##// END OF EJS Templates
Change serialization terminology to serialize/deserialize
Jason Grout -
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@@ -1,455 +1,455 b''
1 1 """Base Widget class. Allows user to create widgets in the back-end that render
2 2 in the IPython notebook front-end.
3 3 """
4 4 #-----------------------------------------------------------------------------
5 5 # Copyright (c) 2013, the IPython Development Team.
6 6 #
7 7 # Distributed under the terms of the Modified BSD License.
8 8 #
9 9 # The full license is in the file COPYING.txt, distributed with this software.
10 10 #-----------------------------------------------------------------------------
11 11
12 12 #-----------------------------------------------------------------------------
13 13 # Imports
14 14 #-----------------------------------------------------------------------------
15 15 from contextlib import contextmanager
16 16
17 17 from IPython.core.getipython import get_ipython
18 18 from IPython.kernel.comm import Comm
19 19 from IPython.config import LoggingConfigurable
20 20 from IPython.utils.traitlets import Unicode, Dict, Instance, Bool, List, Tuple, Int
21 21 from IPython.utils.py3compat import string_types
22 22
23 23 #-----------------------------------------------------------------------------
24 24 # Classes
25 25 #-----------------------------------------------------------------------------
26 26 class CallbackDispatcher(LoggingConfigurable):
27 27 """A structure for registering and running callbacks"""
28 28 callbacks = List()
29 29
30 30 def __call__(self, *args, **kwargs):
31 31 """Call all of the registered callbacks."""
32 32 value = None
33 33 for callback in self.callbacks:
34 34 try:
35 35 local_value = callback(*args, **kwargs)
36 36 except Exception as e:
37 37 ip = get_ipython()
38 38 if ip is None:
39 39 self.log.warn("Exception in callback %s: %s", callback, e, exc_info=True)
40 40 else:
41 41 ip.showtraceback()
42 42 else:
43 43 value = local_value if local_value is not None else value
44 44 return value
45 45
46 46 def register_callback(self, callback, remove=False):
47 47 """(Un)Register a callback
48 48
49 49 Parameters
50 50 ----------
51 51 callback: method handle
52 52 Method to be registered or unregistered.
53 53 remove=False: bool
54 54 Whether to unregister the callback."""
55 55
56 56 # (Un)Register the callback.
57 57 if remove and callback in self.callbacks:
58 58 self.callbacks.remove(callback)
59 59 elif not remove and callback not in self.callbacks:
60 60 self.callbacks.append(callback)
61 61
62 62 def _show_traceback(method):
63 63 """decorator for showing tracebacks in IPython"""
64 64 def m(self, *args, **kwargs):
65 65 try:
66 66 return(method(self, *args, **kwargs))
67 67 except Exception as e:
68 68 ip = get_ipython()
69 69 if ip is None:
70 70 self.log.warn("Exception in widget method %s: %s", method, e, exc_info=True)
71 71 else:
72 72 ip.showtraceback()
73 73 return m
74 74
75 75 class Widget(LoggingConfigurable):
76 76 #-------------------------------------------------------------------------
77 77 # Class attributes
78 78 #-------------------------------------------------------------------------
79 79 _widget_construction_callback = None
80 80 widgets = {}
81 81
82 82 @staticmethod
83 83 def on_widget_constructed(callback):
84 84 """Registers a callback to be called when a widget is constructed.
85 85
86 86 The callback must have the following signature:
87 87 callback(widget)"""
88 88 Widget._widget_construction_callback = callback
89 89
90 90 @staticmethod
91 91 def _call_widget_constructed(widget):
92 92 """Static method, called when a widget is constructed."""
93 93 if Widget._widget_construction_callback is not None and callable(Widget._widget_construction_callback):
94 94 Widget._widget_construction_callback(widget)
95 95
96 96 #-------------------------------------------------------------------------
97 97 # Traits
98 98 #-------------------------------------------------------------------------
99 99 _model_name = Unicode('WidgetModel', help="""Name of the backbone model
100 100 registered in the front-end to create and sync this widget with.""")
101 101 _view_name = Unicode(help="""Default view registered in the front-end
102 102 to use to represent the widget.""", sync=True)
103 103 _comm = Instance('IPython.kernel.comm.Comm')
104 104
105 105 msg_throttle = Int(3, sync=True, help="""Maximum number of msgs the
106 106 front-end can send before receiving an idle msg from the back-end.""")
107 107
108 108 keys = List()
109 109 def _keys_default(self):
110 110 return [name for name in self.traits(sync=True)]
111 111
112 112 _property_lock = Tuple((None, None))
113 113
114 114 _display_callbacks = Instance(CallbackDispatcher, ())
115 115 _msg_callbacks = Instance(CallbackDispatcher, ())
116 116
117 117 #-------------------------------------------------------------------------
118 118 # (Con/de)structor
119 119 #-------------------------------------------------------------------------
120 120 def __init__(self, **kwargs):
121 121 """Public constructor"""
122 122 super(Widget, self).__init__(**kwargs)
123 123
124 124 self.on_trait_change(self._handle_property_changed, self.keys)
125 125 Widget._call_widget_constructed(self)
126 126
127 127 def __del__(self):
128 128 """Object disposal"""
129 129 self.close()
130 130
131 131 #-------------------------------------------------------------------------
132 132 # Properties
133 133 #-------------------------------------------------------------------------
134 134
135 135 @property
136 136 def comm(self):
137 137 """Gets the Comm associated with this widget.
138 138
139 139 If a Comm doesn't exist yet, a Comm will be created automagically."""
140 140 if self._comm is None:
141 141 # Create a comm.
142 142 self._comm = Comm(target_name=self._model_name)
143 143 self._comm.on_msg(self._handle_msg)
144 144 self._comm.on_close(self._close)
145 145 Widget.widgets[self.model_id] = self
146 146
147 147 # first update
148 148 self.send_state()
149 149 return self._comm
150 150
151 151 @property
152 152 def model_id(self):
153 153 """Gets the model id of this widget.
154 154
155 155 If a Comm doesn't exist yet, a Comm will be created automagically."""
156 156 return self.comm.comm_id
157 157
158 158 #-------------------------------------------------------------------------
159 159 # Methods
160 160 #-------------------------------------------------------------------------
161 161 def _close(self):
162 162 """Private close - cleanup objects, registry entries"""
163 163 del Widget.widgets[self.model_id]
164 164 self._comm = None
165 165
166 166 def close(self):
167 167 """Close method.
168 168
169 169 Closes the widget which closes the underlying comm.
170 170 When the comm is closed, all of the widget views are automatically
171 171 removed from the front-end."""
172 172 if self._comm is not None:
173 173 self._comm.close()
174 174 self._close()
175 175
176 176 def send_state(self, key=None):
177 177 """Sends the widget state, or a piece of it, to the front-end.
178 178
179 179 Parameters
180 180 ----------
181 181 key : unicode (optional)
182 182 A single property's name to sync with the front-end.
183 183 """
184 184 self._send({
185 185 "method" : "update",
186 186 "state" : self.get_state()
187 187 })
188 188
189 189 def get_state(self, key=None):
190 190 """Gets the widget state, or a piece of it.
191 191
192 192 Parameters
193 193 ----------
194 194 key : unicode (optional)
195 195 A single property's name to get.
196 196 """
197 197 keys = self.keys if key is None else [key]
198 198 state = {}
199 199 for k in keys:
200 f = self.trait_metadata(k, 'to_json')
200 f = self.trait_metadata(k, 'serialize')
201 201 value = getattr(self, k)
202 202 if f is not None:
203 203 state[k] = f(value)
204 204 else:
205 205 state[k] = self._serialize_trait(value)
206 206 return state
207 207
208 208 def send(self, content):
209 209 """Sends a custom msg to the widget model in the front-end.
210 210
211 211 Parameters
212 212 ----------
213 213 content : dict
214 214 Content of the message to send.
215 215 """
216 216 self._send({"method": "custom", "content": content})
217 217
218 218 def on_msg(self, callback, remove=False):
219 219 """(Un)Register a custom msg receive callback.
220 220
221 221 Parameters
222 222 ----------
223 223 callback: callable
224 224 callback will be passed two arguments when a message arrives::
225 225
226 226 callback(widget, content)
227 227
228 228 remove: bool
229 229 True if the callback should be unregistered."""
230 230 self._msg_callbacks.register_callback(callback, remove=remove)
231 231
232 232 def on_displayed(self, callback, remove=False):
233 233 """(Un)Register a widget displayed callback.
234 234
235 235 Parameters
236 236 ----------
237 237 callback: method handler
238 238 Must have a signature of::
239 239
240 240 callback(widget, **kwargs)
241 241
242 242 kwargs from display are passed through without modification.
243 243 remove: bool
244 244 True if the callback should be unregistered."""
245 245 self._display_callbacks.register_callback(callback, remove=remove)
246 246
247 247 #-------------------------------------------------------------------------
248 248 # Support methods
249 249 #-------------------------------------------------------------------------
250 250 @contextmanager
251 251 def _lock_property(self, key, value):
252 252 """Lock a property-value pair.
253 253
254 254 NOTE: This, in addition to the single lock for all state changes, is
255 255 flawed. In the future we may want to look into buffering state changes
256 256 back to the front-end."""
257 257 self._property_lock = (key, value)
258 258 try:
259 259 yield
260 260 finally:
261 261 self._property_lock = (None, None)
262 262
263 263 def _should_send_property(self, key, value):
264 264 """Check the property lock (property_lock)"""
265 265 return key != self._property_lock[0] or \
266 266 value != self._property_lock[1]
267 267
268 268 # Event handlers
269 269 @_show_traceback
270 270 def _handle_msg(self, msg):
271 271 """Called when a msg is received from the front-end"""
272 272 data = msg['content']['data']
273 273 method = data['method']
274 274 if not method in ['backbone', 'custom']:
275 275 self.log.error('Unknown front-end to back-end widget msg with method "%s"' % method)
276 276
277 277 # Handle backbone sync methods CREATE, PATCH, and UPDATE all in one.
278 278 if method == 'backbone' and 'sync_data' in data:
279 279 sync_data = data['sync_data']
280 280 self._handle_receive_state(sync_data) # handles all methods
281 281
282 282 # Handle a custom msg from the front-end
283 283 elif method == 'custom':
284 284 if 'content' in data:
285 285 self._handle_custom_msg(data['content'])
286 286
287 287 def _handle_receive_state(self, sync_data):
288 288 """Called when a state is received from the front-end."""
289 289 for name in self.keys:
290 290 if name in sync_data:
291 f = self.trait_metadata(name, 'from_json')
291 f = self.trait_metadata(name, 'deserialize')
292 292 if f is not None:
293 293 value = f(sync_data[name])
294 294 else:
295 value = self._unserialize_trait(sync_data[name])
295 value = self._deserialize_trait(sync_data[name])
296 296 with self._lock_property(name, value):
297 297 setattr(self, name, value)
298 298
299 299 def _handle_custom_msg(self, content):
300 300 """Called when a custom msg is received."""
301 301 self._msg_callbacks(self, content)
302 302
303 303 def _handle_property_changed(self, name, old, new):
304 304 """Called when a property has been changed."""
305 305 # Make sure this isn't information that the front-end just sent us.
306 306 if self._should_send_property(name, new):
307 307 # Send new state to front-end
308 308 self.send_state(key=name)
309 309
310 310 def _handle_displayed(self, **kwargs):
311 311 """Called when a view has been displayed for this widget instance"""
312 312 self._display_callbacks(self, **kwargs)
313 313
314 314 def _serialize_trait(self, x):
315 315 """Serialize a trait value to json
316 316
317 317 Traverse lists/tuples and dicts and serialize their values as well.
318 318 Replace any widgets with their model_id
319 319 """
320 320 if isinstance(x, dict):
321 321 return {k: self._serialize_trait(v) for k, v in x.items()}
322 322 elif isinstance(x, (list, tuple)):
323 323 return [self._serialize_trait(v) for v in x]
324 324 elif isinstance(x, Widget):
325 325 return "IPY_MODEL_" + x.model_id
326 326 else:
327 327 return x # Value must be JSON-able
328 328
329 def _unserialize_trait(self, x):
329 def _deserialize_trait(self, x):
330 330 """Convert json values to objects
331 331
332 332 We explicitly support converting valid string widget UUIDs to Widget references.
333 333 """
334 334 if isinstance(x, dict):
335 return {k: self._unserialize_trait(v) for k, v in x.items()}
335 return {k: self._deserialize_trait(v) for k, v in x.items()}
336 336 elif isinstance(x, (list, tuple)):
337 return [self._unserialize_trait(v) for v in x]
337 return [self._deserialize_trait(v) for v in x]
338 338 elif isinstance(x, string_types) and x.startswith('IPY_MODEL_') and x[10:] in Widget.widgets:
339 339 # we want to support having child widgets at any level in a hierarchy
340 340 # trusting that a widget UUID will not appear out in the wild
341 341 return Widget.widgets[x]
342 342 else:
343 343 return x
344 344
345 345 def _ipython_display_(self, **kwargs):
346 346 """Called when `IPython.display.display` is called on the widget."""
347 347 # Show view. By sending a display message, the comm is opened and the
348 348 # initial state is sent.
349 349 self._send({"method": "display"})
350 350 self._handle_displayed(**kwargs)
351 351
352 352 def _send(self, msg):
353 353 """Sends a message to the model in the front-end."""
354 354 self.comm.send(msg)
355 355
356 356
357 357 class DOMWidget(Widget):
358 358 visible = Bool(True, help="Whether the widget is visible.", sync=True)
359 359 _css = List(sync=True) # Internal CSS property list: (selector, key, value)
360 360
361 361 def get_css(self, key, selector=""):
362 362 """Get a CSS property of the widget.
363 363
364 364 Note: This function does not actually request the CSS from the
365 365 front-end; Only properties that have been set with set_css can be read.
366 366
367 367 Parameters
368 368 ----------
369 369 key: unicode
370 370 CSS key
371 371 selector: unicode (optional)
372 372 JQuery selector used when the CSS key/value was set.
373 373 """
374 374 if selector in self._css and key in self._css[selector]:
375 375 return self._css[selector][key]
376 376 else:
377 377 return None
378 378
379 379 def set_css(self, dict_or_key, value=None, selector=''):
380 380 """Set one or more CSS properties of the widget.
381 381
382 382 This function has two signatures:
383 383 - set_css(css_dict, selector='')
384 384 - set_css(key, value, selector='')
385 385
386 386 Parameters
387 387 ----------
388 388 css_dict : dict
389 389 CSS key/value pairs to apply
390 390 key: unicode
391 391 CSS key
392 392 value:
393 393 CSS value
394 394 selector: unicode (optional, kwarg only)
395 395 JQuery selector to use to apply the CSS key/value. If no selector
396 396 is provided, an empty selector is used. An empty selector makes the
397 397 front-end try to apply the css to a default element. The default
398 398 element is an attribute unique to each view, which is a DOM element
399 399 of the view that should be styled with common CSS (see
400 400 `$el_to_style` in the Javascript code).
401 401 """
402 402 if value is None:
403 403 css_dict = dict_or_key
404 404 else:
405 405 css_dict = {dict_or_key: value}
406 406
407 407 for (key, value) in css_dict.items():
408 408 # First remove the selector/key pair from the css list if it exists.
409 409 # Then add the selector/key pair and new value to the bottom of the
410 410 # list.
411 411 self._css = [x for x in self._css if not (x[0]==selector and x[1]==key)]
412 412 self._css += [(selector, key, value)]
413 413 self.send_state('_css')
414 414
415 415 def add_class(self, class_names, selector=""):
416 416 """Add class[es] to a DOM element.
417 417
418 418 Parameters
419 419 ----------
420 420 class_names: unicode or list
421 421 Class name(s) to add to the DOM element(s).
422 422 selector: unicode (optional)
423 423 JQuery selector to select the DOM element(s) that the class(es) will
424 424 be added to.
425 425 """
426 426 class_list = class_names
427 427 if isinstance(class_list, (list, tuple)):
428 428 class_list = ' '.join(class_list)
429 429
430 430 self.send({
431 431 "msg_type" : "add_class",
432 432 "class_list" : class_list,
433 433 "selector" : selector
434 434 })
435 435
436 436 def remove_class(self, class_names, selector=""):
437 437 """Remove class[es] from a DOM element.
438 438
439 439 Parameters
440 440 ----------
441 441 class_names: unicode or list
442 442 Class name(s) to remove from the DOM element(s).
443 443 selector: unicode (optional)
444 444 JQuery selector to select the DOM element(s) that the class(es) will
445 445 be removed from.
446 446 """
447 447 class_list = class_names
448 448 if isinstance(class_list, (list, tuple)):
449 449 class_list = ' '.join(class_list)
450 450
451 451 self.send({
452 452 "msg_type" : "remove_class",
453 453 "class_list" : class_list,
454 454 "selector" : selector,
455 455 })
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