communication.CommandClient Class Reference

Class to be used for sending commands. More...

Public Member Functions
def	__init__ (self, host, port)
	Initialization method for CommandClient. More...
def	sendCommand (self, cmd)
	Method used to send commands from client to CommandServer. More...
def	displayError (self, socketError)
	Qt's slot method to print out received tcpSocket's error. More...

Public Attributes
	host
	A QtHostAddress to the CommandServer. More...
	port
	An int of port at which CommandServer is listening. More...
	tcpSocket
	A QTcpSocket used to contact CommandSErver
	blockSize
	An int representing size of incoming tcp message. More...

Detailed Description

Class to be used for sending commands.

This class can be used in FreeCAD's or regular python console to send commands to a CommandServer using sendCommand(). The class prints logs as it moves along.

To send a commands do:

client = CommandClient("127.0.0.1",54321)
client.sendCommand('FreeCAD.Console.PrintError("Hello World\\n")\n')
client.sendCommand('FreeCAD.Console.PrintError("Bye Bye\\n")\n')

Definition at line 311 of file communication.py.

Constructor & Destructor Documentation

__init__()

def communication.CommandClient.__init__	(		self,
			host,
			port
	)

Initialization method for CommandClient.

A class instance is created and its attributes are initialized.

Parameters

host	A QtHostAddress to the CommandServer.
port	An int of port at which CommandServer is listening.

Definition at line 334 of file communication.py.

    def __init__(self, host, port):
        self.host = host
        self.port = port
        self.tcpSocket = QTcpSocket()
        self.blockSize = 0

Member Function Documentation

displayError()

def communication.CommandClient.displayError	(		self,
			socketError
	)

Qt's slot method to print out received tcpSocket's error.

QAbstractSocket.RemoteHostClosedError is not printed, because it occurs naturally when the tcpSocket closes after a transaction is over. Except that all errors are printed.

Parameters

socketError

A QAbstractSocket::SocketError enum describing occurred error.

Definition at line 446 of file communication.py.

    def displayError(self, socketError):
        if socketError != QAbstractSocket.RemoteHostClosedError:
            if "FreeCAD" in sys.modules:
                FreeCAD.Console.PrintError("CommandClient error occurred> %s."
                                           % self.tcpSocket.errorString()
                                           + "\n")
            else:
                print("CommandClient error occurred> %s."
                      % self.tcpSocket.errorString() + "\n")

sendCommand()

def communication.CommandClient.sendCommand	(		self,
			cmd
	)

Method used to send commands from client to CommandServer.

This method tries to connect to a specified host CommandServer via tcpSocket. If connection was successful, the command cmd is sent. Then the response is expected. If the response is equal to COMMAND_EXECUTED_CONFIRMATION_MESSAGE, then the execution was successful. The progress and result of sendCommand can be obtained from printed logs and return value.

Parameters

cmd	A str command to be executed.

Returns

CLIENT_COMMAND_EXECUTED if all went great and command was executed. CLIENT_COMMAND_FAILED if cmd execution failed. CLIENT_ERROR_RESPONSE_NOT_COMPLETE if a response received was incomplete. CLIENT_ERROR_NO_RESPONSE if there was no response within WAIT_TIME_MS. CLIENT_ERROR_BLOCK_NOT_WRITTEN if communication failed during sending. CLIENT_ERROR_NO_CONNECTION if no connection to a host was established.

Definition at line 361 of file communication.py.

    def sendCommand(self, cmd):

        # connect a Qt slot to receive and print errors
        self.tcpSocket.error.connect(self.displayError)

        # Try to connect to a host server
        self.tcpSocket.connectToHost(self.host, self.port, QIODevice.ReadWrite)
        if not self.tcpSocket.waitForConnected(msecs=WAIT_TIME_MS):
            if "FreeCAD" in sys.modules:
                FreeCAD.Console.PrintError("CommandClient.sendCommand error: "
                                           + "No connection\n")
            else:
                print("CommandClient.sendCommand error: No connection\n")
            return CLIENT_ERROR_NO_CONNECTION

        # Prepare a command message to be sent
        block = QByteArray(
                len(cmd.encode("UTF-8")).to_bytes(2, byteorder='big')
                + cmd.encode("UTF-8"))
        outstr = QDataStream(block, QIODevice.WriteOnly)
        outstr.setVersion(QDataStream.Qt_4_0)

        # Try to send the message
        if "FreeCAD" in sys.modules:
            FreeCAD.Console.PrintMessage("CommandClient sending> "
                                         + cmd + "\n")
        else:
            print("CommandClient sending> " + cmd + "\n")
        self.tcpSocket.write(block)
        if not self.tcpSocket.waitForBytesWritten(msecs=WAIT_TIME_MS):
            if "FreeCAD" in sys.modules:
                FreeCAD.Console.PrintError("CommandClient.sendCommand error: "
                                           + "Block not written\n")
            else:
                print("CommandClient.sendCommand error: Block not written\n")
            return CLIENT_ERROR_BLOCK_NOT_WRITTEN

        # Wait for a response from the host server
        if not self.tcpSocket.waitForReadyRead(msecs=WAIT_TIME_MS):
            if "FreeCAD" in sys.modules:
                FreeCAD.Console.PrintError("CommandClient.sendCommand error: "
                                           + "No response received.\n")
            else:
                print("CommandClient.sendCommand error: "
                      + "No response received.\n")
            return CLIENT_ERROR_NO_RESPONSE

        # Try to read the response
        instr = QDataStream(self.tcpSocket)
        instr.setVersion(QDataStream.Qt_4_0)
        if self.blockSize == 0:
            if self.tcpSocket.bytesAvailable() < 2:
                return CLIENT_ERROR_RESPONSE_NOT_COMPLETE
            self.blockSize = instr.readUInt16()

        if self.tcpSocket.bytesAvailable() < self.blockSize:
            return CLIENT_ERROR_RESPONSE_NOT_COMPLETE
        response = instr.readRawData(self.blockSize).decode("UTF-8")
        if "FreeCAD" in sys.modules:
            FreeCAD.Console.PrintMessage("CommandClient received> "
                                         + response + "\n")
        else:
            print("CommandClient received> " + response + "\n")

        # Wait until the host server terminates the connection
        self.tcpSocket.waitForDisconnected()
        # Reset blockSize to prepare for sending next command
        self.blockSize = 0

        # Return value representing a command execution status
        if response == COMMAND_EXECUTED_CONFIRMATION_MESSAGE:
            return CLIENT_COMMAND_EXECUTED
        else:
            return CLIENT_COMMAND_FAILED

Member Data Documentation

blockSize

communication.CommandClient.blockSize

An int representing size of incoming tcp message.

Definition at line 338 of file communication.py.

host

communication.CommandClient.host

A QtHostAddress to the CommandServer.

Definition at line 335 of file communication.py.

port

communication.CommandClient.port

An int of port at which CommandServer is listening.

Definition at line 336 of file communication.py.

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

• Doxypypy outputs/communication.py