CommandThread. More...
def	run (self)
	Thread's functionality method. More...

Public Attributes
	socketDescriptor
	A Qt's qintptr socket descriptor to initialize tcpSocket. More...
	blockSize
	An int representing size of incoming tcp message. More...

Detailed Description

QThread class used to receive commands, try to execute and respond to them.

This class describes a QThread used to receive a command string from a QTcpSocket, try to execute received string and send a repspondse whether the execution was successful or not.

Definition at line 97 of file communication.py.

Constructor & Destructor Documentation

__init__()

def communication.CommandThread.__init__	(		self,
			socketDescriptor,
			parent
	)

Initialization method for CommandThread.

A class instance is created, socketDescriptor and blockSize are initializated.

Parameters

socketDescriptor	A Qt's qintptr socket descriptor to initialize tcpSocket.
parent	A reference to an instance which will take thread's ownership.

Definition at line 115 of file communication.py.

    def __init__(self, socketDescriptor, parent):
        super(CommandThread, self).__init__(parent)
        self.socketDescriptor = socketDescriptor
        self.blockSize = 0

Member Function Documentation

run()

def communication.CommandThread.run

(

self

)

Thread's functionality method.

The starting point for the thread. After calling start(), the newly created thread calls this function. This function then tries to make QTcpSocket. It waits WAIT_TIME_MS for an incoming message. If message is received it checks its a whole message using blockSize sent in the first word as an UINT16 number. If a whole message is received, the thread tries to execute the message string and sends back an appropriate response. The response is Command failed - "error string" if the execution failed, or Command executed successfully otherwise. Then the thread is terminated.

Definition at line 132 of file communication.py.

    def run(self):
        # Try to connect to an incoming tcp socket using its socket descriptor
        tcpSocket = QTcpSocket()
        if not tcpSocket.setSocketDescriptor(self.socketDescriptor):
            FreeCAD.Console.PrintError("Socket not accepted.\n")
            return
        FreeCAD.Console.PrintLog("Socket accepted.\n")

        # Wait for an incoming message
        if not tcpSocket.waitForReadyRead(msecs=WAIT_TIME_MS):
            FreeCAD.Console.PrintError("No request send.\n")
            return

        # Make an input data stream
        instr = QDataStream(tcpSocket)
        instr.setVersion(QDataStream.Qt_4_0)

        # Try to read the message size
        if self.blockSize == 0:
            if tcpSocket.bytesAvailable() < 2:
                FreeCAD.Console.PrintError("Received message "
                                           + "has too few bytes.\n")
                return
            self.blockSize = instr.readUInt16()

        # Check message is sent complete
        if tcpSocket.bytesAvailable() < self.blockSize:
            FreeCAD.Console.PrintError("Received message has less bytes "
                                       + "then it's supposed to.\n")
            return

        # Read message and inform about it
        cmd = instr.readRawData(self.blockSize).decode("UTF-8")
        FreeCAD.Console.PrintLog("CommandServer received> "
                                 + cmd + "\n")

        # Try to execute the message string and prepare  a response
        try:
            exec(cmd)
        except Exception as e:
            FreeCAD.Console.PrintError("Executing external command failed:"
                                       + str(e) + "\n")
            message = "Command failed - " + str(e)
        else:
            FreeCAD.Console.PrintLog("Executing external command succeeded!\n")
            message = COMMAND_EXECUTED_CONFIRMATION_MESSAGE

        # Prepare the data block to send back and inform about it
        FreeCAD.Console.PrintLog("CommandServer sending> " + message + " \n")
        block = QByteArray(
                len(message.encode("UTF-8")).to_bytes(2, byteorder='big')
                + message.encode("UTF-8"))
        outstr = QDataStream(block, QIODevice.WriteOnly)
        outstr.setVersion(QDataStream.Qt_4_0)

        # Send the block, disconnect from the socket and terminate the QThread
        tcpSocket.write(block)
        tcpSocket.disconnectFromHost()
        tcpSocket.waitForDisconnected()

Member Data Documentation

blockSize

communication.CommandThread.blockSize

An int representing size of incoming tcp message.

Definition at line 118 of file communication.py.

socketDescriptor

communication.CommandThread.socketDescriptor

A Qt's qintptr socket descriptor to initialize tcpSocket.

Definition at line 117 of file communication.py.

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The documentation for this class was generated from the following file:

• Doxypypy outputs/communication.py