create single exporter in NotebookApp

rather than using export_by_name

IPython/nbconvert/nbconvertapp.py

@@ -1,330 +1,321 b''
 #!/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.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 export_by_name, get_export_names, ExporterNameError
+from .exporters.export import get_export_names, exporter_map
 from IPython.nbconvert import exporters, transformers, writers, post_processors
 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' : 'Exporter.template_file',
     'notebooks' : 'NbConvertApp.notebooks',
     'writer' : 'NbConvertApp.writer_class',
     'post': 'NbConvertApp.post_processor_class',
     'output': 'NbConvertApp.output_base'
 })
 
 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 to and 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]
         for pkg in (exporters, transformers, writers):
             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.ipnynb
 
         Both HTML and LaTeX support multiple output templates. LaTeX includes
         'basic', 'book', and 'article'.  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 in self.writer_aliases:
             new = self.writer_aliases[new]
         self.writer_factory = import_item(new)
 
     # Post-processor specific variables
     post_processor = Instance('IPython.nbconvert.post_processors.base.PostProcessorBase',  
                       help="""Instance of the PostProcessor class used to write the 
                       results of the conversion.""")
 
     post_processor_class = DottedOrNone(config=True, 
                                     help="""PostProcessor class used to write the 
                                     results of the conversion""")
     post_processor_aliases = {'PDF': 'IPython.nbconvert.post_processors.pdf.PDFPostProcessor',
                               'serve': 'IPython.nbconvert.post_processors.serve.ServePostProcessor'}
     post_processor_factory = Type()
 
     def _post_processor_class_changed(self, name, old, new):
         if new in self.post_processor_aliases:
             new = self.post_processor_aliases[new]
         if new:
             self.post_processor_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):
         super(NbConvertApp, self).initialize(argv)
         self.init_syspath()
         self.init_notebooks()
         self.init_writer()
         self.init_post_processor()
 
 
 
     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_post_processor(self):
         """
         Initialize the post_processor (which is stateless)
         """
         self._post_processor_class_changed(None, self.post_processor_class, 
             self.post_processor_class)
         if self.post_processor_factory:
             self.post_processor = self.post_processor_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:
-            print(dedent(
+            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 = export_by_name(self.export_format,
-                                              notebook_filename, 
-                                              resources=resources,
-                                              config=self.config)
-            except ExporterNameError as e:
-                print("Error while converting '%s': '%s' exporter not found."
-                      %(notebook_filename, self.export_format),
-                      file=sys.stderr)
-                print("Known exporters are:",
-                      "\n\t" + "\n\t".join(get_export_names()),
-                      file=sys.stderr)
-                self.exit(1)
+                output, resources = exporter.from_filename(notebook_filename, resources=resources)
             except ConversionException as e:
-                print("Error while converting '%s': %s" %(notebook_filename, e),
-                      file=sys.stderr)
+                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, 'post_processor') and self.post_processor:
                     self.post_processor(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