refactor: move output widget to nbclient

Depends on jupyter/nbclient#68

.github/workflows/main.yml

@@ -52,6 +52,7 @@ jobs:
         whereis python
         python --version
 
+        pip install --upgrade --no-deps --force-reinstall git+https://github.com/maartenbreddels/nbclient.git@feat_mimic_output_widget
         python -m pip install --ignore-installed ".[test]"
         cd tests/test_template; pip install .; cd ../../;
 

.travis.yml

@@ -20,6 +20,7 @@ before_install:
   - conda info -a
   - conda create -q -n test-environment -c conda-forge python=$PYTHON_VERSION jupyterlab_pygments==0.1.0 pytest-cov nodejs flake8 ipywidgets matplotlib xeus-cling
   - source activate test-environment
+  - pip install --upgrade --no-deps --force-reinstall git+https://github.com/maartenbreddels/nbclient.git@feat_mimic_output_widget
 install:
   - pip install --ignore-installed ".[test]"
   - cd tests/test_template; pip install .; cd ../../;

setup.py

@@ -378,7 +378,7 @@ def get_data_files():
         'async_generator',
         'jupyter_server>=0.3.0',
         'jupyter_client>=6.1.3',
-        'nbclient>=0.2.0',
+        'nbclient>=0.3.0',
         'nbconvert==6.0.0a1',
         'jupyterlab_pygments>=0.1.0,<0.2',
         'pygments>=2.4.1,<3'  # Explicitly requiring pygments which is a second-order dependency.

voila/execute.py

@@ -6,16 +6,13 @@
 #                                                                           #
 # The full license is in the file LICENSE, distributed with this software.  #
 #############################################################################
-import collections
 import logging
 
 from nbconvert.preprocessors import ClearOutputPreprocessor
 from nbclient.exceptions import CellExecutionError
 from nbclient import NotebookClient
-from nbformat.v4 import output_from_msg
 
 from traitlets import Unicode
-from ipykernel.jsonutil import json_clean
 
 
 def strip_code_cell_warnings(cell):
@@ -38,80 +35,6 @@ def should_strip_error(config):
     return 'Voila' not in config or 'log_level' not in config['Voila'] or config['Voila']['log_level'] != logging.DEBUG
 
 
-class OutputWidget:
-    """This class mimics a front end output widget"""
-    def __init__(self, comm_id, state, kernel_client, executor):
-        self.comm_id = comm_id
-        self.state = state
-        self.kernel_client = kernel_client
-        self.executor = executor
-        self.topic = ('comm-%s' % self.comm_id).encode('ascii')
-        self.outputs = self.state['outputs']
-        self.clear_before_next_output = False
-
-    def clear_output(self, outs, msg, cell_index):
-        self.parent_header = msg['parent_header']
-        content = msg['content']
-        if content.get('wait'):
-            self.clear_before_next_output = True
-        else:
-            self.outputs = []
-            # sync back the state to the kernel
-            self.sync_state()
-            if hasattr(self.executor, 'widget_state'):
-                # sync the state to the nbconvert state as well, since that is used for testing
-                self.executor.widget_state[self.comm_id]['outputs'] = self.outputs
-
-    def sync_state(self):
-        state = {'outputs': self.outputs}
-        msg = {'method': 'update', 'state': state, 'buffer_paths': []}
-        self.send(msg)
-
-    def _publish_msg(self, msg_type, data=None, metadata=None, buffers=None, **keys):
-        """Helper for sending a comm message on IOPub"""
-        data = {} if data is None else data
-        metadata = {} if metadata is None else metadata
-        content = json_clean(dict(data=data, comm_id=self.comm_id, **keys))
-        msg = self.kernel_client.session.msg(msg_type, content=content, parent=self.parent_header, metadata=metadata)
-        self.kernel_client.shell_channel.send(msg)
-
-    def send(self, data=None, metadata=None, buffers=None):
-        self._publish_msg('comm_msg', data=data, metadata=metadata, buffers=buffers)
-
-    def output(self, outs, msg, display_id, cell_index):
-        if self.clear_before_next_output:
-            self.outputs = []
-            self.clear_before_next_output = False
-        self.parent_header = msg['parent_header']
-        output = output_from_msg(msg)
-
-        if self.outputs:
-            # try to coalesce/merge output text
-            last_output = self.outputs[-1]
-            if (last_output['output_type'] == 'stream' and
-                    output['output_type'] == 'stream' and
-                    last_output['name'] == output['name']):
-                last_output['text'] += output['text']
-            else:
-                self.outputs.append(output)
-        else:
-            self.outputs.append(output)
-        self.sync_state()
-        if hasattr(self.executor, 'widget_state'):
-            # sync the state to the nbconvert state as well, since that is used for testing
-            self.executor.widget_state[self.comm_id]['outputs'] = self.outputs
-
-    def set_state(self, state):
-        if 'msg_id' in state:
-            msg_id = state.get('msg_id')
-            if msg_id:
-                self.executor.register_output_hook(msg_id, self)
-                self.msg_id = msg_id
-            else:
-                self.executor.remove_output_hook(self.msg_id, self)
-                self.msg_id = msg_id
-
-
 class VoilaExecutor(NotebookClient):
     """Execute, but respect the output widget behaviour"""
     cell_error_instruction = Unicode(
@@ -132,8 +55,6 @@ class VoilaExecutor(NotebookClient):
 
     def __init__(self, nb, km=None, **kwargs):
         super(VoilaExecutor, self).__init__(nb, km=km, **kwargs)
-        self.output_hook_stack = collections.defaultdict(list)  # maps to list of hooks, where the last is used
-        self.output_objects = {}
 
     def execute(self, nb, resources, km=None):
         try:
@@ -166,52 +87,6 @@ async def execute_cell(self, cell, resources, cell_index, store_history=True):
 
         return result
 
-    def register_output_hook(self, msg_id, hook):
-        # mimics
-        # https://jupyterlab.github.io/jupyterlab/services/interfaces/kernel.ikernelconnection.html#registermessagehook
-        self.output_hook_stack[msg_id].append(hook)
-
-    def remove_output_hook(self, msg_id, hook):
-        # mimics
-        # https://jupyterlab.github.io/jupyterlab/services/interfaces/kernel.ikernelconnection.html#removemessagehook
-        removed_hook = self.output_hook_stack[msg_id].pop()
-        assert removed_hook == hook
-
-    def output(self, outs, msg, display_id, cell_index):
-        parent_msg_id = msg['parent_header'].get('msg_id')
-        if self.output_hook_stack[parent_msg_id]:
-            hook = self.output_hook_stack[parent_msg_id][-1]
-            hook.output(outs, msg, display_id, cell_index)
-            return
-        super(VoilaExecutor, self).output(outs, msg, display_id, cell_index)
-
-    def handle_comm_msg(self, outs, msg, cell_index):
-        super(VoilaExecutor, self).handle_comm_msg(outs, msg, cell_index)
-        self.log.debug('comm msg: %r', msg)
-        if msg['msg_type'] == 'comm_open' and msg['content'].get('target_name') == 'jupyter.widget':
-            content = msg['content']
-            data = content['data']
-            state = data['state']
-            comm_id = msg['content']['comm_id']
-            if state['_model_module'] == '@jupyter-widgets/output' and state['_model_name'] == 'OutputModel':
-                self.output_objects[comm_id] = OutputWidget(comm_id, state, self.kc, self)
-        elif msg['msg_type'] == 'comm_msg':
-            content = msg['content']
-            data = content['data']
-            if 'state' in data:
-                state = data['state']
-                comm_id = msg['content']['comm_id']
-                if comm_id in self.output_objects:
-                    self.output_objects[comm_id].set_state(state)
-
-    def clear_output(self, outs, msg, cell_index):
-        parent_msg_id = msg['parent_header'].get('msg_id')
-        if self.output_hook_stack[parent_msg_id]:
-            hook = self.output_hook_stack[parent_msg_id][-1]
-            hook.clear_output(outs, msg, cell_index)
-            return
-        super(VoilaExecutor, self).clear_output(outs, msg, cell_index)
-
     def strip_notebook_errors(self, nb):
         """Strip error messages and traceback from a Notebook."""
         cells = nb['cells']