Massive work on the notebook document format.

* Finished nbformat work and debugged the versioning API.
* Integrated the nbformat with the notebook. Save/New/Open/Export
  are all now working.

IPython/frontend/html/notebook/notebookmanager.py

@@ -0,0 +1,195 b''
+#-----------------------------------------------------------------------------
+#  Copyright (C) 2011  The IPython Development Team
+#
+#  Distributed under the terms of the BSD License.  The full license is in
+#  the file COPYING.txt, distributed as part of this software.
+#-----------------------------------------------------------------------------
+
+#-----------------------------------------------------------------------------
+# Imports
+#-----------------------------------------------------------------------------
+
+import datetime
+import os
+import uuid
+
+from tornado import web
+
+from IPython.config.configurable import Configurable
+from IPython.nbformat import current
+from IPython.utils.traitlets import Unicode, List, Dict
+
+
+#-----------------------------------------------------------------------------
+# Code
+#-----------------------------------------------------------------------------
+
+
+class NotebookManager(Configurable):
+
+    notebook_dir = Unicode(os.getcwd())
+    filename_ext = Unicode(u'.ipynb')
+    allowed_formats = List([u'json',u'xml',u'py'])
+
+    # Map notebook_ids to notebook names
+    mapping = Dict()
+    # Map notebook names to notebook_ids
+    rev_mapping = Dict()
+
+    def list_notebooks(self):
+        """List all notebooks in the notebook dir.
+
+        This returns a list of dicts of the form::
+
+            dict(notebook_id=notebook,name=name)
+        """
+        names = os.listdir(self.notebook_dir)
+        names = [name.strip(self.filename_ext)\
+            for name in names if name.endswith(self.filename_ext)]
+        data = []
+        for name in names:
+            if name not in self.rev_mapping:
+                notebook_id = self.new_notebook_id(name)
+            else:
+                notebook_id = self.rev_mapping[name]
+            data.append(dict(notebook_id=notebook_id,name=name))
+        return data
+
+    def new_notebook_id(self, name):
+        """Generate a new notebook_id for a name and store its mappings."""
+        notebook_id = unicode(uuid.uuid4())
+        self.mapping[notebook_id] = name
+        self.rev_mapping[name] = notebook_id
+        return notebook_id
+
+    def delete_notebook_id(self, notebook_id):
+        """Delete a notebook's id only. This doesn't delete the actual notebook."""
+        name = self.mapping[notebook_id]
+        del self.mapping[notebook_id]
+        del self.rev_mapping[name]
+
+    def notebook_exists(self, notebook_id):
+        """Does a notebook exist?"""
+        if notebook_id not in self.mapping:
+            return False
+        path = self.get_path_by_name(self.mapping[notebook_id])
+        if not os.path.isfile(path):
+            return False
+        return True        
+
+    def find_path(self, notebook_id):
+        """Return a full path to a notebook given its notebook_id."""
+        try:
+            name = self.mapping[notebook_id]
+        except KeyError:
+            raise web.HTTPError(404)
+        return self.get_path_by_name(name)
+
+    def get_path_by_name(self, name):
+        """Return a full path to a notebook given its name."""
+        filename = name + self.filename_ext
+        path = os.path.join(self.notebook_dir, filename)
+        return path       
+
+    def get_notebook(self, notebook_id, format=u'json'):
+        """Get the representation of a notebook in format by notebook_id."""
+        format = unicode(format)
+        if format not in self.allowed_formats:
+            raise web.HTTPError(415)
+        last_modified, nb = self.get_notebook_object(notebook_id)
+        data = current.writes(nb, format)
+        name = nb.get('name','notebook')
+        return last_modified, name, data
+
+    def get_notebook_object(self, notebook_id):
+        """Get the NotebookNode representation of a notebook by notebook_id."""
+        path = self.find_path(notebook_id)
+        if not os.path.isfile(path):
+            raise web.HTTPError(404)
+        info = os.stat(path)
+        last_modified = datetime.datetime.utcfromtimestamp(info.st_mtime)
+        try:
+            with open(path,'r') as f:
+                s = f.read()
+                try:
+                    # v2 and later have xml in the .ipynb files
+                    nb = current.reads(s, 'xml')
+                except:
+                    # v1 had json in the .ipynb files
+                    nb = current.reads(s, 'json')
+        except:
+            raise web.HTTPError(404)
+        return last_modified, nb
+
+    def save_new_notebook(self, data, format=u'json'):
+        """Save a new notebook and return its notebook_id."""
+        if format not in self.allowed_formats:
+            raise web.HTTPError(415)
+        try:
+            nb = current.reads(data, format)
+        except:
+            raise web.HTTPError(400)
+        try:
+            name = nb.name
+        except AttributeError:
+            raise web.HTTPError(400)
+        notebook_id = self.new_notebook_id(name)
+        self.save_notebook_object(notebook_id, nb)
+        return notebook_id
+
+    def save_notebook(self, notebook_id, data, format=u'json'):
+        """Save an existing notebook by notebook_id."""
+        if format not in self.allowed_formats:
+            raise web.HTTPError(415)
+        try:
+            nb = current.reads(data, format)
+        except:
+            raise web.HTTPError(400)
+        self.save_notebook_object(notebook_id, nb)
+
+    def save_notebook_object(self, notebook_id, nb):
+        """Save an existing notebook object by notebook_id."""
+        if notebook_id not in self.mapping:
+            raise web.HTTPError(404)
+        old_name = self.mapping[notebook_id]
+        try:
+            new_name = nb.name
+        except AttributeError:
+            raise web.HTTPError(400)
+        path = self.get_path_by_name(new_name)
+        try:
+            with open(path,'w') as f:
+                current.write(nb, f, u'xml')
+        except:
+            raise web.HTTPError(400)
+        if old_name != new_name:
+            old_path = self.get_path_by_name(old_name)
+            if os.path.isfile(old_path):
+                os.unlink(old_path)
+            self.mapping[notebook_id] = new_name
+            self.rev_mapping[new_name] = notebook_id
+
+    def delete_notebook(self, notebook_id):
+        """Delete notebook by notebook_id."""
+        path = self.find_path(notebook_id)
+        if not os.path.isfile(path):
+            raise web.HTTPError(404)
+        os.unlink(path)
+        self.delete_notebook_id(notebook_id)
+
+    def new_notebook(self):
+        """Create a new notebook and returns its notebook_id."""
+        i = 0
+        while True:
+            name = u'Untitled%i' % i
+            path = self.get_path_by_name(name)
+            if not os.path.isfile(path):
+                break
+            else:
+                i = i+1
+        notebook_id = self.new_notebook_id(name)
+        nb = current.new_notebook(name=name, id=notebook_id)
+        with open(path,'w') as f:
+            current.write(nb, f, u'xml')
+        return notebook_id
+

IPython/frontend/html/notebook/handlers.py

@@ -4,15 +4,14 b''
 # Imports
 #-----------------------------------------------------------------------------
 
-import datetime
 import json
 import logging
-import os
 import urllib
 
 from tornado import web
 from tornado import websocket
 
+
 #-----------------------------------------------------------------------------
 # Handlers
 #-----------------------------------------------------------------------------
@@ -20,7 +19,16 b' from tornado import websocket'
 
 class MainHandler(web.RequestHandler):
     def get(self):
-        self.render('notebook.html')
+        notebook_id = self.application.notebook_manager.new_notebook()
+        self.render('notebook.html', notebook_id=notebook_id)
+
+
+class NamedNotebookHandler(web.RequestHandler):
+    def get(self, notebook_id):
+        nbm = self.application.notebook_manager
+        if not nbm.notebook_exists(notebook_id):
+            raise web.HTTPError(404)
+        self.render('notebook.html', notebook_id=notebook_id)
 
 
 class KernelHandler(web.RequestHandler):
@@ -30,6 +38,7 b' class KernelHandler(web.RequestHandler):'
 
     def post(self):
         kernel_id = self.application.start_kernel()
+        self.set_header('Location', '/'+kernel_id)
         self.write(json.dumps(kernel_id))
 
 
@@ -65,52 +74,52 b' class ZMQStreamHandler(websocket.WebSocketHandler):'
 class NotebookRootHandler(web.RequestHandler):
 
     def get(self):
-        files = os.listdir(os.getcwd())
-        files = [file for file in files if file.endswith(".ipynb")]
+        nbm = self.application.notebook_manager
+        files = nbm.list_notebooks()
         self.write(json.dumps(files))
 
+    def post(self):
+        nbm = self.application.notebook_manager
+        body = self.request.body.strip()
+        format = self.get_argument('format', default='json')
+        if body:
+            notebook_id = nbm.save_new_notebook(body, format)
+        else:
+            notebook_id = nbm.new_notebook()
+        self.set_header('Location', '/'+notebook_id)
+        self.write(json.dumps(notebook_id))
 
-class NotebookHandler(web.RequestHandler):
-
-    SUPPORTED_METHODS = ("GET", "DELETE", "PUT")
 
-    def find_path(self, filename):
-        filename = urllib.unquote(filename)
-        if not filename.endswith('.ipynb'):
-            raise web.HTTPError(400)
-        path = os.path.join(os.getcwd(), filename)
-        return path
+class NotebookHandler(web.RequestHandler):
 
-    def get(self, filename):
-        path = self.find_path(filename)
-        if not os.path.isfile(path):
-            raise web.HTTPError(404)
-        info = os.stat(path)
-        self.set_header("Content-Type", "application/unknown")
-        self.set_header("Last-Modified", datetime.datetime.utcfromtimestamp(
-            info.st_mtime))
-        f = open(path, "r")
-        try:
-            self.finish(f.read())
-        finally:
-            f.close()
-
-    def put(self, filename):
-        path = self.find_path(filename)
-        f = open(path, "w")
-        f.write(self.request.body)
-        f.close()
+    SUPPORTED_METHODS = ('GET', 'PUT', 'DELETE')
+
+    def get(self, notebook_id):
+        nbm = self.application.notebook_manager
+        format = self.get_argument('format', default='json')
+        last_mod, name, data = nbm.get_notebook(notebook_id, format)
+        if format == u'json':
+            self.set_header('Content-Type', 'application/json')
+            self.set_header('Content-Disposition','attachment; filename=%s.json' % name)
+        elif format == u'xml':
+            self.set_header('Content-Type', 'text/xml')
+            self.set_header('Content-Disposition','attachment; filename=%s.ipynb' % name)
+        elif format == u'py':
+            self.set_header('Content-Type', 'text/plain')
+            self.set_header('Content-Disposition','attachment; filename=%s.py' % name)
+        self.set_header('Last-Modified', last_mod)
+        self.finish(data)
+
+    def put(self, notebook_id):
+        nbm = self.application.notebook_manager
+        format = self.get_argument('format', default='json')
+        nbm.save_notebook(notebook_id, self.request.body, format)
+        self.set_status(204)
         self.finish()
 
-    def delete(self, filename):
-        path = self.find_path(filename)
-        if not os.path.isfile(path):
-            raise web.HTTPError(404)
-        os.unlink(path)
+    def delete(self, notebook_id):
+        nbm = self.application.notebook_manager
+        nbm.delete_notebook(notebook_id)
         self.set_status(204)
         self.finish()
 
-
-
-
-

IPython/frontend/html/notebook/notebookapp.py

@@ -27,13 +27,15 b' tornado.ioloop = ioloop'
 from tornado import httpserver
 from tornado import web
 
-from kernelmanager import KernelManager
-from sessionmanager import SessionManager
-from handlers import (
-    MainHandler, KernelHandler, KernelActionHandler, ZMQStreamHandler,
+from .kernelmanager import KernelManager
+from .sessionmanager import SessionManager
+from .handlers import (
+    MainHandler, NamedNotebookHandler,
+    KernelHandler, KernelActionHandler, ZMQStreamHandler,
     NotebookRootHandler, NotebookHandler
 )
-from routers import IOPubStreamRouter, ShellStreamRouter
+from .routers import IOPubStreamRouter, ShellStreamRouter
+from .notebookmanager import NotebookManager
 
 from IPython.core.application import BaseIPythonApplication
 from IPython.core.profiledir import ProfileDir
@@ -53,6 +55,7 b' from IPython.utils.traitlets import Dict, Unicode, Int, Any, List, Enum'
 
 _kernel_id_regex = r"(?P<kernel_id>\w+-\w+-\w+-\w+-\w+)"
 _kernel_action_regex = r"(?P<action>restart|interrupt)"
+_notebook_id_regex = r"(?P<notebook_id>\w+-\w+-\w+-\w+-\w+)"
 
 LOCALHOST = '127.0.0.1'
 
@@ -65,12 +68,13 b' class NotebookWebApplication(web.Application):'
     def __init__(self, kernel_manager, log, kernel_argv, config):
         handlers = [
             (r"/", MainHandler),
+            (r"/%s" % _notebook_id_regex, NamedNotebookHandler),
             (r"/kernels", KernelHandler),
             (r"/kernels/%s/%s" % (_kernel_id_regex, _kernel_action_regex), KernelActionHandler),
             (r"/kernels/%s/iopub" % _kernel_id_regex, ZMQStreamHandler, dict(stream_name='iopub')),
             (r"/kernels/%s/shell" % _kernel_id_regex, ZMQStreamHandler, dict(stream_name='shell')),
             (r"/notebooks", NotebookRootHandler),
-            (r"/notebooks/([^/]+)", NotebookHandler)
+            (r"/notebooks/%s" % _notebook_id_regex, NotebookHandler)
         ]
         settings = dict(
             template_path=os.path.join(os.path.dirname(__file__), "templates"),
@@ -84,6 +88,7 b' class NotebookWebApplication(web.Application):'
         self.config = config
         self._routers = {}
         self._session_dict = {}
+        self.notebook_manager = NotebookManager(config=self.config)
 
     #-------------------------------------------------------------------------
     # Methods for managing kernels and sessions

IPython/frontend/html/notebook/routers.py

@@ -112,7 +112,7 b' class ShellStreamRouter(ZMQStreamRouter):'
     def forward_msg(self, client_id, msg):
         if len(msg) < self.max_msg_size:
             msg = json.loads(msg)
-            to_send = self.session.serialize(msg)
+            # to_send = self.session.serialize(msg)
             self._request_queue.put(client_id)        
             self.session.send(self.zmq_stream, msg)
 

IPython/frontend/html/notebook/static/css/notebook.css

@@ -206,6 +206,13 b' span.button_label {'
     font-size: 77%;
 }
 
+#download_format {
+    float: right;
+    font-size: 85%;
+    width: 60px;
+    margin: 1px 5px;
+}
+
 div#left_panel_splitter {
     width: 8px;
     top: 0px;

IPython/frontend/html/notebook/static/js/codecell.js

@@ -302,18 +302,28 b' var IPython = (function (IPython) {'
 
     CodeCell.prototype.fromJSON = function (data) {
         if (data.cell_type === 'code') {
-            this.set_code(data.code);
-            this.set_input_prompt(data.prompt_number);
+            if (data.input !== undefined) {
+                this.set_code(data.input);
+            }
+            if (data.prompt_number !== undefined) {
+                this.set_input_prompt(data.prompt_number);
+            } else {
+                this.set_input_prompt();
+            };
         };
     };
 
 
     CodeCell.prototype.toJSON = function () {
-        return {
-            code : this.get_code(),
-            cell_type : 'code',
-            prompt_number : this.input_prompt_number
+        var data = {}
+        data.input = this.get_code();
+        data.cell_type = 'code';
+        if (this.input_prompt_number !== ' ') {
+            data.prompt_number = this.input_prompt_number
         };
+        data.outputs = [];
+        data.language = 'python';
+        return data;
     };
 
     IPython.CodeCell = CodeCell;

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

@@ -14,14 +14,9 b' var IPython = (function (IPython) {'
         this.next_prompt_number = 1;
         this.kernel = null;
         this.msg_cell_map = {};
-        this.filename = null;
-        this.notebook_load_re = /%notebook load/
-        this.notebook_save_re = /%notebook save/
-        this.notebook_filename_re = /(\w)+.ipynb/
         this.style();
         this.create_elements();
         this.bind_events();
-        this.start_kernel();
     };
 
 
@@ -473,24 +468,8 b' var IPython = (function (IPython) {'
         if (cell instanceof IPython.CodeCell) {
             cell.clear_output();
             var code = cell.get_code();
-            if (that.notebook_load_re.test(code)) {
-                // %notebook load
-                var code_parts = code.split(' ');
-                if (code_parts.length === 3) {
-                    that.load_notebook(code_parts[2]);
-                };
-            } else if (that.notebook_save_re.test(code)) {
-                // %notebook save
-                var code_parts = code.split(' ');
-                if (code_parts.length === 3) {
-                    that.save_notebook(code_parts[2]);
-                } else {
-                    that.save_notebook()
-                };
-            } else {
-                var msg_id = that.kernel.execute(cell.get_code());
-                that.msg_cell_map[msg_id] = cell.cell_id;
-            };
+            var msg_id = that.kernel.execute(cell.get_code());
+            that.msg_cell_map[msg_id] = cell.cell_id;
         } else if (cell instanceof IPython.TextCell) {
             cell.render();
         }
@@ -532,18 +511,22 b' var IPython = (function (IPython) {'
             // Always delete cell 0 as they get renumbered as they are deleted.
             this.delete_cell(0);
         };
-        var new_cells = data.cells;
-        ncells = new_cells.length;
-        var cell_data = null;
-        for (var i=0; i<ncells; i++) {
-            cell_data = new_cells[i];
-            if (cell_data.cell_type == 'code') {
-                this.insert_code_cell_after();
-                this.selected_cell().fromJSON(cell_data);
-            } else if (cell_data.cell_type === 'text') {
-                this.insert_text_cell_after();
-                this.selected_cell().fromJSON(cell_data);
-            };
+        // Only handle 1 worksheet for now.
+        var worksheet = data.worksheets[0];
+        if (worksheet !== undefined) {
+            var new_cells = worksheet.cells;
+            ncells = new_cells.length;
+            var cell_data = null;
+            for (var i=0; i<ncells; i++) {
+                cell_data = new_cells[i];
+                if (cell_data.cell_type == 'code') {
+                    this.insert_code_cell_after();
+                    this.selected_cell().fromJSON(cell_data);
+                } else if (cell_data.cell_type === 'text') {
+                    this.insert_text_cell_after();
+                    this.selected_cell().fromJSON(cell_data);
+                };
+            };          
         };
     };
 
@@ -555,67 +538,66 b' var IPython = (function (IPython) {'
         for (var i=0; i<ncells; i++) {
             cell_array[i] = cells[i].toJSON();
         };
-        json = {
-            cells : cell_array
+        data = {
+            // Only handle 1 worksheet for now.
+            worksheets : [{cells:cell_array}]
+        }
+        return data
+    };
+
+    Notebook.prototype.save_notebook = function () {
+        if (IPython.save_widget.test_notebook_name()) {
+            var notebook_id = IPython.save_widget.get_notebook_id();
+            var nbname = IPython.save_widget.get_notebook_name();
+            // We may want to move the name/id/nbformat logic inside toJSON?
+            var data = this.toJSON();
+            data.name = nbname;
+            data.nbformat = 2;
+            data.id = notebook_id
+            // We do the call with settings so we can set cache to false.
+            var settings = {
+              processData : false,
+              cache : false,
+              type : "PUT",
+              data : JSON.stringify(data),
+              success : $.proxy(this.notebook_saved,this)
+            };
+            IPython.save_widget.status_saving();
+            $.ajax("/notebooks/" + notebook_id, settings);
         };
-        return json
     };
 
 
-    Notebook.prototype.test_filename = function (filename) {
-        if (this.notebook_filename_re.test(filename)) {
-            return true;
-        } else {
-            var bad_filename = $('<div/>');
-            bad_filename.html(
-                "The filename you entered (" + filename + ") is not valid. Notebook filenames must have the following form: foo.ipynb"
-            );
-            bad_filename.dialog({title: 'Invalid filename', modal: true});
-            return false;
-        };
-    };
-
-    Notebook.prototype.save_notebook = function (filename) {
-        this.filename = filename || this.filename || '';
-        if (this.filename === '') {
-            var no_filename = $('<div/>');
-            no_filename.html(
-                "This notebook has no filename, please specify a filename of the form: foo.ipynb"
-            );
-            no_filename.dialog({title: 'Missing filename', modal: true});
-            return;
-        }
-        if (!this.test_filename(this.filename)) {return;}
-        var thedata = this.toJSON();
-        var settings = {
-          processData : false,
-          cache : false,
-          type : "PUT",
-          data : JSON.stringify(thedata),
-          success : function (data, status, xhr) {console.log(data);}
-        };
-        $.ajax("/notebooks/" + this.filename, settings);
-    };
+    Notebook.prototype.notebook_saved = function (data, status, xhr) {
+        IPython.save_widget.status_save();
+    }
 
 
-    Notebook.prototype.load_notebook = function (filename) {
-        if (!this.test_filename(filename)) {return;}
-        var that = this;
+    Notebook.prototype.load_notebook = function () {
+        var notebook_id = IPython.save_widget.get_notebook_id();
         // We do the call with settings so we can set cache to false.
         var settings = {
           processData : false,
           cache : false,
           type : "GET",
           dataType : "json",
-          success : function (data, status, xhr) {
-              that.fromJSON(data);
-              that.filename = filename;
-              that.kernel.restart();
-          }
+          success : $.proxy(this.notebook_loaded,this)
         };
-        $.ajax("/notebooks/" + filename, settings);
+        IPython.save_widget.status_loading();
+        $.ajax("/notebooks/" + notebook_id, settings);
     }
 
+
+    Notebook.prototype.notebook_loaded = function (data, status, xhr) {
+        this.fromJSON(data);
+        if (this.ncells() === 0) {
+            this.insert_code_cell_after();
+        };
+        IPython.save_widget.status_save();
+        IPython.save_widget.set_notebook_name(data.name);
+        this.start_kernel();
+    };
+
     IPython.Notebook = Notebook;
 
     return IPython;

IPython/frontend/html/notebook/static/js/notebook_main.js

@@ -30,14 +30,18 b' $(document).ready(function () {'
     IPython.kernel_status_widget.status_idle();
 
     IPython.layout_manager.do_resize();
-    IPython.notebook.insert_code_cell_after();
-    IPython.layout_manager.do_resize();
 
     // These have display: none in the css file and are made visible here to prevent FLOUC.
     $('div#header').css('display','block');
     $('div#notebook_app').css('display','block');
-    IPython.layout_manager.do_resize();
-    IPython.pager.collapse();
-    IPython.layout_manager.do_resize();
+
+    IPython.notebook.load_notebook();
+
+    // Perform these actions after the notebook has been loaded.
+    setTimeout(function () {
+        IPython.save_widget.update_url();
+        IPython.layout_manager.do_resize();
+        IPython.pager.collapse();
+    }, 100);
 });
 

IPython/frontend/html/notebook/static/js/panelsection.js

@@ -82,20 +82,31 b' var IPython = (function (IPython) {'
         this.content.addClass('ui-helper-clearfix');
         this.content.find('div.section_row').addClass('ui-helper-clearfix');
         this.content.find('#new_open').buttonset();
+        this.content.find('#download_notebook').button();
+        this.content.find('#upload_notebook').button();
+        this.content.find('#download_format').addClass('ui-widget ui-widget-content');
+        this.content.find('#download_format option').addClass('ui-widget ui-widget-content');
     };
 
 
     NotebookSection.prototype.bind_events = function () {
         PanelSection.prototype.bind_events.apply(this);
+        var that = this;
         this.content.find('#new_notebook').click(function () {
-            alert('Not Implemented');
+            console.log('click!')
+            window.open('/');
         });
         this.content.find('#open_notebook').click(function () {
             alert('Not Implemented');
         });
+        this.content.find('#download_notebook').click(function () {
+            var format = that.content.find('#download_format').val();
+            var notebook_id = IPython.save_widget.get_notebook_id();
+            var url = '/notebooks/' + notebook_id + '?format=' + format;
+            window.open(url,'_newtab');
+        });
     };
 
-
     // CellSection
 
     var CellSection = function () {

IPython/frontend/html/notebook/static/js/savewidget.js

@@ -9,6 +9,7 b' var IPython = (function (IPython) {'
 
     var SaveWidget = function (selector) {
         this.selector = selector;
+        this.notebook_name_re = /[^/\\]+/
         if (this.selector !== undefined) {
             this.element = $(selector);
             this.style();
@@ -29,7 +30,7 b' var IPython = (function (IPython) {'
     SaveWidget.prototype.bind_events = function () {
         var that = this;
         this.element.find('button#save_notebook').click(function () {
-            IPython.notebook.save_notebook(that.get_notebook_name());
+            IPython.notebook.save_notebook();
         });
     };
 
@@ -39,11 +40,59 b' var IPython = (function (IPython) {'
     }
 
 
-    SaveWidget.prototype.set_notebook_name = function (name) {
-        this.element.find('input#notebook_name').attr('value',name);
+    SaveWidget.prototype.set_notebook_name = function (nbname) {
+        this.element.find('input#notebook_name').attr('value',nbname);
     }
 
 
+    SaveWidget.prototype.get_notebook_id = function () {
+        return this.element.find('span#notebook_id').text()
+    };
+
+
+    SaveWidget.prototype.update_url = function () {
+        var notebook_id = this.get_notebook_id();
+        if (notebook_id !== '') {
+            window.history.replaceState({}, '', notebook_id);
+        };
+    };
+
+
+    SaveWidget.prototype.test_notebook_name = function () {
+        var nbname = this.get_notebook_name();
+        if (this.notebook_name_re.test(nbname)) {
+            return true;
+        } else {
+            var bad_name = $('<div/>');
+            bad_name.html(
+                "The notebook name you entered (" +
+                nbname +
+                ") is not valid. Notebook names can contain any characters except / and \\"
+            );
+            bad_name.dialog({title: 'Invalid name', modal: true});
+            return false;
+        };
+    };
+
+
+    SaveWidget.prototype.status_save = function () {
+        this.element.find('span.ui-button-text').text('Save');
+        this.element.find('button#save_notebook').button('enable');
+    };    
+
+
+    SaveWidget.prototype.status_saving = function () {
+        this.element.find('span.ui-button-text').text('Saving');
+        this.element.find('button#save_notebook').button('disable');
+    };    
+
+
+    SaveWidget.prototype.status_loading = function () {
+        this.element.find('span.ui-button-text').text('Loading');
+        this.element.find('button#save_notebook').button('disable');
+    };    
+
+
     IPython.SaveWidget = SaveWidget;
 
     return IPython;

IPython/frontend/html/notebook/static/js/textcell.js

@@ -129,17 +129,19 b' var IPython = (function (IPython) {'
 
     TextCell.prototype.fromJSON = function (data) {
         if (data.cell_type === 'text') {
-            this.set_text(data.text);
-            this.grow(this.element.find("textarea.text_cell_input"));
+            if (data.text !== undefined) {
+                this.set_text(data.text);
+                this.grow(this.element.find("textarea.text_cell_input"));
+            };
         };
     }
 
 
     TextCell.prototype.toJSON = function () {
-        return {
-            cell_type : 'text',
-            text : this.get_text(),
-        };
+        var data = {}
+        data.cell_type = 'text';
+        data.text = this.get_text();
+        return data;
     };
 
     IPython.TextCell = TextCell;

IPython/frontend/html/notebook/templates/notebook.html

@@ -33,6 +33,7 b''
     <span id="ipython_notebook"><h1>IPython Notebook</h1></span>
     <span id="save_widget">
         <input type="text" id="notebook_name" size="20"></textarea>
+        <span id="notebook_id" style="display:none">{{notebook_id}}</span>
         <button id="save_notebook">Save</button>
     </span>
     <span id="kernel_status">Idle</span>
@@ -52,6 +53,18 b''
                     </span>
                     <span class="section_row_header">Actions</span>
                 </div>
+                <div class="section_row">
+                    <span class="section_row_buttons">
+                        <button id="download_notebook">Export</button>
+                    </span>
+                    <span>
+                        <select id="download_format">
+                            <option value="xml">xml</option>
+                            <option value="json">json</option>
+                            <option value="py">py</option>
+                        </select>
+                    </span>
+                </div>
             </div>
         </div>
 

IPython/nbformat/current.py

@@ -5,6 +5,11 b' import re'
 from IPython.nbformat import v2
 from IPython.nbformat import v1
 
+from IPython.nbformat.v2 import (
+    NotebookNode,
+    new_code_cell, new_text_cell, new_notebook, new_output, new_worksheet
+)
+
 
 current_nbformat = 2
 

IPython/nbformat/v2/nbpy.py

@@ -36,10 +36,11 b' class PyWriter(NotebookWriter):'
         for ws in nb.worksheets:
             for cell in ws.cells:
                 if cell.cell_type == 'code':
-                    input = cell.input
-                    lines.extend([u'# <codecell>',u''])
-                    lines.extend(input.splitlines())
-                    lines.extend([u'',u'# </codecell>'])
+                    input = cell.get('input')
+                    if input is not None:
+                        lines.extend([u'# <codecell>',u''])
+                        lines.extend(input.splitlines())
+                        lines.extend([u'',u'# </codecell>'])
         lines.append('')
         return unicode('\n'.join(lines))