How to embed a Python interpreter in a PyQT widget

Question

I want to be able to bring up an interactive python terminal from my python application. Some, but not all, variables in my program needs to be exposed to the interpreter.

Answer 1

First draft of updated version of my code to support IPython 0.13

'''
Created on 18-03-2012

@author: Paweł Jarosz
'''
import os, sys
import atexit

from PySide import QtCore, QtGui

from IPython.zmq.ipkernel import IPKernelApp
from IPython.lib.kernel import find_connection_file, connect_qtconsole
from IPython.frontend.qt.kernelmanager import QtKernelManager
from IPython.frontend.qt.console.rich_ipython_widget import RichIPythonWidget
from IPython.config.application import catch_config_error

class IPythonLocalKernelApp(IPKernelApp):
    """IPython kernel application with nonblocking loop, running in dedicated thread.
    example:
        app = QtGui.QApplication([])
        kernelapp = IPythonLocalKernelApp.instance()
        kernelapp.start()
        namespace = kernelapp.get_user_namespace()
        namespace["QtGui"]=QtGui
        namespace["QtCore"]=QtCore
        app.exec_()"""
    #DEFAULT_INSTANCE_ARGS starting commandline
    DEFAULT_INSTANCE_ARGS = ['qtconsole','--pylab=inline', '--colors=linux']

    @catch_config_error
    def initialize(self, argv=None):
        super(IPythonLocalKernelApp, self).initialize(argv)
        self.kernel.eventloop = self.loop_qt4_nonblocking

    def loop_qt4_nonblocking(self, kernel):
        """Non-blocking version of the ipython qt4 kernel loop"""
        kernel.timer = QtCore.QTimer()
        kernel.timer.timeout.connect(kernel.do_one_iteration)
        kernel.timer.start(1000*kernel._poll_interval)

    def start(self, argv=DEFAULT_INSTANCE_ARGS):
        """Starts IPython kernel app
            argv: arguments passed to kernel
        """
        self.initialize(argv)
        #self.heartbeat.start()
        #if self.poller is not None:
        #    self.poller.start()

        self.kernel.start()
        super(IPythonLocalKernelApp, self).start()


    def get_connection_file(self):
        """Returne current kernel connection file."""
        return self.connection_file

    def get_user_namespace(self):
        """Returns current kernel userspace dict"""
        return self.kernel.shell.user_ns

class IPythonConsoleQtWidget(RichIPythonWidget):
    """Ipython console Qt4+ widget
        Usage example:
            app = QtGui.QApplication([])
            kernelapp = IPythonLocalKernelApp.instance()
            kernelapp.start()
            namespace = kernelapp.get_user_namespace()
            widget = IPythonConsoleQtWidget()
            widget.set_default_style(colors='linux')
            widget.connect_kernel(connection_file=kernelapp.get_connection_file())
            # if you won't to connect to remote kernel:
            widget.connect_kernel(connection_file='kernel-16098.json')

            widget.show()

            namespace["widget"] = widget
            namespace["QtGui"]=QtGui
            namespace["QtCore"]=QtCore

            app.exec_()"""
    _connection_file = None

    def __init__(self, *args, **kw):
        RichIPythonWidget.__init__(self, *args, **kw)
        self._existing = True
        self._may_close = False
        self._confirm_exit = False

    def _init_kernel_manager(self):
        km = QtKernelManager(connection_file=self._connection_file, config=self.config)
        km.load_connection_file()
        km.start_channels(hb=self._heartbeat)
        self.kernel_manager = km
        atexit.register(self.kernel_manager.cleanup_connection_file)

    def connect_kernel(self, connection_file, heartbeat=False):
        """Connect's to ipython kernel.
        connection_file    - connection file to use
        heartbeat          - should start heartbeat server? Workaround for problems with inproc embedded kernels
                             (right click save image as/save as html kills kernel heartbeat/pool(??) serwer """

        self._heartbeat = heartbeat
        if os.path.exists(connection_file):
            self._connection_file = connection_file
        else:
            self._connection_file = find_connection_file(connection_file)

        self._init_kernel_manager()



app = QtGui.QApplication([])
kernelapp = IPythonLocalKernelApp.instance()
kernelapp.start()
namespace = kernelapp.get_user_namespace()
widget = IPythonConsoleQtWidget()
widget.set_default_style(colors='linux')
widget.connect_kernel(connection_file=kernelapp.get_connection_file())
# if you won't to connect to remote kernel:
# widget.connect_kernel(connection_file='kernel-16098.json')

widget.show()

namespace["widget"] = widget
namespace["QtGui"]=QtGui
namespace["QtCore"]=QtCore

app.exec_()