Source code for holoviews.plotting.bokeh.callbacks

from collections import defaultdict

from bokeh.models import CustomJS, FactorRange, DatetimeAxis

from ...core import OrderedDict
from ...streams import (Stream, PointerXY, RangeXY, Selection1D, RangeX,
                        RangeY, PointerX, PointerY, BoundsX, BoundsY,
                        Tap, SingleTap, DoubleTap, MouseEnter, MouseLeave,
                        PlotSize, Draw, BoundsXY, PlotReset)
from ...streams import PositionX, PositionY, PositionXY, Bounds # Deprecated: remove in 2.0
from ..comms import JupyterCommJS, Comm
from .util import convert_timestamp

[docs]class MessageCallback(object): """ A MessageCallback is an abstract baseclass used to supply Streams with events originating from bokeh plot interactions. The baseclass defines how messages are handled and the basic specification required to define a Callback. """ attributes = {} # The plotting handle(s) to attach the JS callback on models = [] # Additional models available to the callback extra_models = [] # Conditions when callback should be skipped skip = [] # Callback will listen to events of the supplied type on the models on_events = [] # List of change events on the models to listen to on_changes = [] _callbacks = {} def _process_msg(self, msg): """ Subclassable method to preprocess JSON message in callback before passing to stream. """ return msg def __init__(self, plot, streams, source, **params): self.plot = plot self.streams = streams if plot.renderer.mode != 'server': try: self.comm = self._comm_type(plot, on_msg=self.on_msg) except AttributeError: self.comm = Comm(plot) self.source = source self.reset() def reset(self): self.handle_ids = defaultdict(dict) self.callbacks = [] self.plot_handles = {} self._queue = [] def _filter_msg(self, msg, ids): """ Filter event values that do not originate from the plotting handles associated with a particular stream using their ids to match them. """ filtered_msg = {} for k, v in msg.items(): if isinstance(v, dict) and 'id' in v: if v['id'] in ids: filtered_msg[k] = v['value'] else: filtered_msg[k] = v return filtered_msg def on_msg(self, msg): streams = [] for stream in self.streams: handle_ids = self.handle_ids[stream] ids = list(handle_ids.values()) filtered_msg = self._filter_msg(msg, ids) processed_msg = self._process_msg(filtered_msg) if not processed_msg and not stream.transient: continue stream.update(**processed_msg) stream._metadata = {h: {'id': hid, 'events': self.on_events} for h, hid in handle_ids.items()} streams.append(stream) Stream.trigger(streams) for stream in streams: stream._metadata = {} def _init_plot_handles(self): """ Find all requested plotting handles and cache them along with the IDs of the models the callbacks will be attached to. """ plots = [self.plot] if self.plot.subplots: plots += list(self.plot.subplots.values()) handles = {} for plot in plots: for k, v in plot.handles.items(): handles[k] = v self.plot_handles = handles requested = {} for h in self.models+self.extra_models: if h in self.plot_handles: requested[h] = handles[h] elif h in self.extra_models: print("Warning %s could not find the %s model. " "The corresponding stream may not work.") self.handle_ids.update(self._get_stream_handle_ids(requested)) return requested def _get_stream_handle_ids(self, handles): """ Gather the ids of the plotting handles attached to this callback This allows checking that a stream is not given the state of a plotting handle it wasn't attached to """ stream_handle_ids = defaultdict(dict) for stream in self.streams: for h in self.models: if h in handles: handle_id = handles[h].ref['id'] stream_handle_ids[stream][h] = handle_id return stream_handle_ids
[docs]class CustomJSCallback(MessageCallback): """ The CustomJSCallback attaches CustomJS callbacks to a bokeh plot, which looks up the requested attributes and sends back a message to Python using a Comms instance. """ js_callback = """ function unique_events(events) {{ // Processes the event queue ignoring duplicate events // of the same type var unique = []; var unique_events = []; for (var i=0; i<events.length; i++) {{ var _tmpevent = events[i]; event = _tmpevent[0]; data = _tmpevent[1]; if (unique_events.indexOf(event)===-1) {{ unique.unshift(data); unique_events.push(event); }} }} return unique; }} function process_events(comm_state) {{ // Iterates over event queue and sends events via Comm var events = unique_events(comm_state.event_buffer); for (var i=0; i<events.length; i++) {{ var data = events[i]; var comm = HoloViewsWidget.comms[data["comm_id"]]; comm.send(data); }} comm_state.event_buffer = []; }} function on_msg(msg){{ // Receives acknowledgement from Python, processing event // and unblocking Comm if event queue empty msg = JSON.parse(; var comm_id = msg["comm_id"] var comm_state = HoloViewsWidget.comm_state[comm_id]; if (comm_state.event_buffer.length) {{ process_events(comm_state); comm_state.blocked = true; comm_state.time ={debounce}; }} else {{ comm_state.blocked = false; }} comm_state.event_buffer = []; if ((msg.msg_type == "Ready") && msg.content) {{ console.log("Python callback returned following output:", msg.content); }} else if (msg.msg_type == "Error") {{ console.log("Python failed with the following traceback:", msg['traceback']) }} }} // Initialize Comm if ((window.Jupyter !== undefined) && (Jupyter.notebook.kernel != null)) {{ var comm_manager = Jupyter.notebook.kernel.comm_manager; var comm = HoloViewsWidget.comms["{comm_id}"]; if (comm == null) {{ comm = comm_manager.new_comm("{comm_id}", {{}}, {{}}, {{}}); comm.on_msg(on_msg); comm_manager["{comm_id}"] = comm; HoloViewsWidget.comms["{comm_id}"] = comm; }} }} else {{ return }} // Initialize event queue and timeouts for Comm var comm_state = HoloViewsWidget.comm_state["{comm_id}"]; if (comm_state === undefined) {{ comm_state = {{event_buffer: [], blocked: false, time:}} HoloViewsWidget.comm_state["{comm_id}"] = comm_state }} // Add current event to queue and process queue if not blocked event_name = cb_obj.event_name data['comm_id'] = "{comm_id}"; timeout = comm_state.time + {timeout}; if ((window.Jupyter == null) | (Jupyter.notebook.kernel == null)) {{ }} else if ((comm_state.blocked && ( < timeout))) {{ comm_state.event_buffer.unshift([event_name, data]); }} else {{ comm_state.event_buffer.unshift([event_name, data]); setTimeout(function() {{ process_events(comm_state); }}, {debounce}); comm_state.blocked = true; comm_state.time ={debounce}; }} """ code = "" # Timeout if a comm message is swallowed timeout = 20000 # Timeout before the first event is processed debounce = 20 _comm_type = JupyterCommJS
[docs] @classmethod def attributes_js(cls, attributes): """ Generates JS code to look up attributes on JS objects from an attributes specification dictionary. If the specification references a plotting particular plotting handle it will also generate JS code to get the ID of the object. Simple example (when referencing cb_data or cb_obj): Input : {'x': 'cb_data.geometry.x'} Output : data['x'] = cb_data['geometry']['x'] Example referencing plot handle: Input : {'x0': 'x_range.attributes.start'} Output : if ((x_range !== undefined)) { data['x0'] = {id: x_range['id'], value: x_range['attributes']['start']} } """ assign_template = '{assign}{{id: {obj_name}["id"], value: {obj_name}{attr_getters}}};\n' conditional_template = 'if (({obj_name} != undefined)) {{ {assign} }}' code = '' for key, attr_path in sorted(attributes.items()): data_assign = 'data["{key}"] = '.format(key=key) attrs = attr_path.split('.') obj_name = attrs[0] attr_getters = ''.join(['["{attr}"]'.format(attr=attr) for attr in attrs[1:]]) if obj_name not in ['cb_obj', 'cb_data']: assign_str = assign_template.format( assign=data_assign, obj_name=obj_name, attr_getters=attr_getters ) code += conditional_template.format( obj_name=obj_name, assign=assign_str ) else: assign_str = ''.join([data_assign, obj_name, attr_getters, ';\n']) code += assign_str return code
[docs] def get_customjs(self, references): """ Creates a CustomJS callback that will send the requested attributes back to python. """ # Generate callback JS code to get all the requested data self_callback = self.js_callback.format(, timeout=self.timeout, debounce=self.debounce) attributes = self.attributes_js(self.attributes) conditions = ["%s" % cond for cond in self.skip] conditional = '' if conditions: conditional = 'if (%s) { return };\n' % (' || '.join(conditions)) data = "var data = {};\n" code = conditional + data + attributes + self.code + self_callback return CustomJS(args=references, code=code)
[docs] def set_customjs_callback(self, js_callback, handle): """ Generates a CustomJS callback by generating the required JS code and gathering all plotting handles and installs it on the requested callback handle. """ if self.on_events: for event in self.on_events: handle.js_on_event(event, js_callback) elif self.on_changes: for change in self.on_changes: handle.js_on_change(change, js_callback) elif hasattr(handle, 'callback'): handle.callback = js_callback
[docs]class ServerCallback(MessageCallback): """ Implements methods to set up bokeh server callbacks. A ServerCallback resolves the requested attributes on the Python end and then hands the msg off to the general on_msg handler, which will update the Stream(s) attached to the callback. """ def __init__(self, plot, streams, source, **params): super(ServerCallback, self).__init__(plot, streams, source, **params) self._active = False
[docs] @classmethod def resolve_attr_spec(cls, spec, cb_obj, model=None): """ Resolves a Callback attribute specification looking the corresponding attribute up on the cb_obj, which should be a bokeh model. If not model is supplied cb_obj is assumed to be the same as the model. """ if not cb_obj: raise Exception('Bokeh plot attribute %s could not be found' % spec) if model is None: model = cb_obj spec = spec.split('.') resolved = cb_obj for p in spec[1:]: if p == 'attributes': continue if isinstance(resolved, dict): resolved = resolved.get(p) else: resolved = getattr(resolved, p, None) return {'id': model.ref['id'], 'value': resolved}
[docs] def on_change(self, attr, old, new): """ Process change events adding timeout to process multiple concerted value change at once rather than firing off multiple plot updates. """ self._queue.append((attr, old, new)) if not self._active and self.plot.document: self.plot.document.add_timeout_callback(self.process_on_change, 50) self._active = True
[docs] def on_event(self, event): """ Process bokeh UIEvents adding timeout to process multiple concerted value change at once rather than firing off multiple plot updates. """ self._queue.append((event)) if not self._active and self.plot.document: self.plot.document.add_timeout_callback(self.process_on_event, 50) self._active = True
[docs] def process_on_event(self): """ Trigger callback change event and triggering corresponding streams. """ if not self._queue: self._active = False return # Get unique event types in the queue events = list(OrderedDict([(event.event_name, event) for event in self._queue]).values()) self._queue = [] # Process event types for event in events: msg = {} for attr, path in self.attributes.items(): model_obj = self.plot_handles.get(self.models[0]) msg[attr] = self.resolve_attr_spec(path, event, model_obj) self.on_msg(msg) self.plot.document.add_timeout_callback(self.process_on_event, 50)
def process_on_change(self): if not self._queue: self._active = False return self._queue = [] msg = {} for attr, path in self.attributes.items(): attr_path = path.split('.') if attr_path[0] == 'cb_obj': obj_handle = self.models[0] path = '.'.join(self.models[:1]+attr_path[1:]) else: obj_handle = attr_path[0] cb_obj = self.plot_handles.get(obj_handle) msg[attr] = self.resolve_attr_spec(path, cb_obj) self.on_msg(msg) self.plot.document.add_timeout_callback(self.process_on_change, 50)
[docs] def set_server_callback(self, handle): """ Set up on_change events for bokeh server interactions. """ if self.on_events: for event in self.on_events: handle.on_event(event, self.on_event) elif self.on_changes: for change in self.on_changes: handle.on_change(change, self.on_change)
[docs]class Callback(CustomJSCallback, ServerCallback): """ Provides a baseclass to define callbacks, which return data from bokeh model callbacks, events and attribute changes. The callback then makes this data available to any streams attached to it. The definition of a callback consists of a number of components: * models : Defines which bokeh models the callback will be attached on referencing the model by its key in the plots handles, e.g. this could be the x_range, y_range, plot, a plotting tool or any other bokeh mode. * extra_models: Any additional models available in handles which should be made available in the namespace of the objects, e.g. to make a tool available to skip checks. * attributes : The attributes define which attributes to send back to Python. They are defined as a dictionary mapping between the name under which the variable is made available to Python and the specification of the attribute. The specification should start with the variable name that is to be accessed and the location of the attribute separated by periods. All models defined by the models and extra_models attributes can be addressed in this way, e.g. to get the start of the x_range as 'x' you can supply {'x': 'x_range.attributes.start'}. Additionally certain handles additionally make the cb_data and cb_obj variables available containing additional information about the event. * skip : Conditions when the Callback should be skipped specified as a list of valid JS expressions, which can reference models requested by the callback, e.g. [''] would skip the callback if the pan tool is active. * code : Defines any additional JS code to be executed, which can modify the data object that is sent to the backend. * on_events : If the Callback should listen to bokeh events this should declare the types of event as a list (optional) * on_changes : If the Callback should listen to model attribute changes on the defined ``models`` (optional) If either on_events or on_changes are declared the Callback will be registered using the on_event or on_change machinery, otherwise it will be treated as a regular callback on the model. The callback can also define a _process_msg method, which can modify the data sent by the callback before it is passed to the streams. """ def initialize(self): handles = self._init_plot_handles() for handle_name in self.models: if handle_name not in handles: warn_args = (handle_name, type(self.plot).__name__, type(self).__name__) print('%s handle not found on %s, cannot ' 'attach %s callback' % warn_args) continue handle = handles[handle_name] # Hash the plot handle with Callback type allowing multiple # callbacks on one handle to be merged cb_hash = (id(handle), id(type(self))) if cb_hash in self._callbacks: # Merge callbacks if another callback has already been attached cb = self._callbacks[cb_hash] cb.streams = list(set(cb.streams+self.streams)) for k, v in self.handle_ids.items(): cb.handle_ids[k].update(v) continue if self.plot.renderer.mode == 'server': self.set_server_callback(handle) else: js_callback = self.get_customjs(handles) self.set_customjs_callback(js_callback, handle) self.callbacks.append(js_callback) self._callbacks[cb_hash] = self
[docs]class PointerXYCallback(Callback): """ Returns the mouse x/y-position on mousemove event. """ attributes = {'x': 'cb_obj.x', 'y': 'cb_obj.y'} models = ['plot'] extra_models= ['x_range', 'y_range'] on_events = ['mousemove'] # Clip x and y values to available axis range code = """ if (x_range.type.endsWith('Range1d')) { if (cb_obj.x < x_range.start) { data['x'] = x_range.start } else if (cb_obj.x > x_range.end) { data['x'] = x_range.end }} if (y_range.type.endsWith('Range1d')) { if (cb_obj.y < y_range.start) { data['y'] = y_range.start } else if (cb_obj.y > y_range.end) { data['y'] = y_range.end }} """ def _process_msg(self, msg): x_range = self.plot.handles.get('x_range') y_range = self.plot.handles.get('y_range') if isinstance(x_range, FactorRange) and isinstance(msg.get('x'), (int, float)): msg['x'] = x_range.factors[int(msg['x'])] if isinstance(y_range, FactorRange) and isinstance(msg.get('y'), (int, float)): msg['y'] = y_range.factors[int(msg['y'])] xaxis = self.plot.handles.get('xaxis') yaxis = self.plot.handles.get('yaxis') if 'x' in msg and isinstance(xaxis, DatetimeAxis): msg['x'] = convert_timestamp(msg['x']) if 'y' in msg and isinstance(yaxis, DatetimeAxis): msg['y'] = convert_timestamp(msg['y']) return msg
[docs]class PointerXCallback(PointerXYCallback): """ Returns the mouse x-position on mousemove event. """ attributes = {'x': 'cb_obj.x'} extra_models= ['x_range'] code = """ if (x_range.type.endsWith('Range1d')) { if (cb_obj.x < x_range.start) { data['x'] = x_range.start } else if (cb_obj.x > x_range.end) { data['x'] = x_range.end }} """
[docs]class PointerYCallback(PointerXYCallback): """ Returns the mouse x/y-position on mousemove event. """ attributes = {'y': 'cb_obj.y'} extra_models= ['y_range'] code = """ if (y_range.type.endsWith('Range1d')) { if (cb_obj.y < y_range.start) { data['y'] = y_range.start } else if (cb_obj.y > y_range.end) { data['y'] = y_range.end }} """
class DrawCallback(PointerXYCallback): on_events = ['pan', 'panstart', 'panend'] models = ['plot'] extra_models=['pan', 'box_zoom', 'x_range', 'y_range'] skip = ['pan &&', 'box_zoom &&'] attributes = {'x': 'cb_obj.x', 'y': 'cb_obj.y', 'event': 'cb_obj.event_name'} def __init__(self, *args, **kwargs): self.stroke_count = 0 super(DrawCallback, self).__init__(*args, **kwargs) def _process_msg(self, msg): event = msg.pop('event') if event == 'panend': self.stroke_count += 1 return dict(msg, stroke_count=self.stroke_count)
[docs]class TapCallback(PointerXYCallback): """ Returns the mouse x/y-position on tap event. Note: As of bokeh 0.12.5, there is no way to distinguish the individual tap events within a doubletap event. """ on_events = ['tap', 'doubletap']
[docs]class SingleTapCallback(PointerXYCallback): """ Returns the mouse x/y-position on tap event. """ on_events = ['tap']
[docs]class DoubleTapCallback(PointerXYCallback): """ Returns the mouse x/y-position on doubletap event. """ on_events = ['doubletap']
[docs]class MouseEnterCallback(PointerXYCallback): """ Returns the mouse x/y-position on mouseenter event, i.e. when mouse enters the plot canvas. """ on_events = ['mouseenter']
[docs]class MouseLeaveCallback(PointerXYCallback): """ Returns the mouse x/y-position on mouseleave event, i.e. when mouse leaves the plot canvas. """ on_events = ['mouseleave']
[docs]class RangeXYCallback(Callback): """ Returns the x/y-axis ranges of a plot. """ attributes = {'x0': 'x_range.attributes.start', 'x1': 'x_range.attributes.end', 'y0': 'y_range.attributes.start', 'y1': 'y_range.attributes.end'} models = ['x_range', 'y_range'] on_changes = ['start', 'end'] def _process_msg(self, msg): data = {} if 'x0' in msg and 'x1' in msg: x0, x1 = msg['x0'], msg['x1'] if isinstance(self.plot.handles.get('xaxis'), DatetimeAxis): x0 = convert_timestamp(x0) x1 = convert_timestamp(x1) if self.plot.invert_xaxis: x0, x1 = x1, x0 data['x_range'] = (x0, x1) if 'y0' in msg and 'y1' in msg: y0, y1 = msg['y0'], msg['y1'] if isinstance(self.plot.handles.get('yaxis'), DatetimeAxis): y0 = convert_timestamp(y0) y1 = convert_timestamp(y1) if self.plot.invert_yaxis: y0, y1 = y1, y0 data['y_range'] = (y0, y1) return data
[docs]class RangeXCallback(RangeXYCallback): """ Returns the x-axis range of a plot. """ attributes = {'x0': 'x_range.attributes.start', 'x1': 'x_range.attributes.end'} models = ['x_range']
[docs]class RangeYCallback(RangeXYCallback): """ Returns the y-axis range of a plot. """ attributes = {'y0': 'y_range.attributes.start', 'y1': 'y_range.attributes.end'} models = ['y_range']
[docs]class PlotSizeCallback(Callback): """ Returns the actual width and height of a plot once the layout solver has executed. """ models = ['plot'] attributes = {'width': 'cb_obj.inner_width', 'height': 'cb_obj.inner_height'} on_changes = ['inner_width', 'inner_height'] def _process_msg(self, msg): if msg.get('width') and msg.get('height'): return msg else: return {}
[docs]class BoundsCallback(Callback): """ Returns the bounds of a box_select tool. """ attributes = {'x0': 'cb_obj.geometry.x0', 'x1': 'cb_obj.geometry.x1', 'y0': 'cb_obj.geometry.y0', 'y1': 'cb_obj.geometry.y1'} models = ['plot'] extra_models = ['box_select'] on_events = ['selectiongeometry'] skip = ["cb_obj.geometry.type != 'rect'"] def _process_msg(self, msg): if all(c in msg for c in ['x0', 'y0', 'x1', 'y1']): if isinstance(self.plot.handles.get('xaxis'), DatetimeAxis): msg['x0'] = convert_timestamp(msg['x0']) msg['x1'] = convert_timestamp(msg['x1']) if isinstance(self.plot.handles.get('yaxis'), DatetimeAxis): msg['y0'] = convert_timestamp(msg['y0']) msg['y1'] = convert_timestamp(msg['y1']) return {'bounds': (msg['x0'], msg['y0'], msg['x1'], msg['y1'])} else: return {}
[docs]class BoundsXCallback(Callback): """ Returns the bounds of a xbox_select tool. """ attributes = {'x0': 'cb_obj.geometry.x0', 'x1': 'cb_obj.geometry.x1'} models = ['plot'] extra_models = ['xbox_select'] on_events = ['selectiongeometry'] skip = ["cb_obj.geometry.type != 'rect'"] def _process_msg(self, msg): if all(c in msg for c in ['x0', 'x1']): if isinstance(self.plot.handles.get('xaxis'), DatetimeAxis): msg['x0'] = convert_timestamp(msg['x0']) msg['x1'] = convert_timestamp(msg['x1']) return {'boundsx': (msg['x0'], msg['x1'])} else: return {}
[docs]class BoundsYCallback(Callback): """ Returns the bounds of a ybox_select tool. """ attributes = {'y0': 'cb_obj.geometry.y0', 'y1': 'cb_obj.geometry.y1'} models = ['plot'] extra_models = ['ybox_select'] on_events = ['selectiongeometry'] skip = ["cb_obj.geometry.type != 'rect'"] def _process_msg(self, msg): if all(c in msg for c in ['y0', 'y1']): if isinstance(self.plot.handles.get('yaxis'), DatetimeAxis): msg['y0'] = convert_timestamp(msg['y0']) msg['y1'] = convert_timestamp(msg['y1']) return {'boundsy': (msg['y0'], msg['y1'])} else: return {}
[docs]class Selection1DCallback(Callback): """ Returns the current selection on a ColumnDataSource. """ attributes = {'index': 'cb_obj.selected.1d.indices'} models = ['source'] on_changes = ['selected'] def _process_msg(self, msg): if 'index' in msg: return {'index': [int(v) for v in msg['index']]} else: return {}
[docs]class ResetCallback(Callback): """ Signals the Reset stream if an event has been triggered. """ models = ['plot'] on_events = ['reset'] def _process_msg(self, msg): return {'reset': True}
callbacks = Stream._callbacks['bokeh'] callbacks[PointerXY] = PointerXYCallback callbacks[PointerX] = PointerXCallback callbacks[PointerY] = PointerYCallback callbacks[Tap] = TapCallback callbacks[SingleTap] = SingleTapCallback callbacks[DoubleTap] = DoubleTapCallback callbacks[MouseEnter] = MouseEnterCallback callbacks[MouseLeave] = MouseLeaveCallback callbacks[RangeXY] = RangeXYCallback callbacks[RangeX] = RangeXCallback callbacks[RangeY] = RangeYCallback callbacks[Bounds] = BoundsCallback callbacks[BoundsXY] = BoundsCallback callbacks[BoundsX] = BoundsXCallback callbacks[BoundsY] = BoundsYCallback callbacks[Selection1D] = Selection1DCallback callbacks[PlotSize] = PlotSizeCallback callbacks[Draw] = DrawCallback callbacks[PlotReset] = ResetCallback # Aliases for deprecated streams callbacks[PositionXY] = PointerXYCallback callbacks[PositionX] = PointerXCallback callbacks[PositionY] = PointerYCallback