Add a new output filter that excludes widgets if there is no state (#…

…1643)

This allows showing a static mimetype instead of a blank widget

nbconvert/exporters/html.py

@@ -21,6 +21,7 @@
 from jinja2.loaders import split_template_path
 
 from nbconvert.filters.highlight import Highlight2HTML
+from nbconvert.filters.widgetsdatatypefilter import WidgetsDataTypeFilter
 from nbconvert.filters.markdown_mistune import IPythonRenderer, MarkdownWithMath
 
 from .templateexporter import TemplateExporter
@@ -98,22 +99,22 @@ def _template_name_default(self):
     def default_config(self):
         c = Config({
             'NbConvertBase': {
-                'display_data_priority' : ['application/vnd.jupyter.widget-state+json',
-                                           'application/vnd.jupyter.widget-view+json',
-                                           'application/javascript',
-                                           'text/html',
-                                           'text/markdown',
-                                           'image/svg+xml',
-                                           'text/latex',
-                                           'image/png',
-                                           'image/jpeg',
-                                           'text/plain'
-                                          ]
-                },
+                'display_data_priority': [
+                    'application/vnd.jupyter.widget-view+json',
+                    'application/javascript',
+                    'text/html',
+                    'text/markdown',
+                    'image/svg+xml',
+                    'text/latex',
+                    'image/png',
+                    'image/jpeg',
+                    'text/plain'
+                ]
+            },
             'HighlightMagicsPreprocessor': {
-                'enabled':True
-                }
-            })
+                'enabled': True
+            }
+        })
         c.merge(super().default_config)
         return c
 
@@ -136,7 +137,10 @@ def from_notebook_node(self, nb, resources=None, **kw):
         langinfo = nb.metadata.get('language_info', {})
         lexer = langinfo.get('pygments_lexer', langinfo.get('name', None))
         highlight_code = self.filters.get('highlight_code', Highlight2HTML(pygments_lexer=lexer, parent=self))
+        filter_data_type = WidgetsDataTypeFilter(notebook_metadata=nb.metadata, parent=self)
+
         self.register_filter('highlight_code', highlight_code)
+        self.register_filter('filter_data_type', filter_data_type)
         return super().from_notebook_node(nb, resources, **kw)
 
     def _init_resources(self, resources):

nbconvert/filters/widgetsdatatypefilter.py

@@ -0,0 +1,69 @@
+"""Filter used to select the first preferred output format available,
+excluding interactive widget format if the widget state is not available.
+
+The filter contained in the file allows the converter templates to select
+the output format that is most valuable to the active export format.  The
+value of the different formats is set via
+NbConvertBase.display_data_priority
+"""
+#-----------------------------------------------------------------------------
+# 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.
+#-----------------------------------------------------------------------------
+
+#-----------------------------------------------------------------------------
+# Classes and functions
+#-----------------------------------------------------------------------------
+
+from warnings import warn
+
+from ..utils.base import NbConvertBase
+
+__all__ = ['WidgetsDataTypeFilter']
+
+
+WIDGET_VIEW_MIMETYPE = 'application/vnd.jupyter.widget-view+json'
+WIDGET_STATE_MIMETYPE = 'application/vnd.jupyter.widget-state+json'
+
+
+class WidgetsDataTypeFilter(NbConvertBase):
+    """ Returns the preferred display format, excluding the widget output if
+    there is no widget state available """
+
+    def __init__(self, notebook_metadata=None, **kwargs):
+        metadata = notebook_metadata or {}
+
+        self.widgets_state = (
+            metadata['widgets'][WIDGET_STATE_MIMETYPE]['state'] if
+            metadata.get('widgets') is not None else {}
+        )
+
+        super().__init__(**kwargs)
+
+    def __call__(self, output):
+        """ Return the first available format in the priority.
+
+        Produces a UserWarning if no compatible mimetype is found.
+
+        `output` is dict with structure {mimetype-of-element: value-of-element}
+
+        """
+        for fmt in self.display_data_priority:
+            if fmt in output:
+                # If there is no widget state available, we skip this mimetype
+                if (
+                    fmt == WIDGET_VIEW_MIMETYPE and
+                    output[WIDGET_VIEW_MIMETYPE]['model_id'] not in self.widgets_state
+                    ):
+                    continue
+
+                return [fmt]
+        warn("Your element with mimetype(s) {mimetypes}"
+                      " is not able to be represented.".format(
+                          mimetypes=output.keys())
+                      )
+
+        return []

share/jupyter/nbconvert/templates/base/display_priority.j2

@@ -32,9 +32,6 @@
         {%- elif type == 'application/javascript' -%}
             {%- block data_javascript -%}
             {%- endblock -%}
-        {%- elif type == 'application/vnd.jupyter.widget-state+json' -%}
-            {%- block data_widget_state -%}
-            {%- endblock -%}
         {%- elif type == 'application/vnd.jupyter.widget-view+json' -%}
             {%- block data_widget_view -%}
             {%- endblock -%}

share/jupyter/nbconvert/templates/latex/display_priority.j2

@@ -36,9 +36,6 @@
         ((*- elif type == 'application/javascript' -*))
             ((*- block data_javascript -*))
             ((*- endblock -*))
-        ((*- elif type == 'application/vnd.jupyter.widget-state+json' -*))
-            ((*- block data_widget_state -*))
-            ((*- endblock -*))
         ((*- elif type == 'application/vnd.jupyter.widget-view+json' -*))
             ((*- block data_widget_view -*))
             ((*- endblock -*))