add ModifyCheckpoints handler

separates requests that change specified checkpoint IDs from those that do not.

IPython/frontend/html/notebook/handlers.py

@@ -1,925 +1,928 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 Cookie
 import datetime
 import email.utils
 import hashlib
 import logging
 import mimetypes
 import os
 import stat
 import threading
 import time
 import uuid
 
 from tornado.escape import url_escape
 from tornado import web
 from tornado import websocket
 
 try:
     from tornado.log import app_log
 except ImportError:
     app_log = logging.getLogger()
 
 from zmq.eventloop import ioloop
 from zmq.utils import jsonapi
 
 from IPython.config import Application
 from IPython.external.decorator import decorator
 from IPython.kernel.zmq.session import Session
 from IPython.lib.security import passwd_check
 from IPython.utils.jsonutil import date_default
 from IPython.utils.path import filefind
 from IPython.utils.py3compat import PY3
 
 try:
     from docutils.core import publish_string
 except ImportError:
     publish_string = None
 
 #-----------------------------------------------------------------------------
 # Monkeypatch for Tornado <= 2.1.1 - Remove when no longer necessary!
 #-----------------------------------------------------------------------------
 
 # Google Chrome, as of release 16, changed its websocket protocol number.  The
 # parts tornado cares about haven't really changed, so it's OK to continue
 # accepting Chrome connections, but as of Tornado 2.1.1 (the currently released
 # version as of Oct 30/2011) the version check fails, see the issue report:
 
 # https://github.com/facebook/tornado/issues/385
 
 # This issue has been fixed in Tornado post 2.1.1:
 
 # https://github.com/facebook/tornado/commit/84d7b458f956727c3b0d6710
 
 # Here we manually apply the same patch as above so that users of IPython can
 # continue to work with an officially released Tornado.  We make the
 # monkeypatch version check as narrow as possible to limit its effects; once
 # Tornado 2.1.1 is no longer found in the wild we'll delete this code.
 
 import tornado
 
 if tornado.version_info <= (2,1,1):
 
     def _execute(self, transforms, *args, **kwargs):
         from tornado.websocket import WebSocketProtocol8, WebSocketProtocol76
         
         self.open_args = args
         self.open_kwargs = kwargs
 
         # The difference between version 8 and 13 is that in 8 the
         # client sends a "Sec-Websocket-Origin" header and in 13 it's
         # simply "Origin".
         if self.request.headers.get("Sec-WebSocket-Version") in ("7", "8", "13"):
             self.ws_connection = WebSocketProtocol8(self)
             self.ws_connection.accept_connection()
             
         elif self.request.headers.get("Sec-WebSocket-Version"):
             self.stream.write(tornado.escape.utf8(
                 "HTTP/1.1 426 Upgrade Required\r\n"
                 "Sec-WebSocket-Version: 8\r\n\r\n"))
             self.stream.close()
             
         else:
             self.ws_connection = WebSocketProtocol76(self)
             self.ws_connection.accept_connection()
 
     websocket.WebSocketHandler._execute = _execute
     del _execute
 
 #-----------------------------------------------------------------------------
 # Decorator for disabling read-only handlers
 #-----------------------------------------------------------------------------
 
 @decorator
 def not_if_readonly(f, self, *args, **kwargs):
     if self.settings.get('read_only', False):
         raise web.HTTPError(403, "Notebook server is read-only")
     else:
         return f(self, *args, **kwargs)
 
 @decorator
 def authenticate_unless_readonly(f, self, *args, **kwargs):
     """authenticate this page *unless* readonly view is active.
     
     In read-only mode, the notebook list and print view should
     be accessible without authentication.
     """
     
     @web.authenticated
     def auth_f(self, *args, **kwargs):
         return f(self, *args, **kwargs)
 
     if self.settings.get('read_only', False):
         return f(self, *args, **kwargs)
     else:
         return auth_f(self, *args, **kwargs)
 
 def urljoin(*pieces):
     """Join components of url into a relative url
 
     Use to prevent double slash when joining subpath
     """
     striped = [s.strip('/') for s in pieces]
     return '/'.join(s for s in striped if s)
 
 #-----------------------------------------------------------------------------
 # Top-level handlers
 #-----------------------------------------------------------------------------
 
 class RequestHandler(web.RequestHandler):
     """RequestHandler with default variable setting."""
 
     def render(*args, **kwargs):
         kwargs.setdefault('message', '')
         return web.RequestHandler.render(*args, **kwargs)
 
 class AuthenticatedHandler(RequestHandler):
     """A RequestHandler with an authenticated user."""
 
     def clear_login_cookie(self):
         self.clear_cookie(self.cookie_name)
     
     def get_current_user(self):
         user_id = self.get_secure_cookie(self.cookie_name)
         # 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_login_cookie()
             if not self.read_only and not self.login_available:
                 user_id = 'anonymous'
         return user_id
 
     @property
     def cookie_name(self):
         return self.settings.get('cookie_name', '')
     
     @property
     def password(self):
         """our password"""
         return self.settings.get('password', '')
     
     @property
     def logged_in(self):
         """Is a user currently logged in?
 
         """
         user = self.get_current_user()
         return (user and not user == 'anonymous')
 
     @property
     def login_available(self):
         """May a user proceed to log in?
 
         This returns True if login capability is available, irrespective of
         whether the user is already logged in or not.
 
         """
         return bool(self.settings.get('password', ''))
 
     @property
     def read_only(self):
         """Is the notebook read-only?
 
         """
         return self.settings.get('read_only', False)
 
 
 class IPythonHandler(AuthenticatedHandler):
     """IPython-specific extensions to authenticated handling
     
     Mostly property shortcuts to IPython-specific settings.
     """
     
     @property
     def config(self):
         return self.settings.get('config', None)
     
     @property
     def log(self):
         """use the IPython log by default, falling back on tornado's logger"""
         if Application.initialized():
             return Application.instance().log
         else:
             return app_log
     
     @property
     def use_less(self):
         """Use less instead of css in templates"""
         return self.settings.get('use_less', False)
     
     #---------------------------------------------------------------
     # URLs
     #---------------------------------------------------------------
     
     @property
     def ws_url(self):
         """websocket url matching the current request
 
         turns http[s]://host[:port] into
                 ws[s]://host[:port]
         """
         proto = self.request.protocol.replace('http', 'ws')
         host = self.settings.get('websocket_host', '')
         # default to config value
         if host == '':
             host = self.request.host # get from request
         return "%s://%s" % (proto, host)
     
     @property
     def mathjax_url(self):
         return self.settings.get('mathjax_url', '')
     
     @property
     def base_project_url(self):
         return self.settings.get('base_project_url', '/')
     
     @property
     def base_kernel_url(self):
         return self.settings.get('base_kernel_url', '/')
     
     #---------------------------------------------------------------
     # Manager objects
     #---------------------------------------------------------------
     
     @property
     def kernel_manager(self):
         return self.settings['kernel_manager']
 
     @property
     def notebook_manager(self):
         return self.settings['notebook_manager']
     
     @property
     def cluster_manager(self):
         return self.settings['cluster_manager']
     
     @property
     def project(self):
         return self.notebook_manager.notebook_dir
     
     #---------------------------------------------------------------
     # template rendering
     #---------------------------------------------------------------
     
     def get_template(self, name):
         """Return the jinja template object for a given name"""
         return self.settings['jinja2_env'].get_template(name)
     
     def render_template(self, name, **ns):
         ns.update(self.template_namespace)
         template = self.get_template(name)
         return template.render(**ns)
     
     @property
     def template_namespace(self):
         return dict(
             base_project_url=self.base_project_url,
             base_kernel_url=self.base_kernel_url,
             read_only=self.read_only,
             logged_in=self.logged_in,
             login_available=self.login_available,
             use_less=self.use_less,
         )
 
 class AuthenticatedFileHandler(IPythonHandler, web.StaticFileHandler):
     """static files should only be accessible when logged in"""
 
     @authenticate_unless_readonly
     def get(self, path):
         return web.StaticFileHandler.get(self, path)
 
 
 class ProjectDashboardHandler(IPythonHandler):
 
     @authenticate_unless_readonly
     def get(self):
         self.write(self.render_template('projectdashboard.html',
             project=self.project,
             project_component=self.project.split('/'),
         ))
 
 
 class LoginHandler(IPythonHandler):
 
     def _render(self, message=None):
         self.write(self.render_template('login.html',
                 next=url_escape(self.get_argument('next', default=self.base_project_url)),
                 message=message,
         ))
 
     def get(self):
         if self.current_user:
             self.redirect(self.get_argument('next', default=self.base_project_url))
         else:
             self._render()
 
     def post(self):
         pwd = self.get_argument('password', default=u'')
         if self.login_available:
             if passwd_check(self.password, pwd):
                 self.set_secure_cookie(self.cookie_name, str(uuid.uuid4()))
             else:
                 self._render(message={'error': 'Invalid password'})
                 return
 
         self.redirect(self.get_argument('next', default=self.base_project_url))
 
 
 class LogoutHandler(IPythonHandler):
 
     def get(self):
         self.clear_login_cookie()
         if self.login_available:
             message = {'info': 'Successfully logged out.'}
         else:
             message = {'warning': 'Cannot log out.  Notebook authentication '
                        'is disabled.'}
         self.write(self.render_template('logout.html',
                     message=message))
 
 
 class NewHandler(IPythonHandler):
 
     @web.authenticated
     def get(self):
         notebook_id = self.notebook_manager.new_notebook()
         self.redirect('/' + urljoin(self.base_project_url, notebook_id))
 
 class NamedNotebookHandler(IPythonHandler):
 
     @authenticate_unless_readonly
     def get(self, notebook_id):
         nbm = self.notebook_manager
         if not nbm.notebook_exists(notebook_id):
             raise web.HTTPError(404, u'Notebook does not exist: %s' % notebook_id)       
         self.write(self.render_template('notebook.html',
             project=self.project,
             notebook_id=notebook_id,
             kill_kernel=False,
             mathjax_url=self.mathjax_url,
             )
         )
 
 
 #-----------------------------------------------------------------------------
 # Kernel handlers
 #-----------------------------------------------------------------------------
 
 
 class MainKernelHandler(IPythonHandler):
 
     @web.authenticated
     def get(self):
         km = self.kernel_manager
         self.finish(jsonapi.dumps(km.list_kernel_ids()))
 
     @web.authenticated
     def post(self):
         km = self.kernel_manager
         nbm = self.notebook_manager
         notebook_id = self.get_argument('notebook', default=None)
         kernel_id = km.start_kernel(notebook_id, cwd=nbm.notebook_dir)
         data = {'ws_url':self.ws_url,'kernel_id':kernel_id}
         self.set_header('Location', '/'+kernel_id)
         self.finish(jsonapi.dumps(data))
 
 
 class KernelHandler(IPythonHandler):
 
     SUPPORTED_METHODS = ('DELETE')
 
     @web.authenticated
     def delete(self, kernel_id):
         km = self.kernel_manager
         km.shutdown_kernel(kernel_id)
         self.set_status(204)
         self.finish()
 
 
 class KernelActionHandler(IPythonHandler):
 
     @web.authenticated
     def post(self, kernel_id, action):
         km = self.kernel_manager
         if action == 'interrupt':
             km.interrupt_kernel(kernel_id)
             self.set_status(204)
         if action == 'restart':
             km.restart_kernel(kernel_id)
             data = {'ws_url':self.ws_url, 'kernel_id':kernel_id}
             self.set_header('Location', '/'+kernel_id)
             self.write(jsonapi.dumps(data))
         self.finish()
 
 
 class ZMQStreamHandler(websocket.WebSocketHandler):
     
     def clear_cookie(self, *args, **kwargs):
         """meaningless for websockets"""
         pass
 
     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, default=date_default)
 
     def _on_zmq_reply(self, msg_list):
         # Sometimes this gets triggered when the on_close method is scheduled in the
         # eventloop but hasn't been called.
         if self.stream.closed(): return
         try:
             msg = self._reserialize_reply(msg_list)
         except Exception:
             self.log.critical("Malformed message: %r" % msg_list, exc_info=True)
         else:
             self.write_message(msg)
 
     def allow_draft76(self):
         """Allow draft 76, until browsers such as Safari update to RFC 6455.
         
         This has been disabled by default in tornado in release 2.2.0, and
         support will be removed in later versions.
         """
         return True
 
 
 class AuthenticatedZMQStreamHandler(ZMQStreamHandler, IPythonHandler):
 
     def open(self, kernel_id):
         self.kernel_id = kernel_id.decode('ascii')
         self.session = Session(config=self.config)
         self.save_on_message = self.on_message
         self.on_message = self.on_first_message
 
     def _inject_cookie_message(self, msg):
         """Inject the first message, which is the document cookie,
         for authentication."""
         if not PY3 and isinstance(msg, unicode):
             # Cookie constructor doesn't accept unicode strings
             # under Python 2.x for some reason
             msg = msg.encode('utf8', 'replace')
         try:
             identity, msg = msg.split(':', 1)
             self.session.session = identity.decode('ascii')
         except Exception:
             logging.error("First ws message didn't have the form 'identity:[cookie]' - %r", msg)
         
         try:
             self.request._cookies = Cookie.SimpleCookie(msg)
         except:
             self.log.warn("couldn't parse cookie string: %s",msg, exc_info=True)
 
     def on_first_message(self, msg):
         self._inject_cookie_message(msg)
         if self.get_current_user() is None:
             self.log.warn("Couldn't authenticate WebSocket connection")
             raise web.HTTPError(403)
         self.on_message = self.save_on_message
 
 
 class ZMQChannelHandler(AuthenticatedZMQStreamHandler):
     
     @property
     def max_msg_size(self):
         return self.settings.get('max_msg_size', 65535)
     
     def create_stream(self):
         km = self.kernel_manager
         meth = getattr(km, 'connect_%s' % self.channel)
         self.zmq_stream = meth(self.kernel_id, identity=self.session.bsession)
     
     def initialize(self, *args, **kwargs):
         self.zmq_stream = None
     
     def on_first_message(self, msg):
         try:
             super(ZMQChannelHandler, self).on_first_message(msg)
         except web.HTTPError:
             self.close()
             return
         try:
             self.create_stream()
         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.zmq_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.zmq_stream, msg)
 
     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.
         if self.zmq_stream is not None and not self.zmq_stream.closed():
             self.zmq_stream.on_recv(None)
             self.zmq_stream.close()
 
 
 class IOPubHandler(ZMQChannelHandler):
     channel = 'iopub'
     
     def create_stream(self):
         super(IOPubHandler, self).create_stream()
         km = self.kernel_manager
         km.add_restart_callback(self.kernel_id, self.on_kernel_restarted)
         km.add_restart_callback(self.kernel_id, self.on_restart_failed, 'dead')
     
     def on_close(self):
         km = self.kernel_manager
         if self.kernel_id in km:
             km.remove_restart_callback(
                 self.kernel_id, self.on_kernel_restarted,
             )
             km.remove_restart_callback(
                 self.kernel_id, self.on_restart_failed, 'dead',
             )
         super(IOPubHandler, self).on_close()
     
     def _send_status_message(self, status):
         msg = self.session.msg("status",
             {'execution_state': status}
         )
         self.write_message(jsonapi.dumps(msg, default=date_default))
 
     def on_kernel_restarted(self):
         logging.warn("kernel %s restarted", self.kernel_id)
         self._send_status_message('restarting')
 
     def on_restart_failed(self):
         logging.error("kernel %s restarted failed!", self.kernel_id)
         self._send_status_message('dead')
     
     def on_message(self, msg):
         """IOPub messages make no sense"""
         pass
 
 class ShellHandler(ZMQChannelHandler):
     channel = 'shell'
 
 class StdinHandler(ZMQChannelHandler):
     channel = 'stdin'
 
 
 #-----------------------------------------------------------------------------
 # Notebook web service handlers
 #-----------------------------------------------------------------------------
 
 class NotebookRedirectHandler(IPythonHandler):
     
     @authenticate_unless_readonly
     def get(self, notebook_name):
         # strip trailing .ipynb:
         notebook_name = os.path.splitext(notebook_name)[0]
         notebook_id = self.notebook_manager.rev_mapping.get(notebook_name, '')
         if notebook_id:
             url = self.settings.get('base_project_url', '/') + notebook_id
             return self.redirect(url)
         else:
             raise HTTPError(404)
 
 
 class NotebookRootHandler(IPythonHandler):
 
     @authenticate_unless_readonly
     def get(self):
         nbm = self.notebook_manager
         km = self.kernel_manager
         files = nbm.list_notebooks()
         for f in files :
             f['kernel_id'] = km.kernel_for_notebook(f['notebook_id'])
         self.finish(jsonapi.dumps(files))
 
     @web.authenticated
     def post(self):
         nbm = self.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(IPythonHandler):
 
     SUPPORTED_METHODS = ('GET', 'PUT', 'DELETE')
 
     @authenticate_unless_readonly
     def get(self, notebook_id):
         nbm = self.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)
 
     @web.authenticated
     def put(self, notebook_id):
         nbm = self.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()
 
     @web.authenticated
     def delete(self, notebook_id):
         self.notebook_manager.delete_notebook(notebook_id)
         self.set_status(204)
         self.finish()
 
-class NotebookCheckpointHandler(AuthenticatedHandler):
 
-    SUPPORTED_METHODS = ('GET', 'POST', 'PUT', 'DELETE')
+class NotebookCheckpointsHandler(AuthenticatedHandler):
+    
+    SUPPORTED_METHODS = ('GET', 'POST')
     
     @web.authenticated
     def get(self, notebook_id):
         """get lists checkpoints for a notebook"""
         nbm = self.application.notebook_manager
         checkpoints = nbm.list_checkpoints(notebook_id)
-        self.finish(checkpoints)
+        data = jsonapi.dumps(checkpoints, default=date_default)
+        self.finish(data)
     
     @web.authenticated
     def post(self, notebook_id):
+        """post creates a new checkpoint"""
+        nbm = self.application.notebook_manager
+        checkpoint = nbm.create_checkpoint(notebook_id)
+        data = jsonapi.dumps(checkpoint, default=date_default)
+        self.finish(data)
+
+
+class ModifyNotebookCheckpointsHandler(AuthenticatedHandler):
+    
+    SUPPORTED_METHODS = ('POST', 'DELETE')
+    
+    @web.authenticated
+    def post(self, notebook_id, checkpoint_id):
         """post restores a notebook from a checkpoint"""
         nbm = self.application.notebook_manager
-        checkpoint_id = self.get_argument('checkpoint', None)
         nbm.restore_checkpoint(notebook_id, checkpoint_id)
         self.set_status(204)
         self.finish()
     
     @web.authenticated
-    def put(self, notebook_id):
-        """put saves the notebook, and creates a new checkpoint"""
-        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)
-        checkpoint = nbm.create_checkpoint(notebook_id)
-        self.finish(checkpoint)
-
-    @web.authenticated
-    def delete(self, notebook_id):
+    def delete(self, notebook_id, checkpoint_id):
         """delete clears a checkpoint for a given notebook"""
         nbm = self.application.notebook_manager
-        checkpoint_id = self.get_argument('checkpoint', None)
         nbm.delte_checkpoint(notebook_id, checkpoint_id)
         self.set_status(204)
         self.finish()
 
 
 
 class NotebookCopyHandler(IPythonHandler):
 
     @web.authenticated
     def get(self, notebook_id):
         notebook_id = self.notebook_manager.copy_notebook(notebook_id)
         self.redirect('/'+urljoin(self.base_project_url, notebook_id))
 
 
 #-----------------------------------------------------------------------------
 # Cluster handlers
 #-----------------------------------------------------------------------------
 
 
 class MainClusterHandler(IPythonHandler):
 
     @web.authenticated
     def get(self):
         self.finish(jsonapi.dumps(self.cluster_manager.list_profiles()))
 
 
 class ClusterProfileHandler(IPythonHandler):
 
     @web.authenticated
     def get(self, profile):
         self.finish(jsonapi.dumps(self.cluster_manager.profile_info(profile)))
 
 
 class ClusterActionHandler(IPythonHandler):
 
     @web.authenticated
     def post(self, profile, action):
         cm = self.cluster_manager
         if action == 'start':
             n = self.get_argument('n',default=None)
             if n is None:
                 data = cm.start_cluster(profile)
             else:
                 data = cm.start_cluster(profile, int(n))
         if action == 'stop':
             data = cm.stop_cluster(profile)
         self.finish(jsonapi.dumps(data))
 
 
 #-----------------------------------------------------------------------------
 # File handler
 #-----------------------------------------------------------------------------
 
 # to minimize subclass changes:
 HTTPError = web.HTTPError
 
 class FileFindHandler(web.StaticFileHandler):
     """subclass of StaticFileHandler for serving files from a search path"""
     
     _static_paths = {}
     # _lock is needed for tornado < 2.2.0 compat
     _lock = threading.Lock()  # protects _static_hashes
     
     def initialize(self, path, default_filename=None):
         if isinstance(path, basestring):
             path = [path]
         self.roots = tuple(
             os.path.abspath(os.path.expanduser(p)) + os.path.sep for p in path
         )
         self.default_filename = default_filename
     
     @classmethod
     def locate_file(cls, path, roots):
         """locate a file to serve on our static file search path"""
         with cls._lock:
             if path in cls._static_paths:
                 return cls._static_paths[path]
             try:
                 abspath = os.path.abspath(filefind(path, roots))
             except IOError:
                 # empty string should always give exists=False
                 return ''
         
             # os.path.abspath strips a trailing /
             # it needs to be temporarily added back for requests to root/
             if not (abspath + os.path.sep).startswith(roots):
                 raise HTTPError(403, "%s is not in root static directory", path)
         
             cls._static_paths[path] = abspath
             return abspath
     
     def get(self, path, include_body=True):
         path = self.parse_url_path(path)
         
         # begin subclass override
         abspath = self.locate_file(path, self.roots)
         # end subclass override
         
         if os.path.isdir(abspath) and self.default_filename is not None:
             # need to look at the request.path here for when path is empty
             # but there is some prefix to the path that was already
             # trimmed by the routing
             if not self.request.path.endswith("/"):
                 self.redirect(self.request.path + "/")
                 return
             abspath = os.path.join(abspath, self.default_filename)
         if not os.path.exists(abspath):
             raise HTTPError(404)
         if not os.path.isfile(abspath):
             raise HTTPError(403, "%s is not a file", path)
 
         stat_result = os.stat(abspath)
         modified = datetime.datetime.utcfromtimestamp(stat_result[stat.ST_MTIME])
 
         self.set_header("Last-Modified", modified)
 
         mime_type, encoding = mimetypes.guess_type(abspath)
         if mime_type:
             self.set_header("Content-Type", mime_type)
 
         cache_time = self.get_cache_time(path, modified, mime_type)
 
         if cache_time > 0:
             self.set_header("Expires", datetime.datetime.utcnow() + \
                                        datetime.timedelta(seconds=cache_time))
             self.set_header("Cache-Control", "max-age=" + str(cache_time))
         else:
             self.set_header("Cache-Control", "public")
 
         self.set_extra_headers(path)
 
         # Check the If-Modified-Since, and don't send the result if the
         # content has not been modified
         ims_value = self.request.headers.get("If-Modified-Since")
         if ims_value is not None:
             date_tuple = email.utils.parsedate(ims_value)
             if_since = datetime.datetime(*date_tuple[:6])
             if if_since >= modified:
                 self.set_status(304)
                 return
 
         with open(abspath, "rb") as file:
             data = file.read()
             hasher = hashlib.sha1()
             hasher.update(data)
             self.set_header("Etag", '"%s"' % hasher.hexdigest())
             if include_body:
                 self.write(data)
             else:
                 assert self.request.method == "HEAD"
                 self.set_header("Content-Length", len(data))
 
     @classmethod
     def get_version(cls, settings, path):
         """Generate the version string to be used in static URLs.
 
         This method may be overridden in subclasses (but note that it
         is a class method rather than a static method).  The default
         implementation uses a hash of the file's contents.
 
         ``settings`` is the `Application.settings` dictionary and ``path``
         is the relative location of the requested asset on the filesystem.
         The returned value should be a string, or ``None`` if no version
         could be determined.
         """
         # begin subclass override:
         static_paths = settings['static_path']
         if isinstance(static_paths, basestring):
             static_paths = [static_paths]
         roots = tuple(
             os.path.abspath(os.path.expanduser(p)) + os.path.sep for p in static_paths
         )
 
         try:
             abs_path = filefind(path, roots)
         except IOError:
             app_log.error("Could not find static file %r", path)
             return None
         
         # end subclass override
         
         with cls._lock:
             hashes = cls._static_hashes
             if abs_path not in hashes:
                 try:
                     f = open(abs_path, "rb")
                     hashes[abs_path] = hashlib.md5(f.read()).hexdigest()
                     f.close()
                 except Exception:
                     app_log.error("Could not open static file %r", path)
                     hashes[abs_path] = None
             hsh = hashes.get(abs_path)
             if hsh:
                 return hsh[:5]
         return None
 
 
     def parse_url_path(self, url_path):
         """Converts a static URL path into a filesystem path.
 
         ``url_path`` is the path component of the URL with
         ``static_url_prefix`` removed.  The return value should be
         filesystem path relative to ``static_path``.
         """
         if os.path.sep != "/":
             url_path = url_path.replace("/", os.path.sep)
         return url_path
 
 

IPython/frontend/html/notebook/notebookapp.py

@@ -1,741 +1,745 b''
 # coding: utf-8
 """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
 #-----------------------------------------------------------------------------
 
 # stdlib
 import errno
 import logging
 import os
 import random
 import re
 import select
 import signal
 import socket
 import sys
 import threading
 import time
 import uuid
 import webbrowser
 
 
 # Third party
 # check for pyzmq 2.1.11
 from IPython.utils.zmqrelated import check_for_zmq
 check_for_zmq('2.1.11', 'IPython.frontend.html.notebook')
 
 import zmq
 from jinja2 import Environment, FileSystemLoader
 
 # Install the pyzmq ioloop. This has to be done before anything else from
 # tornado is imported.
 from zmq.eventloop import ioloop
 ioloop.install()
 
 # check for tornado 2.1.0
 msg = "The IPython Notebook requires tornado >= 2.1.0"
 try:
     import tornado
 except ImportError:
     raise ImportError(msg)
 try:
     version_info = tornado.version_info
 except AttributeError:
     raise ImportError(msg + ", but you have < 1.1.0")
 if version_info < (2,1,0):
     raise ImportError(msg + ", but you have %s" % tornado.version)
 
 from tornado import httpserver
 from tornado import web
 
 # Our own libraries
 from IPython.frontend.html.notebook import DEFAULT_STATIC_FILES_PATH
 from .kernelmanager import MappingKernelManager
 from .handlers import (LoginHandler, LogoutHandler,
     ProjectDashboardHandler, NewHandler, NamedNotebookHandler,
     MainKernelHandler, KernelHandler, KernelActionHandler, IOPubHandler, StdinHandler,
     ShellHandler, NotebookRootHandler, NotebookHandler, NotebookCopyHandler,
-    AuthenticatedFileHandler, MainClusterHandler, ClusterProfileHandler, 
-    ClusterActionHandler, FileFindHandler,
-    NotebookRedirectHandler, NotebookCheckpointHandler,
+    NotebookRedirectHandler, NotebookCheckpointsHandler, ModifyNotebookCheckpointsHandler,
+    AuthenticatedFileHandler, FileFindHandler,
+    MainClusterHandler, ClusterProfileHandler, ClusterActionHandler, 
 )
 from .nbmanager import NotebookManager
 from .filenbmanager import FileNotebookManager
 from .clustermanager import ClusterManager
 
 from IPython.config.application import catch_config_error, boolean_flag
 from IPython.core.application import BaseIPythonApplication
 from IPython.core.profiledir import ProfileDir
 from IPython.frontend.consoleapp import IPythonConsoleApp
 from IPython.kernel import swallow_argv
 from IPython.kernel.zmq.session import Session, default_secure
 from IPython.kernel.zmq.zmqshell import ZMQInteractiveShell
 from IPython.kernel.zmq.kernelapp import (
     kernel_flags,
     kernel_aliases,
     IPKernelApp
 )
 from IPython.utils.importstring import import_item
 from IPython.utils.localinterfaces import LOCALHOST
 from IPython.utils.traitlets import (
     Dict, Unicode, Integer, List, Enum, Bool,
     DottedObjectName
 )
 from IPython.utils import py3compat
 from IPython.utils.path import filefind
 
 #-----------------------------------------------------------------------------
 # 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+)"
 _notebook_name_regex = r"(?P<notebook_name>.+\.ipynb)"
+_checkpoint_id_regex = r"(?P<checkpoint_id>[\w-]+)"
 _profile_regex = r"(?P<profile>[^\/]+)" # there is almost no text that is invalid
 _cluster_action_regex = r"(?P<action>start|stop)"
 
 _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
 """
 
 #-----------------------------------------------------------------------------
 # Helper functions
 #-----------------------------------------------------------------------------
 
 def url_path_join(a,b):
     if a.endswith('/') and b.startswith('/'):
         return a[:-1]+b
     else:
         return a+b
 
 def random_ports(port, n):
     """Generate a list of n random ports near the given port.
 
     The first 5 ports will be sequential, and the remaining n-5 will be
     randomly selected in the range [port-2*n, port+2*n].
     """
     for i in range(min(5, n)):
         yield port + i
     for i in range(n-5):
         yield port + random.randint(-2*n, 2*n)
 
 #-----------------------------------------------------------------------------
 # The Tornado web application
 #-----------------------------------------------------------------------------
 
 class NotebookWebApplication(web.Application):
 
     def __init__(self, ipython_app, kernel_manager, notebook_manager,
                  cluster_manager, log,
                  base_project_url, settings_overrides):
         handlers = [
             (r"/", ProjectDashboardHandler),
             (r"/login", LoginHandler),
             (r"/logout", LogoutHandler),
             (r"/new", NewHandler),
             (r"/%s" % _notebook_id_regex, NamedNotebookHandler),
             (r"/%s" % _notebook_name_regex, NotebookRedirectHandler),
             (r"/%s/copy" % _notebook_id_regex, NotebookCopyHandler),
             (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"/kernels/%s/stdin" % _kernel_id_regex, StdinHandler),
             (r"/notebooks", NotebookRootHandler),
             (r"/notebooks/%s" % _notebook_id_regex, NotebookHandler),
-            (r"/notebooks/%s/checkpoint" % _notebook_id_regex, NotebookCheckpointHandler),
+            (r"/notebooks/%s/checkpoints" % _notebook_id_regex, NotebookCheckpointsHandler),
+            (r"/notebooks/%s/checkpoints/%s" % (_notebook_id_regex, _checkpoint_id_regex),
+                ModifyNotebookCheckpointsHandler
+            ),
             (r"/files/(.*)", AuthenticatedFileHandler, {'path' : notebook_manager.notebook_dir}),
             (r"/clusters", MainClusterHandler),
             (r"/clusters/%s/%s" % (_profile_regex, _cluster_action_regex), ClusterActionHandler),
             (r"/clusters/%s" % _profile_regex, ClusterProfileHandler),
         ]
 
         # Python < 2.6.5 doesn't accept unicode keys in f(**kwargs), and
         # base_project_url will always be unicode, which will in turn
         # make the patterns unicode, and ultimately result in unicode
         # keys in kwargs to handler._execute(**kwargs) in tornado.
         # This enforces that base_project_url be ascii in that situation.
         # 
         # Note that the URLs these patterns check against are escaped,
         # and thus guaranteed to be ASCII: 'héllo' is really 'h%C3%A9llo'.
         base_project_url = py3compat.unicode_to_str(base_project_url, 'ascii')
         template_path = os.path.join(os.path.dirname(__file__), "templates")
         settings = dict(
             # basics
             base_project_url=base_project_url,
             base_kernel_url=ipython_app.base_kernel_url,
             template_path=template_path,
             static_path=ipython_app.static_file_path,
             static_handler_class = FileFindHandler,
             static_url_prefix = url_path_join(base_project_url,'/static/'),
             
             # authentication
             cookie_secret=os.urandom(1024),
             login_url=url_path_join(base_project_url,'/login'),
             cookie_name='username-%s' % uuid.uuid4(),
             read_only=ipython_app.read_only,
             password=ipython_app.password,
             
             # managers
             kernel_manager=kernel_manager,
             notebook_manager=notebook_manager,
             cluster_manager=cluster_manager,
             
             # IPython stuff
             mathjax_url=ipython_app.mathjax_url,
             max_msg_size=ipython_app.max_msg_size,
             config=ipython_app.config,
             use_less=ipython_app.use_less,
             jinja2_env=Environment(loader=FileSystemLoader(template_path)),
         )
 
         # allow custom overrides for the tornado web app.
         settings.update(settings_overrides)
 
         # prepend base_project_url onto the patterns that we match
         new_handlers = []
         for handler in handlers:
             pattern = url_path_join(base_project_url, handler[0])
             new_handler = tuple([pattern] + list(handler[1:]))
             new_handlers.append(new_handler)
 
         super(NotebookWebApplication, self).__init__(new_handlers, **settings)
 
 
 
 #-----------------------------------------------------------------------------
 # Aliases and Flags
 #-----------------------------------------------------------------------------
 
 flags = dict(kernel_flags)
 flags['no-browser']=(
     {'NotebookApp' : {'open_browser' : False}},
     "Don't open the notebook in a browser after startup."
 )
 flags['no-mathjax']=(
     {'NotebookApp' : {'enable_mathjax' : False}},
     """Disable MathJax
     
     MathJax is the javascript library IPython uses to render math/LaTeX. It is
     very large, so you may want to disable it if you have a slow internet
     connection, or for offline use of the notebook.
     
     When disabled, equations etc. will appear as their untransformed TeX source.
     """
 )
 flags['read-only'] = (
     {'NotebookApp' : {'read_only' : True}},
     """Allow read-only access to notebooks.
     
     When using a password to protect the notebook server, this flag
     allows unauthenticated clients to view the notebook list, and
     individual notebooks, but not edit them, start kernels, or run
     code.
     
     If no password is set, the server will be entirely read-only.
     """
 )
 
 # Add notebook manager flags
 flags.update(boolean_flag('script', 'FileNotebookManager.save_script',
                'Auto-save a .py script everytime the .ipynb notebook is saved',
                'Do not auto-save .py scripts for every notebook'))
 
 # 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', 'no-mathjax', 'read-only', 'script', 'no-script']
 
 aliases = dict(kernel_aliases)
 
 aliases.update({
     'ip': 'NotebookApp.ip',
     'port': 'NotebookApp.port',
     'port-retries': 'NotebookApp.port_retries',
     'transport': 'KernelManager.transport',
     'keyfile': 'NotebookApp.keyfile',
     'certfile': 'NotebookApp.certfile',
     'notebook-dir': 'NotebookManager.notebook_dir',
     'browser': 'NotebookApp.browser',
 })
 
 # remove ipkernel flags that are singletons, and don't make sense in
 # multi-kernel evironment:
 aliases.pop('f', None)
 
 notebook_aliases = [u'port', u'port-retries', u'ip', u'keyfile', u'certfile',
                     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 = IPythonConsoleApp.classes + [MappingKernelManager, NotebookManager,
         FileNotebookManager]
     flags = Dict(flags)
     aliases = Dict(aliases)
 
     kernel_argv = List(Unicode)
 
     max_msg_size = Integer(65536, config=True, help="""
         The max raw message size accepted from the browser
         over a WebSocket connection.
     """)
 
     def _log_level_default(self):
         return logging.INFO
 
     def _log_format_default(self):
         """override default log format to include time"""
         return u"%(asctime)s.%(msecs).03d [%(name)s] %(message)s"
 
     # create requested profiles by default, if they don't exist:
     auto_create = Bool(True)
 
     # file to be opened in the notebook server
     file_to_run = Unicode('')
 
     # 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 = Integer(8888, config=True,
         help="The port the notebook server will listen on."
     )
     port_retries = Integer(50, config=True,
         help="The number of additional ports to try if the specified port is not available."
     )
 
     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="""Hashed password to use for web authentication.
 
                       To generate, type in a python/IPython shell:
 
                         from IPython.lib import passwd; passwd()
 
                       The string should be of the form type:salt:hashed-password.
                       """
     )
 
     open_browser = Bool(True, config=True,
                         help="""Whether to open in a browser after starting.
                         The specific browser used is platform dependent and
                         determined by the python standard library `webbrowser`
                         module, unless it is overridden using the --browser
                         (NotebookApp.browser) configuration option.
                         """)
 
     browser = Unicode(u'', config=True,
                       help="""Specify what command to use to invoke a web
                       browser when opening the notebook. If not specified, the
                       default browser will be determined by the `webbrowser`
                       standard library module, which allows setting of the
                       BROWSER environment variable to override it.
                       """)
     
     read_only = Bool(False, config=True,
         help="Whether to prevent editing/execution of notebooks."
     )
 
     use_less = Bool(False, config=True,
                        help="""Wether to use Browser Side less-css parsing
                        instead of compiled css version in templates that allows
                        it. This is mainly convenient when working on the less
                        file to avoid a build step, or if user want to overwrite
                        some of the less variables without having to recompile
                        everything.
                        
                        You will need to install the less.js component in the static directory
                        either in the source tree or in your profile folder.
                        """)
 
     webapp_settings = Dict(config=True,
             help="Supply overrides for the tornado.web.Application that the "
                  "IPython notebook uses.")
     
     enable_mathjax = Bool(True, config=True,
         help="""Whether to enable MathJax for typesetting math/TeX
 
         MathJax is the javascript library IPython uses to render math/LaTeX. It is
         very large, so you may want to disable it if you have a slow internet
         connection, or for offline use of the notebook.
 
         When disabled, equations etc. will appear as their untransformed TeX source.
         """
     )
     def _enable_mathjax_changed(self, name, old, new):
         """set mathjax url to empty if mathjax is disabled"""
         if not new:
             self.mathjax_url = u''
 
     base_project_url = Unicode('/', config=True,
                                help='''The base URL for the notebook server.
 
                                Leading and trailing slashes can be omitted,
                                and will automatically be added.
                                ''')
     def _base_project_url_changed(self, name, old, new):
         if not new.startswith('/'):
             self.base_project_url = '/'+new
         elif not new.endswith('/'):
             self.base_project_url = new+'/'
 
     base_kernel_url = Unicode('/', config=True,
                                help='''The base URL for the kernel server
 
                                Leading and trailing slashes can be omitted,
                                and will automatically be added.
                                ''')
     def _base_kernel_url_changed(self, name, old, new):
         if not new.startswith('/'):
             self.base_kernel_url = '/'+new
         elif not new.endswith('/'):
             self.base_kernel_url = new+'/'
 
     websocket_host = Unicode("", config=True,
         help="""The hostname for the websocket server."""
     )
 
     extra_static_paths = List(Unicode, config=True,
         help="""Extra paths to search for serving static files.
         
         This allows adding javascript/css to be available from the notebook server machine,
         or overriding individual files in the IPython"""
     )
     def _extra_static_paths_default(self):
         return [os.path.join(self.profile_dir.location, 'static')]
     
     @property
     def static_file_path(self):
         """return extra paths + the default location"""
         return self.extra_static_paths + [DEFAULT_STATIC_FILES_PATH]
 
     mathjax_url = Unicode("", config=True,
         help="""The url for MathJax.js."""
     )
     def _mathjax_url_default(self):
         if not self.enable_mathjax:
             return u''
         static_url_prefix = self.webapp_settings.get("static_url_prefix",
                                                      "/static/")
         try:
             mathjax = filefind(os.path.join('mathjax', 'MathJax.js'), self.static_file_path)
         except IOError:
             if self.certfile:
                 # HTTPS: load from Rackspace CDN, because SSL certificate requires it
                 base = u"https://c328740.ssl.cf1.rackcdn.com"
             else:
                 base = u"http://cdn.mathjax.org"
             
             url = base + u"/mathjax/latest/MathJax.js"
             self.log.info("Using MathJax from CDN: %s", url)
             return url
         else:
             self.log.info("Using local MathJax from %s" % mathjax)
             return static_url_prefix+u"mathjax/MathJax.js"
     
     def _mathjax_url_changed(self, name, old, new):
         if new and not self.enable_mathjax:
             # enable_mathjax=False overrides mathjax_url
             self.mathjax_url = u''
         else:
             self.log.info("Using MathJax: %s", new)
 
     notebook_manager_class = DottedObjectName('IPython.frontend.html.notebook.filenbmanager.FileNotebookManager',
         config=True,
         help='The notebook manager class to use.')
 
     trust_xheaders = Bool(False, config=True,
         help=("Whether to trust or not X-Scheme/X-Forwarded-Proto and X-Real-Ip/X-Forwarded-For headers"
               "sent by the upstream reverse proxy. Neccesary if the proxy handles SSL")
     )
 
     def parse_command_line(self, argv=None):
         super(NotebookApp, self).parse_command_line(argv)
         if argv is None:
             argv = sys.argv[1:]
 
         # Scrub frontend-specific flags
         self.kernel_argv = swallow_argv(argv, notebook_aliases, notebook_flags)
         # Kernel should inherit default config file from frontend
         self.kernel_argv.append("--IPKernelApp.parent_appname='%s'" % self.name)
 
         if self.extra_args:
             f = os.path.abspath(self.extra_args[0])
             if os.path.isdir(f):
                 nbdir = f
             else:
                 self.file_to_run = f
                 nbdir = os.path.dirname(f)
             self.config.NotebookManager.notebook_dir = nbdir
 
     def init_configurables(self):
         # force Session default to be secure
         default_secure(self.config)
         self.kernel_manager = MappingKernelManager(
             config=self.config, log=self.log, kernel_argv=self.kernel_argv,
             connection_dir = self.profile_dir.security_dir,
         )
         kls = import_item(self.notebook_manager_class)
         self.notebook_manager = kls(config=self.config, log=self.log)
         self.notebook_manager.load_notebook_names()
         self.cluster_manager = ClusterManager(config=self.config, log=self.log)
         self.cluster_manager.update_profiles()
 
     def init_logging(self):
         # 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
         
         # set the date format
         formatter = logging.Formatter(self.log_format, datefmt="%Y-%m-%d %H:%M:%S")
         self.log.handlers[0].setFormatter(formatter)
         
         # hook up tornado 3's loggers to our app handlers
         for name in ('access', 'application', 'general'):
             logging.getLogger('tornado.%s' % name).handlers = self.log.handlers
     
     def init_webapp(self):
         """initialize tornado webapp and httpserver"""
         self.web_app = NotebookWebApplication(
             self, self.kernel_manager, self.notebook_manager, 
             self.cluster_manager, self.log,
             self.base_project_url, self.webapp_settings
         )
         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,
                                                  xheaders=self.trust_xheaders)
         if not self.ip:
             warning = "WARNING: The notebook server is listening on all IP addresses"
             if ssl_options is None:
                 self.log.critical(warning + " and not using encryption. This"
                     "is not recommended.")
             if not self.password and not self.read_only:
                 self.log.critical(warning + "and not using authentication."
                     "This is highly insecure and not recommended.")
         success = None
         for port in random_ports(self.port, self.port_retries+1):
             try:
                 self.http_server.listen(port, self.ip)
             except socket.error as e:
                 # XXX: remove the e.errno == -9 block when we require
                 # tornado >= 3.0
                 if e.errno == -9 and tornado.version_info[0] < 3:
                     # The flags passed to socket.getaddrinfo from
                     # tornado.netutils.bind_sockets can cause "gaierror:
                     # [Errno -9] Address family for hostname not supported"
                     # when the interface is not associated, for example.
                     # Changing the flags to exclude socket.AI_ADDRCONFIG does
                     # not cause this error, but the only way to do this is to
                     # monkeypatch socket to remove the AI_ADDRCONFIG attribute
                     saved_AI_ADDRCONFIG = socket.AI_ADDRCONFIG
                     self.log.warn('Monkeypatching socket to fix tornado bug')
                     del(socket.AI_ADDRCONFIG)
                     try:
                         # retry the tornado call without AI_ADDRCONFIG flags
                         self.http_server.listen(port, self.ip)
                     except socket.error as e2:
                         e = e2
                     else:
                         self.port = port
                         success = True
                         break
                     # restore the monekypatch
                     socket.AI_ADDRCONFIG = saved_AI_ADDRCONFIG
                 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
                 success = True
                 break
         if not success:
             self.log.critical('ERROR: the notebook server could not be started because '
                               'no available port could be found.')
             self.exit(1)
     
     def init_signal(self):
         if not sys.platform.startswith('win'):
             signal.signal(signal.SIGINT, self._handle_sigint)
         signal.signal(signal.SIGTERM, self._signal_stop)
         if hasattr(signal, 'SIGUSR1'):
             # Windows doesn't support SIGUSR1
             signal.signal(signal.SIGUSR1, self._signal_info)
         if hasattr(signal, 'SIGINFO'):
             # only on BSD-based systems
             signal.signal(signal.SIGINFO, self._signal_info)
     
     def _handle_sigint(self, sig, frame):
         """SIGINT handler spawns confirmation dialog"""
         # register more forceful signal handler for ^C^C case
         signal.signal(signal.SIGINT, self._signal_stop)
         # request confirmation dialog in bg thread, to avoid
         # blocking the App
         thread = threading.Thread(target=self._confirm_exit)
         thread.daemon = True
         thread.start()
     
     def _restore_sigint_handler(self):
         """callback for restoring original SIGINT handler"""
         signal.signal(signal.SIGINT, self._handle_sigint)
     
     def _confirm_exit(self):
         """confirm shutdown on ^C
         
         A second ^C, or answering 'y' within 5s will cause shutdown,
         otherwise original SIGINT handler will be restored.
         
         This doesn't work on Windows.
         """
         # FIXME: remove this delay when pyzmq dependency is >= 2.1.11
         time.sleep(0.1)
         info = self.log.info
         info('interrupted')
         print self.notebook_info()
         sys.stdout.write("Shutdown this notebook server (y/[n])? ")
         sys.stdout.flush()
         r,w,x = select.select([sys.stdin], [], [], 5)
         if r:
             line = sys.stdin.readline()
             if line.lower().startswith('y'):
                 self.log.critical("Shutdown confirmed")
                 ioloop.IOLoop.instance().stop()
                 return
         else:
             print "No answer for 5s:",
         print "resuming operation..."
         # no answer, or answer is no:
         # set it back to original SIGINT handler
         # use IOLoop.add_callback because signal.signal must be called
         # from main thread
         ioloop.IOLoop.instance().add_callback(self._restore_sigint_handler)
     
     def _signal_stop(self, sig, frame):
         self.log.critical("received signal %s, stopping", sig)
         ioloop.IOLoop.instance().stop()
 
     def _signal_info(self, sig, frame):
         print self.notebook_info()
     
     @catch_config_error
     def initialize(self, argv=None):
         self.init_logging()
         super(NotebookApp, self).initialize(argv)
         self.init_configurables()
         self.init_webapp()
         self.init_signal()
 
     def cleanup_kernels(self):
         """Shutdown all kernels.
         
         The kernels will shutdown themselves when this process no longer exists,
         but explicit shutdown allows the KernelManagers to cleanup the connection files.
         """
         self.log.info('Shutting down kernels')
         self.kernel_manager.shutdown_all()
 
     def notebook_info(self):
         "Return the current working directory and the server url information"
         mgr_info = self.notebook_manager.info_string() + "\n"
         return mgr_info +"The IPython Notebook is running at: %s" % self._url
 
     def start(self):
         """ Start the IPython Notebook server app, after initialization
         
         This method takes no arguments so all configuration and initialization
         must be done prior to calling this method."""
         ip = self.ip if self.ip else '[all ip addresses on your system]'
         proto = 'https' if self.certfile else 'http'
         info = self.log.info
         self._url = "%s://%s:%i%s" % (proto, ip, self.port,
                                       self.base_project_url)
         for line in self.notebook_info().split("\n"):
             info(line)
         info("Use Control-C to stop this server and shut down all kernels.")
 
         if self.open_browser or self.file_to_run:
             ip = self.ip or LOCALHOST
             try:
                 browser = webbrowser.get(self.browser or None)
             except webbrowser.Error as e:
                 self.log.warn('No web browser found: %s.' % e)
                 browser = None
 
             if self.file_to_run:
                 name, _ = os.path.splitext(os.path.basename(self.file_to_run))
                 url = self.notebook_manager.rev_mapping.get(name, '')
             else:
                 url = ''
             if browser:
                 b = lambda : browser.open("%s://%s:%i%s%s" % (proto, ip,
                     self.port, self.base_project_url, url), new=2)
                 threading.Thread(target=b).start()
         try:
             ioloop.IOLoop.instance().start()
         except KeyboardInterrupt:
             info("Interrupted...")
         finally:
             self.cleanup_kernels()
     
 
 #-----------------------------------------------------------------------------
 # Main entry point
 #-----------------------------------------------------------------------------
 
 def launch_new_instance():
     app = NotebookApp.instance()
     app.initialize()
     app.start()