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Added display hook logic to handle widgets
Added display hook logic to handle widgets

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widget.py
147 lines | 4.1 KiB | text/x-python | PythonLexer
from IPython.kernel.comm import Comm
from IPython.config import LoggingConfigurable
from IPython.utils.traitlets import Unicode, Float, Bool, Dict
from IPython.display import clear_output
from copy import copy
import uuid
import sys
class Widget(Comm):
### Public declarations
target_name = Unicode('widget')
default_view_name = Unicode()
### Private/protected declarations
_keys = []
_property_lock = False
_parent = None
_children = []
_css = Dict()
### Public constructor
def __init__(self, parent=None, **kwargs):
super(Widget, self).__init__(**kwargs)
self._children = []
if parent is not None:
parent._children.append(self)
self._parent = parent
self.comm = Comm(target_name=self.target_name)
self.comm.on_msg(self._handle_msg)
# Register after init to allow default values to be specified
self.on_trait_change(self._handle_property_changed, self.keys)
# Set initial properties on client model.
self.send_state()
def __del__(self):
self.close()
def close(self):
self.comm.close()
del self.comm
### Properties
def _get_parent(self):
return self._parent
parent = property(_get_parent)
def _get_children(self):
return copy(self._children)
children = property(_get_children)
def _get_keys(self):
keys = ['_css']
keys.extend(self._keys)
return keys
keys = property(_get_keys)
def _get_css(self, key, selector=""):
if selector in self._css and key in self._css[selector]:
return self._css[selector][key]
else:
return None
def _set_css(self, value, key, selector=""):
if selector not in self._css:
self._css[selector] = {}
# Only update the property if it has changed.
if not (key in self._css[selector] and value in self._css[selector][key]):
self._css[selector][key] = value
self.send_state() # Send new state to client.
css = property(_get_css, _set_css)
### Event handlers
def _handle_msg(self, msg):
# Handle backbone sync methods
sync_method = msg['content']['data']['sync_method']
sync_data = msg['content']['data']['sync_data']
if sync_method.lower() in ['create', 'update']:
self._handle_recieve_state(sync_data)
def _handle_recieve_state(self, sync_data):
self._property_lock = True
try:
# Use _keys instead of keys - Don't get retrieve the css from the client side.
for name in self._keys:
if name in sync_data:
setattr(self, name, sync_data[name])
finally:
self._property_lock = False
def _handle_property_changed(self, name, old, new):
if not self._property_lock:
# TODO: Validate properties.
# Send new state to frontend
self.send_state()
### Public methods
def show(self, view_name=None):
if not view_name:
view_name = self.default_view_name
if not view_name:
view_name = self.target_name
# Make sure model is syncronized
self.send_state()
# Show view.
if self.parent is None:
self.comm.send({"method": "show", "view_name": view_name})
else:
self.comm.send({"method": "show",
"view_name": view_name,
"parent": self.parent.comm.comm_id})
# Now show children if any.
for child in self.children:
child.show()
def send_state(self):
state = {}
for key in self.keys:
try:
state[key] = getattr(self, key)
except Exception as e:
pass # Eat errors, nom nom nom
self.comm.send({"method": "update",
"state": state})