Sat, 14 Dec 2013 23:44:25 +0100
# __IGNORE_WARNING__ added/ removed.
# -*- coding: utf-8 -*- # Copyright (c) 2004 - 2013 Detlev Offenbach <detlev@die-offenbachs.de> # """ Module implementing the single application server and client. """ from __future__ import unicode_literals from PyQt4.QtNetwork import QLocalServer, QLocalSocket class SingleApplicationServer(QLocalServer): """ Class implementing the single application server base class. """ def __init__(self, name): """ Constructor @param name name this server is listening to (string) """ super(SingleApplicationServer, self).__init__() res = self.listen(name) if not res: # maybe it crashed last time self.removeServer(name) self.listen(name) self.newConnection[()].connect(self.__newConnection) self.qsock = None def __newConnection(self): """ Private slot to handle a new connection. """ sock = self.nextPendingConnection() # If we already have a connection, refuse this one. It will be closed # automatically. if self.qsock is not None: return self.qsock = sock self.qsock.readyRead[()].connect(self.__parseLine) self.qsock.disconnected[()].connect(self.__disconnected) def __parseLine(self): """ Private method to handle data from the client. """ while self.qsock and self.qsock.canReadLine(): line = bytes(self.qsock.readLine()).decode() ## print(line) ##debug eoc = line.find('<') + 1 boc = line.find('>') if boc >= 0 and eoc > boc: # handle the command sent by the client. cmd = line[boc:eoc] params = line[eoc:-1] self.handleCommand(cmd, params) def __disconnected(self): """ Private method to handle the closure of the socket. """ self.qsock = None def shutdown(self): """ Public method used to shut down the server. """ if self.qsock is not None: self.qsock.readyRead[()].disconnect(self.__parseLine) self.qsock.disconnected.disconnect(self.__disconnected) self.qsock = None self.close() def handleCommand(self, cmd, params): """ Public slot to handle the command sent by the client. <b>Note</b>: This method must be overridden by subclasses. @param cmd commandstring (string) @param params parameterstring (string) @exception RuntimeError raised to indicate that this method must be implemented by a subclass """ raise RuntimeError("'handleCommand' must be overridden") class SingleApplicationClient(object): """ Class implementing the single application client base class. """ def __init__(self, name): """ Constructor @param name name of the local server to connect to (string) """ self.name = name self.connected = False def connect(self): """ Public method to connect the single application client to its server. @return value indicating success or an error number. Value is one of: <table> <tr><td>0</td><td>No application is running</td></tr> <tr><td>1</td><td>Application is already running</td></tr> </table> """ self.sock = QLocalSocket() self.sock.connectToServer(self.name) if self.sock.waitForConnected(10000): self.connected = True return 1 else: err = self.sock.error() if err == QLocalSocket.ServerNotFoundError: return 0 else: return -err def disconnect(self): """ Public method to disconnect from the Single Appliocation server. """ self.sock.disconnectFromServer() self.connected = False def processArgs(self, args): """ Public method to process the command line args passed to the UI. <b>Note</b>: This method must be overridden by subclasses. @param args command line args (list of strings) @exception RuntimeError raised to indicate that this method must be implemented by a subclass """ raise RuntimeError("'processArgs' must be overridden") def sendCommand(self, cmd): """ Public method to send the command to the application server. @param cmd command to be sent (string) """ if self.connected: self.sock.write(cmd) self.sock.flush() def errstr(self): """ Public method to return a meaningful error string for the last error. @return error string for the last error (string) """ return self.sock.errorString()