add empty metadata field on cells/worksheets

These are unused for now, but will allow adding data to the notebook without a full version bump.

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

@@ -19,6 +19,7 b' var IPython = (function (IPython) {'
         this.read_only = false;
         this.selected = false;
         this.element = null;
+        this.metadata = {};
         this.create_element();
         if (this.element !== null) {
             this.element.data("cell", this);
@@ -90,10 +91,16 b' var IPython = (function (IPython) {'
 
 
     Cell.prototype.toJSON = function () {
+        var data = {};
+        data.metadata = this.metadata;
+        return data;
     };
 
 
     Cell.prototype.fromJSON = function (data) {
+        if (data.metadata !== undefined) {
+            this.metadata = data.metadata;
+        }
     };
 
 

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

@@ -264,6 +264,7 b' var IPython = (function (IPython) {'
     // JSON serialization
 
     CodeCell.prototype.fromJSON = function (data) {
+        IPython.Cell.prototype.fromJSON.apply(this, arguments);
         if (data.cell_type === 'code') {
             if (data.input !== undefined) {
                 this.set_text(data.input);
@@ -286,7 +287,7 b' var IPython = (function (IPython) {'
 
 
     CodeCell.prototype.toJSON = function () {
-        var data = {};
+        var data = IPython.Cell.prototype.toJSON.apply(this);
         data.input = this.get_text();
         data.cell_type = 'code';
         if (this.input_prompt_number) {

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

@@ -25,6 +25,8 b' var IPython = (function (IPython) {'
         this.paste_enabled = false;
         this.dirty = false;
         this.metadata = {};
+        // single worksheet for now
+        this.worksheet_metadata = {};
         this.control_key_active = false;
         this.notebook_id = null;
         this.notebook_name = null;
@@ -1003,6 +1005,9 b' var IPython = (function (IPython) {'
         // Only handle 1 worksheet for now.
         var worksheet = data.worksheets[0];
         if (worksheet !== undefined) {
+            if (worksheet.metadata) {
+                this.worksheet_metadata = worksheet.metadata;
+            }
             var new_cells = worksheet.cells;
             ncells = new_cells.length;
             var cell_data = null;
@@ -1031,7 +1036,10 b' var IPython = (function (IPython) {'
         };
         var data = {
             // Only handle 1 worksheet for now.
-            worksheets : [{cells:cell_array}],
+            worksheets : [{
+                cells: cell_array,
+                metadata: this.worksheet_metadata
+            }],
             metadata : this.metadata
         };
         return data;

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

@@ -155,6 +155,7 b' var IPython = (function (IPython) {'
 
 
     TextCell.prototype.fromJSON = function (data) {
+        IPython.Cell.prototype.fromJSON.apply(this, arguments);
         if (data.cell_type === this.cell_type) {
             if (data.source !== undefined) {
                 this.set_text(data.source);
@@ -167,7 +168,7 b' var IPython = (function (IPython) {'
 
 
     TextCell.prototype.toJSON = function () {
-        var data = {};
+        var data = IPython.Cell.prototype.toJSON.apply(this);
         data.cell_type = this.cell_type;
         data.source = this.get_text();
         return data;

IPython/nbformat/v3/nbbase.py

@@ -92,7 +92,7 b' def new_output(output_type=None, output_text=None, output_png=None,'
 
 
 def new_code_cell(input=None, prompt_number=None, outputs=None,
-    language=u'python', collapsed=False):
+    language=u'python', collapsed=False, metadata=None):
     """Create a new code cell with input and output"""
     cell = NotebookNode()
     cell.cell_type = u'code'
@@ -108,10 +108,11 b' def new_code_cell(input=None, prompt_number=None, outputs=None,'
         cell.outputs = outputs
     if collapsed is not None:
         cell.collapsed = bool(collapsed)
+    cell.metadata = NotebookNode(metadata or {})
 
     return cell
 
-def new_text_cell(cell_type, source=None, rendered=None):
+def new_text_cell(cell_type, source=None, rendered=None, metadata=None):
     """Create a new text cell."""
     cell = NotebookNode()
     # VERSIONHACK: plaintext -> raw
@@ -122,11 +123,12 b' def new_text_cell(cell_type, source=None, rendered=None):'
         cell.source = unicode(source)
     if rendered is not None:
         cell.rendered = unicode(rendered)
+    cell.metadata = NotebookNode(metadata or {})
     cell.cell_type = cell_type
     return cell
 
 
-def new_heading_cell(source=None, rendered=None, level=1):
+def new_heading_cell(source=None, rendered=None, level=1, metadata=None):
     """Create a new section cell with a given integer level."""
     cell = NotebookNode()
     cell.cell_type = u'heading'
@@ -135,10 +137,11 b' def new_heading_cell(source=None, rendered=None, level=1):'
     if rendered is not None:
         cell.rendered = unicode(rendered)
     cell.level = int(level)
+    cell.metadata = NotebookNode(metadata or {})
     return cell
 
 
-def new_worksheet(name=None, cells=None):
+def new_worksheet(name=None, cells=None, metadata=None):
     """Create a worksheet by name with with a list of cells."""
     ws = NotebookNode()
     if name is not None:
@@ -147,6 +150,7 b' def new_worksheet(name=None, cells=None):'
         ws.cells = []
     else:
         ws.cells = list(cells)
+    ws.metadata = NotebookNode(metadata or {})
     return ws