list known formats in help & on unknown fmt error

also added some notes about future things to keep track of.

nbconvert.py

@@ -1,383 +1,395 b''
 #!/usr/bin/env python
-"""A really simple notebook to rst/html exporter.
+"""Convert IPython notebooks to other formats, such as ReST, and HTML.
 
-Usage
-
-  ./nb2html.py file.ipynb
+Example:
+  ./nbconvert.py --format html file.ipynb
 
 Produces 'file.rst' and 'file.html', along with auto-generated figure files
-called nb_figure_NN.png.
-
+called nb_figure_NN.png. To avoid the two-step process, ipynb -> rst -> html,
+use '--format quick-html' which will do ipynb -> html, but won't look as
+pretty.
 """
 
 import os
 import subprocess
 import sys
 from IPython.external import argparse
 from IPython.nbformat import current as nbformat
 from IPython.utils.text import indent
 from decorators import DocInherit
 
 # Cell converters
 
 def unknown_cell(cell):
     """Default converter for cells of unknown type.
     """
 
     return rst_directive('.. warning:: Unknown cell') + \
       [repr(cell)]
 
 
 def rst_directive(directive, text=''):
     out = [directive, '']
     if text:
         out.extend([indent(text), ''])
     return out
 
 # Converters for parts of a cell.
 
 
 class ConversionException(Exception):
     pass
 
 
 class Converter(object):
     default_encoding = 'utf-8'
 
     def __init__(self, infile):
         self.infile = infile
         self.dirpath = os.path.dirname(infile)
 
     @property
     def extension(self):
         raise ConversionException("""extension must be defined in Converter
                 subclass""")
 
     def dispatch(self, cell_type):
         """return cell_type dependent render method,  for example render_code
         """
         # XXX: unknown_cell here is RST specific - make it generic
         return getattr(self, 'render_' + cell_type, unknown_cell)
 
     def convert(self):
         lines = []
         lines.extend(self.optional_header())
         for cell in self.nb.worksheets[0].cells:
             conv_fn = self.dispatch(cell.cell_type)
             lines.extend(conv_fn(cell))
             lines.append('')
         lines.extend(self.optional_footer())
         return '\n'.join(lines)
 
     def render(self):
         "read, convert, and save self.infile"
         self.read()
         self.output = self.convert()
         return self.save()
 
     def read(self):
         "read and parse notebook into NotebookNode called self.nb"
         with open(self.infile) as f:
             self.nb = nbformat.read(f, 'json')
 
     def save(self, infile=None, encoding=None):
         "read and parse notebook into self.nb"
         if infile is None:
             infile = os.path.splitext(self.infile)[0] + '.' + self.extension
         if encoding is None:
             encoding = self.default_encoding
         with open(infile, 'w') as f:
             f.write(self.output.encode(encoding))
         return infile
 
     def optional_header(self):
         return []
 
     def optional_footer(self):
         return []
 
     def render_heading(self, cell):
         """convert a heading cell
 
         Returns list."""
         raise NotImplementedError
 
     def render_code(self, cell):
         """Convert a code cell
 
         Returns list."""
         raise NotImplementedError
 
     def render_markdown(self, cell):
         """convert a markdown cell
 
         Returns list."""
         raise NotImplementedError
 
     def render_pyout(self, cell):
         """convert pyout part of a code cell
 
         Returns list."""
         raise NotImplementedError
 
     def render_display_data(self, cell):
         """convert display data from the output of a code cell
 
         Returns list.
         """
         raise NotImplementedError
 
     def render_stream(self, cell):
         """convert stream part of a code cell
 
         Returns list."""
         raise NotImplementedError
 
     def render_plaintext(self, cell):
         """convert plain text
 
         Returns list."""
         raise NotImplementedError
 
 
 class ConverterRST(Converter):
     extension = 'rst'
     figures_counter = 0
     heading_level = {1: '=', 2: '-', 3: '`', 4: '\'', 5: '.', 6: '~'}
 
     @DocInherit
     def render_heading(self, cell):
         marker = self.heading_level[cell.level]
         return ['{0}\n{1}\n'.format(cell.source, marker * len(cell.source))]
 
     @DocInherit
     def render_code(self, cell):
         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_fn = self.dispatch(output.output_type)
             lines.extend(conv_fn(output))
 
         return lines
 
     @DocInherit
     def render_markdown(self, cell):
         return [cell.source]
 
     @DocInherit
     def render_plaintext(self, cell):
         return [cell.source]
 
     @DocInherit
     def render_pyout(self, output):
         lines = ['Out[%s]:' % output.prompt_number, '']
 
         # output is a dictionary like object with type as a key
         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
 
     @DocInherit
     def render_display_data(self, output):
         lines = []
 
         if 'png' in output:
+            # XXX: make the figures notebooks specific (i.e. self.infile) so
+            # that multiple notebook conversions don't clobber each other's
+            # figures
             infile = 'nb_figure_%s.png' % self.figures_counter
             fullname = os.path.join(self.dirpath, infile)
             with open(fullname, 'w') as f:
                 f.write(output.png.decode('base64'))
 
             self.figures_counter += 1
             lines.append('.. image:: %s' % infile)
             lines.append('')
 
         return lines
 
     @DocInherit
     def render_stream(self, output):
         lines = []
 
         if 'text' in output:
             lines.extend(rst_directive('.. parsed-literal::', output.text))
 
         return lines
 
 class ConverterQuickHTML(Converter):
     extension = 'html'
     figures_counter = 0
 
     def optional_header(self):
         # XXX: inject the IPython standard CSS into here
         s = """<html>
         <head>
         </head>
 
         <body>
         """
         return s.splitlines()
 
     def optional_footer(self):
         s = """</body>
         </html>
         """
         return s.splitlines()
 
     @DocInherit
     def render_heading(self, cell):
         marker = cell.level
         return ['<h{1}>\n  {0}\n</h{1}>'.format(cell.source, marker)]
 
     @DocInherit
     def render_code(self, cell):
         if not cell.input:
             return []
 
         lines = ['<table>']
         lines.append('<tr><td><tt>In [<b>%s</b>]:</tt></td><td><tt>' % cell.prompt_number)
         lines.append("<br>\n".join(cell.input.splitlines()))
         lines.append('</tt></td></tr>')
 
         for output in cell.outputs:
             lines.append('<tr><td></td><td>')
             conv_fn = self.dispatch(output.output_type)
             lines.extend(conv_fn(output))
             lines.append('</td></tr>')
         
         lines.append('</table>')
         return lines
 
     @DocInherit
     def render_markdown(self, cell):
         return ["<pre>"+cell.source+"</pre>"]
 
     @DocInherit
     def render_plaintext(self, cell):
         return ["<pre>"+cell.source+"</pre>"]
 
     @DocInherit
     def render_pyout(self, output):
         lines = ['<tr><td><tt>Out[<b>%s</b>]:</tt></td></tr>' % output.prompt_number, '<td>']
 
         # output is a dictionary like object with type as a key
         if 'latex' in output:
             lines.append("<pre>")
             lines.extend(indent(output.latex))
             lines.append("</pre>")
 
         if 'text' in output:
             lines.append("<pre>")
             lines.extend(indent(output.text))
             lines.append("</pre>")
 
         return lines
 
     @DocInherit
     def render_display_data(self, output):
         lines = []
 
         if 'png' in output:
             infile = 'nb_figure_%s.png' % self.figures_counter
             fullname = os.path.join(self.dirpath, infile)
             with open(fullname, 'w') as f:
                 f.write(output.png.decode('base64'))
 
             self.figures_counter += 1
             lines.append('<img src="%s">' % infile)
             lines.append('')
 
         return lines
 
     @DocInherit
     def render_stream(self, output):
         lines = []
 
         if 'text' in output:
             lines.append(output.text)
 
         return lines
 
 def rst2simplehtml(infile):
     """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, infile)
     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('<body>'):
             break
 
     newfname = os.path.splitext(infile)[0] + '.html'
     with open(newfname, 'w') as f:
         for line in walker:
             if line.startswith('</body>'):
                 break
             f.write(line)
             f.write('\n')
 
     return newfname
 
+known_formats = "rst (default), html, quick-html"
 
 def main(infile, format='rst'):
     """Convert a notebook to html in one step"""
+    # XXX: this is just quick and dirty for now. When adding a new format,
+    # make sure to add it to the `known_formats` string above, which gets
+    # printed in in the catch-all else, as well as in the help
     if format == 'rst':
         converter = ConverterRST(infile)
         converter.render()
     elif format == 'html':
         #Currently, conversion to html is a 2 step process, nb->rst->html
         converter = ConverterRST(infile)
         rstfname = converter.render()
         rst2simplehtml(rstfname)
     elif format == 'quick-html':
         converter = ConverterQuickHTML(infile)
         rstfname = converter.render()
+    else:
+        raise SystemExit("Unknown format '%s', " % format +
+                "known formats are: " + known_formats)
 
 
-if __name__ == '__main__':
-    parser = argparse.ArgumentParser(description='nbconvert: Convert IPython notebooks to other formats')
 
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description=__doc__,
+            formatter_class=argparse.RawTextHelpFormatter)
     # TODO: consider passing file like object around, rather than filenames
     # would allow us to process stdin, or even http streams
     #parser.add_argument('infile', nargs='?', type=argparse.FileType('r'), default=sys.stdin)
 
     #Require a filename as a positional argument
     parser.add_argument('infile', nargs=1)
     parser.add_argument('-f', '--format', default='rst',
-                        help='Output format. Supported formats: rst (default), html.')
+                        help='Output format. Supported formats: \n' +
+                        known_formats)
     args = parser.parse_args()
     main(infile=args.infile[0], format=args.format)