#----------------------------------------------------------------------------- # Copyright (c) 2012 - 2021, Anaconda, Inc., and Bokeh Contributors. # All rights reserved. # # The full license is in the file LICENSE.txt, distributed with this software. #----------------------------------------------------------------------------- ''' The query module provides functions for searching collections of Bokeh models for instances that match specified criteria. ''' #----------------------------------------------------------------------------- # Boilerplate #----------------------------------------------------------------------------- import logging # isort:skip log = logging.getLogger(__name__) #----------------------------------------------------------------------------- # Imports #----------------------------------------------------------------------------- # Standard library imports from typing import Any, Callable, Dict, Iterator, Optional, Type, Union # Bokeh imports from ..model import Model #----------------------------------------------------------------------------- # Globals and constants #----------------------------------------------------------------------------- __all__ = ( 'EQ', 'find', 'GEQ', 'GT', 'IN', 'LEQ', 'LT', 'match', 'NEQ', 'OR', ) ContextType = Optional[Dict[str, Any]] SelectorType = Dict[Union[str, Type["_Operator"]], Any] #----------------------------------------------------------------------------- # General API #----------------------------------------------------------------------------- [docs]def find(objs: Iterator[Model], selector: SelectorType, context: ContextType = None) -> Iterator[Model]: ''' Query a collection of Bokeh models and yield any that match the a selector. Args: obj (Model) : object to test selector (JSON-like) : query selector context (dict) : kwargs to supply callable query attributes Yields: Model : objects that match the query Queries are specified as selectors similar to MongoDB style query selectors, as described for :func:`~bokeh.core.query.match`. Examples: .. code-block:: python # find all objects with type Grid find(p.references(), {'type': Grid}) # find all objects with type Grid or Axis find(p.references(), {OR: [ {'type': Grid}, {'type': Axis} ]}) # same query, using IN operator find(p.references(), {'type': {IN: [Grid, Axis]}}) # find all plot objects on the 'left' layout of the Plot # here layout is a method that takes a plot as context find(p.references(), {'layout': 'left'}, {'plot': p}) ''' return (obj for obj in objs if match(obj, selector, context)) [docs]def match(obj: Model, selector: SelectorType, context: ContextType = None) -> bool: ''' Test whether a given Bokeh model matches a given selector. Args: obj (Model) : object to test selector (JSON-like) : query selector context (dict) : kwargs to supply callable query attributes Returns: bool : True if the object matches, False otherwise In general, the selectors have the form: .. code-block:: python { attrname : predicate } Where a predicate is constructed from the operators ``EQ``, ``GT``, etc. and is used to compare against values of model attributes named ``attrname``. For example: .. code-block:: python >>> from bokeh.plotting import figure >>> p = figure(plot_width=400) >>> match(p, {'plot_width': {EQ: 400}}) True >>> match(p, {'plot_width': {GT: 500}}) False There are two selector keys that are handled especially. The first is 'type', which will do an isinstance check: .. code-block:: python >>> from bokeh.plotting import figure >>> from bokeh.models import Axis >>> p = figure() >>> match(p.xaxis[0], {'type': Axis}) True >>> match(p.title, {'type': Axis}) False There is also a ``'tags'`` attribute that ``Model`` objects have, that is a list of user-supplied values. The ``'tags'`` selector key can be used to query against this list of tags. An object matches if any of the tags in the selector match any of the tags on the object: .. code-block:: python >>> from bokeh.plotting import figure >>> p = figure(tags = ["my plot", 10]) >>> match(p, {'tags': "my plot"}) True >>> match(p, {'tags': ["my plot", 10]}) True >>> match(p, {'tags': ["foo"]}) False ''' context = context or {} for key, val in selector.items(): # test attributes if isinstance(key, str): # special case 'type' if key == "type": # type supports IN, check for that first if isinstance(val, dict) and list(val.keys()) == [IN]: if not any(isinstance(obj, x) for x in val[IN]): return False # otherwise just check the type of the object against val elif not isinstance(obj, val): return False # special case 'tag' elif key == 'tags': if isinstance(val, str): if val not in obj.tags: return False else: try: if not set(val) & set(obj.tags): return False except TypeError: if val not in obj.tags: return False # if the object doesn't have the attr, it doesn't match elif not hasattr(obj, key): return False # if the value to check is a dict, recurse else: attr = getattr(obj, key) if callable(attr): try: if not attr(val, **context): return False except Exception: return False elif isinstance(val, dict): if not match(attr, val, context): return False else: if attr != val: return False # test OR conditionals elif key is OR: if not _or(obj, val): return False # test operands elif key in _operators: if not _operators[key](obj, val): return False else: raise ValueError("malformed query selector") return True #----------------------------------------------------------------------------- # Dev API #----------------------------------------------------------------------------- class _Operator: pass [docs]class OR(_Operator): ''' Form disjunctions from other query predicates. Construct an ``OR`` expression by making a dict with ``OR`` as the key, and a list of other query expressions as the value: .. code-block:: python # matches any Axis subclasses or models with .name == "mycircle" { OR: [dict(type=Axis), dict(name="mycircle")] } ''' pass [docs]class IN(_Operator): ''' Predicate to test if property values are in some collection. Construct and ``IN`` predicate as a dict with ``IN`` as the key, and a list of values to check against. .. code-block:: python # matches any models with .name in ['a', 'mycircle', 'myline'] dict(name={ IN: ['a', 'mycircle', 'myline'] }) ''' pass [docs]class GT(_Operator): ''' Predicate to test if property values are greater than some value. Construct and ``GT`` predicate as a dict with ``GT`` as the key, and a value to compare against. .. code-block:: python # matches any models with .size > 10 dict(size={ GT: 10 }) ''' pass [docs]class LT(_Operator): ''' Predicate to test if property values are less than some value. Construct and ``LT`` predicate as a dict with ``LT`` as the key, and a value to compare against. .. code-block:: python # matches any models with .size < 10 dict(size={ LT: 10 }) ''' pass [docs]class EQ(_Operator): ''' Predicate to test if property values are equal to some value. Construct and ``EQ`` predicate as a dict with ``EQ`` as the key, and a value to compare against. .. code-block:: python # matches any models with .size == 10 dict(size={ EQ: 10 }) ''' pass [docs]class GEQ(_Operator): ''' Predicate to test if property values are greater than or equal to some value. Construct and ``GEQ`` predicate as a dict with ``GEQ`` as the key, and a value to compare against. .. code-block:: python # matches any models with .size >= 10 dict(size={ GEQ: 10 }) ''' pass [docs]class LEQ(_Operator): ''' Predicate to test if property values are less than or equal to some value. Construct and ``LEQ`` predicate as a dict with ``LEQ`` as the key, and a value to compare against. .. code-block:: python # matches any models with .size <= 10 dict(size={ LEQ: 10 }) ''' pass [docs]class NEQ(_Operator): ''' Predicate to test if property values are unequal to some value. Construct and ``NEQ`` predicate as a dict with ``NEQ`` as the key, and a value to compare against. .. code-block:: python # matches any models with .size != 10 dict(size={ NEQ: 10 }) ''' pass #----------------------------------------------------------------------------- # Private API #----------------------------------------------------------------------------- # realizations of the abstract predicate operators _operators: Dict[Type["_Operator"], Callable[[Any, Any], Any]] = { IN: lambda x, y: x in y, GT: lambda x, y: x > y, LT: lambda x, y: x < y, EQ: lambda x, y: x == y, GEQ: lambda x, y: x >= y, LEQ: lambda x, y: x <= y, NEQ: lambda x, y: x != y, } # realization of the OR operator def _or(obj: Model, selectors: Iterator[SelectorType]) -> bool: return any(match(obj, selector) for selector in selectors) #----------------------------------------------------------------------------- # Code #-----------------------------------------------------------------------------