|
|
"""Base Widget class. Allows user to create widgets in the back-end that render
|
|
|
in the IPython notebook front-end.
|
|
|
"""
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# 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
|
|
|
#-----------------------------------------------------------------------------
|
|
|
from contextlib import contextmanager
|
|
|
import collections
|
|
|
|
|
|
from IPython.core.getipython import get_ipython
|
|
|
from IPython.kernel.comm import Comm
|
|
|
from IPython.config import LoggingConfigurable
|
|
|
from IPython.utils.traitlets import Unicode, Dict, Instance, Bool, List, Tuple, Int, Set
|
|
|
from IPython.utils.py3compat import string_types
|
|
|
|
|
|
#-----------------------------------------------------------------------------
|
|
|
# Classes
|
|
|
#-----------------------------------------------------------------------------
|
|
|
class CallbackDispatcher(LoggingConfigurable):
|
|
|
"""A structure for registering and running callbacks"""
|
|
|
callbacks = List()
|
|
|
|
|
|
def __call__(self, *args, **kwargs):
|
|
|
"""Call all of the registered callbacks."""
|
|
|
value = None
|
|
|
for callback in self.callbacks:
|
|
|
try:
|
|
|
local_value = callback(*args, **kwargs)
|
|
|
except Exception as e:
|
|
|
ip = get_ipython()
|
|
|
if ip is None:
|
|
|
self.log.warn("Exception in callback %s: %s", callback, e, exc_info=True)
|
|
|
else:
|
|
|
ip.showtraceback()
|
|
|
else:
|
|
|
value = local_value if local_value is not None else value
|
|
|
return value
|
|
|
|
|
|
def register_callback(self, callback, remove=False):
|
|
|
"""(Un)Register a callback
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
callback: method handle
|
|
|
Method to be registered or unregistered.
|
|
|
remove=False: bool
|
|
|
Whether to unregister the callback."""
|
|
|
|
|
|
# (Un)Register the callback.
|
|
|
if remove and callback in self.callbacks:
|
|
|
self.callbacks.remove(callback)
|
|
|
elif not remove and callback not in self.callbacks:
|
|
|
self.callbacks.append(callback)
|
|
|
|
|
|
def _show_traceback(method):
|
|
|
"""decorator for showing tracebacks in IPython"""
|
|
|
def m(self, *args, **kwargs):
|
|
|
try:
|
|
|
return(method(self, *args, **kwargs))
|
|
|
except Exception as e:
|
|
|
ip = get_ipython()
|
|
|
if ip is None:
|
|
|
self.log.warn("Exception in widget method %s: %s", method, e, exc_info=True)
|
|
|
else:
|
|
|
ip.showtraceback()
|
|
|
return m
|
|
|
|
|
|
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))
|
|
|
_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"""
|
|
|
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, 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')
|
|
|
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)
|
|
|
|
|
|
@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)"""
|
|
|
if (key == self._property_lock[0] and 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']
|
|
|
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[10:]]
|
|
|
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 DOMWidget(Widget):
|
|
|
visible = Bool(True, help="Whether the widget is visible.", sync=True)
|
|
|
_css = List(sync=True) # Internal CSS property list: (selector, key, value)
|
|
|
|
|
|
def get_css(self, key, selector=""):
|
|
|
"""Get a CSS property of the widget.
|
|
|
|
|
|
Note: This function does not actually request the CSS from the
|
|
|
front-end; Only properties that have been set with set_css can be read.
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
key: unicode
|
|
|
CSS key
|
|
|
selector: unicode (optional)
|
|
|
JQuery selector used when the CSS key/value was set.
|
|
|
"""
|
|
|
if selector in self._css and key in self._css[selector]:
|
|
|
return self._css[selector][key]
|
|
|
else:
|
|
|
return None
|
|
|
|
|
|
def set_css(self, dict_or_key, value=None, selector=''):
|
|
|
"""Set one or more CSS properties of the widget.
|
|
|
|
|
|
This function has two signatures:
|
|
|
- set_css(css_dict, selector='')
|
|
|
- set_css(key, value, selector='')
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
css_dict : dict
|
|
|
CSS key/value pairs to apply
|
|
|
key: unicode
|
|
|
CSS key
|
|
|
value:
|
|
|
CSS value
|
|
|
selector: unicode (optional, kwarg only)
|
|
|
JQuery selector to use to apply the CSS key/value. If no selector
|
|
|
is provided, an empty selector is used. An empty selector makes the
|
|
|
front-end try to apply the css to the top-level element.
|
|
|
"""
|
|
|
if value is None:
|
|
|
css_dict = dict_or_key
|
|
|
else:
|
|
|
css_dict = {dict_or_key: value}
|
|
|
|
|
|
for (key, value) in css_dict.items():
|
|
|
# First remove the selector/key pair from the css list if it exists.
|
|
|
# Then add the selector/key pair and new value to the bottom of the
|
|
|
# list.
|
|
|
self._css = [x for x in self._css if not (x[0]==selector and x[1]==key)]
|
|
|
self._css += [(selector, key, value)]
|
|
|
self.send_state('_css')
|
|
|
|
|
|
def add_class(self, class_names, selector=""):
|
|
|
"""Add class[es] to a DOM element.
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
class_names: unicode or list
|
|
|
Class name(s) to add to the DOM element(s).
|
|
|
selector: unicode (optional)
|
|
|
JQuery selector to select the DOM element(s) that the class(es) will
|
|
|
be added to.
|
|
|
"""
|
|
|
class_list = class_names
|
|
|
if isinstance(class_list, (list, tuple)):
|
|
|
class_list = ' '.join(class_list)
|
|
|
|
|
|
self.send({
|
|
|
"msg_type" : "add_class",
|
|
|
"class_list" : class_list,
|
|
|
"selector" : selector
|
|
|
})
|
|
|
|
|
|
def remove_class(self, class_names, selector=""):
|
|
|
"""Remove class[es] from a DOM element.
|
|
|
|
|
|
Parameters
|
|
|
----------
|
|
|
class_names: unicode or list
|
|
|
Class name(s) to remove from the DOM element(s).
|
|
|
selector: unicode (optional)
|
|
|
JQuery selector to select the DOM element(s) that the class(es) will
|
|
|
be removed from.
|
|
|
"""
|
|
|
class_list = class_names
|
|
|
if isinstance(class_list, (list, tuple)):
|
|
|
class_list = ' '.join(class_list)
|
|
|
|
|
|
self.send({
|
|
|
"msg_type" : "remove_class",
|
|
|
"class_list" : class_list,
|
|
|
"selector" : selector,
|
|
|
})
|
|
|
|
