145 lines
4.7 KiB
Python
145 lines
4.7 KiB
Python
"""Create a list of components from an iterable."""
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from __future__ import annotations
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import inspect
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from typing import Any, Callable, Iterable
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from reflex.components.base.fragment import Fragment
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from reflex.components.component import Component
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from reflex.components.tags import IterTag
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from reflex.constants import MemoizationMode
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from reflex.state import ComponentState
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from reflex.utils import console
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from reflex.vars import Var
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class ForeachVarError(TypeError):
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"""Raised when the iterable type is Any."""
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class ForeachRenderError(TypeError):
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"""Raised when there is an error with the foreach render function."""
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class Foreach(Component):
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"""A component that takes in an iterable and a render function and renders a list of components."""
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_memoization_mode = MemoizationMode(recursive=False)
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# The iterable to create components from.
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iterable: Var[Iterable]
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# A function from the render args to the component.
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render_fn: Callable = Fragment.create
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@classmethod
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def create(
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cls,
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iterable: Var[Iterable] | Iterable,
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render_fn: Callable,
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**props,
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) -> Foreach:
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"""Create a foreach component.
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Args:
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iterable: The iterable to create components from.
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render_fn: A function from the render args to the component.
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**props: The attributes to pass to each child component (deprecated).
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Returns:
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The foreach component.
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Raises:
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ForeachVarError: If the iterable is of type Any.
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TypeError: If the render function is a ComponentState.
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"""
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if props:
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console.deprecate(
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feature_name="Passing props to rx.foreach",
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reason="it does not have the intended effect and may be confusing",
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deprecation_version="0.5.0",
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removal_version="0.6.0",
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)
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iterable = Var.create_safe(iterable, _var_is_string=False)
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if iterable._var_type == Any:
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raise ForeachVarError(
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f"Could not foreach over var `{iterable._var_full_name}` of type Any. "
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"(If you are trying to foreach over a state var, add a type annotation to the var). "
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"See https://reflex.dev/docs/library/layout/foreach/"
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)
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if (
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hasattr(render_fn, "__qualname__")
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and render_fn.__qualname__ == ComponentState.create.__qualname__
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):
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raise TypeError(
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"Using a ComponentState as `render_fn` inside `rx.foreach` is not supported yet."
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)
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component = cls(
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iterable=iterable,
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render_fn=render_fn,
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)
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# Keep a ref to a rendered component to determine correct imports/hooks/styles.
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component.children = [component._render().render_component()]
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return component
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def _render(self) -> IterTag:
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props = {}
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render_sig = inspect.signature(self.render_fn)
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params = list(render_sig.parameters.values())
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# Validate the render function signature.
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if len(params) == 0 or len(params) > 2:
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raise ForeachRenderError(
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"Expected 1 or 2 parameters in foreach render function, got "
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f"{[p.name for p in params]}. See https://reflex.dev/docs/library/layout/foreach/"
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)
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if len(params) >= 1:
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# Determine the arg var name based on the params accepted by render_fn.
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props["arg_var_name"] = params[0].name
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if len(params) == 2:
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# Determine the index var name based on the params accepted by render_fn.
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props["index_var_name"] = params[1].name
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else:
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# Otherwise, use a deterministic index, based on the render function bytecode.
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code_hash = (
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hash(self.render_fn.__code__)
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.to_bytes(
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length=8,
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byteorder="big",
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signed=True,
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)
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.hex()
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)
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props["index_var_name"] = f"index_{code_hash}"
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return IterTag(
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iterable=self.iterable,
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render_fn=self.render_fn,
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children=self.children,
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**props,
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)
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def render(self):
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"""Render the component.
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Returns:
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The dictionary for template of component.
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"""
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tag = self._render()
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return dict(
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tag,
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iterable_state=tag.iterable._var_full_name,
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arg_name=tag.arg_var_name,
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arg_index=tag.get_index_var_arg(),
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iterable_type=tag.iterable._var_type.mro()[0].__name__,
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)
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foreach = Foreach.create
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