catch pandoc failures in nbconvert handlers

IPython/html/nbconvert/handlers.py

@@ -1,117 +1,123 b''
 import io
 import os
 import zipfile
 
 from tornado import web
 
 from ..base.handlers import IPythonHandler, notebook_path_regex
 from IPython.nbformat.current import to_notebook_json
 from IPython.nbconvert.exporters.export import exporter_map
 from IPython.utils import tz
 from IPython.utils.py3compat import cast_bytes
 
 import sys
 
 def find_resource_files(output_files_dir):
     files = []
     for dirpath, dirnames, filenames in os.walk(output_files_dir):
         files.extend([os.path.join(dirpath, f) for f in filenames])
     return files
 
 def respond_zip(handler, name, output, resources):
     """Zip up the output and resource files and respond with the zip file.
 
     Returns True if it has served a zip file, False if there are no resource
     files, in which case we serve the plain output file.
     """
     # Check if we have resource files we need to zip
     output_files = resources.get('outputs', None)
     if not output_files:
         return False
 
     # Headers
     zip_filename = os.path.splitext(name)[0] + '.zip'
     handler.set_header('Content-Disposition',
                        'attachment; filename="%s"' % zip_filename)
     handler.set_header('Content-Type', 'application/zip')
 
     # Prepare the zip file
     buffer = io.BytesIO()
     zipf = zipfile.ZipFile(buffer, mode='w', compression=zipfile.ZIP_DEFLATED)
     output_filename = os.path.splitext(name)[0] + '.' + resources['output_extension']
     zipf.writestr(output_filename, cast_bytes(output, 'utf-8'))
     for filename, data in output_files.items():
         zipf.writestr(os.path.basename(filename), data)
     zipf.close()
 
     handler.finish(buffer.getvalue())
     return True
 
 class NbconvertFileHandler(IPythonHandler):
 
     SUPPORTED_METHODS = ('GET',)
     
     @web.authenticated
     def get(self, format, path='', name=None):
         exporter = exporter_map[format](config=self.config)
         
         path = path.strip('/')
         os_path = self.notebook_manager.get_os_path(name, path)
         if not os.path.isfile(os_path):
             raise web.HTTPError(404, u'Notebook does not exist: %s' % name)
 
         info = os.stat(os_path)
         self.set_header('Last-Modified', tz.utcfromtimestamp(info.st_mtime))
 
+        try:
         output, resources = exporter.from_filename(os_path)
+        except Exception as e:
+            raise web.HTTPError(500, "nbconvert failed: %s" % e)
 
         if respond_zip(self, name, output, resources):
             return
 
         # Force download if requested
         if self.get_argument('download', 'false').lower() == 'true':
             filename = os.path.splitext(name)[0] + '.' + resources['output_extension']
             self.set_header('Content-Disposition',
                                'attachment; filename="%s"' % filename)
 
         # MIME type
         if exporter.output_mimetype:
             self.set_header('Content-Type',
                             '%s; charset=utf-8' % exporter.output_mimetype)
 
         self.finish(output)
 
 class NbconvertPostHandler(IPythonHandler):
     SUPPORTED_METHODS = ('POST',)
 
     @web.authenticated 
     def post(self, format):
         exporter = exporter_map[format](config=self.config)
         
         model = self.get_json_body()
         nbnode = to_notebook_json(model['content'])
 
+        try:
         output, resources = exporter.from_notebook_node(nbnode)
+        except Exception as e:
+            raise web.HTTPError(500, "nbconvert failed: %s" % e)
 
         if respond_zip(self, nbnode.metadata.name, output, resources):
             return
 
         # MIME type
         if exporter.output_mimetype:
             self.set_header('Content-Type',
                             '%s; charset=utf-8' % exporter.output_mimetype)
 
         self.finish(output)
 
 #-----------------------------------------------------------------------------
 # URL to handler mappings
 #-----------------------------------------------------------------------------
 
 _format_regex = r"(?P<format>\w+)"
 
 
 default_handlers = [
     (r"/nbconvert/%s%s" % (_format_regex, notebook_path_regex),
          NbconvertFileHandler),
     (r"/nbconvert/%s" % _format_regex, NbconvertPostHandler),
 ]
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