Allow notebook server to run in read-only mode

Kernels are never started, and all save/delete/execution handlers raise
403: Forbidden.

/cc @fperez

IPython/frontend/html/notebook/handlers.py

@@ -1,450 +1,470 b''
 """Tornado handlers for the notebook.
 
 Authors:
 
 * Brian Granger
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import logging
 import Cookie
 import uuid
 
 from tornado import web
 from tornado import websocket
 
 from zmq.eventloop import ioloop
 from zmq.utils import jsonapi
 
+from IPython.external.decorator import decorator
 from IPython.zmq.session import Session
 
 try:
     from docutils.core import publish_string
 except ImportError:
     publish_string = None
 
 
+#-----------------------------------------------------------------------------
+# Decorator for disabling read-only handlers
+#-----------------------------------------------------------------------------
+
+@decorator
+def not_if_readonly(f, self, *args, **kwargs):
+    if self.application.ipython_app.read_only:
+        raise web.HTTPError(403, "Notebook server is read-only")
+    else:
+        return f(self, *args, **kwargs)
 
 #-----------------------------------------------------------------------------
 # Top-level handlers
 #-----------------------------------------------------------------------------
 
 class AuthenticatedHandler(web.RequestHandler):
     """A RequestHandler with an authenticated user."""
 
     def get_current_user(self):
         user_id = self.get_secure_cookie("username")
         # For now the user_id should not return empty, but it could eventually
         if user_id == '':
             user_id = 'anonymous'
         if user_id is None:
             # prevent extra Invalid cookie sig warnings:
             self.clear_cookie('username')
             if not self.application.password:
                 user_id = 'anonymous'
         return user_id
 
 
 class ProjectDashboardHandler(AuthenticatedHandler):
 
     @web.authenticated
     def get(self):
         nbm = self.application.notebook_manager
         project = nbm.notebook_dir
         self.render(
             'projectdashboard.html', project=project,
             base_project_url=u'/', base_kernel_url=u'/'
         )
 
 
 class LoginHandler(AuthenticatedHandler):
 
     def get(self):
         self.render('login.html', next='/')
 
     def post(self):
         pwd = self.get_argument('password', default=u'')
         if self.application.password and pwd == self.application.password:
             self.set_secure_cookie('username', str(uuid.uuid4()))
         url = self.get_argument('next', default='/')
         self.redirect(url)
 
 
 class NewHandler(AuthenticatedHandler):
 
+    @not_if_readonly
     @web.authenticated
     def get(self):
         nbm = self.application.notebook_manager
         project = nbm.notebook_dir
         notebook_id = nbm.new_notebook()
         self.render(
             'notebook.html', project=project,
             notebook_id=notebook_id,
             base_project_url=u'/', base_kernel_url=u'/',
             kill_kernel=False
         )
 
 
 class NamedNotebookHandler(AuthenticatedHandler):
 
     @web.authenticated
     def get(self, notebook_id):
         nbm = self.application.notebook_manager
         project = nbm.notebook_dir
         if not nbm.notebook_exists(notebook_id):
             raise web.HTTPError(404, u'Notebook does not exist: %s' % notebook_id)
         self.render(
             'notebook.html', project=project,
             notebook_id=notebook_id,
             base_project_url=u'/', base_kernel_url=u'/',
             kill_kernel=False
         )
 
 
 #-----------------------------------------------------------------------------
 # Kernel handlers
 #-----------------------------------------------------------------------------
 
 
 class MainKernelHandler(AuthenticatedHandler):
 
+    @not_if_readonly
     @web.authenticated
     def get(self):
         km = self.application.kernel_manager
         self.finish(jsonapi.dumps(km.kernel_ids))
 
+    @not_if_readonly
     @web.authenticated
     def post(self):
         km = self.application.kernel_manager
         notebook_id = self.get_argument('notebook', default=None)
         kernel_id = km.start_kernel(notebook_id)
         ws_url = self.application.ipython_app.get_ws_url()
         data = {'ws_url':ws_url,'kernel_id':kernel_id}
         self.set_header('Location', '/'+kernel_id)
         self.finish(jsonapi.dumps(data))
 
 
 class KernelHandler(AuthenticatedHandler):
 
     SUPPORTED_METHODS = ('DELETE')
 
+    @not_if_readonly
     @web.authenticated
     def delete(self, kernel_id):
         km = self.application.kernel_manager
         km.kill_kernel(kernel_id)
         self.set_status(204)
         self.finish()
 
 
 class KernelActionHandler(AuthenticatedHandler):
 
+    @not_if_readonly
     @web.authenticated
     def post(self, kernel_id, action):
         km = self.application.kernel_manager
         if action == 'interrupt':
             km.interrupt_kernel(kernel_id)
             self.set_status(204)
         if action == 'restart':
             new_kernel_id = km.restart_kernel(kernel_id)
             ws_url = self.application.ipython_app.get_ws_url()
             data = {'ws_url':ws_url,'kernel_id':new_kernel_id}
             self.set_header('Location', '/'+new_kernel_id)
             self.write(jsonapi.dumps(data))
         self.finish()
 
 
 class ZMQStreamHandler(websocket.WebSocketHandler):
 
     def _reserialize_reply(self, msg_list):
         """Reserialize a reply message using JSON.
 
         This takes the msg list from the ZMQ socket, unserializes it using
         self.session and then serializes the result using JSON. This method
         should be used by self._on_zmq_reply to build messages that can
         be sent back to the browser.
         """
         idents, msg_list = self.session.feed_identities(msg_list)
         msg = self.session.unserialize(msg_list)
         try:
             msg['header'].pop('date')
         except KeyError:
             pass
         try:
             msg['parent_header'].pop('date')
         except KeyError:
             pass
         msg.pop('buffers')
         return jsonapi.dumps(msg)
 
     def _on_zmq_reply(self, msg_list):
         try:
             msg = self._reserialize_reply(msg_list)
         except:
             self.application.log.critical("Malformed message: %r" % msg_list)
         else:
             self.write_message(msg)
 
 
 class AuthenticatedZMQStreamHandler(ZMQStreamHandler):
 
     def open(self, kernel_id):
         self.kernel_id = kernel_id.decode('ascii')
         try:
             cfg = self.application.ipython_app.config
         except AttributeError:
             # protect from the case where this is run from something other than
             # the notebook app:
             cfg = None
         self.session = Session(config=cfg)
         self.save_on_message = self.on_message
         self.on_message = self.on_first_message
 
     def get_current_user(self):
         user_id = self.get_secure_cookie("username")
         if user_id == '' or (user_id is None and not self.application.password):
             user_id = 'anonymous'
         return user_id
 
     def _inject_cookie_message(self, msg):
         """Inject the first message, which is the document cookie,
         for authentication."""
         if isinstance(msg, unicode):
             # Cookie can't constructor doesn't accept unicode strings for some reason
             msg = msg.encode('utf8', 'replace')
         try:
             self.request._cookies = Cookie.SimpleCookie(msg)
         except:
             logging.warn("couldn't parse cookie string: %s",msg, exc_info=True)
 
+    @not_if_readonly
     def on_first_message(self, msg):
         self._inject_cookie_message(msg)
         if self.get_current_user() is None:
             logging.warn("Couldn't authenticate WebSocket connection")
             raise web.HTTPError(403)
         self.on_message = self.save_on_message
 
 
 class IOPubHandler(AuthenticatedZMQStreamHandler):
 
     def initialize(self, *args, **kwargs):
         self._kernel_alive = True
         self._beating = False
         self.iopub_stream = None
         self.hb_stream = None
 
     def on_first_message(self, msg):
         try:
             super(IOPubHandler, self).on_first_message(msg)
         except web.HTTPError:
             self.close()
             return
         km = self.application.kernel_manager
         self.time_to_dead = km.time_to_dead
         kernel_id = self.kernel_id
         try:
             self.iopub_stream = km.create_iopub_stream(kernel_id)
             self.hb_stream = km.create_hb_stream(kernel_id)
         except web.HTTPError:
             # WebSockets don't response to traditional error codes so we
             # close the connection.
             if not self.stream.closed():
                 self.stream.close()
             self.close()
         else:
             self.iopub_stream.on_recv(self._on_zmq_reply)
             self.start_hb(self.kernel_died)
 
     def on_message(self, msg):
         pass
 
     def on_close(self):
         # This method can be called twice, once by self.kernel_died and once
         # from the WebSocket close event. If the WebSocket connection is
         # closed before the ZMQ streams are setup, they could be None.
         self.stop_hb()
         if self.iopub_stream is not None and not self.iopub_stream.closed():
             self.iopub_stream.on_recv(None)
             self.iopub_stream.close()
         if self.hb_stream is not None and not self.hb_stream.closed():
             self.hb_stream.close()
 
     def start_hb(self, callback):
         """Start the heartbeating and call the callback if the kernel dies."""
         if not self._beating:
             self._kernel_alive = True
 
             def ping_or_dead():
                 if self._kernel_alive:
                     self._kernel_alive = False
                     self.hb_stream.send(b'ping')
                 else:
                     try:
                         callback()
                     except:
                         pass
                     finally:
                         self._hb_periodic_callback.stop()
 
             def beat_received(msg):
                 self._kernel_alive = True
 
             self.hb_stream.on_recv(beat_received)
             self._hb_periodic_callback = ioloop.PeriodicCallback(ping_or_dead, self.time_to_dead*1000)
             self._hb_periodic_callback.start()
             self._beating= True
 
     def stop_hb(self):
         """Stop the heartbeating and cancel all related callbacks."""
         if self._beating:
             self._hb_periodic_callback.stop()
             if not self.hb_stream.closed():
                 self.hb_stream.on_recv(None)
 
     def kernel_died(self):
         self.application.kernel_manager.delete_mapping_for_kernel(self.kernel_id)
         self.write_message(
             {'header': {'msg_type': 'status'},
              'parent_header': {},
              'content': {'execution_state':'dead'}
             }
         )
         self.on_close()
 
 
 class ShellHandler(AuthenticatedZMQStreamHandler):
 
     def initialize(self, *args, **kwargs):
         self.shell_stream = None
 
     def on_first_message(self, msg):
         try:
             super(ShellHandler, self).on_first_message(msg)
         except web.HTTPError:
             self.close()
             return
         km = self.application.kernel_manager
         self.max_msg_size = km.max_msg_size
         kernel_id = self.kernel_id
         try:
             self.shell_stream = km.create_shell_stream(kernel_id)
         except web.HTTPError:
             # WebSockets don't response to traditional error codes so we
             # close the connection.
             if not self.stream.closed():
                 self.stream.close()
             self.close()
         else:
             self.shell_stream.on_recv(self._on_zmq_reply)
 
     def on_message(self, msg):
         if len(msg) < self.max_msg_size:
             msg = jsonapi.loads(msg)
             self.session.send(self.shell_stream, msg)
 
     def on_close(self):
         # Make sure the stream exists and is not already closed.
         if self.shell_stream is not None and not self.shell_stream.closed():
             self.shell_stream.close()
 
 
 #-----------------------------------------------------------------------------
 # Notebook web service handlers
 #-----------------------------------------------------------------------------
 
 class NotebookRootHandler(AuthenticatedHandler):
 
     @web.authenticated
     def get(self):
         nbm = self.application.notebook_manager
         files = nbm.list_notebooks()
         self.finish(jsonapi.dumps(files))
 
+    @not_if_readonly
     @web.authenticated
     def post(self):
         nbm = self.application.notebook_manager
         body = self.request.body.strip()
         format = self.get_argument('format', default='json')
         name = self.get_argument('name', default=None)
         if body:
             notebook_id = nbm.save_new_notebook(body, name=name, format=format)
         else:
             notebook_id = nbm.new_notebook()
         self.set_header('Location', '/'+notebook_id)
         self.finish(jsonapi.dumps(notebook_id))
 
 
 class NotebookHandler(AuthenticatedHandler):
 
     SUPPORTED_METHODS = ('GET', 'PUT', 'DELETE')
 
     @web.authenticated
     def get(self, notebook_id):
         nbm = self.application.notebook_manager
         format = self.get_argument('format', default='json')
         last_mod, name, data = nbm.get_notebook(notebook_id, format)
         if format == u'json':
             self.set_header('Content-Type', 'application/json')
             self.set_header('Content-Disposition','attachment; filename="%s.ipynb"' % name)
         elif format == u'py':
             self.set_header('Content-Type', 'application/x-python')
             self.set_header('Content-Disposition','attachment; filename="%s.py"' % name)
         self.set_header('Last-Modified', last_mod)
         self.finish(data)
 
+    @not_if_readonly
     @web.authenticated
     def put(self, notebook_id):
         nbm = self.application.notebook_manager
         format = self.get_argument('format', default='json')
         name = self.get_argument('name', default=None)
         nbm.save_notebook(notebook_id, self.request.body, name=name, format=format)
         self.set_status(204)
         self.finish()
 
+    @not_if_readonly
     @web.authenticated
     def delete(self, notebook_id):
         nbm = self.application.notebook_manager
         nbm.delete_notebook(notebook_id)
         self.set_status(204)
         self.finish()
 
 #-----------------------------------------------------------------------------
 # RST web service handlers
 #-----------------------------------------------------------------------------
 
 
 class RSTHandler(AuthenticatedHandler):
 
     @web.authenticated
     def post(self):
         if publish_string is None:
             raise web.HTTPError(503, u'docutils not available')
         body = self.request.body.strip()
         source = body
         # template_path=os.path.join(os.path.dirname(__file__), u'templates', u'rst_template.html')
         defaults = {'file_insertion_enabled': 0,
                     'raw_enabled': 0,
                     '_disable_config': 1,
                     'stylesheet_path': 0
                     # 'template': template_path
         }
         try:
             html = publish_string(source, writer_name='html',
                                   settings_overrides=defaults
             )
         except:
             raise web.HTTPError(400, u'Invalid RST')
         print html
         self.set_header('Content-Type', 'text/html')
         self.finish(html)
 
 

IPython/frontend/html/notebook/notebookapp.py

@@ -1,315 +1,323 b''
 """A tornado based IPython notebook server.
 
 Authors:
 
 * Brian Granger
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import errno
 import logging
 import os
 import signal
 import socket
 import sys
 import webbrowser
 
 import zmq
 
 # Install the pyzmq ioloop. This has to be done before anything else from
 # tornado is imported.
 from zmq.eventloop import ioloop
 import tornado.ioloop
 tornado.ioloop.IOLoop = ioloop.IOLoop
 
 from tornado import httpserver
 from tornado import web
 
 from .kernelmanager import MappingKernelManager
 from .handlers import (LoginHandler,
     ProjectDashboardHandler, NewHandler, NamedNotebookHandler,
     MainKernelHandler, KernelHandler, KernelActionHandler, IOPubHandler,
     ShellHandler, NotebookRootHandler, NotebookHandler, RSTHandler
 )
 from .notebookmanager import NotebookManager
 
 from IPython.core.application import BaseIPythonApplication
 from IPython.core.profiledir import ProfileDir
 from IPython.zmq.session import Session, default_secure
 from IPython.zmq.zmqshell import ZMQInteractiveShell
 from IPython.zmq.ipkernel import (
     flags as ipkernel_flags,
     aliases as ipkernel_aliases,
     IPKernelApp
 )
 from IPython.utils.traitlets import Dict, Unicode, Int, List, Enum, Bool
 
 #-----------------------------------------------------------------------------
 # Module globals
 #-----------------------------------------------------------------------------
 
 _kernel_id_regex = r"(?P<kernel_id>\w+-\w+-\w+-\w+-\w+)"
 _kernel_action_regex = r"(?P<action>restart|interrupt)"
 _notebook_id_regex = r"(?P<notebook_id>\w+-\w+-\w+-\w+-\w+)"
 
 LOCALHOST = '127.0.0.1'
 
 _examples = """
 ipython notebook                       # start the notebook
 ipython notebook --profile=sympy       # use the sympy profile
 ipython notebook --pylab=inline        # pylab in inline plotting mode
 ipython notebook --certfile=mycert.pem # use SSL/TLS certificate
 ipython notebook --port=5555 --ip=*    # Listen on port 5555, all interfaces
 """
 
 #-----------------------------------------------------------------------------
 # The Tornado web application
 #-----------------------------------------------------------------------------
 
 class NotebookWebApplication(web.Application):
 
     def __init__(self, ipython_app, kernel_manager, notebook_manager, log):
         handlers = [
             (r"/", ProjectDashboardHandler),
             (r"/login", LoginHandler),
             (r"/new", NewHandler),
             (r"/%s" % _notebook_id_regex, NamedNotebookHandler),
             (r"/kernels", MainKernelHandler),
             (r"/kernels/%s" % _kernel_id_regex, KernelHandler),
             (r"/kernels/%s/%s" % (_kernel_id_regex, _kernel_action_regex), KernelActionHandler),
             (r"/kernels/%s/iopub" % _kernel_id_regex, IOPubHandler),
             (r"/kernels/%s/shell" % _kernel_id_regex, ShellHandler),
             (r"/notebooks", NotebookRootHandler),
             (r"/notebooks/%s" % _notebook_id_regex, NotebookHandler),
             (r"/rstservice/render", RSTHandler)
         ]
         settings = dict(
             template_path=os.path.join(os.path.dirname(__file__), "templates"),
             static_path=os.path.join(os.path.dirname(__file__), "static"),
             cookie_secret=os.urandom(1024),
             login_url="/login",
         )
         web.Application.__init__(self, handlers, **settings)
 
         self.kernel_manager = kernel_manager
         self.log = log
         self.notebook_manager = notebook_manager
         self.ipython_app = ipython_app
 
 
 #-----------------------------------------------------------------------------
 # Aliases and Flags
 #-----------------------------------------------------------------------------
 
 flags = dict(ipkernel_flags)
 flags['no-browser']=(
     {'NotebookApp' : {'open_browser' : False}},
     "Don't open the notebook in a browser after startup."
 )
+flags['read-only'] = (
+    {'NotebookApp' : {'read_only' : True}},
+    "Launch the Notebook server in read-only mode, not allowing execution or editing"
+)
 
 # 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
 notebook_flags = ['no-browser']
 
 aliases = dict(ipkernel_aliases)
 
 aliases.update({
     'ip': 'NotebookApp.ip',
     'port': 'NotebookApp.port',
     'keyfile': 'NotebookApp.keyfile',
     'certfile': 'NotebookApp.certfile',
     'ws-hostname': 'NotebookApp.ws_hostname',
     'notebook-dir': 'NotebookManager.notebook_dir',
 })
 
 # remove ipkernel flags that are singletons, and don't make sense in
 # multi-kernel evironment:
 aliases.pop('f', None)
 
 notebook_aliases = [u'port', u'ip', u'keyfile', u'certfile', u'ws-hostname',
                     u'notebook-dir']
 
 #-----------------------------------------------------------------------------
 # NotebookApp
 #-----------------------------------------------------------------------------
 
 class NotebookApp(BaseIPythonApplication):
 
     name = 'ipython-notebook'
     default_config_file_name='ipython_notebook_config.py'
     
     description = """
         The IPython HTML Notebook.
         
         This launches a Tornado based HTML Notebook Server that serves up an
         HTML5/Javascript Notebook client.
     """
     examples = _examples
     
     classes = [IPKernelApp, ZMQInteractiveShell, ProfileDir, Session,
                MappingKernelManager, NotebookManager]
     flags = Dict(flags)
     aliases = Dict(aliases)
 
     kernel_argv = List(Unicode)
 
     log_level = Enum((0,10,20,30,40,50,'DEBUG','INFO','WARN','ERROR','CRITICAL'),
                     default_value=logging.INFO,
                     config=True,
                     help="Set the log level by value or name.")
 
     # Network related information.
 
     ip = Unicode(LOCALHOST, config=True,
         help="The IP address the notebook server will listen on."
     )
 
     def _ip_changed(self, name, old, new):
         if new == u'*': self.ip = u''
 
     port = Int(8888, config=True,
         help="The port the notebook server will listen on."
     )
 
     ws_hostname = Unicode(LOCALHOST, config=True,
         help="""The FQDN or IP for WebSocket connections. The default will work
                 fine when the server is listening on localhost, but this needs to
                 be set if the ip option is used. It will be used as the hostname part
                 of the WebSocket url: ws://hostname/path."""
     )
 
     certfile = Unicode(u'', config=True, 
         help="""The full path to an SSL/TLS certificate file."""
     )
     
     keyfile = Unicode(u'', config=True, 
         help="""The full path to a private key file for usage with SSL/TLS."""
     )
 
     password = Unicode(u'', config=True,
                       help="""Password to use for web authentication"""
     )
     
     open_browser = Bool(True, config=True,
                         help="Whether to open in a browser after starting.")
 
+    read_only = Bool(False, config=True,
+        help="Whether to prevent editing/execution of notebooks."
+    )
+
     def get_ws_url(self):
         """Return the WebSocket URL for this server."""
         if self.certfile:
             prefix = u'wss://'
         else:
             prefix = u'ws://'
         return prefix + self.ws_hostname + u':' + unicode(self.port)
 
     def parse_command_line(self, argv=None):
         super(NotebookApp, self).parse_command_line(argv)
         if argv is None:
             argv = sys.argv[1:]
 
         self.kernel_argv = list(argv) # copy
         # Kernel should inherit default config file from frontend
         self.kernel_argv.append("--KernelApp.parent_appname='%s'"%self.name)
         # Scrub frontend-specific flags
         for a in argv:
             if a.startswith('-') and a.lstrip('-') in notebook_flags:
                 self.kernel_argv.remove(a)
         swallow_next = False
         for a in argv:
             if swallow_next:
                 self.kernel_argv.remove(a)
                 swallow_next = False
                 continue
             if a.startswith('-'):
                 split = a.lstrip('-').split('=')
                 alias = split[0]
                 if alias in notebook_aliases:
                     self.kernel_argv.remove(a)
                     if len(split) == 1:
                         # alias passed with arg via space
                         swallow_next = True
 
     def init_configurables(self):
         # Don't let Qt or ZMQ swallow KeyboardInterupts.
         signal.signal(signal.SIGINT, signal.SIG_DFL)
 
         # force Session default to be secure
         default_secure(self.config)
         # Create a KernelManager and start a kernel.
         self.kernel_manager = MappingKernelManager(
             config=self.config, log=self.log, kernel_argv=self.kernel_argv,
             connection_dir = self.profile_dir.security_dir,
         )
         self.notebook_manager = NotebookManager(config=self.config, log=self.log)
         self.notebook_manager.list_notebooks()
 
     def init_logging(self):
         super(NotebookApp, self).init_logging()
         # This prevents double log messages because tornado use a root logger that
         # self.log is a child of. The logging module dipatches log messages to a log
         # and all of its ancenstors until propagate is set to False.
         self.log.propagate = False
 
     def initialize(self, argv=None):
         super(NotebookApp, self).initialize(argv)
         self.init_configurables()
         self.web_app = NotebookWebApplication(
             self, self.kernel_manager, self.notebook_manager, self.log
         )
         if self.certfile:
             ssl_options = dict(certfile=self.certfile)
             if self.keyfile:
                 ssl_options['keyfile'] = self.keyfile
         else:
             ssl_options = None
         self.web_app.password = self.password
         self.http_server = httpserver.HTTPServer(self.web_app, ssl_options=ssl_options)
         if ssl_options is None and not self.ip:
             self.log.critical('WARNING: the notebook server is listening on all IP addresses '
                               'but not using any encryption or authentication. This is highly '
                               'insecure and not recommended.')
 
         # Try random ports centered around the default.
         from random import randint
         n = 50  # Max number of attempts, keep reasonably large.
-        for port in [self.port] + [self.port + randint(-2*n, 2*n) for i in range(n)]:
+        for port in range(self.port, self.port+5) + [self.port + randint(-2*n, 2*n) for i in range(n-5)]:
             try:
                 self.http_server.listen(port, self.ip)
             except socket.error, e:
                 if e.errno != errno.EADDRINUSE:
                     raise
                 self.log.info('The port %i is already in use, trying another random port.' % port)
             else:
                 self.port = port
                 break
 
     def start(self):
         ip = self.ip if self.ip else '[all ip addresses on your system]'
         proto = 'https' if self.certfile else 'http'
         self.log.info("The IPython Notebook is running at: %s://%s:%i" % (proto,
                                                                           ip,
                                                                           self.port))
         if self.open_browser:
             ip = self.ip or '127.0.0.1'
             webbrowser.open("%s://%s:%i" % (proto, ip, self.port), new=2)
         ioloop.IOLoop.instance().start()
 
 #-----------------------------------------------------------------------------
 # Main entry point
 #-----------------------------------------------------------------------------
 
 def launch_new_instance():
     app = NotebookApp()
     app.initialize()
     app.start()