Various minor fixes from review

IPython/html/base/handlers.py

@@ -1,482 +1,481 b''
 """Base Tornado handlers for the notebook server."""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import functools
 import json
 import logging
 import os
 import re
 import sys
 import traceback
 try:
     # py3
     from http.client import responses
 except ImportError:
     from httplib import responses
 
 from jinja2 import TemplateNotFound
 from tornado import web
 
 try:
     from tornado.log import app_log
 except ImportError:
     app_log = logging.getLogger()
 
 import IPython
 from IPython.utils.sysinfo import get_sys_info
 
 from IPython.config import Application
 from IPython.utils.path import filefind
 from IPython.utils.py3compat import string_types
 from IPython.html.utils import is_hidden, url_path_join, url_escape
 
 #-----------------------------------------------------------------------------
 # Top-level handlers
 #-----------------------------------------------------------------------------
 non_alphanum = re.compile(r'[^A-Za-z0-9]')
 
 sys_info = json.dumps(get_sys_info())
 
 class AuthenticatedHandler(web.RequestHandler):
     """A RequestHandler with an authenticated user."""
 
     def set_default_headers(self):
         headers = self.settings.get('headers', {})
 
         if "X-Frame-Options" not in headers:
             headers["X-Frame-Options"] = "SAMEORIGIN"
 
         for header_name,value in headers.items() :
             try:
                 self.set_header(header_name, value)
             except Exception:
                 # tornado raise Exception (not a subclass)
                 # if method is unsupported (websocket and Access-Control-Allow-Origin
                 # for example, so just ignore)
                 pass
     
     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.login_available:
                 user_id = 'anonymous'
         return user_id
 
     @property
     def cookie_name(self):
         default_cookie_name = non_alphanum.sub('-', 'username-{}'.format(
             self.request.host
         ))
         return self.settings.get('cookie_name', default_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', ''))
 
 
 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
     
     #---------------------------------------------------------------
     # URLs
     #---------------------------------------------------------------
     
     @property
     def mathjax_url(self):
         return self.settings.get('mathjax_url', '')
     
     @property
     def base_url(self):
         return self.settings.get('base_url', '/')
 
     @property
     def ws_url(self):
         return self.settings.get('websocket_url', '')
 
     @property
     def contents_js_source(self):
         self.log.debug("Using contents: %s", self.settings.get('contents_js_source',
             'services/contents'))
-        return self.settings.get('contents_js_source',
-            'services/contents')
+        return self.settings.get('contents_js_source', 'services/contents')
     
     #---------------------------------------------------------------
     # Manager objects
     #---------------------------------------------------------------
     
     @property
     def kernel_manager(self):
         return self.settings['kernel_manager']
 
     @property
     def contents_manager(self):
         return self.settings['contents_manager']
     
     @property
     def cluster_manager(self):
         return self.settings['cluster_manager']
     
     @property
     def session_manager(self):
         return self.settings['session_manager']
     
     @property
     def kernel_spec_manager(self):
         return self.settings['kernel_spec_manager']
 
     #---------------------------------------------------------------
     # CORS
     #---------------------------------------------------------------
     
     @property
     def allow_origin(self):
         """Normal Access-Control-Allow-Origin"""
         return self.settings.get('allow_origin', '')
     
     @property
     def allow_origin_pat(self):
         """Regular expression version of allow_origin"""
         return self.settings.get('allow_origin_pat', None)
     
     @property
     def allow_credentials(self):
         """Whether to set Access-Control-Allow-Credentials"""
         return self.settings.get('allow_credentials', False)
     
     def set_default_headers(self):
         """Add CORS headers, if defined"""
         super(IPythonHandler, self).set_default_headers()
         if self.allow_origin:
             self.set_header("Access-Control-Allow-Origin", self.allow_origin)
         elif self.allow_origin_pat:
             origin = self.get_origin()
             if origin and self.allow_origin_pat.match(origin):
                 self.set_header("Access-Control-Allow-Origin", origin)
         if self.allow_credentials:
             self.set_header("Access-Control-Allow-Credentials", 'true')
     
     def get_origin(self):
         # Handle WebSocket Origin naming convention differences
         # 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 "Origin" in self.request.headers:
             origin = self.request.headers.get("Origin")
         else:
             origin = self.request.headers.get("Sec-Websocket-Origin", None)
         return origin
     
     #---------------------------------------------------------------
     # 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_url=self.base_url,
             ws_url=self.ws_url,
             logged_in=self.logged_in,
             login_available=self.login_available,
             static_url=self.static_url,
             sys_info=sys_info,
             contents_js_source=self.contents_js_source,
         )
     
     def get_json_body(self):
         """Return the body of the request as JSON data."""
         if not self.request.body:
             return None
         # Do we need to call body.decode('utf-8') here?
         body = self.request.body.strip().decode(u'utf-8')
         try:
             model = json.loads(body)
         except Exception:
             self.log.debug("Bad JSON: %r", body)
             self.log.error("Couldn't parse JSON", exc_info=True)
             raise web.HTTPError(400, u'Invalid JSON in body of request')
         return model
 
     def write_error(self, status_code, **kwargs):
         """render custom error pages"""
         exc_info = kwargs.get('exc_info')
         message = ''
         status_message = responses.get(status_code, 'Unknown HTTP Error')
         if exc_info:
             exception = exc_info[1]
             # get the custom message, if defined
             try:
                 message = exception.log_message % exception.args
             except Exception:
                 pass
             
             # construct the custom reason, if defined
             reason = getattr(exception, 'reason', '')
             if reason:
                 status_message = reason
         
         # build template namespace
         ns = dict(
             status_code=status_code,
             status_message=status_message,
             message=message,
             exception=exception,
         )
         
         self.set_header('Content-Type', 'text/html')
         # render the template
         try:
             html = self.render_template('%s.html' % status_code, **ns)
         except TemplateNotFound:
             self.log.debug("No template for %d", status_code)
             html = self.render_template('error.html', **ns)
         
         self.write(html)
         
 
 
 class Template404(IPythonHandler):
     """Render our 404 template"""
     def prepare(self):
         raise web.HTTPError(404)
 
 
 class AuthenticatedFileHandler(IPythonHandler, web.StaticFileHandler):
     """static files should only be accessible when logged in"""
 
     @web.authenticated
     def get(self, path):
         if os.path.splitext(path)[1] == '.ipynb':
             name = os.path.basename(path)
             self.set_header('Content-Type', 'application/json')
             self.set_header('Content-Disposition','attachment; filename="%s"' % name)
         
         return web.StaticFileHandler.get(self, path)
     
     def compute_etag(self):
         return None
     
     def validate_absolute_path(self, root, absolute_path):
         """Validate and return the absolute path.
         
         Requires tornado 3.1
         
         Adding to tornado's own handling, forbids the serving of hidden files.
         """
         abs_path = super(AuthenticatedFileHandler, self).validate_absolute_path(root, absolute_path)
         abs_root = os.path.abspath(root)
         if is_hidden(abs_path, abs_root):
             self.log.info("Refusing to serve hidden file, via 404 Error")
             raise web.HTTPError(404)
         return abs_path
 
 
 def json_errors(method):
     """Decorate methods with this to return GitHub style JSON errors.
     
     This should be used on any JSON API on any handler method that can raise HTTPErrors.
     
     This will grab the latest HTTPError exception using sys.exc_info
     and then:
     
     1. Set the HTTP status code based on the HTTPError
     2. Create and return a JSON body with a message field describing
        the error in a human readable form.
     """
     @functools.wraps(method)
     def wrapper(self, *args, **kwargs):
         try:
             result = method(self, *args, **kwargs)
         except web.HTTPError as e:
             status = e.status_code
             message = e.log_message
             self.log.warn(message)
             self.set_status(e.status_code)
             self.finish(json.dumps(dict(message=message)))
         except Exception:
             self.log.error("Unhandled error in API request", exc_info=True)
             status = 500
             message = "Unknown server error"
             t, value, tb = sys.exc_info()
             self.set_status(status)
             tb_text = ''.join(traceback.format_exception(t, value, tb))
             reply = dict(message=message, traceback=tb_text)
             self.finish(json.dumps(reply))
         else:
             return result
     return wrapper
 
 
 
 #-----------------------------------------------------------------------------
 # File handler
 #-----------------------------------------------------------------------------
 
 # to minimize subclass changes:
 HTTPError = web.HTTPError
 
 class FileFindHandler(web.StaticFileHandler):
     """subclass of StaticFileHandler for serving files from a search path"""
     
     # cache search results, don't search for files more than once
     _static_paths = {}
     
     def initialize(self, path, default_filename=None):
         if isinstance(path, string_types):
             path = [path]
         
         self.root = tuple(
             os.path.abspath(os.path.expanduser(p)) + os.sep for p in path
         )
         self.default_filename = default_filename
     
     def compute_etag(self):
         return None
     
     @classmethod
     def get_absolute_path(cls, roots, path):
         """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:
                 # IOError means not found
                 return ''
             
             cls._static_paths[path] = abspath
             return abspath
     
     def validate_absolute_path(self, root, absolute_path):
         """check if the file should be served (raises 404, 403, etc.)"""
         if absolute_path == '':
             raise web.HTTPError(404)
         
         for root in self.root:
             if (absolute_path + os.sep).startswith(root):
                 break
         
         return super(FileFindHandler, self).validate_absolute_path(root, absolute_path)
 
 
 class ApiVersionHandler(IPythonHandler):
 
     @json_errors
     def get(self):
         # not authenticated, so give as few info as possible
         self.finish(json.dumps({"version":IPython.__version__}))
 
 class TrailingSlashHandler(web.RequestHandler):
     """Simple redirect handler that strips trailing slashes
     
     This should be the first, highest priority handler.
     """
     
     SUPPORTED_METHODS = ['GET']
     
     def get(self):
         self.redirect(self.request.uri.rstrip('/'))
 
 
 class FilesRedirectHandler(IPythonHandler):
     """Handler for redirecting relative URLs to the /files/ handler"""
     def get(self, path=''):
         cm = self.contents_manager
         if cm.path_exists(path):
             # it's a *directory*, redirect to /tree
             url = url_path_join(self.base_url, 'tree', path)
         else:
             orig_path = path
             # otherwise, redirect to /files
             parts = path.split('/')
             path = '/'.join(parts[:-1])
             name = parts[-1]
 
             if not cm.file_exists(name=name, path=path) and 'files' in parts:
                 # redirect without files/ iff it would 404
                 # this preserves pre-2.0-style 'files/' links
                 self.log.warn("Deprecated files/ URL: %s", orig_path)
                 parts.remove('files')
                 path = '/'.join(parts[:-1])
 
             if not cm.file_exists(name=name, path=path):
                 raise web.HTTPError(404)
 
             url = url_path_join(self.base_url, 'files', path, name)
         url = url_escape(url)
         self.log.debug("Redirecting %s to %s", self.request.path, url)
         self.redirect(url)
 
 
 #-----------------------------------------------------------------------------
 # URL pattern fragments for re-use
 #-----------------------------------------------------------------------------
 
 path_regex = r"(?P<path>(?:/.*)*)"
 notebook_name_regex = r"(?P<name>[^/]+\.ipynb)"
 notebook_path_regex = "%s/%s" % (path_regex, notebook_name_regex)
 file_name_regex = r"(?P<name>[^/]+)"
 file_path_regex = "%s/%s" % (path_regex, file_name_regex)
 
 #-----------------------------------------------------------------------------
 # URL to handler mappings
 #-----------------------------------------------------------------------------
 
 
 default_handlers = [
     (r".*/", TrailingSlashHandler),
     (r"api", ApiVersionHandler)
 ]

IPython/html/static/notebook/js/notebook.js

@@ -1,2515 +1,2515 b''
 // Copyright (c) IPython Development Team.
 // Distributed under the terms of the Modified BSD License.
 
 define([
     'base/js/namespace',
     'jquery',
     'base/js/utils',
     'base/js/dialog',
     'notebook/js/textcell',
     'notebook/js/codecell',
     'services/sessions/session',
     'notebook/js/celltoolbar',
     'components/marked/lib/marked',
     'highlight',
     'notebook/js/mathjaxutils',
     'base/js/keyboard',
     'notebook/js/tooltip',
     'notebook/js/celltoolbarpresets/default',
     'notebook/js/celltoolbarpresets/rawcell',
     'notebook/js/celltoolbarpresets/slideshow',
     'notebook/js/scrollmanager'
 ], function (
     IPython, 
     $, 
     utils, 
     dialog, 
     textcell, 
     codecell, 
     session, 
     celltoolbar, 
     marked,
     hljs,
     mathjaxutils,
     keyboard,
     tooltip,
     default_celltoolbar,
     rawcell_celltoolbar,
     slideshow_celltoolbar,
     scrollmanager
     ) {
 
     var Notebook = function (selector, options) {
         // Constructor
         //
         // A notebook contains and manages cells.
         //
         // Parameters:
         //  selector: string
         //  options: dictionary
         //      Dictionary of keyword arguments.
         //          events: $(Events) instance
         //          keyboard_manager: KeyboardManager instance
         //          contents: Contents instance
         //          save_widget: SaveWidget instance
         //          config: dictionary
         //          base_url : string
         //          notebook_path : string
         //          notebook_name : string
         this.config = utils.mergeopt(Notebook, options.config);
         this.base_url = options.base_url;
         this.notebook_path = options.notebook_path;
         this.notebook_name = options.notebook_name;
         this.events = options.events;
         this.keyboard_manager = options.keyboard_manager;
         this.contents = options.contents;
         this.save_widget = options.save_widget;
         this.tooltip = new tooltip.Tooltip(this.events);
         this.ws_url = options.ws_url;
         this._session_starting = false;
         this.default_cell_type = this.config.default_cell_type || 'code';
 
         //  Create default scroll manager.
         this.scroll_manager = new scrollmanager.ScrollManager(this);
 
         // TODO: This code smells (and the other `= this` line a couple lines down)
         // We need a better way to deal with circular instance references.
         this.keyboard_manager.notebook = this;
         this.save_widget.notebook = this;
         
         mathjaxutils.init();
 
         if (marked) {
             marked.setOptions({
                 gfm : true,
                 tables: true,
                 langPrefix: "language-",
                 highlight: function(code, lang) {
                     if (!lang) {
                         // no language, no highlight
                         return code;
                     }
                     var highlighted;
                     try {
                         highlighted = hljs.highlight(lang, code, false);
                     } catch(err) {
                         highlighted = hljs.highlightAuto(code);
                     }
                     return highlighted.value;
                 }
             });
         }
 
         this.element = $(selector);
         this.element.scroll();
         this.element.data("notebook", this);
         this.next_prompt_number = 1;
         this.session = null;
         this.kernel = null;
         this.clipboard = null;
         this.undelete_backup = null;
         this.undelete_index = null;
         this.undelete_below = false;
         this.paste_enabled = false;
         // It is important to start out in command mode to match the intial mode
         // of the KeyboardManager.
         this.mode = 'command';
         this.set_dirty(false);
         this.metadata = {};
         this._checkpoint_after_save = false;
         this.last_checkpoint = null;
         this.checkpoints = [];
         this.autosave_interval = 0;
         this.autosave_timer = null;
         // autosave *at most* every two minutes
         this.minimum_autosave_interval = 120000;
         this.notebook_name_blacklist_re = /[\/\\:]/;
         this.nbformat = 4; // Increment this when changing the nbformat
         this.nbformat_minor = 0; // Increment this when changing the nbformat
         this.codemirror_mode = 'ipython';
         this.create_elements();
         this.bind_events();
         this.save_notebook = function() { // don't allow save until notebook_loaded
             this.save_notebook_error(null, null, "Load failed, save is disabled");
         };
 
         // Trigger cell toolbar registration.
         default_celltoolbar.register(this);
         rawcell_celltoolbar.register(this);
         slideshow_celltoolbar.register(this);
     };
 
     Notebook.options_default = {
         // can be any cell type, or the special values of
         // 'above', 'below', or 'selected' to get the value from another cell.
         Notebook: {
             default_cell_type: 'code',
         }
     };
 
 
     /**
      * Create an HTML and CSS representation of the notebook.
      * 
      * @method create_elements
      */
     Notebook.prototype.create_elements = function () {
         var that = this;
         this.element.attr('tabindex','-1');
         this.container = $("<div/>").addClass("container").attr("id", "notebook-container");
         // We add this end_space div to the end of the notebook div to:
         // i) provide a margin between the last cell and the end of the notebook
         // ii) to prevent the div from scrolling up when the last cell is being
         // edited, but is too low on the page, which browsers will do automatically.
         var end_space = $('<div/>').addClass('end_space');
         end_space.dblclick(function (e) {
             var ncells = that.ncells();
             that.insert_cell_below('code',ncells-1);
         });
         this.element.append(this.container);
         this.container.append(end_space);
     };
 
     /**
      * Bind JavaScript events: key presses and custom IPython events.
      * 
      * @method bind_events
      */
     Notebook.prototype.bind_events = function () {
         var that = this;
 
         this.events.on('set_next_input.Notebook', function (event, data) {
             var index = that.find_cell_index(data.cell);
             var new_cell = that.insert_cell_below('code',index);
             new_cell.set_text(data.text);
             that.dirty = true;
         });
 
         this.events.on('set_dirty.Notebook', function (event, data) {
             that.dirty = data.value;
         });
 
         this.events.on('trust_changed.Notebook', function (event, trusted) {
             that.trusted = trusted;
         });
 
         this.events.on('select.Cell', function (event, data) {
             var index = that.find_cell_index(data.cell);
             that.select(index);
         });
 
         this.events.on('edit_mode.Cell', function (event, data) {
             that.handle_edit_mode(data.cell);
         });
 
         this.events.on('command_mode.Cell', function (event, data) {
             that.handle_command_mode(data.cell);
         });
         
         this.events.on('spec_changed.Kernel', function(event, data) {
             that.metadata.kernelspec = 
                 {name: data.name, display_name: data.display_name};
         });
 
         this.events.on('kernel_ready.Kernel', function(event, data) {
             var kinfo = data.kernel.info_reply
             var langinfo = kinfo.language_info || {};
             if (!langinfo.name)  langinfo.name = kinfo.language;
                 
             that.metadata.language_info = langinfo;
             // Mode 'null' should be plain, unhighlighted text.
             var cm_mode = langinfo.codemirror_mode || langinfo.language || 'null'
             that.set_codemirror_mode(cm_mode);
         });
 
         var collapse_time = function (time) {
             var app_height = $('#ipython-main-app').height(); // content height
             var splitter_height = $('div#pager_splitter').outerHeight(true);
             var new_height = app_height - splitter_height;
             that.element.animate({height : new_height + 'px'}, time);
         };
 
         this.element.bind('collapse_pager', function (event, extrap) {
             var time = (extrap !== undefined) ? ((extrap.duration !== undefined ) ? extrap.duration : 'fast') : 'fast';
             collapse_time(time);
         });
 
         var expand_time = function (time) {
             var app_height = $('#ipython-main-app').height(); // content height
             var splitter_height = $('div#pager_splitter').outerHeight(true);
             var pager_height = $('div#pager').outerHeight(true);
             var new_height = app_height - pager_height - splitter_height;
             that.element.animate({height : new_height + 'px'}, time);
         };
 
         this.element.bind('expand_pager', function (event, extrap) {
             var time = (extrap !== undefined) ? ((extrap.duration !== undefined ) ? extrap.duration : 'fast') : 'fast';
             expand_time(time);
         });
         
         // Firefox 22 broke $(window).on("beforeunload")
         // I'm not sure why or how.
         window.onbeforeunload = function (e) {
             // TODO: Make killing the kernel configurable.
             var kill_kernel = false;
             if (kill_kernel) {
                 that.session.delete();
             }
             // if we are autosaving, trigger an autosave on nav-away.
             // still warn, because if we don't the autosave may fail.
             if (that.dirty) {
                 if ( that.autosave_interval ) {
                     // schedule autosave in a timeout
                     // this gives you a chance to forcefully discard changes
                     // by reloading the page if you *really* want to.
                     // the timer doesn't start until you *dismiss* the dialog.
                     setTimeout(function () {
                         if (that.dirty) {
                             that.save_notebook();
                         }
                     }, 1000);
                     return "Autosave in progress, latest changes may be lost.";
                 } else {
                     return "Unsaved changes will be lost.";
                 }
             }
             // Null is the *only* return value that will make the browser not
             // pop up the "don't leave" dialog.
             return null;
         };
     };
 
     /**
      * Set the dirty flag, and trigger the set_dirty.Notebook event
      * 
      * @method set_dirty
      */
     Notebook.prototype.set_dirty = function (value) {
         if (value === undefined) {
             value = true;
         }
         if (this.dirty == value) {
             return;
         }
         this.events.trigger('set_dirty.Notebook', {value: value});
     };
 
     /**
      * Scroll the top of the page to a given cell.
      * 
      * @method scroll_to_cell
      * @param {Number} cell_number An index of the cell to view
      * @param {Number} time Animation time in milliseconds
      * @return {Number} Pixel offset from the top of the container
      */
     Notebook.prototype.scroll_to_cell = function (cell_number, time) {
         var cells = this.get_cells();
         time = time || 0;
         cell_number = Math.min(cells.length-1,cell_number);
         cell_number = Math.max(0             ,cell_number);
         var scroll_value = cells[cell_number].element.position().top-cells[0].element.position().top ;
         this.element.animate({scrollTop:scroll_value}, time);
         return scroll_value;
     };
 
     /**
      * Scroll to the bottom of the page.
      * 
      * @method scroll_to_bottom
      */
     Notebook.prototype.scroll_to_bottom = function () {
         this.element.animate({scrollTop:this.element.get(0).scrollHeight}, 0);
     };
 
     /**
      * Scroll to the top of the page.
      * 
      * @method scroll_to_top
      */
     Notebook.prototype.scroll_to_top = function () {
         this.element.animate({scrollTop:0}, 0);
     };
 
     // Edit Notebook metadata
 
     Notebook.prototype.edit_metadata = function () {
         var that = this;
         dialog.edit_metadata({
             md: this.metadata, 
             callback: function (md) {
                 that.metadata = md;
             },
             name: 'Notebook',
             notebook: this,
             keyboard_manager: this.keyboard_manager});
     };
 
     // Cell indexing, retrieval, etc.
 
     /**
      * Get all cell elements in the notebook.
      * 
      * @method get_cell_elements
      * @return {jQuery} A selector of all cell elements
      */
     Notebook.prototype.get_cell_elements = function () {
         return this.container.children("div.cell");
     };
 
     /**
      * Get a particular cell element.
      * 
      * @method get_cell_element
      * @param {Number} index An index of a cell to select
      * @return {jQuery} A selector of the given cell.
      */
     Notebook.prototype.get_cell_element = function (index) {
         var result = null;
         var e = this.get_cell_elements().eq(index);
         if (e.length !== 0) {
             result = e;
         }
         return result;
     };
 
     /**
      * Try to get a particular cell by msg_id.
      * 
      * @method get_msg_cell
      * @param {String} msg_id A message UUID
      * @return {Cell} Cell or null if no cell was found.
      */
     Notebook.prototype.get_msg_cell = function (msg_id) {
         return codecell.CodeCell.msg_cells[msg_id] || null;
     };
 
     /**
      * Count the cells in this notebook.
      * 
      * @method ncells
      * @return {Number} The number of cells in this notebook
      */
     Notebook.prototype.ncells = function () {
         return this.get_cell_elements().length;
     };
 
     /**
      * Get all Cell objects in this notebook.
      * 
      * @method get_cells
      * @return {Array} This notebook's Cell objects
      */
     // TODO: we are often calling cells as cells()[i], which we should optimize
     // to cells(i) or a new method.
     Notebook.prototype.get_cells = function () {
         return this.get_cell_elements().toArray().map(function (e) {
             return $(e).data("cell");
         });
     };
 
     /**
      * Get a Cell object from this notebook.
      * 
      * @method get_cell
      * @param {Number} index An index of a cell to retrieve
      * @return {Cell} Cell or null if no cell was found.
      */
     Notebook.prototype.get_cell = function (index) {
         var result = null;
         var ce = this.get_cell_element(index);
         if (ce !== null) {
             result = ce.data('cell');
         }
         return result;
     };
 
     /**
      * Get the cell below a given cell.
      * 
      * @method get_next_cell
      * @param {Cell} cell The provided cell
      * @return {Cell} the next cell or null if no cell was found.
      */
     Notebook.prototype.get_next_cell = function (cell) {
         var result = null;
         var index = this.find_cell_index(cell);
         if (this.is_valid_cell_index(index+1)) {
             result = this.get_cell(index+1);
         }
         return result;
     };
 
     /**
      * Get the cell above a given cell.
      * 
      * @method get_prev_cell
      * @param {Cell} cell The provided cell
      * @return {Cell} The previous cell or null if no cell was found.
      */
     Notebook.prototype.get_prev_cell = function (cell) {
         var result = null;
         var index = this.find_cell_index(cell);
         if (index !== null && index > 0) {
             result = this.get_cell(index-1);
         }
         return result;
     };
     
     /**
      * Get the numeric index of a given cell.
      * 
      * @method find_cell_index
      * @param {Cell} cell The provided cell
      * @return {Number} The cell's numeric index or null if no cell was found.
      */
     Notebook.prototype.find_cell_index = function (cell) {
         var result = null;
         this.get_cell_elements().filter(function (index) {
             if ($(this).data("cell") === cell) {
                 result = index;
             }
         });
         return result;
     };
 
     /**
      * Get a given index , or the selected index if none is provided.
      * 
      * @method index_or_selected
      * @param {Number} index A cell's index
      * @return {Number} The given index, or selected index if none is provided.
      */
     Notebook.prototype.index_or_selected = function (index) {
         var i;
         if (index === undefined || index === null) {
             i = this.get_selected_index();
             if (i === null) {
                 i = 0;
             }
         } else {
             i = index;
         }
         return i;
     };
 
     /**
      * Get the currently selected cell.
      * @method get_selected_cell
      * @return {Cell} The selected cell
      */
     Notebook.prototype.get_selected_cell = function () {
         var index = this.get_selected_index();
         return this.get_cell(index);
     };
 
     /**
      * Check whether a cell index is valid.
      * 
      * @method is_valid_cell_index
      * @param {Number} index A cell index
      * @return True if the index is valid, false otherwise
      */
     Notebook.prototype.is_valid_cell_index = function (index) {
         if (index !== null && index >= 0 && index < this.ncells()) {
             return true;
         } else {
             return false;
         }
     };
 
     /**
      * Get the index of the currently selected cell.
      
      * @method get_selected_index
      * @return {Number} The selected cell's numeric index
      */
     Notebook.prototype.get_selected_index = function () {
         var result = null;
         this.get_cell_elements().filter(function (index) {
             if ($(this).data("cell").selected === true) {
                 result = index;
             }
         });
         return result;
     };
 
 
     // Cell selection.
 
     /**
      * Programmatically select a cell.
      * 
      * @method select
      * @param {Number} index A cell's index
      * @return {Notebook} This notebook
      */
     Notebook.prototype.select = function (index) {
         if (this.is_valid_cell_index(index)) {
             var sindex = this.get_selected_index();
             if (sindex !== null && index !== sindex) {
                 // If we are about to select a different cell, make sure we are
                 // first in command mode.
                 if (this.mode !== 'command') {
                     this.command_mode();
                 }
                 this.get_cell(sindex).unselect();
             }
             var cell = this.get_cell(index);
             cell.select();
             if (cell.cell_type === 'heading') {
                 this.events.trigger('selected_cell_type_changed.Notebook',
                     {'cell_type':cell.cell_type,level:cell.level}
                 );
             } else {
                 this.events.trigger('selected_cell_type_changed.Notebook',
                     {'cell_type':cell.cell_type}
                 );
             }
         }
         return this;
     };
 
     /**
      * Programmatically select the next cell.
      *
      * @method select_next
      * @return {Notebook} This notebook
      */
     Notebook.prototype.select_next = function () {
         var index = this.get_selected_index();
         this.select(index+1);
         return this;
     };
 
     /**
      * Programmatically select the previous cell.
      *
      * @method select_prev
      * @return {Notebook} This notebook
      */
     Notebook.prototype.select_prev = function () {
         var index = this.get_selected_index();
         this.select(index-1);
         return this;
     };
 
 
     // Edit/Command mode
 
     /**
      * Gets the index of the cell that is in edit mode.
      *
      * @method get_edit_index
      *
      * @return index {int}
      **/
     Notebook.prototype.get_edit_index = function () {
         var result = null;
         this.get_cell_elements().filter(function (index) {
             if ($(this).data("cell").mode === 'edit') {
                 result = index;
             }
         });
         return result;
     };
 
     /**
      * Handle when a a cell blurs and the notebook should enter command mode.
      *
      * @method handle_command_mode
      * @param [cell] {Cell} Cell to enter command mode on.
      **/
     Notebook.prototype.handle_command_mode = function (cell) {
         if (this.mode !== 'command') {
             cell.command_mode();
             this.mode = 'command';
             this.events.trigger('command_mode.Notebook');
             this.keyboard_manager.command_mode();
         }
     };
 
     /**
      * Make the notebook enter command mode.
      *
      * @method command_mode
      **/
     Notebook.prototype.command_mode = function () {
         var cell = this.get_cell(this.get_edit_index());
         if (cell && this.mode !== 'command') {
             // We don't call cell.command_mode, but rather call cell.focus_cell()
             // which will blur and CM editor and trigger the call to
             // handle_command_mode.
             cell.focus_cell();
         }
     };
 
     /**
      * Handle when a cell fires it's edit_mode event.
      *
      * @method handle_edit_mode
      * @param [cell] {Cell} Cell to enter edit mode on.
      **/
     Notebook.prototype.handle_edit_mode = function (cell) {
         if (cell && this.mode !== 'edit') {
             cell.edit_mode();
             this.mode = 'edit';
             this.events.trigger('edit_mode.Notebook');
             this.keyboard_manager.edit_mode();
         }
     };
 
     /**
      * Make a cell enter edit mode.
      *
      * @method edit_mode
      **/
     Notebook.prototype.edit_mode = function () {
         var cell = this.get_selected_cell();
         if (cell && this.mode !== 'edit') {
             cell.unrender();
             cell.focus_editor();
         }
     };
 
     /**
      * Focus the currently selected cell.
      *
      * @method focus_cell
      **/
     Notebook.prototype.focus_cell = function () {
         var cell = this.get_selected_cell();
         if (cell === null) {return;}  // No cell is selected
         cell.focus_cell();
     };
 
     // Cell movement
 
     /**
      * Move given (or selected) cell up and select it.
      * 
      * @method move_cell_up
      * @param [index] {integer} cell index
      * @return {Notebook} This notebook
      **/
     Notebook.prototype.move_cell_up = function (index) {
         var i = this.index_or_selected(index);
         if (this.is_valid_cell_index(i) && i > 0) {
             var pivot = this.get_cell_element(i-1);
             var tomove = this.get_cell_element(i);
             if (pivot !== null && tomove !== null) {
                 tomove.detach();
                 pivot.before(tomove);
                 this.select(i-1);
                 var cell = this.get_selected_cell();
                 cell.focus_cell();
             }
             this.set_dirty(true);
         }
         return this;
     };
 
 
     /**
      * Move given (or selected) cell down and select it
      * 
      * @method move_cell_down
      * @param [index] {integer} cell index
      * @return {Notebook} This notebook
      **/
     Notebook.prototype.move_cell_down = function (index) {
         var i = this.index_or_selected(index);
         if (this.is_valid_cell_index(i) && this.is_valid_cell_index(i+1)) {
             var pivot = this.get_cell_element(i+1);
             var tomove = this.get_cell_element(i);
             if (pivot !== null && tomove !== null) {
                 tomove.detach();
                 pivot.after(tomove);
                 this.select(i+1);
                 var cell = this.get_selected_cell();
                 cell.focus_cell();
             }
         }
         this.set_dirty();
         return this;
     };
 
 
     // Insertion, deletion.
 
     /**
      * Delete a cell from the notebook.
      * 
      * @method delete_cell
      * @param [index] A cell's numeric index
      * @return {Notebook} This notebook
      */
     Notebook.prototype.delete_cell = function (index) {
         var i = this.index_or_selected(index);
         var cell = this.get_cell(i);
         if (!cell.is_deletable()) {
             return this;
         }
 
         this.undelete_backup = cell.toJSON();
         $('#undelete_cell').removeClass('disabled');
         if (this.is_valid_cell_index(i)) {
             var old_ncells = this.ncells();
             var ce = this.get_cell_element(i);
             ce.remove();
             if (i === 0) {
                 // Always make sure we have at least one cell.
                 if (old_ncells === 1) {
                     this.insert_cell_below('code');
                 }
                 this.select(0);
                 this.undelete_index = 0;
                 this.undelete_below = false;
             } else if (i === old_ncells-1 && i !== 0) {
                 this.select(i-1);
                 this.undelete_index = i - 1;
                 this.undelete_below = true;
             } else {
                 this.select(i);
                 this.undelete_index = i;
                 this.undelete_below = false;
             }
             this.events.trigger('delete.Cell', {'cell': cell, 'index': i});
             this.set_dirty(true);
         }
         return this;
     };
 
     /**
      * Restore the most recently deleted cell.
      * 
      * @method undelete
      */
     Notebook.prototype.undelete_cell = function() {
         if (this.undelete_backup !== null && this.undelete_index !== null) {
             var current_index = this.get_selected_index();
             if (this.undelete_index < current_index) {
                 current_index = current_index + 1;
             }
             if (this.undelete_index >= this.ncells()) {
                 this.select(this.ncells() - 1);
             }
             else {
                 this.select(this.undelete_index);
             }
             var cell_data = this.undelete_backup;
             var new_cell = null;
             if (this.undelete_below) {
                 new_cell = this.insert_cell_below(cell_data.cell_type);
             } else {
                 new_cell = this.insert_cell_above(cell_data.cell_type);
             }
             new_cell.fromJSON(cell_data);
             if (this.undelete_below) {
                 this.select(current_index+1);
             } else {
                 this.select(current_index);
             }
             this.undelete_backup = null;
             this.undelete_index = null;
         }
         $('#undelete_cell').addClass('disabled');
     };
 
     /**
      * Insert a cell so that after insertion the cell is at given index.
      *
      * If cell type is not provided, it will default to the type of the
      * currently active cell.
      *
      * Similar to insert_above, but index parameter is mandatory
      *
      * Index will be brought back into the accessible range [0,n]
      *
      * @method insert_cell_at_index
      * @param [type] {string} in ['code','markdown', 'raw'], defaults to 'code'
      * @param [index] {int} a valid index where to insert cell
      *
      * @return cell {cell|null} created cell or null
      **/
     Notebook.prototype.insert_cell_at_index = function(type, index){
 
         var ncells = this.ncells();
         index = Math.min(index, ncells);
         index = Math.max(index, 0);
         var cell = null;
         type = type || this.default_cell_type;
         if (type === 'above') {
             if (index > 0) {
                 type = this.get_cell(index-1).cell_type;
             } else {
                 type = 'code';
             }
         } else if (type === 'below') {
             if (index < ncells) {
                 type = this.get_cell(index).cell_type;
             } else {
                 type = 'code';
             }
         } else if (type === 'selected') {
             type = this.get_selected_cell().cell_type;
         }
 
         if (ncells === 0 || this.is_valid_cell_index(index) || index === ncells) {
             var cell_options = {
                 events: this.events, 
                 config: this.config, 
                 keyboard_manager: this.keyboard_manager, 
                 notebook: this,
                 tooltip: this.tooltip,
             };
             switch(type) {
             case 'code':
                 cell = new codecell.CodeCell(this.kernel, cell_options);
                 cell.set_input_prompt();
                 break;
             case 'markdown':
                 cell = new textcell.MarkdownCell(cell_options);
                 break;
             case 'raw':
                 cell = new textcell.RawCell(cell_options);
                 break;
             default:
                 console.log("invalid cell type: ", type);
             }
 
             if(this._insert_element_at_index(cell.element,index)) {
                 cell.render();
                 this.events.trigger('create.Cell', {'cell': cell, 'index': index});
                 cell.refresh();
                 // We used to select the cell after we refresh it, but there
                 // are now cases were this method is called where select is
                 // not appropriate. The selection logic should be handled by the
                 // caller of the the top level insert_cell methods.
                 this.set_dirty(true);
             }
         }
         return cell;
 
     };
 
     /**
      * Insert an element at given cell index.
      *
      * @method _insert_element_at_index
      * @param element {dom_element} a cell element
      * @param [index] {int} a valid index where to inser cell
      * @private
      *
      * return true if everything whent fine.
      **/
     Notebook.prototype._insert_element_at_index = function(element, index){
         if (element === undefined){
             return false;
         }
 
         var ncells = this.ncells();
 
         if (ncells === 0) {
             // special case append if empty
             this.element.find('div.end_space').before(element);
         } else if ( ncells === index ) {
             // special case append it the end, but not empty
             this.get_cell_element(index-1).after(element);
         } else if (this.is_valid_cell_index(index)) {
             // otherwise always somewhere to append to
             this.get_cell_element(index).before(element);
         } else {
             return false;
         }
 
         if (this.undelete_index !== null && index <= this.undelete_index) {
             this.undelete_index = this.undelete_index + 1;
             this.set_dirty(true);
         }
         return true;
     };
 
     /**
      * Insert a cell of given type above given index, or at top
      * of notebook if index smaller than 0.
      *
      * default index value is the one of currently selected cell
      *
      * @method insert_cell_above
      * @param [type] {string} cell type
      * @param [index] {integer}
      *
      * @return handle to created cell or null
      **/
     Notebook.prototype.insert_cell_above = function (type, index) {
         index = this.index_or_selected(index);
         return this.insert_cell_at_index(type, index);
     };
 
     /**
      * Insert a cell of given type below given index, or at bottom
      * of notebook if index greater than number of cells
      *
      * default index value is the one of currently selected cell
      *
      * @method insert_cell_below
      * @param [type] {string} cell type
      * @param [index] {integer}
      *
      * @return handle to created cell or null
      *
      **/
     Notebook.prototype.insert_cell_below = function (type, index) {
         index = this.index_or_selected(index);
         return this.insert_cell_at_index(type, index+1);
     };
 
 
     /**
      * Insert cell at end of notebook
      *
      * @method insert_cell_at_bottom
      * @param {String} type cell type
      *
      * @return the added cell; or null
      **/
     Notebook.prototype.insert_cell_at_bottom = function (type){
         var len = this.ncells();
         return this.insert_cell_below(type,len-1);
     };
 
     /**
      * Turn a cell into a code cell.
      * 
      * @method to_code
      * @param {Number} [index] A cell's index
      */
     Notebook.prototype.to_code = function (index) {
         var i = this.index_or_selected(index);
         if (this.is_valid_cell_index(i)) {
             var source_cell = this.get_cell(i);
             if (!(source_cell instanceof codecell.CodeCell)) {
                 var target_cell = this.insert_cell_below('code',i);
                 var text = source_cell.get_text();
                 if (text === source_cell.placeholder) {
                     text = '';
                 }
                 //metadata
                 target_cell.metadata = source_cell.metadata;
 
                 target_cell.set_text(text);
                 // make this value the starting point, so that we can only undo
                 // to this state, instead of a blank cell
                 target_cell.code_mirror.clearHistory();
                 source_cell.element.remove();
                 this.select(i);
                 var cursor = source_cell.code_mirror.getCursor();
                 target_cell.code_mirror.setCursor(cursor);
                 this.set_dirty(true);
             }
         }
     };
 
     /**
      * Turn a cell into a Markdown cell.
      * 
      * @method to_markdown
      * @param {Number} [index] A cell's index
      */
     Notebook.prototype.to_markdown = function (index) {
         var i = this.index_or_selected(index);
         if (this.is_valid_cell_index(i)) {
             var source_cell = this.get_cell(i);
 
             if (!(source_cell instanceof textcell.MarkdownCell)) {
                 var target_cell = this.insert_cell_below('markdown',i);
                 var text = source_cell.get_text();
 
                 if (text === source_cell.placeholder) {
                     text = '';
                 }
                 // metadata
                 target_cell.metadata = source_cell.metadata
                 // We must show the editor before setting its contents
                 target_cell.unrender();
                 target_cell.set_text(text);
                 // make this value the starting point, so that we can only undo
                 // to this state, instead of a blank cell
                 target_cell.code_mirror.clearHistory();
                 source_cell.element.remove();
                 this.select(i);
                 if ((source_cell instanceof textcell.TextCell) && source_cell.rendered) {
                     target_cell.render();
                 }
                 var cursor = source_cell.code_mirror.getCursor();
                 target_cell.code_mirror.setCursor(cursor);
                 this.set_dirty(true);
             }
         }
     };
 
     /**
      * Turn a cell into a raw text cell.
      * 
      * @method to_raw
      * @param {Number} [index] A cell's index
      */
     Notebook.prototype.to_raw = function (index) {
         var i = this.index_or_selected(index);
         if (this.is_valid_cell_index(i)) {
             var target_cell = null;
             var source_cell = this.get_cell(i);
 
             if (!(source_cell instanceof textcell.RawCell)) {
                 target_cell = this.insert_cell_below('raw',i);
                 var text = source_cell.get_text();
                 if (text === source_cell.placeholder) {
                     text = '';
                 }
                 //metadata
                 target_cell.metadata = source_cell.metadata;
                 // We must show the editor before setting its contents
                 target_cell.unrender();
                 target_cell.set_text(text);
                 // make this value the starting point, so that we can only undo
                 // to this state, instead of a blank cell
                 target_cell.code_mirror.clearHistory();
                 source_cell.element.remove();
                 this.select(i);
                 var cursor = source_cell.code_mirror.getCursor();
                 target_cell.code_mirror.setCursor(cursor);
                 this.set_dirty(true);
             }
         }
     };
 
     /**
      * Turn a cell into a heading cell.
      * 
      * @method to_heading
      * @param {Number} [index] A cell's index
      * @param {Number} [level] A heading level (e.g., 1 becomes &lt;h1&gt;)
      */
     Notebook.prototype.to_heading = function (index, level) {
         level = level || 1;
         var i = this.index_or_selected(index);
         if (this.is_valid_cell_index(i)) {
             var source_cell = this.get_cell(i);
             var target_cell = null;
             if (source_cell instanceof textcell.MarkdownCell) {
                 source_cell.set_heading_level(level);
             } else {
                 target_cell = this.insert_cell_below('markdown',i);
                 var text = source_cell.get_text();
                 if (text === source_cell.placeholder) {
                     text = '';
                 }
                 //metadata
                 target_cell.metadata = source_cell.metadata;
                 // We must show the editor before setting its contents
                 target_cell.unrender();
                 target_cell.set_text(text);
                 target_cell.set_heading_level(level);
                 // make this value the starting point, so that we can only undo
                 // to this state, instead of a blank cell
                 target_cell.code_mirror.clearHistory();
                 source_cell.element.remove();
                 this.select(i);
                 var cursor = source_cell.code_mirror.getCursor();
                 target_cell.code_mirror.setCursor(cursor);
                 if ((source_cell instanceof textcell.TextCell) && source_cell.rendered) {
                     target_cell.render();
                 }
             }
             this.set_dirty(true);
             this.events.trigger('selected_cell_type_changed.Notebook',
                 {'cell_type':'markdown',level:level}
             );
         }
     };
 
 
     // Cut/Copy/Paste
 
     /**
      * Enable UI elements for pasting cells.
      * 
      * @method enable_paste
      */
     Notebook.prototype.enable_paste = function () {
         var that = this;
         if (!this.paste_enabled) {
             $('#paste_cell_replace').removeClass('disabled')
                 .on('click', function () {that.paste_cell_replace();});
             $('#paste_cell_above').removeClass('disabled')
                 .on('click', function () {that.paste_cell_above();});
             $('#paste_cell_below').removeClass('disabled')
                 .on('click', function () {that.paste_cell_below();});
             this.paste_enabled = true;
         }
     };
 
     /**
      * Disable UI elements for pasting cells.
      * 
      * @method disable_paste
      */
     Notebook.prototype.disable_paste = function () {
         if (this.paste_enabled) {
             $('#paste_cell_replace').addClass('disabled').off('click');
             $('#paste_cell_above').addClass('disabled').off('click');
             $('#paste_cell_below').addClass('disabled').off('click');
             this.paste_enabled = false;
         }
     };
 
     /**
      * Cut a cell.
      * 
      * @method cut_cell
      */
     Notebook.prototype.cut_cell = function () {
         this.copy_cell();
         this.delete_cell();
     };
 
     /**
      * Copy a cell.
      * 
      * @method copy_cell
      */
     Notebook.prototype.copy_cell = function () {
         var cell = this.get_selected_cell();
         this.clipboard = cell.toJSON();
         // remove undeletable status from the copied cell
         if (this.clipboard.metadata.deletable !== undefined) {
             delete this.clipboard.metadata.deletable;
         }
         this.enable_paste();
     };
 
     /**
      * Replace the selected cell with a cell in the clipboard.
      * 
      * @method paste_cell_replace
      */
     Notebook.prototype.paste_cell_replace = function () {
         if (this.clipboard !== null && this.paste_enabled) {
             var cell_data = this.clipboard;
             var new_cell = this.insert_cell_above(cell_data.cell_type);
             new_cell.fromJSON(cell_data);
             var old_cell = this.get_next_cell(new_cell);
             this.delete_cell(this.find_cell_index(old_cell));
             this.select(this.find_cell_index(new_cell));
         }
     };
 
     /**
      * Paste a cell from the clipboard above the selected cell.
      * 
      * @method paste_cell_above
      */
     Notebook.prototype.paste_cell_above = function () {
         if (this.clipboard !== null && this.paste_enabled) {
             var cell_data = this.clipboard;
             var new_cell = this.insert_cell_above(cell_data.cell_type);
             new_cell.fromJSON(cell_data);
             new_cell.focus_cell();
         }
     };
 
     /**
      * Paste a cell from the clipboard below the selected cell.
      * 
      * @method paste_cell_below
      */
     Notebook.prototype.paste_cell_below = function () {
         if (this.clipboard !== null && this.paste_enabled) {
             var cell_data = this.clipboard;
             var new_cell = this.insert_cell_below(cell_data.cell_type);
             new_cell.fromJSON(cell_data);
             new_cell.focus_cell();
         }
     };
 
     // Split/merge
 
     /**
      * Split the selected cell into two, at the cursor.
      * 
      * @method split_cell
      */
     Notebook.prototype.split_cell = function () {
         var mdc = textcell.MarkdownCell;
         var rc = textcell.RawCell;
         var cell = this.get_selected_cell();
         if (cell.is_splittable()) {
             var texta = cell.get_pre_cursor();
             var textb = cell.get_post_cursor();
             cell.set_text(textb);
             var new_cell = this.insert_cell_above(cell.cell_type);
             // Unrender the new cell so we can call set_text.
             new_cell.unrender();
             new_cell.set_text(texta);
         }
     };
 
     /**
      * Combine the selected cell into the cell above it.
      * 
      * @method merge_cell_above
      */
     Notebook.prototype.merge_cell_above = function () {
         var mdc = textcell.MarkdownCell;
         var rc = textcell.RawCell;
         var index = this.get_selected_index();
         var cell = this.get_cell(index);
         var render = cell.rendered;
         if (!cell.is_mergeable()) {
             return;
         }
         if (index > 0) {
             var upper_cell = this.get_cell(index-1);
             if (!upper_cell.is_mergeable()) {
                 return;
             }
             var upper_text = upper_cell.get_text();
             var text = cell.get_text();
             if (cell instanceof codecell.CodeCell) {
                 cell.set_text(upper_text+'\n'+text);
             } else {
                 cell.unrender(); // Must unrender before we set_text.
                 cell.set_text(upper_text+'\n\n'+text);
                 if (render) {
                     // The rendered state of the final cell should match
                     // that of the original selected cell;
                     cell.render();
                 }
             }
             this.delete_cell(index-1);
             this.select(this.find_cell_index(cell));
         }
     };
 
     /**
      * Combine the selected cell into the cell below it.
      * 
      * @method merge_cell_below
      */
     Notebook.prototype.merge_cell_below = function () {
         var mdc = textcell.MarkdownCell;
         var rc = textcell.RawCell;
         var index = this.get_selected_index();
         var cell = this.get_cell(index);
         var render = cell.rendered;
         if (!cell.is_mergeable()) {
             return;
         }
         if (index < this.ncells()-1) {
             var lower_cell = this.get_cell(index+1);
             if (!lower_cell.is_mergeable()) {
                 return;
             }
             var lower_text = lower_cell.get_text();
             var text = cell.get_text();
             if (cell instanceof codecell.CodeCell) {
                 cell.set_text(text+'\n'+lower_text);
             } else {
                 cell.unrender(); // Must unrender before we set_text.
                 cell.set_text(text+'\n\n'+lower_text);
                 if (render) {
                     // The rendered state of the final cell should match
                     // that of the original selected cell;
                     cell.render();
                 }
             }
             this.delete_cell(index+1);
             this.select(this.find_cell_index(cell));
         }
     };
 
 
     // Cell collapsing and output clearing
 
     /**
      * Hide a cell's output.
      * 
      * @method collapse_output
      * @param {Number} index A cell's numeric index
      */
     Notebook.prototype.collapse_output = function (index) {
         var i = this.index_or_selected(index);
         var cell = this.get_cell(i);
         if (cell !== null && (cell instanceof codecell.CodeCell)) {
             cell.collapse_output();
             this.set_dirty(true);
         }
     };
 
     /**
      * Hide each code cell's output area.
      * 
      * @method collapse_all_output
      */
     Notebook.prototype.collapse_all_output = function () {
         $.map(this.get_cells(), function (cell, i) {
             if (cell instanceof codecell.CodeCell) {
                 cell.collapse_output();
             }
         });
         // this should not be set if the `collapse` key is removed from nbformat
         this.set_dirty(true);
     };
 
     /**
      * Show a cell's output.
      * 
      * @method expand_output
      * @param {Number} index A cell's numeric index
      */
     Notebook.prototype.expand_output = function (index) {
         var i = this.index_or_selected(index);
         var cell = this.get_cell(i);
         if (cell !== null && (cell instanceof codecell.CodeCell)) {
             cell.expand_output();
             this.set_dirty(true);
         }
     };
 
     /**
      * Expand each code cell's output area, and remove scrollbars.
      * 
      * @method expand_all_output
      */
     Notebook.prototype.expand_all_output = function () {
         $.map(this.get_cells(), function (cell, i) {
             if (cell instanceof codecell.CodeCell) {
                 cell.expand_output();
             }
         });
         // this should not be set if the `collapse` key is removed from nbformat
         this.set_dirty(true);
     };
 
     /**
      * Clear the selected CodeCell's output area.
      * 
      * @method clear_output
      * @param {Number} index A cell's numeric index
      */
     Notebook.prototype.clear_output = function (index) {
         var i = this.index_or_selected(index);
         var cell = this.get_cell(i);
         if (cell !== null && (cell instanceof codecell.CodeCell)) {
             cell.clear_output();
             this.set_dirty(true);
         }
     };
 
     /**
      * Clear each code cell's output area.
      * 
      * @method clear_all_output
      */
     Notebook.prototype.clear_all_output = function () {
         $.map(this.get_cells(), function (cell, i) {
             if (cell instanceof codecell.CodeCell) {
                 cell.clear_output();
             }
         });
         this.set_dirty(true);
     };
 
     /**
      * Scroll the selected CodeCell's output area.
      * 
      * @method scroll_output
      * @param {Number} index A cell's numeric index
      */
     Notebook.prototype.scroll_output = function (index) {
         var i = this.index_or_selected(index);
         var cell = this.get_cell(i);
         if (cell !== null && (cell instanceof codecell.CodeCell)) {
             cell.scroll_output();
             this.set_dirty(true);
         }
     };
 
     /**
      * Expand each code cell's output area, and add a scrollbar for long output.
      * 
      * @method scroll_all_output
      */
     Notebook.prototype.scroll_all_output = function () {
         $.map(this.get_cells(), function (cell, i) {
             if (cell instanceof codecell.CodeCell) {
                 cell.scroll_output();
             }
         });
         // this should not be set if the `collapse` key is removed from nbformat
         this.set_dirty(true);
     };
 
     /** Toggle whether a cell's output is collapsed or expanded.
      * 
      * @method toggle_output
      * @param {Number} index A cell's numeric index
      */
     Notebook.prototype.toggle_output = function (index) {
         var i = this.index_or_selected(index);
         var cell = this.get_cell(i);
         if (cell !== null && (cell instanceof codecell.CodeCell)) {
             cell.toggle_output();
             this.set_dirty(true);
         }
     };
 
     /**
      * Hide/show the output of all cells.
      * 
      * @method toggle_all_output
      */
     Notebook.prototype.toggle_all_output = function () {
         $.map(this.get_cells(), function (cell, i) {
             if (cell instanceof codecell.CodeCell) {
                 cell.toggle_output();
             }
         });
         // this should not be set if the `collapse` key is removed from nbformat
         this.set_dirty(true);
     };
 
     /**
      * Toggle a scrollbar for long cell outputs.
      * 
      * @method toggle_output_scroll
      * @param {Number} index A cell's numeric index
      */
     Notebook.prototype.toggle_output_scroll = function (index) {
         var i = this.index_or_selected(index);
         var cell = this.get_cell(i);
         if (cell !== null && (cell instanceof codecell.CodeCell)) {
             cell.toggle_output_scroll();
             this.set_dirty(true);
         }
     };
 
     /**
      * Toggle the scrolling of long output on all cells.
      * 
      * @method toggle_all_output_scrolling
      */
     Notebook.prototype.toggle_all_output_scroll = function () {
         $.map(this.get_cells(), function (cell, i) {
             if (cell instanceof codecell.CodeCell) {
                 cell.toggle_output_scroll();
             }
         });
         // this should not be set if the `collapse` key is removed from nbformat
         this.set_dirty(true);
     };
 
     // Other cell functions: line numbers, ...
 
     /**
      * Toggle line numbers in the selected cell's input area.
      * 
      * @method cell_toggle_line_numbers
      */
     Notebook.prototype.cell_toggle_line_numbers = function() {
         this.get_selected_cell().toggle_line_numbers();
     };
     
     /**
      * Set the codemirror mode for all code cells, including the default for
      * new code cells.
      * 
      * @method set_codemirror_mode
      */
     Notebook.prototype.set_codemirror_mode = function(newmode){
         if (newmode === this.codemirror_mode) {
             return;
         }
         this.codemirror_mode = newmode;
         codecell.CodeCell.options_default.cm_config.mode = newmode;
         modename = newmode.mode || newmode.name || newmode;
         
         that = this;
         utils.requireCodeMirrorMode(modename, function () {
             $.map(that.get_cells(), function(cell, i) {
                 if (cell.cell_type === 'code'){
                     cell.code_mirror.setOption('mode', newmode);
                     // This is currently redundant, because cm_config ends up as
                     // codemirror's own .options object, but I don't want to
                     // rely on that.
                     cell.cm_config.mode = newmode;
                 }
             });
         });
     };
 
     // Session related things
 
     /**
      * Start a new session and set it on each code cell.
      * 
      * @method start_session
      */
     Notebook.prototype.start_session = function (kernel_name) {
         var that = this;
         if (this._session_starting) {
             throw new session.SessionAlreadyStarting();
         }
         this._session_starting = true;
 
         var options = {
             base_url: this.base_url,
             ws_url: this.ws_url,
             notebook_path: this.notebook_path,
             notebook_name: this.notebook_name,
             kernel_name: kernel_name,
             notebook: this
         };
 
         var success = $.proxy(this._session_started, this);
         var failure = $.proxy(this._session_start_failed, this);
 
         if (this.session !== null) {
             this.session.restart(options, success, failure);
         } else {
             this.session = new session.Session(options);
             this.session.start(success, failure);
         }
     };
 
 
     /**
      * Once a session is started, link the code cells to the kernel and pass the 
      * comm manager to the widget manager
      *
      */
     Notebook.prototype._session_started = function (){
         this._session_starting = false;
         this.kernel = this.session.kernel;
         var ncells = this.ncells();
         for (var i=0; i<ncells; i++) {
             var cell = this.get_cell(i);
             if (cell instanceof codecell.CodeCell) {
                 cell.set_kernel(this.session.kernel);
             }
         }
     };
     Notebook.prototype._session_start_failed = function (jqxhr, status, error){
         this._session_starting = false;
         utils.log_ajax_error(jqxhr, status, error);
     };
     
     /**
      * Prompt the user to restart the IPython kernel.
      * 
      * @method restart_kernel
      */
     Notebook.prototype.restart_kernel = function () {
         var that = this;
         dialog.modal({
             notebook: this,
             keyboard_manager: this.keyboard_manager,
             title : "Restart kernel or continue running?",
             body : $("<p/>").text(
                 'Do you want to restart the current kernel?  You will lose all variables defined in it.'
             ),
             buttons : {
                 "Continue running" : {},
                 "Restart" : {
                     "class" : "btn-danger",
                     "click" : function() {
                         that.kernel.restart();
                     }
                 }
             }
         });
     };
     
     /**
      * Execute or render cell outputs and go into command mode.
      * 
      * @method execute_cell
      */
     Notebook.prototype.execute_cell = function () {
         // mode = shift, ctrl, alt
         var cell = this.get_selected_cell();
         var cell_index = this.find_cell_index(cell);
         
         cell.execute();
         this.command_mode();
         this.set_dirty(true);
     };
 
     /**
      * Execute or render cell outputs and insert a new cell below.
      * 
      * @method execute_cell_and_insert_below
      */
     Notebook.prototype.execute_cell_and_insert_below = function () {
         var cell = this.get_selected_cell();
         var cell_index = this.find_cell_index(cell);
         
         cell.execute();
 
         // If we are at the end always insert a new cell and return
         if (cell_index === (this.ncells()-1)) {
             this.command_mode();
             this.insert_cell_below();
             this.select(cell_index+1);
             this.edit_mode();
             this.scroll_to_bottom();
             this.set_dirty(true);
             return;
         }
 
         this.command_mode();
         this.insert_cell_below();
         this.select(cell_index+1);
         this.edit_mode();
         this.set_dirty(true);
     };
 
     /**
      * Execute or render cell outputs and select the next cell.
      * 
      * @method execute_cell_and_select_below
      */
     Notebook.prototype.execute_cell_and_select_below = function () {
 
         var cell = this.get_selected_cell();
         var cell_index = this.find_cell_index(cell);
         
         cell.execute();
 
         // If we are at the end always insert a new cell and return
         if (cell_index === (this.ncells()-1)) {
             this.command_mode();
             this.insert_cell_below();
             this.select(cell_index+1);
             this.edit_mode();
             this.scroll_to_bottom();
             this.set_dirty(true);
             return;
         }
 
         this.command_mode();
         this.select(cell_index+1);
         this.focus_cell();
         this.set_dirty(true);
     };
 
     /**
      * Execute all cells below the selected cell.
      * 
      * @method execute_cells_below
      */
     Notebook.prototype.execute_cells_below = function () {
         this.execute_cell_range(this.get_selected_index(), this.ncells());
         this.scroll_to_bottom();
     };
 
     /**
      * Execute all cells above the selected cell.
      * 
      * @method execute_cells_above
      */
     Notebook.prototype.execute_cells_above = function () {
         this.execute_cell_range(0, this.get_selected_index());
     };
 
     /**
      * Execute all cells.
      * 
      * @method execute_all_cells
      */
     Notebook.prototype.execute_all_cells = function () {
         this.execute_cell_range(0, this.ncells());
         this.scroll_to_bottom();
     };
 
     /**
      * Execute a contiguous range of cells.
      * 
      * @method execute_cell_range
      * @param {Number} start Index of the first cell to execute (inclusive)
      * @param {Number} end Index of the last cell to execute (exclusive)
      */
     Notebook.prototype.execute_cell_range = function (start, end) {
         this.command_mode();
         for (var i=start; i<end; i++) {
             this.select(i);
             this.execute_cell();
         }
     };
 
     // Persistance and loading
 
     /**
      * Getter method for this notebook's name.
      * 
      * @method get_notebook_name
      * @return {String} This notebook's name (excluding file extension)
      */
     Notebook.prototype.get_notebook_name = function () {
         var nbname = this.notebook_name.substring(0,this.notebook_name.length-6);
         return nbname;
     };
 
     /**
      * Setter method for this notebook's name.
      *
      * @method set_notebook_name
      * @param {String} name A new name for this notebook
      */
     Notebook.prototype.set_notebook_name = function (name) {
         this.notebook_name = name;
     };
 
     /**
      * Check that a notebook's name is valid.
      * 
      * @method test_notebook_name
      * @param {String} nbname A name for this notebook
      * @return {Boolean} True if the name is valid, false if invalid
      */
     Notebook.prototype.test_notebook_name = function (nbname) {
         nbname = nbname || '';
         if (nbname.length>0 && !this.notebook_name_blacklist_re.test(nbname)) {
             return true;
         } else {
             return false;
         }
     };
 
     /**
      * Load a notebook from JSON (.ipynb).
      * 
      * @method fromJSON
      * @param {Object} data JSON representation of a notebook
      */
     Notebook.prototype.fromJSON = function (data) {
 
         var content = data.content;
         var ncells = this.ncells();
         var i;
         for (i=0; i<ncells; i++) {
             // Always delete cell 0 as they get renumbered as they are deleted.
             this.delete_cell(0);
         }
         // Save the metadata and name.
         this.metadata = content.metadata;
         this.notebook_name = data.name;
         var trusted = true;
         
         // Trigger an event changing the kernel spec - this will set the default
         // codemirror mode
         if (this.metadata.kernelspec !== undefined) {
             this.events.trigger('spec_changed.Kernel', this.metadata.kernelspec);
         }
         
         // Set the codemirror mode from language_info metadata
         if (this.metadata.language_info !== undefined) {
             var langinfo = this.metadata.language_info;
             // Mode 'null' should be plain, unhighlighted text.
             var cm_mode = langinfo.codemirror_mode || langinfo.language || 'null'
             this.set_codemirror_mode(cm_mode);
         }
         
         var new_cells = content.cells;
         ncells = new_cells.length;
         var cell_data = null;
         var new_cell = null;
         for (i=0; i<ncells; i++) {
             cell_data = new_cells[i];
             new_cell = this.insert_cell_at_index(cell_data.cell_type, i);
             new_cell.fromJSON(cell_data);
             if (new_cell.cell_type == 'code' && !new_cell.output_area.trusted) {
                 trusted = false;
             }
         }
         if (trusted !== this.trusted) {
             this.trusted = trusted;
             this.events.trigger("trust_changed.Notebook", trusted);
         }
     };
 
     /**
      * Dump this notebook into a JSON-friendly object.
      * 
      * @method toJSON
      * @return {Object} A JSON-friendly representation of this notebook.
      */
     Notebook.prototype.toJSON = function () {
         // remove the conversion indicator, which only belongs in-memory
         delete this.metadata.orig_nbformat;
         delete this.metadata.orig_nbformat_minor;
 
         var cells = this.get_cells();
         var ncells = cells.length;
         var cell_array = new Array(ncells);
         var trusted = true;
         for (var i=0; i<ncells; i++) {
             var cell = cells[i];
             if (cell.cell_type == 'code' && !cell.output_area.trusted) {
                 trusted = false;
             }
             cell_array[i] = cell.toJSON();
         }
         var data = {
             cells: cell_array,
             metadata : this.metadata
         };
         if (trusted != this.trusted) {
             this.trusted = trusted;
             this.events.trigger("trust_changed.Notebook", trusted);
         }
         return data;
     };
 
     /**
      * Start an autosave timer, for periodically saving the notebook.
      * 
      * @method set_autosave_interval
      * @param {Integer} interval the autosave interval in milliseconds
      */
     Notebook.prototype.set_autosave_interval = function (interval) {
         var that = this;
         // clear previous interval, so we don't get simultaneous timers
         if (this.autosave_timer) {
             clearInterval(this.autosave_timer);
         }
         
         this.autosave_interval = this.minimum_autosave_interval = interval;
         if (interval) {
             this.autosave_timer = setInterval(function() {
                 if (that.dirty) {
                     that.save_notebook();
                 }
             }, interval);
             this.events.trigger("autosave_enabled.Notebook", interval);
         } else {
             this.autosave_timer = null;
             this.events.trigger("autosave_disabled.Notebook");
         }
     };
     
     /**
      * Save this notebook on the server. This becomes a notebook instance's
      * .save_notebook method *after* the entire notebook has been loaded.
      * 
      * @method save_notebook
      */
     Notebook.prototype.save_notebook = function (extra_settings) {
         var content = $.extend(this.toJSON(), {
             nbformat : this.nbformat,
             nbformat_minor : this.nbformat_minor
-        })
+        });
         // Create a JSON model to be sent to the server.
         var model = {
             name : this.notebook_name,
             path : this.notebook_path,
             type : "notebook",
             content : content
         };
         // time the ajax call for autosave tuning purposes.
         var start =  new Date().getTime();
 
         var that = this;
         this.contents.save_file(this.notebook_path, this.notebook_name, model, {
                 extra_settings: extra_settings,
                 success: $.proxy(this.save_notebook_success, this, start),
                 error: function (xhr, status, error) {
                     that.events.trigger('notebook_save_failed.Notebook');
                 }
             });
     };
     
     /**
      * Success callback for saving a notebook.
      * 
      * @method save_notebook_success
      * @param {Integer} start Time when the save request start
      * @param {Object} data JSON representation of a notebook
      * @param {String} status Description of response status
      * @param {jqXHR} xhr jQuery Ajax object
      */
     Notebook.prototype.save_notebook_success = function (start, data, status, xhr) {
         this.set_dirty(false);
         if (data.message) {
             // save succeeded, but validation failed.
             var body = $("<div>");
             var title = "Notebook validation failed";
 
             body.append($("<p>").text(
                 "The save operation succeeded," +
                 " but the notebook does not appear to be valid." +
                 " The validation error was:"
             )).append($("<div>").addClass("validation-error").append(
                 $("<pre>").text(data.message)
             ));
             dialog.modal({
                 notebook: this,
                 keyboard_manager: this.keyboard_manager,
                 title: title,
                 body: body,
                 buttons : {
                     OK : {
                         "class" : "btn-primary"
                     }
                 }
             });
         }
         this.events.trigger('notebook_saved.Notebook');
         this._update_autosave_interval(start);
         if (this._checkpoint_after_save) {
             this.create_checkpoint();
             this._checkpoint_after_save = false;
         }
     };
     
     /**
      * update the autosave interval based on how long the last save took
      * 
      * @method _update_autosave_interval
      * @param {Integer} timestamp when the save request started
      */
     Notebook.prototype._update_autosave_interval = function (start) {
         var duration = (new Date().getTime() - start);
         if (this.autosave_interval) {
             // new save interval: higher of 10x save duration or parameter (default 30 seconds)
             var interval = Math.max(10 * duration, this.minimum_autosave_interval);
             // round to 10 seconds, otherwise we will be setting a new interval too often
             interval = 10000 * Math.round(interval / 10000);
             // set new interval, if it's changed
             if (interval != this.autosave_interval) {
                 this.set_autosave_interval(interval);
             }
         }
     };
 
     /**
      * Explicitly trust the output of this notebook.
      *
      * @method trust_notebook
      */
     Notebook.prototype.trust_notebook = function (extra_settings) {
         var body = $("<div>").append($("<p>")
             .text("A trusted IPython notebook may execute hidden malicious code ")
             .append($("<strong>")
                 .append(
                     $("<em>").text("when you open it")
                 )
             ).append(".").append(
                 " Selecting trust will immediately reload this notebook in a trusted state."
             ).append(
                 " For more information, see the "
             ).append($("<a>").attr("href", "http://ipython.org/ipython-doc/2/notebook/security.html")
                 .text("IPython security documentation")
             ).append(".")
         );
 
         var nb = this;
         dialog.modal({
             notebook: this,
             keyboard_manager: this.keyboard_manager,
             title: "Trust this notebook?",
             body: body,
 
             buttons: {
                 Cancel : {},
                 Trust : {
                     class : "btn-danger",
                     click : function () {
                         var cells = nb.get_cells();
                         for (var i = 0; i < cells.length; i++) {
                             var cell = cells[i];
                             if (cell.cell_type == 'code') {
                                 cell.output_area.trusted = true;
                             }
                         }
                         nb.events.on('notebook_saved.Notebook', function () {
                             window.location.reload();
                         });
                         nb.save_notebook();
                     }
                 }
             }
         });
     };
 
     Notebook.prototype.copy_notebook = function(){
         var path = this.notebook_path;
         var base_url = this.base_url;
         var settings = {
             processData : false,
             cache : false,
             type : "POST",
             dataType : "json",
             data : JSON.stringify({copy_from : this.notebook_name}),
             async : false,
             success : function (data, status, xhr) {
                 window.open(utils.url_join_encode(
                     base_url,
                     'notebooks',
                     data.path,
                     data.name
                 ), '_blank');
             },
             error : utils.log_ajax_error,
         };
         var url = utils.url_join_encode(
             base_url,
             'api/contents',
             path
         );
         $.ajax(url,settings);
     };
 
     Notebook.prototype.rename = function (new_name) {
         if (!new_name.match(/\.ipynb$/)) {
             new_name = new_name + ".ipynb";
         }
 
         var that = this;
         this.contents.rename_file(this.notebook_path, this.notebook_name,
                                   this.notebook_path, new_name, {
             success: function (json, status, xhr) {
                 var name = that.notebook_name = json.name;
                 that.session.rename_notebook(name, json.path);
                 that.events.trigger('notebook_renamed.Notebook', json);
             },
             error: $.proxy(this.rename_error, this)
         });
     };
 
     Notebook.prototype.delete = function () {
         this.contents.delete_file(this.notebook_name, this.notebook_path);
     };
 
     Notebook.prototype.rename_error = function (xhr, status, error) {
         var that = this;
         var dialog_body = $('<div/>').append(
             $("<p/>").text('This notebook name already exists.')
         );
         this.events.trigger('notebook_rename_failed.Notebook', [xhr, status, error]);
         dialog.modal({
             notebook: this,
             keyboard_manager: this.keyboard_manager,
             title: "Notebook Rename Error!",
             body: dialog_body,
             buttons : {
                 "Cancel": {},
                 "OK": {
                     class: "btn-primary",
                     click: function () {
                         that.save_widget.rename_notebook({notebook:that});
                 }}
                 },
             open : function (event, ui) {
                 var that = $(this);
                 // Upon ENTER, click the OK button.
                 that.find('input[type="text"]').keydown(function (event, ui) {
                     if (event.which === this.keyboard.keycodes.enter) {
                         that.find('.btn-primary').first().click();
                     }
                 });
                 that.find('input[type="text"]').focus();
             }
         });
     };
 
     /**
      * Request a notebook's data from the server.
      * 
      * @method load_notebook
      * @param {String} notebook_name and path A notebook to load
      */
     Notebook.prototype.load_notebook = function (notebook_name, notebook_path) {
         this.notebook_name = notebook_name;
         this.notebook_path = notebook_path;
         this.events.trigger('notebook_loading.Notebook');
         this.contents.load_file(notebook_path, notebook_name, {
             success: $.proxy(this.load_notebook_success, this),
             error: $.proxy(this.load_notebook_error, this)
         });
     };
 
     /**
      * Success callback for loading a notebook from the server.
      * 
      * Load notebook data from the JSON response.
      * 
      * @method load_notebook_success
      * @param {Object} data JSON representation of a notebook
      * @param {String} status Description of response status
      * @param {jqXHR} xhr jQuery Ajax object
      */
     Notebook.prototype.load_notebook_success = function (data, status, xhr) {
         var failed;
         try {
             this.fromJSON(data);
         } catch (e) {
             failed = e;
             console.log("Notebook failed to load from JSON:", e);
         }
         if (failed || data.message) {
             // *either* fromJSON failed or validation failed
             var body = $("<div>");
             var title;
             if (failed) {
                 title = "Notebook failed to load";
                 body.append($("<p>").text(
                     "The error was: "
                 )).append($("<div>").addClass("js-error").text(
                     failed.toString()
                 )).append($("<p>").text(
                     "See the error console for details."
                 ));
             } else {
                 title = "Notebook validation failed";
             }
 
             if (data.message) {
                 var msg;
                 if (failed) {
                     msg = "The notebook also failed validation:"
                 } else {
                     msg = "An invalid notebook may not function properly." +
                     " The validation error was:"
                 }
                 body.append($("<p>").text(
                     msg
                 )).append($("<div>").addClass("validation-error").append(
                     $("<pre>").text(data.message)
                 ));
             }
 
             dialog.modal({
                 notebook: this,
                 keyboard_manager: this.keyboard_manager,
                 title: title,
                 body: body,
                 buttons : {
                     OK : {
                         "class" : "btn-primary"
                     }
                 }
             });
         }
         if (this.ncells() === 0) {
             this.insert_cell_below('code');
             this.edit_mode(0);
         } else {
             this.select(0);
             this.handle_command_mode(this.get_cell(0));
         }
         this.set_dirty(false);
         this.scroll_to_top();
         var nbmodel = data.content;
         var orig_nbformat = nbmodel.metadata.orig_nbformat;
         var orig_nbformat_minor = nbmodel.metadata.orig_nbformat_minor;
         if (orig_nbformat !== undefined && nbmodel.nbformat !== orig_nbformat) {
             var msg = "This notebook has been converted from an older " +
             "notebook format (v"+orig_nbformat+") to the current notebook " +
             "format (v"+nbmodel.nbformat+"). The next time you save this notebook, the " +
             "newer notebook format will be used and older versions of IPython " +
             "may not be able to read it. To keep the older version, close the " +
             "notebook without saving it.";
             dialog.modal({
                 notebook: this,
                 keyboard_manager: this.keyboard_manager,
                 title : "Notebook converted",
                 body : msg,
                 buttons : {
                     OK : {
                         class : "btn-primary"
                     }
                 }
             });
         } else if (orig_nbformat_minor !== undefined && nbmodel.nbformat_minor !== orig_nbformat_minor) {
             var that = this;
             var orig_vs = 'v' + nbmodel.nbformat + '.' + orig_nbformat_minor;
             var this_vs = 'v' + nbmodel.nbformat + '.' + this.nbformat_minor;
             var msg = "This notebook is version " + orig_vs + ", but we only fully support up to " +
             this_vs + ".  You can still work with this notebook, but some features " +
             "introduced in later notebook versions may not be available.";
 
             dialog.modal({
                 notebook: this,
                 keyboard_manager: this.keyboard_manager,
                 title : "Newer Notebook",
                 body : msg,
                 buttons : {
                     OK : {
                         class : "btn-danger"
                     }
                 }
             });
 
         }
         
         // Create the session after the notebook is completely loaded to prevent
         // code execution upon loading, which is a security risk.
         if (this.session === null) {
             var kernelspec = this.metadata.kernelspec || {};
             var kernel_name = kernelspec.name;
 
             this.start_session(kernel_name);
         }
         // load our checkpoint list
         this.list_checkpoints();
         
         // load toolbar state
         if (this.metadata.celltoolbar) {
             celltoolbar.CellToolbar.global_show();
             celltoolbar.CellToolbar.activate_preset(this.metadata.celltoolbar);
         } else {
             celltoolbar.CellToolbar.global_hide();
         }
 
         // now that we're fully loaded, it is safe to restore save functionality
         delete(this.save_notebook);
         this.events.trigger('notebook_loaded.Notebook');
     };
 
     /**
      * Failure callback for loading a notebook from the server.
      * 
      * @method load_notebook_error
      * @param {jqXHR} xhr jQuery Ajax object
      * @param {String} status Description of response status
      * @param {String} error HTTP error message
      */
     Notebook.prototype.load_notebook_error = function (xhr, status, error) {
         this.events.trigger('notebook_load_failed.Notebook', [xhr, status, error]);
         utils.log_ajax_error(xhr, status, error);
         var msg = $("<div>");
         if (xhr.status === 400) {
             msg.text(utils.ajax_error_msg(xhr));
         } else if (xhr.status === 500) {
             msg.text("An unknown error occurred while loading this notebook. " +
             "This version can load notebook formats " +
             "v" + this.nbformat + " or earlier. See the server log for details.");
         }
         dialog.modal({
             notebook: this,
             keyboard_manager: this.keyboard_manager,
             title: "Error loading notebook",
             body : msg,
             buttons : {
                 "OK": {}
             }
         });
     };
 
     /*********************  checkpoint-related  *********************/
     
     /**
      * Save the notebook then immediately create a checkpoint.
      * 
      * @method save_checkpoint
      */
     Notebook.prototype.save_checkpoint = function () {
         this._checkpoint_after_save = true;
         this.save_notebook();
     };
     
     /**
      * Add a checkpoint for this notebook.
      * for use as a callback from checkpoint creation.
      * 
      * @method add_checkpoint
      */
     Notebook.prototype.add_checkpoint = function (checkpoint) {
         var found = false;
         for (var i = 0; i < this.checkpoints.length; i++) {
             var existing = this.checkpoints[i];
             if (existing.id == checkpoint.id) {
                 found = true;
                 this.checkpoints[i] = checkpoint;
                 break;
             }
         }
         if (!found) {
             this.checkpoints.push(checkpoint);
         }
         this.last_checkpoint = this.checkpoints[this.checkpoints.length - 1];
     };
     
     /**
      * List checkpoints for this notebook.
      * 
      * @method list_checkpoints
      */
     Notebook.prototype.list_checkpoints = function () {
         var that = this;
         this.contents.list_checkpoints(this.notebook_path, this.notebook_name, {
             success: $.proxy(this.list_checkpoints_success, this),
             error: function(xhr, status, error_msg) {
                 that.events.trigger('list_checkpoints_failed.Notebook');
             }
         });
     };
 
     /**
      * Success callback for listing checkpoints.
      * 
      * @method list_checkpoint_success
      * @param {Object} data JSON representation of a checkpoint
      * @param {String} status Description of response status
      * @param {jqXHR} xhr jQuery Ajax object
      */
     Notebook.prototype.list_checkpoints_success = function (data, status, xhr) {
         data = $.parseJSON(data);
         this.checkpoints = data;
         if (data.length) {
             this.last_checkpoint = data[data.length - 1];
         } else {
             this.last_checkpoint = null;
         }
         this.events.trigger('checkpoints_listed.Notebook', [data]);
     };
 
     /**
      * Create a checkpoint of this notebook on the server from the most recent save.
      * 
      * @method create_checkpoint
      */
     Notebook.prototype.create_checkpoint = function () {
         var that = this;
         this.contents.create_checkpoint(this.notebook_path, this.notebook_name, {
             success: $.proxy(this.create_checkpoint_success, this),
             error: function (xhr, status, error_msg) {
                 that.events.trigger('checkpoint_failed.Notebook');
             }
         });
     };
 
     /**
      * Success callback for creating a checkpoint.
      * 
      * @method create_checkpoint_success
      * @param {Object} data JSON representation of a checkpoint
      * @param {String} status Description of response status
      * @param {jqXHR} xhr jQuery Ajax object
      */
     Notebook.prototype.create_checkpoint_success = function (data, status, xhr) {
         data = $.parseJSON(data);
         this.add_checkpoint(data);
         this.events.trigger('checkpoint_created.Notebook', data);
     };
 
     Notebook.prototype.restore_checkpoint_dialog = function (checkpoint) {
         var that = this;
         checkpoint = checkpoint || this.last_checkpoint;
         if ( ! checkpoint ) {
             console.log("restore dialog, but no checkpoint to restore to!");
             return;
         }
         var body = $('<div/>').append(
             $('<p/>').addClass("p-space").text(
                 "Are you sure you want to revert the notebook to " +
                 "the latest checkpoint?"
             ).append(
                 $("<strong/>").text(
                     " This cannot be undone."
                 )
             )
         ).append(
             $('<p/>').addClass("p-space").text("The checkpoint was last updated at:")
         ).append(
             $('<p/>').addClass("p-space").text(
                 Date(checkpoint.last_modified)
             ).css("text-align", "center")
         );
         
         dialog.modal({
             notebook: this,
             keyboard_manager: this.keyboard_manager,
             title : "Revert notebook to checkpoint",
             body : body,
             buttons : {
                 Revert : {
                     class : "btn-danger",
                     click : function () {
                         that.restore_checkpoint(checkpoint.id);
                     }
                 },
                 Cancel : {}
                 }
         });
     };
     
     /**
      * Restore the notebook to a checkpoint state.
      * 
      * @method restore_checkpoint
      * @param {String} checkpoint ID
      */
     Notebook.prototype.restore_checkpoint = function (checkpoint) {
         this.events.trigger('notebook_restoring.Notebook', checkpoint);
         var that = this;
         this.contents.restore_checkpoint(this.notebook_path, this.notebook_name,
                                          checkpoint, {
             success: $.proxy(this.create_checkpoint_success, this),
             error: function (xhr, status, error_msg) {
                 that.events.trigger('checkpoint_restore_failed.Notebook');
             }
         });
     };
     
     /**
      * Success callback for restoring a notebook to a checkpoint.
      * 
      * @method restore_checkpoint_success
      * @param {Object} data (ignored, should be empty)
      * @param {String} status Description of response status
      * @param {jqXHR} xhr jQuery Ajax object
      */
     Notebook.prototype.restore_checkpoint_success = function (data, status, xhr) {
         this.events.trigger('checkpoint_restored.Notebook');
         this.load_notebook(this.notebook_name, this.notebook_path);
     };
 
     /**
      * Delete a notebook checkpoint.
      * 
      * @method delete_checkpoint
      * @param {String} checkpoint ID
      */
     Notebook.prototype.delete_checkpoint = function (checkpoint) {
         this.events.trigger('notebook_restoring.Notebook', checkpoint);
         var that = this;
         this.contents.delete_checkpoint(this.notebook_path, this.notebook_name, 
                                         checkpoint, {
             success: $.proxy(this.create_checkpoint_success, this),
             error: function (xhr, status, error_msg) {
                 that.events.trigger('checkpoint_delete_failed.Notebook', [xhr, status, error]);
             }
         });
     };
     
     /**
      * Success callback for deleting a notebook checkpoint
      * 
      * @method delete_checkpoint_success
      * @param {Object} data (ignored, should be empty)
      * @param {String} status Description of response status
      * @param {jqXHR} xhr jQuery Ajax object
      */
     Notebook.prototype.delete_checkpoint_success = function (data, status, xhr) {
         this.events.trigger('checkpoint_deleted.Notebook', data);
         this.load_notebook(this.notebook_name, this.notebook_path);
     };
 
 
     // For backwards compatability.
     IPython.Notebook = Notebook;
 
     return {'Notebook': Notebook};
 });

IPython/html/static/tree/js/main.js

@@ -1,149 +1,149 b''
 // Copyright (c) IPython Development Team.
 // Distributed under the terms of the Modified BSD License.
 
 require([
     'base/js/namespace',
     'jquery',
     'base/js/events',
     'base/js/page',
     'base/js/utils',
     'contents',
     'tree/js/notebooklist',
     'tree/js/clusterlist',
     'tree/js/sessionlist',
     'tree/js/kernellist',
     'tree/js/terminallist',
     'auth/js/loginwidget',
     // only loaded, not used:
     'jqueryui',
     'bootstrap',
     'custom/custom',
 ], function(
     IPython, 
     $, 
     events,
     page, 
     utils, 
     contents,
     notebooklist, 
     clusterlist, 
     sesssionlist, 
     kernellist,
     terminallist,
     loginwidget){
 
     page = new page.Page();
     
     var common_options = {
         base_url: utils.get_body_data("baseUrl"),
         notebook_path: utils.get_body_data("notebookPath"),
     };
     session_list = new sesssionlist.SesssionList($.extend({
         events: events}, 
         common_options));
     contents = new contents.Contents($.extend({
         events: events},
         common_options));
     notebook_list = new notebooklist.NotebookList('#notebook_list', $.extend({
         contents: contents,
         session_list:  session_list}, 
         common_options));
     cluster_list = new clusterlist.ClusterList('#cluster_list', common_options);
     kernel_list = new kernellist.KernelList('#running_list',  $.extend({
         session_list:  session_list}, 
         common_options));
     
     if (utils.get_body_data("terminalsAvailable") === "True") {
         terminal_list = new terminallist.TerminalList('#terminal_list', common_options);
     }
 
     login_widget = new loginwidget.LoginWidget('#login_widget', common_options);
 
-    $('#new_notebook').button().click(function (e) {
+    $('#new_notebook').click(function (e) {
         contents.new_notebook(common_options.notebook_path,
             {
                 success: function (data, status, xhr) {
                     window.open(
                         utils.url_join_encode(
                             common_options.base_url, 'notebooks',
                             data.path, data.name
                         ), '_blank');
                     },
                 error: function(xhr, status, error) {
                     var msg;
                     if (xhr.responseJSON && xhr.responseJSON.message) {
                         msg = xhr.responseJSON.message;
                     } else {
                         msg = xhr.statusText;
                     }
                     dialog.modal({
                         title : 'Creating Notebook Failed',
                         body : "The error was: " + msg,
                         buttons : {'OK' : {'class' : 'btn-primary'}}
                     });
                 }
             });
     });
 
     var interval_id=0;
     // auto refresh every xx secondes, no need to be fast,
     //  update is done at least when page get focus
     var time_refresh = 60; // in sec
 
     var enable_autorefresh = function(){
         //refresh immediately , then start interval
         session_list.load_sessions();
         cluster_list.load_list();
         if (!interval_id){
             interval_id = setInterval(function(){
                     session_list.load_sessions();
                     cluster_list.load_list();
                 }, time_refresh*1000);
             }
     };
 
     var disable_autorefresh = function(){
         clearInterval(interval_id);
         interval_id = 0;
     };
 
     // stop autorefresh when page lose focus
     $(window).blur(function() {
         disable_autorefresh();
     });
 
     //re-enable when page get focus back
     $(window).focus(function() {
         enable_autorefresh();
     });
 
     // finally start it, it will refresh immediately
     enable_autorefresh();
 
     page.show();
 
     // For backwards compatability.
     IPython.page = page;
     IPython.notebook_list = notebook_list;
     IPython.cluster_list = cluster_list;
     IPython.session_list = session_list;
     IPython.kernel_list = kernel_list;
     IPython.login_widget = login_widget;
 
     events.trigger('app_initialized.DashboardApp');
     
     // bound the upload method to the on change of the file select list
     $("#alternate_upload").change(function (event){
         notebook_list.handleFilesUpload(event,'form');
     });
     
     // set hash on tab click
     $("#tabs").find("a").click(function() {
         window.location.hash = $(this).attr("href");
     });
     
     // load tab if url hash
     if (window.location.hash) {
         $("#tabs").find("a[href=" + window.location.hash + "]").click();
     }
 });

IPython/html/static/tree/js/notebooklist.js

@@ -1,486 +1,486 b''
 // Copyright (c) IPython Development Team.
 // Distributed under the terms of the Modified BSD License.
 
 define([
     'base/js/namespace',
     'jquery',
     'base/js/utils',
     'base/js/dialog',
 ], function(IPython, $, utils, dialog) {
     "use strict";
     
     var NotebookList = function (selector, options) {
         // Constructor
         //
         // Parameters:
         //  selector: string
         //  options: dictionary
         //      Dictionary of keyword arguments.
         //          session_list: SessionList instance
         //          element_name: string
         //          base_url: string
         //          notebook_path: string
         //          contents: Contents instance
         var that = this;
         this.session_list = options.session_list;
         // allow code re-use by just changing element_name in kernellist.js
         this.element_name = options.element_name || 'notebook';
         this.selector = selector;
         if (this.selector !== undefined) {
             this.element = $(selector);
             this.style();
             this.bind_events();
         }
         this.notebooks_list = [];
         this.sessions = {};
         this.base_url = options.base_url || utils.get_body_data("baseUrl");
         this.notebook_path = options.notebook_path || utils.get_body_data("notebookPath");
         this.contents = options.contents;
         if (this.session_list && this.session_list.events) {
             this.session_list.events.on('sessions_loaded.Dashboard', 
                 function(e, d) { that.sessions_loaded(d); });
         }
     };
 
     NotebookList.prototype.style = function () {
         var prefix = '#' + this.element_name;
         $(prefix + '_toolbar').addClass('list_toolbar');
         $(prefix + '_list_info').addClass('toolbar_info');
         $(prefix + '_buttons').addClass('toolbar_buttons');
         $(prefix + '_list_header').addClass('list_header');
         this.element.addClass("list_container");
     };
 
 
     NotebookList.prototype.bind_events = function () {
         var that = this;
         $('#refresh_' + this.element_name + '_list').click(function () {
             that.load_sessions();
         });
         this.element.bind('dragover', function () {
             return false;
         });
         this.element.bind('drop', function(event){
             that.handleFilesUpload(event,'drop');
             return false;
         });
     };
 
     NotebookList.prototype.handleFilesUpload =  function(event, dropOrForm) {
         var that = this;
         var files;
         if(dropOrForm =='drop'){
             files = event.originalEvent.dataTransfer.files;
         } else 
         {
             files = event.originalEvent.target.files;
         }
         for (var i = 0; i < files.length; i++) {
             var f = files[i];
             var name_and_ext = utils.splitext(f.name);
             var file_ext = name_and_ext[1];
 
             var reader = new FileReader();
             if (file_ext === '.ipynb') {
                 reader.readAsText(f);
             } else {
                 // read non-notebook files as binary
                 reader.readAsArrayBuffer(f);
             }
             var item = that.new_item(0);
             item.addClass('new-file');
             that.add_name_input(f.name, item, file_ext == '.ipynb' ? 'notebook' : 'file');
             // Store the list item in the reader so we can use it later
             // to know which item it belongs to.
             $(reader).data('item', item);
             reader.onload = function (event) {
                 var item = $(event.target).data('item');
                 that.add_file_data(event.target.result, item);
                 that.add_upload_button(item);
             };
             reader.onerror = function (event) {
                 var item = $(event.target).data('item');
                 var name = item.data('name')
                 item.remove();
                 dialog.modal({
                     title : 'Failed to read file',
                     body : "Failed to read file '" + name + "'",
                     buttons : {'OK' : { 'class' : 'btn-primary' }}
                 });
             };
         }
         // Replace the file input form wth a clone of itself. This is required to
         // reset the form. Otherwise, if you upload a file, delete it and try to 
         // upload it again, the changed event won't fire.
         var form = $('input.fileinput');
         form.replaceWith(form.clone(true));
         return false;
     };
 
     NotebookList.prototype.clear_list = function (remove_uploads) {
         // Clears the navigation tree.
         //
         // Parameters
         // remove_uploads: bool=False
         //      Should upload prompts also be removed from the tree.
         if (remove_uploads) {
             this.element.children('.list_item').remove();
         } else {
             this.element.children('.list_item:not(.new-file)').remove();  
         }
     };
 
     NotebookList.prototype.load_sessions = function(){
         this.session_list.load_sessions();
     };
 
 
     NotebookList.prototype.sessions_loaded = function(data){
         this.sessions = data;
         this.load_list();
     };
 
     NotebookList.prototype.load_list = function () {
         var that = this
         this.contents.list_contents(that.notebook_path, {
             success: $.proxy(this.draw_notebook_list, this),
             error: function(xhr, status, error) { 
                 utils.log_ajax_error(xhr, status, error);
                 that.draw_notebook_list([], "Error connecting to server.");
             }
         });
     };
 
     /**
      * Draw the list of notebooks
      * @method draw_notebook_list
      * @param {Array} list An array of dictionaries representing files or
      *     direcotories.
      * @param {String} error_msg An error message
      */
     NotebookList.prototype.draw_notebook_list = function (list, error_msg) {
         var message = error_msg || 'Notebook list empty.';
         var item = null;
         var model = null;
         var len = list.content.length;
         this.clear_list();
         var n_uploads = this.element.children('.list_item').length;
         if (len === 0) {
             item = this.new_item(0);
             var span12 = item.children().first();
             span12.empty();
             span12.append($('<div style="margin:auto;text-align:center;color:grey"/>').text(message));
         }
         var path = this.notebook_path;
         var offset = n_uploads;
         if (path !== '') {
             item = this.new_item(offset);
             model = {
                 type: 'directory',
                 name: '..',
                 path: path,
             };
             this.add_link(model, item);
             offset += 1;
         }
         for (var i=0; i<len; i++) {
             model = list.content[i];
             item = this.new_item(i+offset);
             this.add_link(model, item);
         }
     };
 
 
     NotebookList.prototype.new_item = function (index) {
         var item = $('<div/>').addClass("list_item").addClass("row");
         // item.addClass('list_item ui-widget ui-widget-content ui-helper-clearfix');
         // item.css('border-top-style','none');
         item.append($("<div/>").addClass("col-md-12").append(
             $('<i/>').addClass('item_icon')
         ).append(
             $("<a/>").addClass("item_link").append(
                 $("<span/>").addClass("item_name")
             )
         ).append(
             $('<div/>').addClass("item_buttons btn-group pull-right")
         ));
         
         if (index === -1) {
             this.element.append(item);
         } else {
             this.element.children().eq(index).after(item);
         }
         return item;
     };
 
 
     NotebookList.icons = {
         directory: 'folder_icon',
         notebook: 'notebook_icon',
         file: 'file_icon',
     };
 
     NotebookList.uri_prefixes = {
         directory: 'tree',
         notebook: 'notebooks',
         file: 'files',
     };
 
 
     NotebookList.prototype.add_link = function (model, item) {
         var path = model.path,
             name = model.name;
         item.data('name', name);
         item.data('path', path);
         item.find(".item_name").text(name);
         var icon = NotebookList.icons[model.type];
         var uri_prefix = NotebookList.uri_prefixes[model.type];
         item.find(".item_icon").addClass(icon).addClass('icon-fixed-width');
         var link = item.find("a.item_link")
             .attr('href',
                 utils.url_join_encode(
                     this.base_url,
                     uri_prefix,
                     path,
                     name
                 )
             );
         // directory nav doesn't open new tabs
         // files, notebooks do
         if (model.type !== "directory") {
             link.attr('target','_blank');
         }
         var path_name = utils.url_path_join(path, name);
         if (model.type == 'file') {
             this.add_delete_button(item);
         } else if (model.type == 'notebook') {
             if(this.sessions[path_name] === undefined){
                 this.add_delete_button(item);
             } else {
                 this.add_shutdown_button(item, this.sessions[path_name]);
             }
         }
     };
 
 
     NotebookList.prototype.add_name_input = function (name, item, icon_type) {
         item.data('name', name);
         item.find(".item_icon").addClass(NotebookList.icons[icon_type]).addClass('icon-fixed-width');
         item.find(".item_name").empty().append(
             $('<input/>')
             .addClass("filename_input")
             .attr('value', name)
             .attr('size', '30')
             .attr('type', 'text')
             .keyup(function(event){
                 if(event.keyCode == 13){item.find('.upload_button').click();}
                 else if(event.keyCode == 27){item.remove();}
             })
         );
     };
 
 
     NotebookList.prototype.add_file_data = function (data, item) {
         item.data('filedata', data);
     };
 
 
     NotebookList.prototype.add_shutdown_button = function (item, session) {
         var that = this;
         var shutdown_button = $("<button/>").text("Shutdown").addClass("btn btn-xs btn-danger").
             click(function (e) {
                 var settings = {
                     processData : false,
                     cache : false,
                     type : "DELETE",
                     dataType : "json",
                     success : function () {
                         that.load_sessions();
                     },
                     error : utils.log_ajax_error,
                 };
                 var url = utils.url_join_encode(
                     that.base_url,
                     'api/sessions',
                     session
                 );
                 $.ajax(url, settings);
                 return false;
             });
         // var new_buttons = item.find('a'); // shutdown_button;
         item.find(".item_buttons").text("").append(shutdown_button);
     };
 
     NotebookList.prototype.add_delete_button = function (item) {
         var new_buttons = $('<span/>').addClass("btn-group pull-right");
         var notebooklist = this;
         var delete_button = $("<button/>").text("Delete").addClass("btn btn-default btn-xs").
             click(function (e) {
                 // $(this) is the button that was clicked.
                 var that = $(this);
                 // We use the filename from the parent list_item element's
                 // data because the outer scope's values change as we iterate through the loop.
                 var parent_item = that.parents('div.list_item');
-                var nbname = parent_item.data('nbname');
+                var name = parent_item.data('nbname');
                 var path = parent_item.data('path');
-                var message = 'Are you sure you want to permanently delete the notebook: ' + nbname + '?';
+                var message = 'Are you sure you want to permanently delete the file: ' + nbname + '?';
                 dialog.modal({
                     title : "Delete file",
                     body : message,
                     buttons : {
                         Delete : {
                             class: "btn-danger",
                             click: function() {
-                                notebooklist.contents.delete_file(nbname, path, {
+                                notebooklist.contents.delete_file(name, path, {
                                     success: function() {
-                                        notebooklist.notebook_deleted(path, nbname);
+                                        notebooklist.notebook_deleted(path, name);
                                     }
                                 });
                             }
                         },
                         Cancel : {}
                     }
                 });
                 return false;
             });
         item.find(".item_buttons").text("").append(delete_button);
     };
 
     NotebookList.prototype.notebook_deleted = function(path, name) {
         // Remove the deleted notebook.
         $( ":data(nbname)" ).each(function() {
             var element = $( this );
             if (element.data( "nbname" ) == d.name &&
                 element.data( "path" ) == d.path) {
                 element.remove();
             }
         });
     }
 
 
     NotebookList.prototype.add_upload_button = function (item, type) {
         var that = this;
         var upload_button = $('<button/>').text("Upload")
             .addClass('btn btn-primary btn-xs upload_button')
             .click(function (e) {
                 var path = that.notebook_path;
                 var filename = item.find('.item_name > input').val();
                 var filedata = item.data('filedata');
                 var format = 'text';
                 if (filename.length === 0 || filename[0] === '.') {
                     dialog.modal({
                         title : 'Invalid file name',
                         body : "File names must be at least one character and not start with a dot",
                         buttons : {'OK' : { 'class' : 'btn-primary' }}
                     });
                     return false;
                 }
                 if (filedata instanceof ArrayBuffer) {
                     // base64-encode binary file data
                     var bytes = '';
                     var buf = new Uint8Array(filedata);
                     var nbytes = buf.byteLength;
                     for (var i=0; i<nbytes; i++) {
                         bytes += String.fromCharCode(buf[i]);
                     }
                     filedata = btoa(bytes);
                     format = 'base64';
                 }
                 var model = {
                     path: path,
                     name: filename
                 };
 
                 var name_and_ext = utils.splitext(filename);
                 var file_ext = name_and_ext[1];
                 var content_type;
                 if (file_ext === '.ipynb') {
                     model.type = 'notebook';
                     model.format = 'json';
                     try {
                         model.content = JSON.parse(filedata);
                     } catch (e) {
                         dialog.modal({
                             title : 'Cannot upload invalid Notebook',
                             body : "The error was: " + e,
                             buttons : {'OK' : {
                                 'class' : 'btn-primary',
                                 click: function () {
                                     item.remove();
                                 }
                             }}
                         });
                         return false;
                     }
                     content_type = 'application/json';
                 } else {
                     model.type = 'file';
                     model.format = format;
                     model.content = filedata;
                     content_type = 'application/octet-stream';
                 }
                 var filedata = item.data('filedata');
 
                 var settings = {
                     processData : false,
                     cache : false,
                     type : 'PUT',
                     data : JSON.stringify(model),
                     contentType: content_type,
                     success : function (data, status, xhr) {
                         item.removeClass('new-file');
                         that.add_link(model, item);
                         that.add_delete_button(item);
                         that.session_list.load_sessions();
                     },
                     error : utils.log_ajax_error,
                 };
 
                 var url = utils.url_join_encode(
                     that.base_url,
                     'api/contents',
                     that.notebook_path,
                     filename
                 );
                 
                 var exists = false;
                 $.each(that.element.find('.list_item:not(.new-file)'), function(k,v){
                     if ($(v).data('name') === filename) { exists = true; return false; }
                 });
                 if (exists) {
                     dialog.modal({
                         title : "Replace file",
                         body : 'There is already a file named ' + filename + ', do you want to replace it?',
                         buttons : {
                             Overwrite : {
                                 class: "btn-danger",
                                 click: function() { $.ajax(url, settings); }
                             },
                             Cancel : {
                                 click: function() { item.remove(); }
                             }
                         }
                     });
                 } else {
                     $.ajax(url, settings);
                 }
                 
                 return false;
             });
         var cancel_button = $('<button/>').text("Cancel")
             .addClass("btn btn-default btn-xs")
             .click(function (e) {
                 item.remove();
                 return false;
             });
         item.find(".item_buttons").empty()
             .append(upload_button)
             .append(cancel_button);
     };
 
 
     // Backwards compatability.    
     IPython.NotebookList = NotebookList;
 
     return {'NotebookList': NotebookList};
 });