Moved nb conversion into its own method. Additional error handling.

IPython/nbconvert/nbconvertapp.py

@@ -1,180 +1,196 b''
 #!/usr/bin/env python
 """NBConvert is a utility for conversion of IPYNB files.
 
 Commandline interface for the NBConvert conversion utility.  Read the
 readme.rst for usage information
 """
 #-----------------------------------------------------------------------------
 #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 sys
 import os
 import glob
 
 #From IPython
 from IPython.core.application import BaseIPythonApplication
 from IPython.config.application import catch_config_error
 from IPython.utils.traitlets import Unicode, List, Instance, DottedObjectName, Type
 from IPython.utils.importstring import import_item
 
 from .exporters.export import export_by_name, get_export_names, ExporterNameError
 from .exporters.exporter import Exporter
 from .writers.base import WriterBase
 from .utils.config import GlobalConfigurable
 
 #-----------------------------------------------------------------------------
 #Classes and functions
 #-----------------------------------------------------------------------------
 
 class NbConvertApp(BaseIPythonApplication):
     """Application used to convert to and from notebook file type (*.ipynb)"""
 
 
     description = Unicode(
         u"""This application is used to convert notebook files (*.ipynb).
         An ipython config file can be used to batch convert notebooks in the 
         current directory.""")
 
     examples = Unicode(u"""
         Running `ipython nbconvert` will read the directory config file and then 
         apply it to one or more notebooks.
 
         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
         > ipython nbconvert # this will use the config file to fill in the notebooks
         """)
     
     config_file_name = Unicode(u'ipython_nbconvert_config.py')
 
     #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)
 
 
     #Other configurable variables
     export_format = Unicode(
         "", config=True,
         help="""If specified, nbconvert will convert the document(s) specified
                 using this format.""")
 
     notebooks = List([], config=True, help="""List of notebooks to convert.
                      Search patterns are supported.""")
 
     aliases = {'format':'NbConvertApp.export_format',
                'notebooks':'NbConvertApp.notebooks',
                'writer':'NbConvertApp.writer_class'} 
 
 
     @catch_config_error
     def initialize(self, argv=None):
         super(NbConvertApp, self).initialize(argv)
 
         #Register class here to have help with help all
         self.classes.insert(0, Exporter)
         self.classes.insert(0, WriterBase)
         self.classes.insert(0, GlobalConfigurable)
 
         #Init
         self.init_config(self.extra_args)
         self.init_writer()
 
 
     def init_config(self, extra_args):
         """
         Add notebooks to the config if needed.  Glob each notebook to replace
         notebook patterns with filenames.
         """
 
         #Get any additional notebook patterns from the commandline
         if len(extra_args) > 0:
             for pattern in extra_args:
                 self.notebooks.append(pattern)
 
         #Use glob to replace all the notebook patterns with filenames.
         filenames = []
         for pattern in self.notebooks:
             for filename in glob.glob(pattern):
                 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 start(self, argv=None):
         """
         Entrypoint of NbConvert application.
         """
-
-        #Call base
         super(NbConvertApp, self).start()
+        self.convert_notebooks()
+
 
+    def convert_notebooks(self):
+        """
+        Convert the notebooks in the self.notebook traitlet
+        """
         #Export each notebook
-        #TODO: Empty check
+        conversion_success = 0
         for notebook_filename in self.notebooks:
 
             #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('.')]
             resources = {}
             resources['unique_key'] = notebook_name
 
             #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: '%s' exporter not found." % self.export_format,
                       file=sys.stderr)
                 print("Known exporters are:",
                       "\n\t" + "\n\t".join(get_export_names()),
                       file=sys.stderr)
                 sys.exit(-1)
-            except Exception as e:
-                print("Error: could no export '%s'" % notebook_filename, file=sys.stderr)
-                print(e, file=sys.stderr)
-
-            #Write
-            self.writer.write(output, resources, notebook_name=notebook_name)
+            #except Exception as e:
+                #print("Error: could not export '%s'" % notebook_filename, file=sys.stderr)
+                #print(e, file=sys.stderr)
+            else:
+                self.writer.write(output, resources, notebook_name=notebook_name)
+                conversion_success += 1
+
+        #If nothing was converted successfully, help the user.
+        if conversion_success == 0:
+
+            #No notebooks were specified, show help.
+            if len(self.notebooks) == 0:
+                self.print_help()
+
+            #Notebooks were specified, but not converted successfully.  Show how
+            #to access help.
+            else:
+                print('For help, use "ipython nbconvert --help"')
 
 
 #-----------------------------------------------------------------------------
 # Main entry point
 #-----------------------------------------------------------------------------
 
 launch_new_instance = NbConvertApp.launch_instance