improve rst_directive and fix bug in unknown_cell

nb2html.py

@@ -1,186 +1,189 b''
 #!/usr/bin/env python
 """A really simple notebook to rst/html exporter.
 
 Usage
 
   ./nb2html.py file.ipynb
 
 Produces 'file.rst' and 'file.html', along with auto-generated figure files
 called nb_figure_NN.png.
 
 """
 
 import os
 import subprocess
 import sys
 
 from IPython.nbformat import current as nbformat
 from IPython.utils.text import wrap_paragraphs, indent
 
 
 # Cell converters
 
 def unknown_cell(cell):
     """Default converter for cells of unknown type.
     """
 
-    return [rst_directive('.. warning:: Unknown cell'),
-            repr(cell)]
+    return rst_directive('.. warning:: Unknown cell') + \
+      [repr(cell)]
 
 def markdown_cell(cell):
     """convert a markdown cell to rst
 
     Returns list."""
     return [cell.source]
 
 
-def rst_directive(directive, text):
-    return [directive, '', indent(text), '']
+def rst_directive(directive, text=''):
+    out = [directive, '']
+    if text:
+        out.extend([indent(text), ''])
+    return out
 
 def code_cell(cell):
     """Convert a code cell to rst
 
     Returns list."""
 
     if not cell.input:
         return []
 
     lines = ['In[%s]:' % cell.prompt_number, '']
     lines.extend(rst_directive('.. code:: python', cell.input))
     
     for output in cell.outputs:
-        conv = converters[output.output_type]
+        conv = converters.get(output.output_type, unknown_cell)
         lines.extend(conv(output))
 
     return lines
 
 # Converters for parts of a cell.
 figures_counter = 1
 
 def out_display(output):
     """convert display data from the output of a code cell to rst.
 
     Returns list.
     """
     global figures_counter
 
     lines = []
 
     if 'png' in output:
         fname = 'nb_figure_%s.png' % figures_counter
         with open(fname, 'w') as f:
             f.write(output.png.decode('base64'))
 
         figures_counter += 1
         lines.append('.. image:: %s' % fname)
         lines.append('')
     
     return lines
 
     
 def out_pyout(output):
     """convert pyout part of a code cell to rst
 
     Returns list."""
 
     lines = ['Out[%s]:' % output.prompt_number, '']
     
     if 'latex' in output:
         lines.extend(rst_directive('.. math::', output.latex))
 
     if 'text' in output:
         lines.extend(rst_directive('.. parsed-literal::', output.text))
 
     return lines
 
 
 converters = dict(code = code_cell,
                   markdown = markdown_cell,
                   pyout = out_pyout,
                   display_data = out_display,
     )
 
 
 
 def convert_notebook(nb):
     lines = []
     for cell in nb.worksheets[0].cells:
         conv = converters.get(cell.cell_type, unknown_cell)
         lines.extend(conv(cell))
         lines.append('')
                 
     return '\n'.join(lines)
 
 
 def nb2rst(fname):
     "Convert notebook to rst"
     
     with open(fname) as f:
         nb = nbformat.read(f, 'json')
 
     rst = convert_notebook(nb)
 
     newfname = os.path.splitext(fname)[0] + '.rst'
     with open(newfname, 'w') as f:
         f.write(rst.encode('utf8'))
 
     return newfname
 
 
 def rst2simplehtml(fname):
     """Convert a rst file to simplified html suitable for blogger.
 
     This just runs rst2html with certain parameters to produce really simple
     html and strips the document header, so the resulting file can be easily
     pasted into a blogger edit window.
     """
 
     # This is the template for the rst2html call that produces the cleanest,
     # simplest html I could find.  This should help in making it easier to
     # paste into the blogspot html window, though I'm still having problems
     # with linebreaks there...
     cmd_template = ("rst2html --link-stylesheet --no-xml-declaration "
                     "--no-generator --no-datestamp --no-source-link "
                     "--no-toc-backlinks --no-section-numbering "
                     "--strip-comments ")
 
     cmd = "%s %s" % (cmd_template, fname)
     proc = subprocess.Popen(cmd,
                             stdout=subprocess.PIPE,
                             stderr=subprocess.PIPE,
                             shell=True)
     html, stderr = proc.communicate()
     if stderr:
         raise IOError(stderr)
 
     # Make an iterator so breaking out holds state.  Our implementation of
     # searching for the html body below is basically a trivial little state
     # machine, so we need this.
     walker = iter(html.splitlines())
 
     # Find start of main text, break out to then print until we find end /div.
     # This may only work if there's a real title defined so we get a 'div class'
     # tag, I haven't really tried.
     for line in walker:
         if line.startswith('<div class'):
             break
 
     newfname = os.path.splitext(fname)[0] + '.html'
     with open(newfname, 'w') as f:
         for line in walker:
             if line.startswith('</div>'):
                 break
             f.write(line)
             f.write('\n')
             
     return newfname
 
 
 def main(fname):
     """Convert a notebook to html in one step"""
     newfname = nb2rst(fname)
     rst2simplehtml(newfname)
 
 
 if __name__ == '__main__':
     main(sys.argv[1])