Source code for panel.param

Defines the Param pane which converts Parameterized classes into a
set of widgets.
from __future__ import annotations

import asyncio
import inspect
import itertools
import json
import os
import sys
import textwrap
import types

from collections import OrderedDict, defaultdict, namedtuple
from import Callable
from contextlib import contextmanager
from functools import partial
from typing import (
    TYPE_CHECKING, Any, ClassVar, Generator, List, Mapping, Optional, Tuple,

import param

from param.parameterized import (
    classlist, discard_events, eval_function_with_deps, get_method_owner,
from param.reactive import rx

from .config import config
from .io import state
from .layout import (
    Column, HSpacer, Panel, Row, Spacer, Tabs, WidgetBox,
from .pane import DataFrame as DataFramePane
from .pane.base import PaneBase, ReplacementPane
from .reactive import Reactive
from .util import (
    abbreviated_repr, flatten, full_groupby, fullpath, is_parameterized,
    param_name, recursive_parameterized,
from .util.checks import is_dataframe, is_mpl_axes, is_series
from .viewable import Layoutable, Viewable
from .widgets import (
    ArrayInput, Button, Checkbox, ColorPicker, DataFrame, DatePicker,
    DateRangeSlider, DatetimeInput, DatetimeRangeSlider, DiscreteSlider,
    FileInput, FileSelector, FloatInput, FloatSlider, IntInput, IntSlider,
    LiteralInput, MultiSelect, RangeSlider, Select, StaticText, Tabulator,
    TextInput, Toggle, Widget,
from .widgets.button import _ButtonBase

    from bokeh.document import Document
    from bokeh.model import Model
    from pyviz_comms import Comm

def SingleFileSelector(pobj: param.Parameter) -> Type[Widget]:
    Determines whether to use a TextInput or Select widget for FileSelector
    if pobj.path:
        return Select
        return TextInput

def LiteralInputTyped(pobj: param.Parameter) -> Type[Widget]:
    if isinstance(pobj, param.Tuple):
        return type(str('TupleInput'), (LiteralInput,), {'type': tuple})
    elif isinstance(pobj, param.Number):
        return type(str('NumberInput'), (LiteralInput,), {'type': (int, float)})
    elif isinstance(pobj, param.Dict):
        return type(str('DictInput'), (LiteralInput,), {'type': dict})
    elif isinstance(pobj, param.List):
        return type(str('ListInput'), (LiteralInput,), {'type': list})
    return LiteralInput

def DataFrameWidget(pobj: param.DataFrame) -> Type[Widget]:
    if 'panel.models.tabulator' in sys.modules:
        return Tabulator
        return DataFrame

[docs]@contextmanager def set_values(*parameterizeds, **param_values): """ Temporarily sets parameter values to the specified values on all supplied Parameterized objects. Arguments --------- parameterizeds: tuple(param.Parameterized) Any number of parameterized objects. param_values: dict A dictionary of parameter names and temporary values. """ old = [] for parameterized in parameterizeds: old_values = {p: getattr(parameterized, p) for p in param_values} old.append((parameterized, old_values)) parameterized.param.update(**param_values) try: yield finally: for parameterized, old_values in old: parameterized.param.update(**old_values)
[docs]class Param(PaneBase): """ Param panes render a Parameterized class to a set of widgets which are linked to the parameter values on the class. """ display_threshold = param.Number(default=0, precedence=-10, doc=""" Parameters with precedence below this value are not displayed.""") default_layout = param.ClassSelector(default=Column, class_=Panel, is_instance=False) default_precedence = param.Number(default=1e-8, precedence=-10, doc=""" Precedence value to use for parameters with no declared precedence. By default, zero predecence is available for forcing some parameters to the top of the list, and other values above the default_precedence values can be used to sort or group parameters arbitrarily.""") expand = param.Boolean(default=False, doc=""" Whether parameterized subobjects are expanded or collapsed on instantiation.""") expand_button = param.Boolean(default=None, doc=""" Whether to add buttons to expand and collapse sub-objects.""") expand_layout = param.Parameter(default=Column, doc=""" Layout to expand sub-objects into.""") height = param.Integer(default=None, bounds=(0, None), doc=""" Height of widgetbox the parameter widgets are displayed in.""") hide_constant = param.Boolean(default=False, doc=""" Whether to hide widgets of constant parameters.""") initializer = param.Callable(default=None, doc=""" User-supplied function that will be called on initialization, usually to update the default Parameter values of the underlying parameterized object.""") name = param.String(default='', doc=""" Title of the pane.""") object = param.Parameter(default=None, allow_refs=False, doc=""" The object being wrapped, which will be converted to a Bokeh model.""") parameters = param.List(default=[], allow_None=True, doc=""" If set this serves as a whitelist of parameters to display on the supplied Parameterized object.""") show_labels = param.Boolean(default=True, doc=""" Whether to show labels for each widget""") show_name = param.Boolean(default=True, doc=""" Whether to show the parameterized object's name""") sort = param.ClassSelector(default=False, class_=(bool, Callable), doc=""" If True the widgets will be sorted alphabetically by label. If a callable is provided it will be used to sort the Parameters, for example lambda x: x[1].label[::-1] will sort by the reversed label.""") width = param.Integer(default=None, allow_None=True, bounds=(0, None), doc=""" Width of widgetbox the parameter widgets are displayed in.""") widgets = param.Dict(doc=""" Dictionary of widget overrides, mapping from parameter name to widget class.""") mapping: ClassVar[Mapping[param.Parameter, Widget | Callable[[param.Parameter], Widget]]] = { param.Action: Button, param.Array: ArrayInput, param.Boolean: Checkbox, param.Bytes: FileInput, param.CalendarDate: DatePicker, param.Color: ColorPicker, param.Date: DatetimeInput, param.DateRange: DatetimeRangeSlider, param.CalendarDateRange: DateRangeSlider, param.DataFrame: DataFrameWidget, param.Dict: LiteralInputTyped, param.FileSelector: SingleFileSelector, param.Filename: TextInput, param.Foldername: TextInput, param.Integer: IntSlider, param.List: LiteralInputTyped, param.MultiFileSelector: FileSelector, param.ListSelector: MultiSelect, param.Number: FloatSlider, param.ObjectSelector: Select, param.Parameter: LiteralInputTyped, param.Range: RangeSlider, param.Selector: Select, param.String: TextInput, } if hasattr(param, 'Event'): mapping[param.Event] = Button _ignored_refs: ClassVar[Tuple[str,...]] = ('object',) _linkable_properties: ClassVar[Tuple[str,...]] = () _rerender_params: ClassVar[List[str]] = [] _unpack: ClassVar[bool] = True def __init__(self, object=None, **params): if isinstance(object, param.Parameter): if 'show_name' not in params: params['show_name'] = False params['parameters'] = [] object = object.owner if isinstance(object, param.parameterized.Parameters): object = object.cls if object.self is None else object.self if 'parameters' not in params and object is not None: params['parameters'] = [p for p in object.param if p != 'name'] self._explicit_parameters = False else: self._explicit_parameters = object is not None if object and 'name' not in params: params['name'] = param_name( super().__init__(object, **params) self._updating = [] # Construct Layout kwargs = {p: v for p, v in self.param.values().items() if p in Layoutable.param and v is not None} self._widget_box = self.default_layout(**kwargs) layout = self.expand_layout if isinstance(layout, Panel): self._expand_layout = layout self.layout = self._widget_box elif isinstance(self._widget_box, layout): self.layout = self._expand_layout = self._widget_box elif isinstance(layout, type) and issubclass(layout, Panel): self.layout = self._expand_layout = layout(self._widget_box, **kwargs) else: raise ValueError('expand_layout expected to be a panel.layout.Panel' 'type or instance, found %s type.' % type(layout).__name__), [ 'object', 'parameters', 'name', 'display_threshold', 'expand_button', 'expand', 'expand_layout', 'widgets', 'show_labels', 'show_name', 'hide_constant']) self._update_widgets() def __repr__(self, depth=0): cls = type(self).__name__ obj_cls = type(self.object).__name__ params = [] if self.object is None else list(self.object.param) parameters = [k for k in params if k != 'name'] params = [] for p, v in sorted(self.param.values().items()): if v == self.param[p].default: continue elif v is None: continue elif isinstance(v, str) and v == '': continue elif p == 'object' or (p == 'name' and (v.startswith(obj_cls) or v.startswith(cls))): continue elif p == 'parameters' and v == parameters: continue try: params.append('%s=%s' % (p, abbreviated_repr(v))) except RuntimeError: params.append('%s=%s' % (p, '...')) obj = 'None' if self.object is None else '%s' % type(self.object).__name__ template = '{cls}({obj}, {params})' if params else '{cls}({obj})' return template.format(cls=cls, params=', '.join(params), obj=obj) #---------------------------------------------------------------- # Callback API #---------------------------------------------------------------- @property def _synced_params(self): ignored_params = ['default_layout', 'loading', 'background'] return [p for p in Layoutable.param if p not in ignored_params] def _update_widgets(self, *events): parameters = [] for event in sorted(events, key=lambda x: if == 'object': if isinstance(, param.parameterized.Parameters): # Setting object will trigger this method a second time self.object = if is None else return if self._explicit_parameters: parameters = self.parameters elif is None: parameters = [] else: parameters = [p for p in if p != 'name'] if is not None: = param_name( if == 'parameters': if is None: self._explicit_parameters = False if self.object is not None: parameters = [p for p in self.object.param if p != 'name'] else: self._explicit_parameters = True parameters = [] if == [] else if parameters != [] and parameters != self.parameters: # Setting parameters will trigger this method a second time self.parameters = parameters return for cb in list(self._internal_callbacks): if cb.inst in self._widget_box.objects: cb.inst.param.unwatch(cb) self._internal_callbacks.remove(cb) # Construct widgets if self.object is None: self._widgets = {} else: self._widgets = self._get_widgets() alias = {'_title': 'name'} widgets = [widget for p, widget in self._widgets.items() if (self.object.param[alias.get(p, p)].precedence is None) or (self.object.param[alias.get(p, p)].precedence >= self.display_threshold)] self._widget_box.objects = widgets if not (self.expand_button == False and not self.expand): self._link_subobjects() def _link_subobjects(self): for pname, widget in self._widgets.items(): widgets = [widget] if isinstance(widget, Widget) else widget if not any(is_parameterized(getattr(w, 'value', None)) or any(is_parameterized(o) for o in getattr(w, 'options', [])) for w in widgets): continue if (isinstance(widgets, Row) and isinstance(widgets[1], Toggle)): selector, toggle = (widgets[0], widgets[1]) else: selector, toggle = (widget, None) def toggle_pane(change, parameter=pname): "Adds or removes subpanel from layout" parameterized = getattr(self.object, parameter) existing = [p for p in self._expand_layout.objects if isinstance(p, Param) and p.object in recursive_parameterized(parameterized)] if not self._expand_layout[:] = [ e for e in self._expand_layout.objects if e not in existing ] elif kwargs = {k: v for k, v in self.param.values().items() if k not in ['name', 'object', 'parameters']} pane = Param(parameterized,, **kwargs) if isinstance(self._expand_layout, Tabs): title = self.object.param[pname].label pane = (title, pane) self._expand_layout.append(pane) def update_pane(change, parameter=pname): "Adds or removes subpanel from layout" layout = self._expand_layout existing = [p for p in layout.objects if isinstance(p, Param) and p.object is change.old] if toggle: toggle.disabled = not is_parameterized( if not existing: return elif is_parameterized( parameterized = kwargs = {k: v for k, v in self.param.values().items() if k not in ['name', 'object', 'parameters']} pane = Param(parameterized,, **kwargs) layout[layout.objects.index(existing[0])] = pane else: layout.remove(existing[0]) watchers = [, 'value')] if toggle: watchers.append(, 'value')) self._internal_callbacks += watchers if self.expand: if self.expand_button: toggle.value = True else: toggle_pane(namedtuple('Change', 'new')(True))
[docs] def widget(self, p_name): """Get widget for param_name""" p_obj = self.object.param[p_name] kw_widget = {} widget_class_overridden = True if self.widgets is None or p_name not in self.widgets: widget_class_overridden = False widget_class = self.widget_type(p_obj) elif isinstance(self.widgets[p_name], dict): kw_widget = dict(self.widgets[p_name]) if 'widget_type' in self.widgets[p_name]: widget_class = kw_widget.pop('widget_type') elif 'type' in self.widgets[p_name]: widget_class = kw_widget.pop('type') else: widget_class_overridden = False widget_class = self.widget_type(p_obj) else: widget_class = self.widgets[p_name] if not self.show_labels and not issubclass(widget_class, _ButtonBase): label = '' else: label = p_obj.label kw = dict(disabled=p_obj.constant, name=label) if self.hide_constant: kw['visible'] = not p_obj.constant value = getattr(self.object, p_name) allow_None = p_obj.allow_None or False if isinstance(widget_class, type) and issubclass(widget_class, Widget): allow_None &= widget_class.param.value.allow_None if value is not None or allow_None: kw['value'] = value if hasattr(p_obj, 'get_range'): options = p_obj.get_range() # This applies to widgets whose `options` Parameter is a List type, # such as AutoCompleteInput. if ('options' in widget_class.param and isinstance(widget_class.param['options'], param.List)): options = list(options.values()) if not options and value is not None: options = [value] kw['options'] = options if hasattr(p_obj, 'get_soft_bounds'): bounds = p_obj.get_soft_bounds() if bounds[0] is not None: kw['start'] = bounds[0] if bounds[1] is not None: kw['end'] = bounds[1] if (('start' not in kw or 'end' not in kw) and not isinstance(p_obj, (param.Date, param.CalendarDate))): # Do not change widget class if mapping was overridden if not widget_class_overridden: if isinstance(p_obj, param.Number): widget_class = FloatInput if isinstance(p_obj, param.Integer): widget_class = IntInput elif not issubclass(widget_class, LiteralInput): widget_class = LiteralInput if hasattr(widget_class, 'step') and getattr(p_obj, 'step', None): kw['step'] = p_obj.step if hasattr(widget_class, 'fixed_start') and getattr(p_obj, 'bounds', None): kw['fixed_start'] = p_obj.bounds[0] if hasattr(widget_class, 'fixed_end') and getattr(p_obj, 'bounds', None): kw['fixed_end'] = p_obj.bounds[1] if p_obj.doc: kw['description'] = textwrap.dedent(p_obj.doc).strip() # Update kwargs onkeyup = kw_widget.pop('onkeyup', False) throttled = kw_widget.pop('throttled', False) ignored_kws = [repr(k) for k in kw_widget if k not in widget_class.param] if ignored_kws: self.param.warning( f'Param pane was given unknown keyword argument(s) for {p_name!r} ' f'parameter with a widget of type {widget_class!r}. The following ' f'keyword arguments could not be applied: {", ".join(ignored_kws)}.' ) kw.update(kw_widget) kwargs = {k: v for k, v in kw.items() if k in widget_class.param} if isinstance(widget_class, type) and issubclass(widget_class, Button): kwargs.pop('value', None) if isinstance(widget_class, Widget): widget = widget_class else: widget = widget_class(**kwargs) widget._param_pane = self widget._param_name = p_name watchers = self._internal_callbacks def link_widget(change): if p_name in self._updating: return try: self._updating.append(p_name) self.object.param.update(**{p_name:}) finally: self._updating.remove(p_name) if hasattr(param, 'Event') and isinstance(p_obj, param.Event): def event(change): self.object.param.trigger(p_name) watcher =, 'clicks') elif isinstance(p_obj, param.Action): def action(change): value(self.object) watcher =, 'clicks') elif onkeyup and hasattr(widget, 'value_input'): watcher =, 'value_input') elif throttled and hasattr(widget, 'value_throttled'): watcher =, 'value_throttled') else: watcher =, 'value') watchers.append(watcher) def link(change, watchers=[watcher]): updates = {} if p_name not in self._widgets: return widget = self._widgets[p_name] if change.what == 'constant': updates['disabled'] = if self.hide_constant: updates['visible'] = not elif change.what == 'precedence': if is change.old: return elif is None: self._rerender() elif ( < self.display_threshold and widget in self._widget_box.objects): self._widget_box.remove(widget) elif >= self.display_threshold: self._rerender() return elif change.what == 'objects': options = p_obj.get_range() if ('options' in widget.param and isinstance(widget.param['options'], param.List)): options = list(options) updates['options'] = options elif change.what == 'bounds': start, end = p_obj.get_soft_bounds() supports_bounds = hasattr(widget, 'start') if start is None or end is None: rerender = supports_bounds else: rerender = not supports_bounds if supports_bounds: updates['start'] = start updates['end'] = end if rerender: self._rerender_widget(p_name) return elif change.what == 'step': updates['step'] = p_obj.step elif change.what == 'label': updates['name'] = p_obj.label elif p_name in self._updating: return elif hasattr(param, 'Event') and isinstance(p_obj, param.Event): return elif isinstance(p_obj, param.Action): prev_watcher = watchers[0] widget.param.unwatch(prev_watcher) def action(event): watchers[0] =, 'clicks') idx = self._internal_callbacks.index(prev_watcher) self._internal_callbacks[idx] = watchers[0] return elif throttled and hasattr(widget, 'value_throttled'): updates['value_throttled'] = updates['value'] = elif isinstance(widget, Row) and len(widget) == 2: updates['value'] = widget = widget[0] else: updates['value'] = try: self._updating.append(p_name) if change.type == 'triggered': with discard_events(widget): widget.param.update(**updates) widget.param.trigger(*updates) else: widget.param.update(**updates) finally: self._updating.remove(p_name) # Set up links to parameterized object watchers.append(, p_name, 'constant')) watchers.append(, p_name, 'precedence')) watchers.append(, p_name, 'label')) if hasattr(p_obj, 'get_range'): watchers.append(, p_name, 'objects')) if hasattr(p_obj, 'get_soft_bounds'): watchers.append(, p_name, 'bounds')) if 'step' in kw: watchers.append(, p_name, 'step')) watchers.append(, p_name)) options = kwargs.get('options', []) if isinstance(options, dict): options = options.values() if ((is_parameterized(value) or any(is_parameterized(o) for o in options)) and (self.expand_button or (self.expand_button is None and not self.expand))): toggle = Toggle( name='\u22EE', button_type='primary', disabled=not is_parameterized(value), max_height=30, max_width=20, height_policy='fit', align='end', margin=(0, 0, 5, 10) ) width = widget.width widget.param.update( margin=(5, 0, 5, 10), sizing_mode='stretch_width', width=None ) return Row(widget, toggle, width=width, margin=0) else: return widget
@property def _ordered_params(self): params = [(p, pobj) for p, pobj in self.object.param.objects('existing').items() if p in self.parameters or p == 'name'] if self.sort: if callable(self.sort): key_fn = self.sort else: key_fn = lambda x: x[1].label sorted_params = sorted(params, key=key_fn) sorted_params = [el[0] for el in sorted_params if (el[0] != 'name' or el[0] in self.parameters)] return sorted_params key_fn = lambda x: x[1].precedence if x[1].precedence is not None else self.default_precedence sorted_precedence = sorted(params, key=key_fn) filtered = [(k, p) for k, p in sorted_precedence] groups = itertools.groupby(filtered, key=key_fn) # Params preserve definition order in Python 3.6+ ordered_groups = [list(grp) for (_, grp) in groups] ordered_params = [el[0] for group in ordered_groups for el in group if (el[0] != 'name' or el[0] in self.parameters)] return ordered_params #---------------------------------------------------------------- # Model API #---------------------------------------------------------------- def _rerender(self): precedence = lambda k: self.object.param['name' if k == '_title' else k].precedence params = self._ordered_params if self.show_name: params.insert(0, '_title') widgets = [] for k in params: if precedence(k) is None or precedence(k) >= self.display_threshold: widgets.append(self._widgets[k]) self._widget_box.objects = widgets def _rerender_widget(self, p_name): watchers = [] for w in self._internal_callbacks: if w.inst is self._widgets[p_name]: w.inst.param.unwatch(w) else: watchers.append(w) self._widgets[p_name] = self.widget(p_name) self._rerender() def _get_widgets(self): """Return name,widget boxes for all parameters (i.e., a property sheet)""" # Format name specially if self.expand_layout is Tabs: widgets = [] elif self.show_name: widgets = [('_title', StaticText(value='<b>{0}</b>'.format(] else: widgets = [] widgets += [(pname, self.widget(pname)) for pname in self._ordered_params] return OrderedDict(widgets) def _get_model( self, doc: Document, root: Optional[Model] = None, parent: Optional[Model] = None, comm: Optional[Comm] = None ) -> Model: model = self.layout._get_model(doc, root, parent, comm) self._models[root.ref['id']] = (model, parent) return model def _cleanup(self, root: Model | None = None) -> None: self.layout._cleanup(root) super()._cleanup(root) #---------------------------------------------------------------- # Public API #----------------------------------------------------------------
[docs] @classmethod def applies(cls, obj: Any) -> float | bool | None: if isinstance(obj, param.parameterized.Parameters): return 0.8 elif (is_parameterized(obj) or (isinstance(obj, param.Parameter) and obj.owner is not None)): return 0.1 return False
@classmethod def widget_type(cls, pobj): ptype = type(pobj) for t in classlist(ptype)[::-1]: if t not in cls.mapping: continue wtype = cls.mapping[t] if isinstance(wtype, types.FunctionType): return wtype(pobj) return wtype
[docs] def get_root( self, doc: Optional[Document] = None, comm: Comm | None = None, preprocess: bool = True ) -> Model: root = super().get_root(doc, comm, preprocess) ref = root.ref['id'] self._models[ref] = (root, None) return root
[docs] def select(self, selector=None): """ Iterates over the Viewable and any potential children in the applying the Selector. Arguments --------- selector: type or callable or None The selector allows selecting a subset of Viewables by declaring a type or callable function to filter by. Returns ------- viewables: list(Viewable) """ return super().select(selector) +
[docs]class ParamMethod(ReplacementPane): """ ParamMethod panes wrap methods on parameterized classes and rerenders the plot when any of the method's parameters change. By default ParamMethod will watch all parameters on the class owning the method or can be restricted to certain parameters by annotating the method using the param.depends decorator. The method may return any object which itself can be rendered as a Pane. """ defer_load = param.Boolean(default=None, doc=""" Whether to defer load until after the page is rendered. Can be set as parameter or by setting panel.config.defer_load.""") generator_mode = param.Selector(default='replace', objects=['append', 'replace'], doc=""" Whether generators should 'append' to or 'replace' existing output.""") lazy = param.Boolean(default=False, doc=""" Whether to lazily evaluate the contents of the object only when it is required for rendering.""") loading_indicator = param.Boolean(default=config.loading_indicator, doc=""" Whether to show a loading indicator while the pane is updating. Can be set as parameter or by setting panel.config.loading_indicator.""") def __init__(self, object=None, **params): if 'defer_load' not in params: params['defer_load'] = config.defer_load super().__init__(object, **params) self._async_task = None self._evaled = not (self.lazy or self.defer_load) self._link_object_params() if object is not None: self._validate_object() if not self.defer_load: self._replace_pane() @param.depends('object', watch=True) def _validate_object(self): dependencies = getattr(self.object, '_dinfo', None) if not dependencies or not dependencies.get('watch'): return fn_type = 'method' if type(self) is ParamMethod else 'function' self.param.warning( f"The {fn_type} supplied for Panel to display was declared " f"with `watch=True`, which will cause the {fn_type} to be " "called twice for any change in a dependent Parameter. " "`watch` should be False when Panel is responsible for " f"displaying the result of the {fn_type} call, while " f"`watch=True` should be reserved for {fn_type}s that work " "via side-effects, e.g. by modifying internal state of a " "class or global state in an application's namespace." ) #---------------------------------------------------------------- # Callback API #---------------------------------------------------------------- @classmethod def eval(self, function): return eval_function_with_deps(function) async def _eval_async(self, awaitable): if self._async_task: self._async_task.cancel() self._async_task = task = asyncio.current_task() curdoc = state.curdoc has_context = bool(curdoc.session_context) if curdoc else False if has_context: curdoc.on_session_destroyed(lambda context: task.cancel()) try: if isinstance(awaitable, types.AsyncGeneratorType): append_mode = self.generator_mode == 'append' if append_mode: self._inner_layout[:] = [] async for new_obj in awaitable: if append_mode: self._inner_layout.append(new_obj) self._pane = self._inner_layout[-1] else: self._update_inner(new_obj) else: self._update_inner(await awaitable) except Exception as e: if not curdoc or (has_context and curdoc.session_context): raise e finally: self._async_task = None self._inner_layout.loading = False def _replace_pane(self, *args, force=False): deferred = self.defer_load and not state.loaded if not self._inner_layout.loading: self._inner_layout.loading = bool(self.loading_indicator or deferred) self._evaled |= force or not (self.lazy or deferred) if not self._evaled: return try: if self.object is None: new_object = Spacer() else: new_object = self.eval(self.object) if inspect.isawaitable(new_object) or isinstance(new_object, types.AsyncGeneratorType): param.parameterized.async_executor(partial(self._eval_async, new_object)) return elif isinstance(new_object, Generator): append_mode = self.generator_mode == 'append' if append_mode: self._inner_layout[:] = [] for new_obj in new_object: if append_mode: self._inner_layout.append(new_obj) self._pane = self._inner_layout[-1] else: self._update_inner(new_obj) else: self._update_inner(new_object) finally: self._inner_layout.loading = False def _update_pane(self, *events): callbacks = [] for watcher in self._internal_callbacks: obj = watcher.inst if watcher.inst is None else watcher.cls if obj is self: callbacks.append(watcher) continue obj.param.unwatch(watcher) self._internal_callbacks = callbacks self._link_object_params() self._replace_pane() def _link_object_params(self): parameterized = get_method_owner(self.object) params = parameterized.param.method_dependencies(self.object.__name__) deps = params def update_pane(*events): # Update nested dependencies if parameterized object events if any(is_parameterized( for event in events): new_deps = parameterized.param.method_dependencies(self.object.__name__) for p in list(deps): if p in new_deps: continue watchers = self._internal_callbacks for w in list(watchers): if (w.inst is p.inst and w.cls is p.cls and in w.parameter_names): obj = p.cls if p.inst is None else p.inst obj.param.unwatch(w) watchers.remove(w) deps.remove(p) new_deps = [dep for dep in new_deps if dep not in deps] for _, params in full_groupby(new_deps, lambda x: (x.inst or x.cls, x.what)): p = params[0] pobj = p.cls if p.inst is None else p.inst ps = [ for _p in params] watcher =, ps, p.what) self._internal_callbacks.append(watcher) for p in params: deps.append(p) self._replace_pane() for _, params in full_groupby(params, lambda x: (x.inst or x.cls, x.what)): p = params[0] pobj = (p.inst or p.cls) ps = [ for _p in params] if isinstance(pobj, Reactive) and self.loading_indicator: props = {p: 'loading' for p in ps if p in pobj._linkable_params} if props: pobj.jslink(self._inner_layout, **props) watcher =, ps, p.what) self._internal_callbacks.append(watcher) def _get_model( self, doc: Document, root: Optional[Model] = None, parent: Optional[Model] = None, comm: Optional[Comm] = None ) -> Model: if not self._evaled: deferred = self.defer_load and not state.loaded if deferred: state.onload( partial(self._replace_pane, force=True), threaded=bool(state._thread_pool) ) self._replace_pane(force=not deferred) return super()._get_model(doc, root, parent, comm) #---------------------------------------------------------------- # Public API #----------------------------------------------------------------
[docs] @classmethod def applies(cls, obj: Any) -> float | bool | None: return inspect.ismethod(obj) and isinstance(get_method_owner(obj), param.Parameterized)
@param.depends(config.param.defer_load, watch=True) def _update_defer_load_default(default_value): ParamMethod.param.defer_load.default = default_value @param.depends(config.param.loading_indicator, watch=True) def _update_loading_indicator_default(default_value): ParamMethod.param.loading_indicator.default = default_value
[docs]class ParamFunction(ParamMethod): """ ParamFunction panes wrap functions decorated with the param.depends decorator and rerenders the output when any of the function's dependencies change. This allows building reactive components into a Panel which depend on other parameters, e.g. tying the value of a widget to some other output. """ priority: ClassVar[float | bool | None] = 0.6 _applies_kw: ClassVar[bool] = True def _link_object_params(self): deps = getattr(self.object, '_dinfo', {}) dep_params = list(deps.get('dependencies', [])) + list(deps.get('kw', {}).values()) if not dep_params and not self.lazy and not self.defer_load and not iscoroutinefunction(self.object): fn = getattr(self.object, '__bound_function__', self.object) fn_name = getattr(fn, '__name__', repr(self.object)) self.param.warning( f"The function {fn_name!r} does not have any dependencies " "and will never update. Are you sure you did not intend " "to depend on or bind a parameter or widget to this function? " "If not simply call the function before passing it to Panel. " "Otherwise, when passing a parameter as an argument, " "ensure you pass at least one parameter and reference the " "actual parameter object not the current value, i.e. use " "object.param.parameter not object.parameter." ) grouped = defaultdict(list) for dep in dep_params: grouped[id(dep.owner)].append(dep) for group in grouped.values(): pobj = group[0].owner watcher =, [ for dep in group]) if isinstance(pobj, Reactive) and self.loading_indicator: props = { 'loading' for dep in group if in pobj._linkable_params} if props: pobj.jslink(self._inner_layout, **props) self._internal_callbacks.append(watcher) #---------------------------------------------------------------- # Public API #----------------------------------------------------------------
[docs] @classmethod def applies(cls, obj: Any, **kwargs) -> float | bool | None: if isinstance(obj, types.FunctionType): if hasattr(obj, '_dinfo'): return True if ( kwargs.get('defer_load') or cls.param.defer_load.default or (cls.param.defer_load.default is None and config.defer_load) or iscoroutinefunction(obj) ): return True return None return False
[docs]class ReactiveExpr(PaneBase): """ ReactiveExpr generates a UI for param.rx objects by rendering the widgets and outputs. """ center = param.Boolean(default=False, doc=""" Whether to center the output.""") object = param.Parameter(default=None, allow_refs=False, doc=""" The object being wrapped, which will be converted to a Bokeh model.""") show_widgets = param.Boolean(default=True, doc=""" Whether to display the widget inputs.""") widget_layout = param.Selector( objects=[WidgetBox, Row, Column], constant=True, default=WidgetBox, doc=""" The layout object to display the widgets in.""") widget_location = param.Selector(default='left_top', objects=[ 'left', 'right', 'top', 'bottom', 'top_left', 'top_right', 'bottom_left', 'bottom_right', 'left_top', 'right_top', 'right_bottom'], doc=""" The location of the widgets relative to the output of the reactive expression.""") priority: ClassVar[float | bool | None] = 1 _layouts = { 'left': (Row, ('start', 'center'), True), 'right': (Row, ('end', 'center'), False), 'top': (Column, ('center', 'start'), True), 'bottom': (Column, ('center', 'end'), False), 'top_left': (Column, 'start', True), 'top_right': (Column, ('end', 'start'), True), 'bottom_left': (Column, ('start', 'end'), False), 'bottom_right': (Column, 'end', False), 'left_top': (Row, 'start', True), 'left_bottom': (Row, ('start', 'end'), True), 'right_top': (Row, ('end', 'start'), False), 'right_bottom': (Row, 'end', False) } _unpack: ClassVar[bool] = False def __init__(self, object=None, **params): super().__init__(object=object, **params) self._update_layout() @param.depends('center', 'object', 'widget_layout', 'widget_location', watch=True) def _update_layout(self, *events): if self.object is None: self.layout[:] = [] else: self.layout[:] = [self._generate_layout()]
[docs] @classmethod def applies(self, object): return isinstance(object, param.rx)
@classmethod def _find_widgets(cls, op): widgets = [] op_args = list(op['args']) + list(op['kwargs'].values()) op_args = flatten(op_args) for op_arg in op_args: # Find widgets introduced as `widget` in an expression if isinstance(op_arg, Widget) and op_arg not in widgets: widgets.append(op_arg) continue # Find Ipywidgets if 'ipywidgets' in sys.modules: from ipywidgets import Widget as IPyWidget if isinstance(op_arg, IPyWidget) and op_arg not in widgets: widgets.append(op_arg) continue # Find widgets introduced as `widget.param.value` in an expression if (isinstance(op_arg, param.Parameter) and isinstance(op_arg.owner, Widget) and op_arg.owner not in widgets): widgets.append(op_arg.owner) continue # Recurse into object if hasattr(op_arg, '_dinfo'): dinfo = op_arg._dinfo args = list(dinfo.get('dependencies', [])) kwargs = dinfo.get('kw', {}) nested_op = {"args": args, "kwargs": kwargs} elif isinstance(op_arg, slice): nested_op = {"args": [op_arg.start, op_arg.stop, op_arg.step], "kwargs": {}} elif isinstance(op_arg, (list, tuple)): nested_op = {"args": op_arg, "kwargs": {}} elif isinstance(op_arg, dict): nested_op = {"args": (), "kwargs": op_arg} elif isinstance(op_arg, param.rx): nested_op = {"args": op_arg._params, "kwargs": {}} else: continue for widget in cls._find_widgets(nested_op): if widget not in widgets: widgets.append(widget) return widgets @property def widgets(self): widgets = [] if self.object is None: return [] for p in self.object._fn_params: if (isinstance(p.owner, Widget) and p.owner not in widgets): widgets.append(p.owner) operations = [] prev = self.object while prev is not None: if prev._operation: operations.append(prev._operation) prev = prev._prev for op in operations[::-1]: for w in self._find_widgets(op): if w not in widgets: widgets.append(w) return self.widget_layout(*widgets) def _generate_layout(self): panel = ParamFunction(self.object._callback) if not self.show_widgets: return panel widget_box = self.widgets loc = self.widget_location layout, align, widget_first = self._layouts[loc] widget_box.align = align if not len(widget_box): if components = [HSpacer(), panel, HSpacer()] else: components = [panel] return Row(*components) items = (widget_box, panel) if widget_first else (panel, widget_box) if not if layout is Row: components = list(items) else: components = [layout(*items, sizing_mode=self.sizing_mode)] elif layout is Column: components = [HSpacer(), layout(*items, sizing_mode=self.sizing_mode), HSpacer()] elif loc.startswith('left'): components = [widget_box, HSpacer(), panel, HSpacer()] else: components = [HSpacer(), panel, HSpacer(), widget_box] return Row(*components)
class JSONInit(param.Parameterized): """ Callable that can be passed to Widgets.initializer to set Parameter values using JSON. There are three approaches that may be used: 1. If the json_file argument is specified, this takes precedence. 2. The JSON file path can be specified via an environment variable. 3. The JSON can be read directly from an environment variable. Here is an easy example of setting such an environment variable on the commandline: PARAM_JSON_INIT='{"p1":5}' jupyter notebook This addresses any JSONInit instances that are inspecting the default environment variable called PARAM_JSON_INIT, instructing it to set the 'p1' parameter to 5. """ varname = param.String(default='PARAM_JSON_INIT', doc=""" The name of the environment variable containing the JSON specification.""") target = param.String(default=None, doc=""" Optional key in the JSON specification dictionary containing the desired parameter values.""") json_file = param.String(default=None, doc=""" Optional path to a JSON file containing the parameter settings.""") def __call__(self, parameterized): warnobj = param.main.param if isinstance(parameterized, type) else parameterized.param param_class = (parameterized if isinstance(parameterized, type) else parameterized.__class__) target = if is not None else param_class.__name__ env_var = os.environ.get(self.varname, None) if env_var is None and self.json_file is None: return if self.json_file or env_var.endswith('.json'): try: fname = self.json_file if self.json_file else env_var with open(fullpath(fname), 'r') as f: spec = json.load(f) except Exception: warnobj.warning('Could not load JSON file %r' % spec) else: spec = json.loads(env_var) if not isinstance(spec, dict): warnobj.warning('JSON parameter specification must be a dictionary.') return if target in spec: params = spec[target] else: params = spec for name, value in params.items(): try: parameterized.param.update(**{name:value}) except ValueError as e: warnobj.warning(str(e)) def link_param_method(root_view, root_model): """ This preprocessor jslinks ParamMethod loading parameters to any widgets generated from those parameters ensuring that the loading indicator is enabled client side. """ methods = p: isinstance(p, ParamMethod) and p.loading_indicator) widgets = w: isinstance(w, Widget) and getattr(w, '_param_pane', None) is not None) for widget in widgets: for method in methods: for cb in method._internal_callbacks: pobj = cb.cls if cb.inst is None else cb.inst if widget._param_pane.object is pobj and widget._param_name in cb.parameter_names: if isinstance(widget, DiscreteSlider): w = widget._slider else: w = widget if 'value' in w._linkable_params: w.jslink(method._inner_layout, value='loading') Viewable._preprocessing_hooks.insert(0, link_param_method) class FigureWrapper(param.Parameterized): figure = param.Parameter() def get_ax(self): from matplotlib.backends.backend_agg import FigureCanvas from matplotlib.pyplot import Figure self.figure = fig = Figure() FigureCanvas(fig) return fig.subplots() def _repr_mimebundle_(self, include=[], exclude=[]): return self.layout()._repr_mimebundle_() def __panel__(self): return self.layout() def _plot_handler(reactive): fig_wrapper = FigureWrapper() def plot(obj, *args, **kwargs): if 'ax' not in kwargs: kwargs['ax'] = fig_wrapper.get_ax() obj.plot(*args, **kwargs) return fig_wrapper.figure return plot rx.register_display_handler(is_dataframe, handler=DataFramePane, max_rows=100) rx.register_display_handler(is_series, handler=DataFramePane, max_rows=100) rx.register_display_handler(is_mpl_axes, handler=lambda ax: ax.get_figure()) rx.register_method_handler('plot', _plot_handler) __all__= ( "Param", "ParamFunction", "ParamMethod", "ReactiveExpr", "set_values" )