fix `--existing` with non-localhost IP

there's still some cleanup to do with duplicate code in ConsoleApp that should be invoked from ConnectionFileMixin, but this fixes the bug.

IPython/consoleapp.py

@@ -1,392 +1,395 b''
 """ A minimal application base mixin for all ZMQ based IPython frontends.
 
 This is not a complete console app, as subprocess will not be able to receive
 input, there is no real readline support, among other limitations. This is a
 refactoring of what used to be the IPython/qt/console/qtconsoleapp.py
 
 Authors:
 
 * Evan Patterson
 * Min RK
 * Erik Tollerud
 * Fernando Perez
 * Bussonnier Matthias
 * Thomas Kluyver
 * Paul Ivanov
 
 """
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # stdlib imports
 import atexit
 import json
 import os
 import shutil
 import signal
 import sys
 import uuid
 
 
 # Local imports
 from IPython.config.application import boolean_flag
 from IPython.config.configurable import Configurable
 from IPython.core.profiledir import ProfileDir
 from IPython.kernel.blocking import BlockingKernelClient
 from IPython.kernel import KernelManager
 from IPython.kernel import tunnel_to_kernel, find_connection_file, swallow_argv
 from IPython.utils.path import filefind
 from IPython.utils.py3compat import str_to_bytes
 from IPython.utils.traitlets import (
     Dict, List, Unicode, CUnicode, Int, CBool, Any, CaselessStrEnum
 )
 from IPython.kernel.zmq.kernelapp import (
     kernel_flags,
     kernel_aliases,
     IPKernelApp
 )
 from IPython.kernel.zmq.session import Session, default_secure
 from IPython.kernel.zmq.zmqshell import ZMQInteractiveShell
+from IPython.kernel.connect import ConnectionFileMixin
 
 #-----------------------------------------------------------------------------
 # Network Constants
 #-----------------------------------------------------------------------------
 
 from IPython.utils.localinterfaces import LOCALHOST, LOCAL_IPS
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 
 #-----------------------------------------------------------------------------
 # Aliases and Flags
 #-----------------------------------------------------------------------------
 
 flags = dict(kernel_flags)
 
 # the flags that are specific to the frontend
 # these must be scrubbed before being passed to the kernel,
 # or it will raise an error on unrecognized flags
 app_flags = {
     'existing' : ({'IPythonConsoleApp' : {'existing' : 'kernel*.json'}},
             "Connect to an existing kernel. If no argument specified, guess most recent"),
 }
 app_flags.update(boolean_flag(
     'confirm-exit', 'IPythonConsoleApp.confirm_exit',
     """Set to display confirmation dialog on exit. You can always use 'exit' or 'quit',
        to force a direct exit without any confirmation.
     """,
     """Don't prompt the user when exiting. This will terminate the kernel
        if it is owned by the frontend, and leave it alive if it is external.
     """
 ))
 flags.update(app_flags)
 
 aliases = dict(kernel_aliases)
 
 # also scrub aliases from the frontend
 app_aliases = dict(
-    ip = 'KernelManager.ip',
-    transport = 'KernelManager.transport',
+    ip = 'IPythonConsoleApp.ip',
+    transport = 'IPythonConsoleApp.transport',
     hb = 'IPythonConsoleApp.hb_port',
     shell = 'IPythonConsoleApp.shell_port',
     iopub = 'IPythonConsoleApp.iopub_port',
     stdin = 'IPythonConsoleApp.stdin_port',
     existing = 'IPythonConsoleApp.existing',
     f = 'IPythonConsoleApp.connection_file',
 
 
     ssh = 'IPythonConsoleApp.sshserver',
 )
 aliases.update(app_aliases)
 
 #-----------------------------------------------------------------------------
 # Classes
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # IPythonConsole
 #-----------------------------------------------------------------------------
 
 classes = [IPKernelApp, ZMQInteractiveShell, KernelManager, ProfileDir, Session]
 
 try:
     from IPython.kernel.zmq.pylab.backend_inline import InlineBackend
 except ImportError:
     pass
 else:
     classes.append(InlineBackend)
 
-class IPythonConsoleApp(Configurable):
+class IPythonConsoleApp(ConnectionFileMixin):
     name = 'ipython-console-mixin'
 
     description = """
         The IPython Mixin Console.
         
         This class contains the common portions of console client (QtConsole,
         ZMQ-based terminal console, etc).  It is not a full console, in that
         launched terminal subprocesses will not be able to accept input.
         
         The Console using this mixing supports various extra features beyond
         the single-process Terminal IPython shell, such as connecting to
         existing kernel, via:
         
             ipython <appname> --existing
         
         as well as tunnel via SSH
         
     """
 
     classes = classes
     flags = Dict(flags)
     aliases = Dict(aliases)
     kernel_manager_class = KernelManager
     kernel_client_class = BlockingKernelClient
 
     kernel_argv = List(Unicode)
     # frontend flags&aliases to be stripped when building kernel_argv
     frontend_flags = Any(app_flags)
     frontend_aliases = Any(app_aliases)
 
     # create requested profiles by default, if they don't exist:
     auto_create = CBool(True)
     # connection info:
     
     sshserver = Unicode('', config=True,
         help="""The SSH server to use to connect to the kernel.""")
     sshkey = Unicode('', config=True,
         help="""Path to the ssh key to use for logging in to the ssh server.""")
     
     hb_port = Int(0, config=True,
         help="set the heartbeat port [default: random]")
     shell_port = Int(0, config=True,
         help="set the shell (ROUTER) port [default: random]")
     iopub_port = Int(0, config=True,
         help="set the iopub (PUB) port [default: random]")
     stdin_port = Int(0, config=True,
         help="set the stdin (DEALER) port [default: random]")
     connection_file = Unicode('', config=True,
         help="""JSON file in which to store connection info [default: kernel-<pid>.json]
 
         This file will contain the IP, ports, and authentication key needed to connect
         clients to this kernel. By default, this file will be created in the security-dir
         of the current profile, but can be specified by absolute path.
         """)
     def _connection_file_default(self):
         return 'kernel-%i.json' % os.getpid()
 
     existing = CUnicode('', config=True,
         help="""Connect to an already running kernel""")
 
     confirm_exit = CBool(True, config=True,
         help="""
         Set to display confirmation dialog on exit. You can always use 'exit' or 'quit',
         to force a direct exit without any confirmation.""",
     )
 
 
     def build_kernel_argv(self, argv=None):
         """build argv to be passed to kernel subprocess"""
         if argv is None:
             argv = sys.argv[1:]
         self.kernel_argv = swallow_argv(argv, self.frontend_aliases, self.frontend_flags)
         # kernel should inherit default config file from frontend
         self.kernel_argv.append("--IPKernelApp.parent_appname='%s'" % self.name)
     
     def init_connection_file(self):
         """find the connection file, and load the info if found.
         
         The current working directory and the current profile's security
         directory will be searched for the file if it is not given by
         absolute path.
         
         When attempting to connect to an existing kernel and the `--existing`
         argument does not match an existing file, it will be interpreted as a
         fileglob, and the matching file in the current profile's security dir
         with the latest access time will be used.
         
         After this method is called, self.connection_file contains the *full path*
         to the connection file, never just its name.
         """
         if self.existing:
             try:
                 cf = find_connection_file(self.existing)
             except Exception:
                 self.log.critical("Could not find existing kernel connection file %s", self.existing)
                 self.exit(1)
             self.log.info("Connecting to existing kernel: %s" % cf)
             self.connection_file = cf
         else:
             # not existing, check if we are going to write the file
             # and ensure that self.connection_file is a full path, not just the shortname
             try:
                 cf = find_connection_file(self.connection_file)
             except Exception:
                 # file might not exist
                 if self.connection_file == os.path.basename(self.connection_file):
                     # just shortname, put it in security dir
                     cf = os.path.join(self.profile_dir.security_dir, self.connection_file)
                 else:
                     cf = self.connection_file
                 self.connection_file = cf
         
         # should load_connection_file only be used for existing?
         # as it is now, this allows reusing ports if an existing
         # file is requested
         try:
             self.load_connection_file()
         except Exception:
             self.log.error("Failed to load connection file: %r", self.connection_file, exc_info=True)
             self.exit(1)
     
     def load_connection_file(self):
         """load ip/port/hmac config from JSON connection file"""
         # this is identical to IPKernelApp.load_connection_file
         # perhaps it can be centralized somewhere?
         try:
             fname = filefind(self.connection_file, ['.', self.profile_dir.security_dir])
         except IOError:
             self.log.debug("Connection File not found: %s", self.connection_file)
             return
         self.log.debug(u"Loading connection file %s", fname)
         with open(fname) as f:
             cfg = json.load(f)
-        
-        self.config.KernelManager.transport = cfg.get('transport', 'tcp')
-        self.config.KernelManager.ip = cfg.get('ip', LOCALHOST)
+        self.transport = cfg.get('transport', 'tcp')
+        self.ip = cfg.get('ip', LOCALHOST)
         
         for channel in ('hb', 'shell', 'iopub', 'stdin'):
             name = channel + '_port'
             if getattr(self, name) == 0 and name in cfg:
                 # not overridden by config or cl_args
                 setattr(self, name, cfg[name])
         if 'key' in cfg:
             self.config.Session.key = str_to_bytes(cfg['key'])
         if 'signature_scheme' in cfg:
             self.config.Session.signature_scheme = cfg['signature_scheme']
     
     def init_ssh(self):
         """set up ssh tunnels, if needed."""
         if not self.existing or (not self.sshserver and not self.sshkey):
             return
-        
         self.load_connection_file()
         
-        transport = self.config.KernelManager.transport
-        ip = self.config.KernelManager.ip
+        transport = self.transport
+        ip = self.ip
         
         if transport != 'tcp':
             self.log.error("Can only use ssh tunnels with TCP sockets, not %s", transport)
             sys.exit(-1)
         
         if self.sshkey and not self.sshserver:
             # specifying just the key implies that we are connecting directly
             self.sshserver = ip
             ip = LOCALHOST
         
         # build connection dict for tunnels:
         info = dict(ip=ip,
                     shell_port=self.shell_port,
                     iopub_port=self.iopub_port,
                     stdin_port=self.stdin_port,
                     hb_port=self.hb_port
         )
         
         self.log.info("Forwarding connections to %s via %s"%(ip, self.sshserver))
         
         # tunnels return a new set of ports, which will be on localhost:
-        self.config.KernelManager.ip = LOCALHOST
+        self.ip = LOCALHOST
         try:
             newports = tunnel_to_kernel(info, self.sshserver, self.sshkey)
         except:
             # even catch KeyboardInterrupt
             self.log.error("Could not setup tunnels", exc_info=True)
             self.exit(1)
         
         self.shell_port, self.iopub_port, self.stdin_port, self.hb_port = newports
         
         cf = self.connection_file
         base,ext = os.path.splitext(cf)
         base = os.path.basename(base)
         self.connection_file = os.path.basename(base)+'-ssh'+ext
         self.log.critical("To connect another client via this tunnel, use:")
         self.log.critical("--existing %s" % self.connection_file)
     
     def _new_connection_file(self):
         cf = ''
         while not cf:
             # we don't need a 128b id to distinguish kernels, use more readable
             # 48b node segment (12 hex chars).  Users running more than 32k simultaneous
             # kernels can subclass.
             ident = str(uuid.uuid4()).split('-')[-1]
             cf = os.path.join(self.profile_dir.security_dir, 'kernel-%s.json' % ident)
             # only keep if it's actually new.  Protect against unlikely collision
             # in 48b random search space
             cf = cf if not os.path.exists(cf) else ''
         return cf
 
     def init_kernel_manager(self):
         # Don't let Qt or ZMQ swallow KeyboardInterupts.
         if self.existing:
             self.kernel_manager = None
             return
         signal.signal(signal.SIGINT, signal.SIG_DFL)
 
         # Create a KernelManager and start a kernel.
         self.kernel_manager = self.kernel_manager_class(
+                                ip=self.ip,
+                                transport=self.transport,
                                 shell_port=self.shell_port,
                                 iopub_port=self.iopub_port,
                                 stdin_port=self.stdin_port,
                                 hb_port=self.hb_port,
                                 connection_file=self.connection_file,
                                 parent=self,
         )
         self.kernel_manager.client_factory = self.kernel_client_class
         self.kernel_manager.start_kernel(extra_arguments=self.kernel_argv)
         atexit.register(self.kernel_manager.cleanup_ipc_files)
 
         if self.sshserver:
             # ssh, write new connection file
             self.kernel_manager.write_connection_file()
 
         # in case KM defaults / ssh writing changes things:
         km = self.kernel_manager
         self.shell_port=km.shell_port
         self.iopub_port=km.iopub_port
         self.stdin_port=km.stdin_port
         self.hb_port=km.hb_port
         self.connection_file = km.connection_file
 
         atexit.register(self.kernel_manager.cleanup_connection_file)
 
     def init_kernel_client(self):
         if self.kernel_manager is not None:
             self.kernel_client = self.kernel_manager.client()
         else:
             self.kernel_client = self.kernel_client_class(
+                                ip=self.ip,
+                                transport=self.transport,
                                 shell_port=self.shell_port,
                                 iopub_port=self.iopub_port,
                                 stdin_port=self.stdin_port,
                                 hb_port=self.hb_port,
                                 connection_file=self.connection_file,
                                 parent=self,
             )
 
         self.kernel_client.start_channels()
 
 
 
     def initialize(self, argv=None):
         """
         Classes which mix this class in should call:
                IPythonConsoleApp.initialize(self,argv)
         """
         self.init_connection_file()
         default_secure(self.config)
         self.init_ssh()
         self.init_kernel_manager()
         self.init_kernel_client()
 

IPython/qt/console/qtconsoleapp.py

@@ -1,385 +1,382 b''
 """ A minimal application using the Qt console-style IPython frontend.
 
 This is not a complete console app, as subprocess will not be able to receive
 input, there is no real readline support, among other limitations.
 
 Authors:
 
 * Evan Patterson
 * Min RK
 * Erik Tollerud
 * Fernando Perez
 * Bussonnier Matthias
 * Thomas Kluyver
 * Paul Ivanov
 
 """
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # stdlib imports
 import os
 import signal
 import sys
 
 # If run on Windows, install an exception hook which pops up a
 # message box. Pythonw.exe hides the console, so without this
 # the application silently fails to load.
 #
 # We always install this handler, because the expectation is for
 # qtconsole to bring up a GUI even if called from the console.
 # The old handler is called, so the exception is printed as well.
 # If desired, check for pythonw with an additional condition
 # (sys.executable.lower().find('pythonw.exe') >= 0).
 if os.name == 'nt':
     old_excepthook = sys.excepthook
 
     def gui_excepthook(exctype, value, tb):
         try:
             import ctypes, traceback
             MB_ICONERROR = 0x00000010L
             title = u'Error starting IPython QtConsole'
             msg = u''.join(traceback.format_exception(exctype, value, tb))
             ctypes.windll.user32.MessageBoxW(0, msg, title, MB_ICONERROR)
         finally:
             # Also call the old exception hook to let it do
             # its thing too.
             old_excepthook(exctype, value, tb)
 
     sys.excepthook = gui_excepthook
 
 # System library imports
 from IPython.external.qt import QtCore, QtGui
 
 # Local imports
 from IPython.config.application import catch_config_error
 from IPython.core.application import BaseIPythonApplication
 from IPython.qt.console.ipython_widget import IPythonWidget
 from IPython.qt.console.rich_ipython_widget import RichIPythonWidget
 from IPython.qt.console import styles
 from IPython.qt.console.mainwindow import MainWindow
 from IPython.qt.client import QtKernelClient
 from IPython.qt.manager import QtKernelManager
 from IPython.utils.traitlets import (
     Dict, Unicode, CBool, Any
 )
 
 from IPython.consoleapp import (
         IPythonConsoleApp, app_aliases, app_flags, flags, aliases
     )
 
 #-----------------------------------------------------------------------------
 # Network Constants
 #-----------------------------------------------------------------------------
 
 from IPython.utils.localinterfaces import LOCALHOST, LOCAL_IPS
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 _examples = """
 ipython qtconsole                      # start the qtconsole
 ipython qtconsole --matplotlib=inline  # start with matplotlib inline plotting mode
 """
 
 #-----------------------------------------------------------------------------
 # Aliases and Flags
 #-----------------------------------------------------------------------------
 
 # start with copy of flags
 flags = dict(flags)
 qt_flags = {
     'plain' : ({'IPythonQtConsoleApp' : {'plain' : True}},
             "Disable rich text support."),
 }
 
 # and app_flags from the Console Mixin
 qt_flags.update(app_flags)
 # add frontend flags to the full set
 flags.update(qt_flags)
 
 # start with copy of front&backend aliases list
 aliases = dict(aliases)
 qt_aliases = dict(
     style = 'IPythonWidget.syntax_style',
     stylesheet = 'IPythonQtConsoleApp.stylesheet',
     colors = 'ZMQInteractiveShell.colors',
 
     editor = 'IPythonWidget.editor',
     paging = 'ConsoleWidget.paging',
 )
 # and app_aliases from the Console Mixin
 qt_aliases.update(app_aliases)
 qt_aliases.update({'gui-completion':'ConsoleWidget.gui_completion'})
 # add frontend aliases to the full set
 aliases.update(qt_aliases)
 
 # get flags&aliases into sets, and remove a couple that
 # shouldn't be scrubbed from backend flags:
 qt_aliases = set(qt_aliases.keys())
 qt_aliases.remove('colors')
 qt_flags = set(qt_flags.keys())
 
 #-----------------------------------------------------------------------------
 # Classes
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # IPythonQtConsole
 #-----------------------------------------------------------------------------
 
 
 class IPythonQtConsoleApp(BaseIPythonApplication, IPythonConsoleApp):
     name = 'ipython-qtconsole'
 
     description = """
         The IPython QtConsole.
         
         This launches a Console-style application using Qt.  It is not a full
         console, in that launched terminal subprocesses will not be able to accept
         input.
         
         The QtConsole supports various extra features beyond the Terminal IPython
         shell, such as inline plotting with matplotlib, via:
         
             ipython qtconsole --matplotlib=inline
         
         as well as saving your session as HTML, and printing the output.
         
     """
     examples = _examples
 
     classes = [IPythonWidget] + IPythonConsoleApp.classes
     flags = Dict(flags)
     aliases = Dict(aliases)
     frontend_flags = Any(qt_flags)
     frontend_aliases = Any(qt_aliases)
     kernel_client_class = QtKernelClient
     kernel_manager_class = QtKernelManager
 
     stylesheet = Unicode('', config=True,
         help="path to a custom CSS stylesheet")
 
     hide_menubar = CBool(False, config=True,
         help="Start the console window with the menu bar hidden.")
 
     maximize = CBool(False, config=True,
         help="Start the console window maximized.")
 
     plain = CBool(False, config=True,
         help="Use a plaintext widget instead of rich text (plain can't print/save).")
 
     def _plain_changed(self, name, old, new):
         kind = 'plain' if new else 'rich'
         self.config.ConsoleWidget.kind = kind
         if new:
             self.widget_factory = IPythonWidget
         else:
             self.widget_factory = RichIPythonWidget
 
     # the factory for creating a widget
     widget_factory = Any(RichIPythonWidget)
 
     def parse_command_line(self, argv=None):
         super(IPythonQtConsoleApp, self).parse_command_line(argv)
         self.build_kernel_argv(argv)
 
 
     def new_frontend_master(self):
         """ Create and return new frontend attached to new kernel, launched on localhost.
         """
         kernel_manager = self.kernel_manager_class(
                                 connection_file=self._new_connection_file(),
                                 parent=self,
                                 autorestart=True,
         )
         # start the kernel
         kwargs = dict()
         kwargs['extra_arguments'] = self.kernel_argv
         kernel_manager.start_kernel(**kwargs)
         kernel_manager.client_factory = self.kernel_client_class
         kernel_client = kernel_manager.client()
         kernel_client.start_channels(shell=True, iopub=True)
         widget = self.widget_factory(config=self.config,
                                    local_kernel=True)
         self.init_colors(widget)
         widget.kernel_manager = kernel_manager
         widget.kernel_client = kernel_client
         widget._existing = False
         widget._may_close = True
         widget._confirm_exit = self.confirm_exit
         return widget
 
     def new_frontend_slave(self, current_widget):
         """Create and return a new frontend attached to an existing kernel.
         
         Parameters
         ----------
         current_widget : IPythonWidget
             The IPythonWidget whose kernel this frontend is to share
         """
         kernel_client = self.kernel_client_class(
                                 connection_file=current_widget.kernel_client.connection_file,
                                 config = self.config,
         )
         kernel_client.load_connection_file()
         kernel_client.start_channels()
         widget = self.widget_factory(config=self.config,
                                 local_kernel=False)
         self.init_colors(widget)
         widget._existing = True
         widget._may_close = False
         widget._confirm_exit = False
         widget.kernel_client = kernel_client
         widget.kernel_manager = current_widget.kernel_manager
         return widget
 
     def init_qt_app(self):
         # separate from qt_elements, because it must run first
         self.app = QtGui.QApplication([])
 
     def init_qt_elements(self):
         # Create the widget.
 
         base_path = os.path.abspath(os.path.dirname(__file__))
         icon_path = os.path.join(base_path, 'resources', 'icon', 'IPythonConsole.svg')
         self.app.icon = QtGui.QIcon(icon_path)
         QtGui.QApplication.setWindowIcon(self.app.icon)
 
-        try:
-            ip = self.config.KernelManager.ip
-        except AttributeError:
-            ip = LOCALHOST
+        ip = self.ip
         local_kernel = (not self.existing) or ip in LOCAL_IPS
         self.widget = self.widget_factory(config=self.config,
                                         local_kernel=local_kernel)
         self.init_colors(self.widget)
         self.widget._existing = self.existing
         self.widget._may_close = not self.existing
         self.widget._confirm_exit = self.confirm_exit
 
         self.widget.kernel_manager = self.kernel_manager
         self.widget.kernel_client = self.kernel_client
         self.window = MainWindow(self.app,
                                 confirm_exit=self.confirm_exit,
                                 new_frontend_factory=self.new_frontend_master,
                                 slave_frontend_factory=self.new_frontend_slave,
                                 )
         self.window.log = self.log
         self.window.add_tab_with_frontend(self.widget)
         self.window.init_menu_bar()
 
         # Ignore on OSX, where there is always a menu bar
         if sys.platform != 'darwin' and self.hide_menubar:
             self.window.menuBar().setVisible(False)
 
         self.window.setWindowTitle('IPython')
 
     def init_colors(self, widget):
         """Configure the coloring of the widget"""
         # Note: This will be dramatically simplified when colors
         # are removed from the backend.
 
         # parse the colors arg down to current known labels
         try:
             colors = self.config.ZMQInteractiveShell.colors
         except AttributeError:
             colors = None
         try:
             style = self.config.IPythonWidget.syntax_style
         except AttributeError:
             style = None
         try:
             sheet = self.config.IPythonWidget.style_sheet
         except AttributeError:
             sheet = None
 
         # find the value for colors:
         if colors:
             colors=colors.lower()
             if colors in ('lightbg', 'light'):
                 colors='lightbg'
             elif colors in ('dark', 'linux'):
                 colors='linux'
             else:
                 colors='nocolor'
         elif style:
             if style=='bw':
                 colors='nocolor'
             elif styles.dark_style(style):
                 colors='linux'
             else:
                 colors='lightbg'
         else:
             colors=None
 
         # Configure the style
         if style:
             widget.style_sheet = styles.sheet_from_template(style, colors)
             widget.syntax_style = style
             widget._syntax_style_changed()
             widget._style_sheet_changed()
         elif colors:
             # use a default dark/light/bw style
             widget.set_default_style(colors=colors)
 
         if self.stylesheet:
             # we got an explicit stylesheet
             if os.path.isfile(self.stylesheet):
                 with open(self.stylesheet) as f:
                     sheet = f.read()
             else:
                 raise IOError("Stylesheet %r not found." % self.stylesheet)
         if sheet:
             widget.style_sheet = sheet
             widget._style_sheet_changed()
             
 
     def init_signal(self):
         """allow clean shutdown on sigint"""
         signal.signal(signal.SIGINT, lambda sig, frame: self.exit(-2))
         # need a timer, so that QApplication doesn't block until a real
         # Qt event fires (can require mouse movement)
         # timer trick from http://stackoverflow.com/q/4938723/938949
         timer = QtCore.QTimer()
          # Let the interpreter run each 200 ms:
         timer.timeout.connect(lambda: None)
         timer.start(200)
         # hold onto ref, so the timer doesn't get cleaned up
         self._sigint_timer = timer
 
     @catch_config_error
     def initialize(self, argv=None):
         self.init_qt_app()
         super(IPythonQtConsoleApp, self).initialize(argv)
         IPythonConsoleApp.initialize(self,argv)
         self.init_qt_elements()
         self.init_signal()
 
     def start(self):
 
         # draw the window
         if self.maximize:
             self.window.showMaximized()
         else:
             self.window.show()
         self.window.raise_()
 
         # Start the application main loop.
         self.app.exec_()
 
 #-----------------------------------------------------------------------------
 # Main entry point
 #-----------------------------------------------------------------------------
 
 def main():
     app = IPythonQtConsoleApp()
     app.initialize()
     app.start()
 
 
 if __name__ == '__main__':
     main()