nbconvertapp.py

#!/usr/bin/env python
"""NBConvert is a utility for conversion of .ipynb files.

Command-line interface for the NbConvert conversion utility.
"""
#-----------------------------------------------------------------------------
#Copyright (c) 2013, the IPython Development Team.
#
#Distributed under the terms of the Modified BSD License.
#
#The full license is in the file COPYING.txt, distributed with this software.
#-----------------------------------------------------------------------------

#-----------------------------------------------------------------------------
#Imports
#-----------------------------------------------------------------------------

# Stdlib imports
from __future__ import print_function

import logging
import sys
import os
import glob

# From IPython
from IPython.core.application import BaseIPythonApplication, base_aliases, base_flags
from IPython.core.profiledir import ProfileDir
from IPython.config import catch_config_error, Configurable
from IPython.utils.traitlets import (
    Unicode, List, Instance, DottedObjectName, Type, CaselessStrEnum,
)
from IPython.utils.importstring import import_item
from IPython.utils.text import dedent

from .exporters.export import get_export_names, exporter_map
from IPython.nbconvert import exporters, preprocessors, writers, postprocessors
from .utils.base import NbConvertBase
from .utils.exceptions import ConversionException

#-----------------------------------------------------------------------------
#Classes and functions
#-----------------------------------------------------------------------------

class DottedOrNone(DottedObjectName):
    """
    A string holding a valid dotted object name in Python, such as A.b3._c
    Also allows for None type."""
    
    default_value = u''

    def validate(self, obj, value):
        if value is not None and len(value) > 0:
            return super(DottedOrNone, self).validate(obj, value)
        else:
            return value
            
nbconvert_aliases = {}
nbconvert_aliases.update(base_aliases)
nbconvert_aliases.update({
    'to' : 'NbConvertApp.export_format',
    'template' : 'TemplateExporter.template_file',
    'writer' : 'NbConvertApp.writer_class',
    'post': 'NbConvertApp.postprocessor_class',
    'output': 'NbConvertApp.output_base',
    'reveal-prefix': 'RevealHelpPreprocessor.url_prefix',
})

nbconvert_flags = {}
nbconvert_flags.update(base_flags)
nbconvert_flags.update({
    'stdout' : (
        {'NbConvertApp' : {'writer_class' : "StdoutWriter"}},
        "Write notebook output to stdout instead of files."
        )
})


class NbConvertApp(BaseIPythonApplication):
    """Application used to convert from notebook file type (``*.ipynb``)"""

    name = 'ipython-nbconvert'
    aliases = nbconvert_aliases
    flags = nbconvert_flags
    
    def _log_level_default(self):
        return logging.INFO
    
    def _classes_default(self):
        classes = [NbConvertBase, ProfileDir]
        for pkg in (exporters, preprocessors, writers, postprocessors):
            for name in dir(pkg):
                cls = getattr(pkg, name)
                if isinstance(cls, type) and issubclass(cls, Configurable):
                    classes.append(cls)
        
        return classes

    description = Unicode(
        u"""This application is used to convert notebook files (*.ipynb)
        to various other formats.

        WARNING: THE COMMANDLINE INTERFACE MAY CHANGE IN FUTURE RELEASES.""")

    output_base = Unicode('', config=True, help='''overwrite base name use for output files.
            can only  be use when converting one notebook at a time.
            ''')

    examples = Unicode(u"""
        The simplest way to use nbconvert is
        
        > ipython nbconvert mynotebook.ipynb
        
        which will convert mynotebook.ipynb to the default format (probably HTML).
        
        You can specify the export format with `--to`.
        Options include {0}
        
        > ipython nbconvert --to latex mynotebook.ipynb

        Both HTML and LaTeX support multiple output templates. LaTeX includes
        'base', 'article' and 'report'.  HTML includes 'basic' and 'full'. You
        can specify the flavor of the format used.

        > ipython nbconvert --to html --template basic mynotebook.ipynb
        
        You can also pipe the output to stdout, rather than a file
        
        > ipython nbconvert mynotebook.ipynb --stdout

        A post-processor can be used to compile a PDF

        > ipython nbconvert mynotebook.ipynb --to latex --post PDF
        
        You can get (and serve) a Reveal.js-powered slideshow
        
        > ipython nbconvert myslides.ipynb --to slides --post serve
        
        Multiple notebooks can be given at the command line in a couple of 
        different ways:
  
        > ipython nbconvert notebook*.ipynb
        > ipython nbconvert notebook1.ipynb notebook2.ipynb
        
        or you can specify the notebooks list in a config file, containing::
        
            c.NbConvertApp.notebooks = ["my_notebook.ipynb"]
        
        > ipython nbconvert --config mycfg.py
        """.format(get_export_names()))

    # Writer specific variables
    writer = Instance('IPython.nbconvert.writers.base.WriterBase',  
                      help="""Instance of the writer class used to write the 
                      results of the conversion.""")
    writer_class = DottedObjectName('FilesWriter', config=True, 
                                    help="""Writer class used to write the 
                                    results of the conversion""")
    writer_aliases = {'fileswriter': 'IPython.nbconvert.writers.files.FilesWriter',
                      'debugwriter': 'IPython.nbconvert.writers.debug.DebugWriter',
                      'stdoutwriter': 'IPython.nbconvert.writers.stdout.StdoutWriter'}
    writer_factory = Type()

    def _writer_class_changed(self, name, old, new):
        if new.lower() in self.writer_aliases:
            new = self.writer_aliases[new.lower()]
        self.writer_factory = import_item(new)

    # Post-processor specific variables
    postprocessor = Instance('IPython.nbconvert.postprocessors.base.PostProcessorBase',  
                      help="""Instance of the PostProcessor class used to write the 
                      results of the conversion.""")

    postprocessor_class = DottedOrNone(config=True, 
                                    help="""PostProcessor class used to write the 
                                    results of the conversion""")
    postprocessor_aliases = {'pdf': 'IPython.nbconvert.postprocessors.pdf.PDFPostProcessor',
                              'serve': 'IPython.nbconvert.postprocessors.serve.ServePostProcessor'}
    postprocessor_factory = Type()

    def _postprocessor_class_changed(self, name, old, new):
        if new.lower() in self.postprocessor_aliases:
            new = self.postprocessor_aliases[new.lower()]
        if new:
            self.postprocessor_factory = import_item(new)


    # Other configurable variables
    export_format = CaselessStrEnum(get_export_names(),
        default_value="html",
        config=True,
        help="""The export format to be used."""
    )

    notebooks = List([], config=True, help="""List of notebooks to convert.
                     Wildcards are supported.
                     Filenames passed positionally will be added to the list.
                     """)

    @catch_config_error
    def initialize(self, argv=None):
        self.init_syspath()
        super(NbConvertApp, self).initialize(argv)
        self.init_notebooks()
        self.init_writer()
        self.init_postprocessor()



    def init_syspath(self):
        """
        Add the cwd to the sys.path ($PYTHONPATH)
        """
        sys.path.insert(0, os.getcwd())
        

    def init_notebooks(self):
        """Construct the list of notebooks.
        If notebooks are passed on the command-line,
        they override notebooks specified in config files.
        Glob each notebook to replace notebook patterns with filenames.
        """

        # Specifying notebooks on the command-line overrides (rather than adds)
        # the notebook list
        if self.extra_args:
            patterns = self.extra_args
        else:
            patterns = self.notebooks

        # Use glob to replace all the notebook patterns with filenames.
        filenames = []
        for pattern in patterns:
            
            # Use glob to find matching filenames.  Allow the user to convert 
            # notebooks without having to type the extension.
            globbed_files = glob.glob(pattern)
            globbed_files.extend(glob.glob(pattern + '.ipynb'))
            if not globbed_files:
                self.log.warn("pattern %r matched no files", pattern)

            for filename in globbed_files:
                if not filename in filenames:
                    filenames.append(filename)
        self.notebooks = filenames

    def init_writer(self):
        """
        Initialize the writer (which is stateless)
        """
        self._writer_class_changed(None, self.writer_class, self.writer_class)
        self.writer = self.writer_factory(parent=self)

    def init_postprocessor(self):
        """
        Initialize the postprocessor (which is stateless)
        """
        self._postprocessor_class_changed(None, self.postprocessor_class, 
            self.postprocessor_class)
        if self.postprocessor_factory:
            self.postprocessor = self.postprocessor_factory(parent=self)

    def start(self):
        """
        Ran after initialization completed
        """
        super(NbConvertApp, self).start()
        self.convert_notebooks()

    def convert_notebooks(self):
        """
        Convert the notebooks in the self.notebook traitlet
        """
        # Export each notebook
        conversion_success = 0

        if self.output_base != '' and len(self.notebooks) > 1:
            self.log.error(
            """UsageError: --output flag or `NbConvertApp.output_base` config option
            cannot be used when converting multiple notebooks.
            """)
            self.exit(1)
        
        exporter = exporter_map[self.export_format](config=self.config)

        for notebook_filename in self.notebooks:
            self.log.info("Converting notebook %s to %s", notebook_filename, self.export_format)

            # Get a unique key for the notebook and set it in the resources object.
            basename = os.path.basename(notebook_filename)
            notebook_name = basename[:basename.rfind('.')]
            if self.output_base:
                notebook_name = self.output_base
            resources = {}
            resources['unique_key'] = notebook_name
            resources['output_files_dir'] = '%s_files' % notebook_name
            self.log.info("Support files will be in %s", os.path.join(resources['output_files_dir'], ''))

            # Try to export
            try:
                output, resources = exporter.from_filename(notebook_filename, resources=resources)
            except ConversionException as e:
                self.log.error("Error while converting '%s'", notebook_filename,
                      exc_info=True)
                self.exit(1)
            else:
                write_resultes = self.writer.write(output, resources, notebook_name=notebook_name)

                #Post-process if post processor has been defined.
                if hasattr(self, 'postprocessor') and self.postprocessor:
                    self.postprocessor(write_resultes)
                conversion_success += 1

        # If nothing was converted successfully, help the user.
        if conversion_success == 0:
            self.print_help()
            sys.exit(-1)
            
#-----------------------------------------------------------------------------
# Main entry point
#-----------------------------------------------------------------------------

launch_new_instance = NbConvertApp.launch_instance