class CommSocket(object):
"""
Manages the Comm connection between IPython and the browser (client).
Comms are 2 way, with the CommSocket being able to publish a message
via the send_json method, and handle a message with on_message. On the
JS side figure.send_message and figure.ws.onmessage do the sending and
receiving respectively.
"""
def __init__(self, manager):
self.supports_binary = None
self.manager = manager
self.uuid = str(uuid())
display(HTML("<div id=%r></div>" % self.uuid))
try:
self.comm = Comm('matplotlib', data={'id': self.uuid})
except AttributeError:
raise RuntimeError('Unable to create an IPython notebook Comm '
'instance. Are you in the IPython notebook?')
self.comm.on_msg(self.on_message)
def on_close(self):
# When the socket is closed, deregister the websocket with
# the FigureManager.
if self.comm in self.manager.web_sockets:
self.manager.remove_web_socket(self)
self.comm.close()
def send_json(self, content):
self.comm.send({'data': json.dumps(content)})
def send_binary(self, blob):
# The comm is ascii, so we always send the image in base64
# encoded data URL form.
data_uri = "data:image/png;base64,{0}".format(b64encode(blob))
self.comm.send({'data': data_uri})
def on_message(self, message):
# The 'supports_binary' message is relevant to the
# websocket itself. The other messages get passed along
# to matplotlib as-is.
# Every message has a "type" and a "figure_id".
message = json.loads(message['content']['data'])
if message['type'] == 'closing':
self.on_close()
elif message['type'] == 'supports_binary':
self.supports_binary = message['value']
else:
self.manager.handle_json(message)
class CommSocket(object):
"""
Manages the Comm connection between IPython and the browser (client).
Comms are 2 way, with the CommSocket being able to publish a message
via the send_json method, and handle a message with on_message. On the
JS side figure.send_message and figure.ws.onmessage do the sending and
receiving respectively.
"""
def __init__(self, manager):
self.supports_binary = None
self.manager = manager
self.uuid = str(uuid())
display(HTML("<div id=%r></div>" % self.uuid))
try:
self.comm = Comm('matplotlib', data={'id': self.uuid})
except AttributeError:
raise RuntimeError('Unable to create an IPython notebook Comm '
'instance. Are you in the IPython notebook?')
self.comm.on_msg(self.on_message)
def on_close(self):
# When the socket is closed, deregister the websocket with
# the FigureManager.
if self.comm in self.manager.web_sockets:
self.manager.remove_web_socket(self)
self.comm.close()
def send_json(self, content):
self.comm.send({'data': json.dumps(content)})
def send_binary(self, blob):
# The comm is ascii, so we always send the image in base64
# encoded data URL form.
data_uri = "data:image/png;base64,{0}".format(b64encode(blob))
self.comm.send({'data': data_uri})
def on_message(self, message):
# The 'supports_binary' message is relevant to the
# websocket itself. The other messages get passed along
# to matplotlib as-is.
# Every message has a "type" and a "figure_id".
message = json.loads(message['content']['data'])
if message['type'] == 'closing':
self.on_close()
elif message['type'] == 'supports_binary':
self.supports_binary = message['value']
else:
self.manager.handle_json(message)
class Widget(LoggingConfigurable):
#-------------------------------------------------------------------------
# Class attributes
#-------------------------------------------------------------------------
_widget_construction_callback = None
widgets = {}
@staticmethod
def on_widget_constructed(callback):
"""Registers a callback to be called when a widget is constructed.
The callback must have the following signature:
callback(widget)"""
Widget._widget_construction_callback = callback
@staticmethod
def _call_widget_constructed(widget):
"""Static method, called when a widget is constructed."""
if Widget._widget_construction_callback is not None and callable(
Widget._widget_construction_callback):
Widget._widget_construction_callback(widget)
#-------------------------------------------------------------------------
# Traits
#-------------------------------------------------------------------------
model_name = Unicode('WidgetModel',
help="""Name of the backbone model
registered in the front-end to create and sync this widget with.""")
_view_name = Unicode(help="""Default view registered in the front-end
to use to represent the widget.""",
sync=True)
_comm = Instance('IPython.kernel.comm.Comm')
closed = Bool(False)
keys = List()
def _keys_default(self):
return [name for name in self.traits(sync=True)]
_property_lock = Tuple((None, None))
_display_callbacks = Instance(CallbackDispatcher, ())
_msg_callbacks = Instance(CallbackDispatcher, ())
#-------------------------------------------------------------------------
# (Con/de)structor
#-------------------------------------------------------------------------
def __init__(self, **kwargs):
"""Public constructor"""
super(Widget, self).__init__(**kwargs)
self.on_trait_change(self._handle_property_changed, self.keys)
Widget._call_widget_constructed(self)
def __del__(self):
"""Object disposal"""
self.close()
#-------------------------------------------------------------------------
# Properties
#-------------------------------------------------------------------------
@property
def comm(self):
"""Gets the Comm associated with this widget.
If a Comm doesn't exist yet, a Comm will be created automagically."""
if self._comm is None:
# Create a comm.
self._comm = Comm(target_name=self.model_name)
self._comm.on_msg(self._handle_msg)
self._comm.on_close(self._close)
Widget.widgets[self.model_id] = self
# first update
self.send_state()
return self._comm
@property
def model_id(self):
"""Gets the model id of this widget.
If a Comm doesn't exist yet, a Comm will be created automagically."""
return self.comm.comm_id
#-------------------------------------------------------------------------
# Methods
#-------------------------------------------------------------------------
def _close(self):
"""Private close - cleanup objects, registry entries"""
del Widget.widgets[self.model_id]
self._comm = None
self.closed = True
def close(self):
"""Close method.
Closes the widget which closes the underlying comm.
When the comm is closed, all of the widget views are automatically
removed from the front-end."""
if not self.closed:
self._comm.close()
self._close()
def send_state(self, key=None):
"""Sends the widget state, or a piece of it, to the front-end.
Parameters
----------
key : unicode (optional)
A single property's name to sync with the front-end.
"""
self._send({"method": "update", "state": self.get_state()})
def get_state(self, key=None):
"""Gets the widget state, or a piece of it.
Parameters
----------
key : unicode (optional)
A single property's name to get.
"""
keys = self.keys if key is None else [key]
return {k: self._pack_widgets(getattr(self, k)) for k in keys}
def send(self, content):
"""Sends a custom msg to the widget model in the front-end.
Parameters
----------
content : dict
Content of the message to send.
"""
self._send({"method": "custom", "content": content})
def on_msg(self, callback, remove=False):
"""(Un)Register a custom msg receive callback.
Parameters
----------
callback: callable
callback will be passed two arguments when a message arrives::
callback(widget, content)
remove: bool
True if the callback should be unregistered."""
self._msg_callbacks.register_callback(callback, remove=remove)
def on_displayed(self, callback, remove=False):
"""(Un)Register a widget displayed callback.
Parameters
----------
callback: method handler
Must have a signature of::
callback(widget, **kwargs)
kwargs from display are passed through without modification.
remove: bool
True if the callback should be unregistered."""
self._display_callbacks.register_callback(callback, remove=remove)
#-------------------------------------------------------------------------
# Support methods
#-------------------------------------------------------------------------
@contextmanager
def _lock_property(self, key, value):
"""Lock a property-value pair.
NOTE: This, in addition to the single lock for all state changes, is
flawed. In the future we may want to look into buffering state changes
back to the front-end."""
self._property_lock = (key, value)
try:
yield
finally:
self._property_lock = (None, None)
def _should_send_property(self, key, value):
"""Check the property lock (property_lock)"""
return key != self._property_lock[0] or \
value != self._property_lock[1]
# Event handlers
def _handle_msg(self, msg):
"""Called when a msg is received from the front-end"""
data = msg['content']['data']
method = data['method']
if not method in ['backbone', 'custom']:
self.log.error(
'Unknown front-end to back-end widget msg with method "%s"' %
method)
# Handle backbone sync methods CREATE, PATCH, and UPDATE all in one.
if method == 'backbone' and 'sync_data' in data:
sync_data = data['sync_data']
self._handle_receive_state(sync_data) # handles all methods
# Handle a custom msg from the front-end
elif method == 'custom':
if 'content' in data:
self._handle_custom_msg(data['content'])
def _handle_receive_state(self, sync_data):
"""Called when a state is received from the front-end."""
for name in self.keys:
if name in sync_data:
value = self._unpack_widgets(sync_data[name])
with self._lock_property(name, value):
setattr(self, name, value)
def _handle_custom_msg(self, content):
"""Called when a custom msg is received."""
self._msg_callbacks(self, content)
def _handle_property_changed(self, name, old, new):
"""Called when a property has been changed."""
# Make sure this isn't information that the front-end just sent us.
if self._should_send_property(name, new):
# Send new state to front-end
self.send_state(key=name)
def _handle_displayed(self, **kwargs):
"""Called when a view has been displayed for this widget instance"""
self._display_callbacks(self, **kwargs)
def _pack_widgets(self, x):
"""Recursively converts all widget instances to model id strings.
Children widgets will be stored and transmitted to the front-end by
their model ids. Return value must be JSON-able."""
if isinstance(x, dict):
return {k: self._pack_widgets(v) for k, v in x.items()}
elif isinstance(x, list):
return [self._pack_widgets(v) for v in x]
elif isinstance(x, Widget):
return x.model_id
else:
return x # Value must be JSON-able
def _unpack_widgets(self, x):
"""Recursively converts all model id strings to widget instances.
Children widgets will be stored and transmitted to the front-end by
their model ids."""
if isinstance(x, dict):
return {k: self._unpack_widgets(v) for k, v in x.items()}
elif isinstance(x, list):
return [self._unpack_widgets(v) for v in x]
elif isinstance(x, string_types):
return x if x not in Widget.widgets else Widget.widgets[x]
else:
return x
def _ipython_display_(self, **kwargs):
"""Called when `IPython.display.display` is called on the widget."""
# Show view. By sending a display message, the comm is opened and the
# initial state is sent.
self._send({"method": "display"})
self._handle_displayed(**kwargs)
def _send(self, msg):
"""Sends a message to the model in the front-end."""
self.comm.send(msg)
class Widget(LoggingConfigurable):
#-------------------------------------------------------------------------
# Class attributes
#-------------------------------------------------------------------------
_widget_construction_callback = None
widgets = {}
widget_types = {}
@staticmethod
def on_widget_constructed(callback):
"""Registers a callback to be called when a widget is constructed.
The callback must have the following signature:
callback(widget)"""
Widget._widget_construction_callback = callback
@staticmethod
def _call_widget_constructed(widget):
"""Static method, called when a widget is constructed."""
if Widget._widget_construction_callback is not None and callable(Widget._widget_construction_callback):
Widget._widget_construction_callback(widget)
@staticmethod
def handle_comm_opened(comm, msg):
"""Static method, called when a widget is constructed."""
widget_class = import_item(msg['content']['data']['widget_class'])
widget = widget_class(comm=comm)
#-------------------------------------------------------------------------
# Traits
#-------------------------------------------------------------------------
_model_module = Unicode(None, allow_none=True, help="""A requirejs module name
in which to find _model_name. If empty, look in the global registry.""")
_model_name = Unicode('WidgetModel', help="""Name of the backbone model
registered in the front-end to create and sync this widget with.""")
_view_module = Unicode(help="""A requirejs module in which to find _view_name.
If empty, look in the global registry.""", sync=True)
_view_name = Unicode(None, allow_none=True, help="""Default view registered in the front-end
to use to represent the widget.""", sync=True)
comm = Instance('IPython.kernel.comm.Comm')
msg_throttle = Int(3, sync=True, help="""Maximum number of msgs the
front-end can send before receiving an idle msg from the back-end.""")
version = Int(0, sync=True, help="""Widget's version""")
keys = List()
def _keys_default(self):
return [name for name in self.traits(sync=True)]
_property_lock = Tuple((None, None))
_send_state_lock = Int(0)
_states_to_send = Set(allow_none=False)
_display_callbacks = Instance(CallbackDispatcher, ())
_msg_callbacks = Instance(CallbackDispatcher, ())
#-------------------------------------------------------------------------
# (Con/de)structor
#-------------------------------------------------------------------------
def __init__(self, **kwargs):
"""Public constructor"""
self._model_id = kwargs.pop('model_id', None)
super(Widget, self).__init__(**kwargs)
Widget._call_widget_constructed(self)
self.open()
def __del__(self):
"""Object disposal"""
self.close()
#-------------------------------------------------------------------------
# Properties
#-------------------------------------------------------------------------
def open(self):
"""Open a comm to the frontend if one isn't already open."""
if self.comm is None:
args = dict(target_name='ipython.widget',
data={'model_name': self._model_name,
'model_module': self._model_module})
if self._model_id is not None:
args['comm_id'] = self._model_id
self.comm = Comm(**args)
def _comm_changed(self, name, new):
"""Called when the comm is changed."""
if new is None:
return
self._model_id = self.model_id
self.comm.on_msg(self._handle_msg)
Widget.widgets[self.model_id] = self
# first update
self.send_state()
@property
def model_id(self):
"""Gets the model id of this widget.
If a Comm doesn't exist yet, a Comm will be created automagically."""
return self.comm.comm_id
#-------------------------------------------------------------------------
# Methods
#-------------------------------------------------------------------------
def close(self):
"""Close method.
Closes the underlying comm.
When the comm is closed, all of the widget views are automatically
removed from the front-end."""
if self.comm is not None:
Widget.widgets.pop(self.model_id, None)
self.comm.close()
self.comm = None
def send_state(self, key=None):
"""Sends the widget state, or a piece of it, to the front-end.
Parameters
----------
key : unicode, or iterable (optional)
A single property's name or iterable of property names to sync with the front-end.
"""
self._send({
"method" : "update",
"state" : self.get_state(key=key)
})
def get_state(self, key=None):
"""Gets the widget state, or a piece of it.
Parameters
----------
key : unicode or iterable (optional)
A single property's name or iterable of property names to get.
"""
if key is None:
keys = self.keys
elif isinstance(key, string_types):
keys = [key]
elif isinstance(key, collections.Iterable):
keys = key
else:
raise ValueError("key must be a string, an iterable of keys, or None")
state = {}
for k in keys:
f = self.trait_metadata(k, 'to_json', self._trait_to_json)
value = getattr(self, k)
state[k] = f(value)
return state
def set_state(self, sync_data):
"""Called when a state is received from the front-end."""
for name in self.keys:
if name in sync_data:
json_value = sync_data[name]
from_json = self.trait_metadata(name, 'from_json', self._trait_from_json)
with self._lock_property(name, json_value):
setattr(self, name, from_json(json_value))
def send(self, content):
"""Sends a custom msg to the widget model in the front-end.
Parameters
----------
content : dict
Content of the message to send.
"""
self._send({"method": "custom", "content": content})
def on_msg(self, callback, remove=False):
"""(Un)Register a custom msg receive callback.
Parameters
----------
callback: callable
callback will be passed two arguments when a message arrives::
callback(widget, content)
remove: bool
True if the callback should be unregistered."""
self._msg_callbacks.register_callback(callback, remove=remove)
def on_displayed(self, callback, remove=False):
"""(Un)Register a widget displayed callback.
Parameters
----------
callback: method handler
Must have a signature of::
callback(widget, **kwargs)
kwargs from display are passed through without modification.
remove: bool
True if the callback should be unregistered."""
self._display_callbacks.register_callback(callback, remove=remove)
#-------------------------------------------------------------------------
# Support methods
#-------------------------------------------------------------------------
@contextmanager
def _lock_property(self, key, value):
"""Lock a property-value pair.
The value should be the JSON state of the property.
NOTE: This, in addition to the single lock for all state changes, is
flawed. In the future we may want to look into buffering state changes
back to the front-end."""
self._property_lock = (key, value)
try:
yield
finally:
self._property_lock = (None, None)
@contextmanager
def hold_sync(self):
"""Hold syncing any state until the context manager is released"""
# We increment a value so that this can be nested. Syncing will happen when
# all levels have been released.
self._send_state_lock += 1
try:
yield
finally:
self._send_state_lock -=1
if self._send_state_lock == 0:
self.send_state(self._states_to_send)
self._states_to_send.clear()
def _should_send_property(self, key, value):
"""Check the property lock (property_lock)"""
to_json = self.trait_metadata(key, 'to_json', self._trait_to_json)
if (key == self._property_lock[0]
and to_json(value) == self._property_lock[1]):
return False
elif self._send_state_lock > 0:
self._states_to_send.add(key)
return False
else:
return True
# Event handlers
@_show_traceback
def _handle_msg(self, msg):
"""Called when a msg is received from the front-end"""
data = msg['content']['data']
method = data['method']
# Handle backbone sync methods CREATE, PATCH, and UPDATE all in one.
if method == 'backbone':
if 'sync_data' in data:
sync_data = data['sync_data']
self.set_state(sync_data) # handles all methods
# Handle a state request.
elif method == 'request_state':
self.send_state()
# Handle a custom msg from the front-end.
elif method == 'custom':
if 'content' in data:
self._handle_custom_msg(data['content'])
# Catch remainder.
else:
self.log.error('Unknown front-end to back-end widget msg with method "%s"' % method)
def _handle_custom_msg(self, content):
"""Called when a custom msg is received."""
self._msg_callbacks(self, content)
def _notify_trait(self, name, old_value, new_value):
"""Called when a property has been changed."""
# Trigger default traitlet callback machinery. This allows any user
# registered validation to be processed prior to allowing the widget
# machinery to handle the state.
LoggingConfigurable._notify_trait(self, name, old_value, new_value)
# Send the state after the user registered callbacks for trait changes
# have all fired (allows for user to validate values).
if self.comm is not None and name in self.keys:
# Make sure this isn't information that the front-end just sent us.
if self._should_send_property(name, new_value):
# Send new state to front-end
self.send_state(key=name)
def _handle_displayed(self, **kwargs):
"""Called when a view has been displayed for this widget instance"""
self._display_callbacks(self, **kwargs)
def _trait_to_json(self, x):
"""Convert a trait value to json
Traverse lists/tuples and dicts and serialize their values as well.
Replace any widgets with their model_id
"""
if isinstance(x, dict):
return {k: self._trait_to_json(v) for k, v in x.items()}
elif isinstance(x, (list, tuple)):
return [self._trait_to_json(v) for v in x]
elif isinstance(x, Widget):
return "IPY_MODEL_" + x.model_id
else:
return x # Value must be JSON-able
def _trait_from_json(self, x):
"""Convert json values to objects
Replace any strings representing valid model id values to Widget references.
"""
if isinstance(x, dict):
return {k: self._trait_from_json(v) for k, v in x.items()}
elif isinstance(x, (list, tuple)):
return [self._trait_from_json(v) for v in x]
elif isinstance(x, string_types) and x.startswith('IPY_MODEL_') and x[10:] in Widget.widgets:
# we want to support having child widgets at any level in a hierarchy
# trusting that a widget UUID will not appear out in the wild
return Widget.widgets[x[10:]]
else:
return x
def _ipython_display_(self, **kwargs):
"""Called when `IPython.display.display` is called on the widget."""
# Show view.
if self._view_name is not None:
self._send({"method": "display"})
self._handle_displayed(**kwargs)
def _send(self, msg):
"""Sends a message to the model in the front-end."""
self.comm.send(msg)
class Widget(LoggingConfigurable):
#-------------------------------------------------------------------------
# Class attributes
#-------------------------------------------------------------------------
_widget_construction_callback = None
widgets = {}
@staticmethod
def on_widget_constructed(callback):
"""Registers a callback to be called when a widget is constructed.
The callback must have the following signature:
callback(widget)"""
Widget._widget_construction_callback = callback
@staticmethod
def _call_widget_constructed(widget):
"""Static method, called when a widget is constructed."""
if Widget._widget_construction_callback is not None and callable(Widget._widget_construction_callback):
Widget._widget_construction_callback(widget)
#-------------------------------------------------------------------------
# Traits
#-------------------------------------------------------------------------
_model_name = Unicode('WidgetModel', help="""Name of the backbone model
registered in the front-end to create and sync this widget with.""")
_view_name = Unicode('WidgetView', help="""Default view registered in the front-end
to use to represent the widget.""", sync=True)
_comm = Instance('IPython.kernel.comm.Comm')
msg_throttle = Int(3, sync=True, help="""Maximum number of msgs the
front-end can send before receiving an idle msg from the back-end.""")
keys = List()
def _keys_default(self):
return [name for name in self.traits(sync=True)]
_property_lock = Tuple((None, None))
_display_callbacks = Instance(CallbackDispatcher, ())
_msg_callbacks = Instance(CallbackDispatcher, ())
#-------------------------------------------------------------------------
# (Con/de)structor
#-------------------------------------------------------------------------
def __init__(self, **kwargs):
"""Public constructor"""
super(Widget, self).__init__(**kwargs)
self.on_trait_change(self._handle_property_changed, self.keys)
Widget._call_widget_constructed(self)
def __del__(self):
"""Object disposal"""
self.close()
#-------------------------------------------------------------------------
# Properties
#-------------------------------------------------------------------------
@property
def comm(self):
"""Gets the Comm associated with this widget.
If a Comm doesn't exist yet, a Comm will be created automagically."""
if self._comm is None:
# Create a comm.
self._comm = Comm(target_name=self._model_name)
self._comm.on_msg(self._handle_msg)
Widget.widgets[self.model_id] = self
# first update
self.send_state()
return self._comm
@property
def model_id(self):
"""Gets the model id of this widget.
If a Comm doesn't exist yet, a Comm will be created automagically."""
return self.comm.comm_id
#-------------------------------------------------------------------------
# Methods
#-------------------------------------------------------------------------
def close(self):
"""Close method.
Closes the underlying comm.
When the comm is closed, all of the widget views are automatically
removed from the front-end."""
if self._comm is not None:
Widget.widgets.pop(self.model_id, None)
self._comm.close()
self._comm = None
def send_state(self, key=None):
"""Sends the widget state, or a piece of it, to the front-end.
Parameters
----------
key : unicode (optional)
A single property's name to sync with the front-end.
"""
self._send({
"method" : "update",
"state" : self.get_state()
})
def get_state(self, key=None):
"""Gets the widget state, or a piece of it.
Parameters
----------
key : unicode (optional)
A single property's name to get.
"""
keys = self.keys if key is None else [key]
state = {}
for k in keys:
f = self.trait_metadata(k, 'to_json')
if f is None:
f = self._trait_to_json
value = getattr(self, k)
state[k] = f(value)
return state
def send(self, content):
"""Sends a custom msg to the widget model in the front-end.
Parameters
----------
content : dict
Content of the message to send.
"""
self._send({"method": "custom", "content": content})
def on_msg(self, callback, remove=False):
"""(Un)Register a custom msg receive callback.
Parameters
----------
callback: callable
callback will be passed two arguments when a message arrives::
callback(widget, content)
remove: bool
True if the callback should be unregistered."""
self._msg_callbacks.register_callback(callback, remove=remove)
def on_displayed(self, callback, remove=False):
"""(Un)Register a widget displayed callback.
Parameters
----------
callback: method handler
Must have a signature of::
callback(widget, **kwargs)
kwargs from display are passed through without modification.
remove: bool
True if the callback should be unregistered."""
self._display_callbacks.register_callback(callback, remove=remove)
#-------------------------------------------------------------------------
# Support methods
#-------------------------------------------------------------------------
@contextmanager
def _lock_property(self, key, value):
"""Lock a property-value pair.
NOTE: This, in addition to the single lock for all state changes, is
flawed. In the future we may want to look into buffering state changes
back to the front-end."""
self._property_lock = (key, value)
try:
yield
finally:
self._property_lock = (None, None)
def _should_send_property(self, key, value):
"""Check the property lock (property_lock)"""
return key != self._property_lock[0] or \
value != self._property_lock[1]
# Event handlers
@_show_traceback
def _handle_msg(self, msg):
"""Called when a msg is received from the front-end"""
data = msg['content']['data']
method = data['method']
if not method in ['backbone', 'custom']:
self.log.error('Unknown front-end to back-end widget msg with method "%s"' % method)
# Handle backbone sync methods CREATE, PATCH, and UPDATE all in one.
if method == 'backbone' and 'sync_data' in data:
sync_data = data['sync_data']
self._handle_receive_state(sync_data) # handles all methods
# Handle a custom msg from the front-end
elif method == 'custom':
if 'content' in data:
self._handle_custom_msg(data['content'])
def _handle_receive_state(self, sync_data):
"""Called when a state is received from the front-end."""
for name in self.keys:
if name in sync_data:
f = self.trait_metadata(name, 'from_json')
if f is None:
f = self._trait_from_json
value = f(sync_data[name])
with self._lock_property(name, value):
setattr(self, name, value)
def _handle_custom_msg(self, content):
"""Called when a custom msg is received."""
self._msg_callbacks(self, content)
def _handle_property_changed(self, name, old, new):
"""Called when a property has been changed."""
# Make sure this isn't information that the front-end just sent us.
if self._should_send_property(name, new):
# Send new state to front-end
self.send_state(key=name)
def _handle_displayed(self, **kwargs):
"""Called when a view has been displayed for this widget instance"""
self._display_callbacks(self, **kwargs)
def _trait_to_json(self, x):
"""Convert a trait value to json
Traverse lists/tuples and dicts and serialize their values as well.
Replace any widgets with their model_id
"""
if isinstance(x, dict):
return {k: self._trait_to_json(v) for k, v in x.items()}
elif isinstance(x, (list, tuple)):
return [self._trait_to_json(v) for v in x]
elif isinstance(x, Widget):
return "IPY_MODEL_" + x.model_id
else:
return x # Value must be JSON-able
def _trait_from_json(self, x):
"""Convert json values to objects
Replace any strings representing valid model id values to Widget references.
"""
if isinstance(x, dict):
return {k: self._trait_from_json(v) for k, v in x.items()}
elif isinstance(x, (list, tuple)):
return [self._trait_from_json(v) for v in x]
elif isinstance(x, string_types) and x.startswith('IPY_MODEL_') and x[10:] in Widget.widgets:
# we want to support having child widgets at any level in a hierarchy
# trusting that a widget UUID will not appear out in the wild
return Widget.widgets[x]
else:
return x
def _ipython_display_(self, **kwargs):
"""Called when `IPython.display.display` is called on the widget."""
# Show view. By sending a display message, the comm is opened and the
# initial state is sent.
self._send({"method": "display"})
self._handle_displayed(**kwargs)
def _send(self, msg):
"""Sends a message to the model in the front-end."""
self.comm.send(msg)
class Widget(LoggingConfigurable):
# -------------------------------------------------------------------------
# Class attributes
# -------------------------------------------------------------------------
_widget_construction_callback = None
widgets = {}
@staticmethod
def on_widget_constructed(callback):
"""Registers a callback to be called when a widget is constructed.
The callback must have the following signature:
callback(widget)"""
Widget._widget_construction_callback = callback
@staticmethod
def _call_widget_constructed(widget):
"""Static method, called when a widget is constructed."""
if Widget._widget_construction_callback is not None and callable(Widget._widget_construction_callback):
Widget._widget_construction_callback(widget)
# -------------------------------------------------------------------------
# Traits
# -------------------------------------------------------------------------
model_name = Unicode(
"WidgetModel",
help="""Name of the backbone model
registered in the front-end to create and sync this widget with.""",
)
_view_name = Unicode(
help="""Default view registered in the front-end
to use to represent the widget.""",
sync=True,
)
_comm = Instance("IPython.kernel.comm.Comm")
closed = Bool(False)
keys = List()
def _keys_default(self):
return [name for name in self.traits(sync=True)]
_property_lock = Tuple((None, None))
_display_callbacks = Instance(CallbackDispatcher, ())
_msg_callbacks = Instance(CallbackDispatcher, ())
# -------------------------------------------------------------------------
# (Con/de)structor
# -------------------------------------------------------------------------
def __init__(self, **kwargs):
"""Public constructor"""
super(Widget, self).__init__(**kwargs)
self.on_trait_change(self._handle_property_changed, self.keys)
Widget._call_widget_constructed(self)
def __del__(self):
"""Object disposal"""
self.close()
# -------------------------------------------------------------------------
# Properties
# -------------------------------------------------------------------------
@property
def comm(self):
"""Gets the Comm associated with this widget.
If a Comm doesn't exist yet, a Comm will be created automagically."""
if self._comm is None:
# Create a comm.
self._comm = Comm(target_name=self.model_name)
self._comm.on_msg(self._handle_msg)
self._comm.on_close(self._close)
Widget.widgets[self.model_id] = self
# first update
self.send_state()
return self._comm
@property
def model_id(self):
"""Gets the model id of this widget.
If a Comm doesn't exist yet, a Comm will be created automagically."""
return self.comm.comm_id
# -------------------------------------------------------------------------
# Methods
# -------------------------------------------------------------------------
def _close(self):
"""Private close - cleanup objects, registry entries"""
del Widget.widgets[self.model_id]
self._comm = None
self.closed = True
def close(self):
"""Close method.
Closes the widget which closes the underlying comm.
When the comm is closed, all of the widget views are automatically
removed from the front-end."""
if not self.closed:
self._comm.close()
self._close()
def send_state(self, key=None):
"""Sends the widget state, or a piece of it, to the front-end.
Parameters
----------
key : unicode (optional)
A single property's name to sync with the front-end.
"""
self._send({"method": "update", "state": self.get_state()})
def get_state(self, key=None):
"""Gets the widget state, or a piece of it.
Parameters
----------
key : unicode (optional)
A single property's name to get.
"""
keys = self.keys if key is None else [key]
return {k: self._pack_widgets(getattr(self, k)) for k in keys}
def send(self, content):
"""Sends a custom msg to the widget model in the front-end.
Parameters
----------
content : dict
Content of the message to send.
"""
self._send({"method": "custom", "content": content})
def on_msg(self, callback, remove=False):
"""(Un)Register a custom msg receive callback.
Parameters
----------
callback: callable
callback will be passed two arguments when a message arrives:
callback(widget, content)
remove: bool
True if the callback should be unregistered."""
self._msg_callbacks.register_callback(callback, remove=remove)
def on_displayed(self, callback, remove=False):
"""(Un)Register a widget displayed callback.
Parameters
----------
callback: method handler
Must have a signature of:
callback(widget, **kwargs)
kwargs from display are passed through without modification.
remove: bool
True if the callback should be unregistered."""
self._display_callbacks.register_callback(callback, remove=remove)
# -------------------------------------------------------------------------
# Support methods
# -------------------------------------------------------------------------
@contextmanager
def _lock_property(self, key, value):
"""Lock a property-value pair.
NOTE: This, in addition to the single lock for all state changes, is
flawed. In the future we may want to look into buffering state changes
back to the front-end."""
self._property_lock = (key, value)
try:
yield
finally:
self._property_lock = (None, None)
def _should_send_property(self, key, value):
"""Check the property lock (property_lock)"""
return key != self._property_lock[0] or value != self._property_lock[1]
# Event handlers
def _handle_msg(self, msg):
"""Called when a msg is received from the front-end"""
data = msg["content"]["data"]
method = data["method"]
if not method in ["backbone", "custom"]:
self.log.error('Unknown front-end to back-end widget msg with method "%s"' % method)
# Handle backbone sync methods CREATE, PATCH, and UPDATE all in one.
if method == "backbone" and "sync_data" in data:
sync_data = data["sync_data"]
self._handle_receive_state(sync_data) # handles all methods
# Handle a custom msg from the front-end
elif method == "custom":
if "content" in data:
self._handle_custom_msg(data["content"])
def _handle_receive_state(self, sync_data):
"""Called when a state is received from the front-end."""
for name in self.keys:
if name in sync_data:
value = self._unpack_widgets(sync_data[name])
with self._lock_property(name, value):
setattr(self, name, value)
def _handle_custom_msg(self, content):
"""Called when a custom msg is received."""
self._msg_callbacks(self, content)
def _handle_property_changed(self, name, old, new):
"""Called when a property has been changed."""
# Make sure this isn't information that the front-end just sent us.
if self._should_send_property(name, new):
# Send new state to front-end
self.send_state(key=name)
def _handle_displayed(self, **kwargs):
"""Called when a view has been displayed for this widget instance"""
self._display_callbacks(self, **kwargs)
def _pack_widgets(self, x):
"""Recursively converts all widget instances to model id strings.
Children widgets will be stored and transmitted to the front-end by
their model ids. Return value must be JSON-able."""
if isinstance(x, dict):
return {k: self._pack_widgets(v) for k, v in x.items()}
elif isinstance(x, list):
return [self._pack_widgets(v) for v in x]
elif isinstance(x, Widget):
return x.model_id
else:
return x # Value must be JSON-able
def _unpack_widgets(self, x):
"""Recursively converts all model id strings to widget instances.
Children widgets will be stored and transmitted to the front-end by
their model ids."""
if isinstance(x, dict):
return {k: self._unpack_widgets(v) for k, v in x.items()}
elif isinstance(x, list):
return [self._unpack_widgets(v) for v in x]
elif isinstance(x, string_types):
return x if x not in Widget.widgets else Widget.widgets[x]
else:
return x
def _ipython_display_(self, **kwargs):
"""Called when `IPython.display.display` is called on the widget."""
# Show view. By sending a display message, the comm is opened and the
# initial state is sent.
self._send({"method": "display"})
self._handle_displayed(**kwargs)
def _send(self, msg):
"""Sends a message to the model in the front-end."""
self.comm.send(msg)
class CommSocket(object):
"""
Manages the Comm connection between IPython and the browser (client).
Comms are 2 way, with the CommSocket being able to publish a message
via the send_json method, and handle a message with on_message. On the
JS side figure.send_message and figure.ws.onmessage do the sending and
receiving respectively.
"""
def __init__(self, manager):
self.supports_binary = None
self.manager = manager
self.uuid = str(uuid())
# Publish an output area with a unique ID. The javascript can then
# hook into this area.
display(HTML("<div id=%r></div>" % self.uuid))
try:
self.comm = Comm("matplotlib", data={"id": self.uuid})
except AttributeError:
raise RuntimeError(
"Unable to create an IPython notebook Comm " "instance. Are you in the IPython notebook?"
)
self.comm.on_msg(self.on_message)
manager = self.manager
self.comm.on_close(lambda close_message: manager.clearup_closed())
def is_open(self):
return not self.comm._closed
def on_close(self):
# When the socket is closed, deregister the websocket with
# the FigureManager.
self.comm.close()
self.manager.clearup_closed()
def send_json(self, content):
self.comm.send({"data": json.dumps(content)})
def send_binary(self, blob):
# The comm is ascii, so we always send the image in base64
# encoded data URL form.
data = b64encode(blob)
if six.PY3:
data = data.decode("ascii")
data_uri = "data:image/png;base64,{0}".format(data)
self.comm.send({"data": data_uri})
def on_message(self, message):
# The 'supports_binary' message is relevant to the
# websocket itself. The other messages get passed along
# to matplotlib as-is.
# Every message has a "type" and a "figure_id".
message = json.loads(message["content"]["data"])
if message["type"] == "closing":
self.on_close()
elif message["type"] == "supports_binary":
self.supports_binary = message["value"]
else:
self.manager.handle_json(message)