|
|
"""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.importstring import import_item
|
|
|
from IPython.utils.traitlets import Unicode, Dict, Instance, Bool, List, \
|
|
|
CaselessStrEnum, Tuple, CUnicode, 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
|
|
|
|
|
|
|
|
|
def register(key=None):
|
|
|
"""Returns a decorator registering a widget class in the widget registry.
|
|
|
If no key is provided, the class name is used as a key. A key is
|
|
|
provided for each core IPython widget so that the frontend can use
|
|
|
this key regardless of the language of the kernel"""
|
|
|
def wrap(widget):
|
|
|
l = key if key is not None else widget.__module__ + widget.__name__
|
|
|
Widget.widget_types[l] = widget
|
|
|
return widget
|
|
|
return wrap
|
|
|
|
|
|
|
|
|
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 DOMWidget(Widget):
|
|
|
visible = Bool(True, allow_none=True, help="Whether the widget is visible. False collapses the empty space, while None preserves the empty space.", sync=True)
|
|
|
_css = Tuple(sync=True, help="CSS property list: (selector, key, value)")
|
|
|
_dom_classes = Tuple(sync=True, help="DOM classes applied to widget.$el.")
|
|
|
|
|
|
width = CUnicode(sync=True)
|
|
|
height = CUnicode(sync=True)
|
|
|
# A default padding of 2.5 px makes the widgets look nice when displayed inline.
|
|
|
padding = CUnicode("2.5px", sync=True)
|
|
|
margin = CUnicode(sync=True)
|
|
|
|
|
|
color = Unicode(sync=True)
|
|
|
background_color = Unicode(sync=True)
|
|
|
border_color = Unicode(sync=True)
|
|
|
|
|
|
border_width = CUnicode(sync=True)
|
|
|
border_radius = CUnicode(sync=True)
|
|
|
border_style = CaselessStrEnum(values=[ # http://www.w3schools.com/cssref/pr_border-style.asp
|
|
|
'none',
|
|
|
'hidden',
|
|
|
'dotted',
|
|
|
'dashed',
|
|
|
'solid',
|
|
|
'double',
|
|
|
'groove',
|
|
|
'ridge',
|
|
|
'inset',
|
|
|
'outset',
|
|
|
'initial',
|
|
|
'inherit', ''],
|
|
|
default_value='', sync=True)
|
|
|
|
|
|
font_style = CaselessStrEnum(values=[ # http://www.w3schools.com/cssref/pr_font_font-style.asp
|
|
|
'normal',
|
|
|
'italic',
|
|
|
'oblique',
|
|
|
'initial',
|
|
|
'inherit', ''],
|
|
|
default_value='', sync=True)
|
|
|
font_weight = CaselessStrEnum(values=[ # http://www.w3schools.com/cssref/pr_font_weight.asp
|
|
|
'normal',
|
|
|
'bold',
|
|
|
'bolder',
|
|
|
'lighter',
|
|
|
'initial',
|
|
|
'inherit', ''] + list(map(str, range(100,1000,100))),
|
|
|
default_value='', sync=True)
|
|
|
font_size = CUnicode(sync=True)
|
|
|
font_family = Unicode(sync=True)
|
|
|
|
|
|
def __init__(self, *pargs, **kwargs):
|
|
|
super(DOMWidget, self).__init__(*pargs, **kwargs)
|
|
|
|
|
|
def _validate_border(name, old, new):
|
|
|
if new is not None and new != '':
|
|
|
if name != 'border_width' and not self.border_width:
|
|
|
self.border_width = 1
|
|
|
if name != 'border_style' and self.border_style == '':
|
|
|
self.border_style = 'solid'
|
|
|
self.on_trait_change(_validate_border, ['border_width', 'border_style', 'border_color'])
|
|
|
|
