from __future__ import annotations
import inspect
import re
import weakref
from copy import copy
from pathlib import Path
from typing import TYPE_CHECKING, Any, Callable, ClassVar, Dict, Iterator, List, Optional, Sequence, Union, cast
from typing_extensions import Self
from . import core, events, helpers, json, storage
from .awaitable_response import AwaitableResponse, NullResponse
from .classes import Classes
from .context import context
from .dependencies import (
Component,
Library,
register_dynamic_resource,
register_library,
register_resource,
register_vue_component,
)
from .elements.mixins.visibility import Visibility
from .event_listener import EventListener
from .props import Props
from .slot import Slot
from .style import Style
from .tailwind import Tailwind
from .version import __version__
if TYPE_CHECKING:
from .client import Client
# https://www.w3.org/TR/xml/#sec-common-syn
TAG_START_CHAR = r':|[A-Z]|_|[a-z]|[\u00C0-\u00D6]|[\u00D8-\u00F6]|[\u00F8-\u02FF]|[\u0370-\u037D]|[\u037F-\u1FFF]|[\u200C-\u200D]|[\u2070-\u218F]|[\u2C00-\u2FEF]|[\u3001-\uD7FF]|[\uF900-\uFDCF]|[\uFDF0-\uFFFD]|[\U00010000-\U000EFFFF]'
TAG_CHAR = TAG_START_CHAR + r'|-|\.|[0-9]|\u00B7|[\u0300-\u036F]|[\u203F-\u2040]'
TAG_PATTERN = re.compile(fr'^({TAG_START_CHAR})({TAG_CHAR})*$')
class Element(Visibility):
component: Optional[Component] = None
libraries: ClassVar[List[Library]] = []
extra_libraries: ClassVar[List[Library]] = []
exposed_libraries: ClassVar[List[Library]] = []
_default_props: ClassVar[Dict[str, Any]] = {}
_default_classes: ClassVar[List[str]] = []
_default_style: ClassVar[Dict[str, str]] = {}
def __init__(self, tag: Optional[str] = None, *, _client: Optional[Client] = None) -> None:
"""Generic Element
This class is the base class for all other UI elements.
But you can use it to create elements with arbitrary HTML tags.
:param tag: HTML tag of the element
:param _client: client for this element (for internal use only)
"""
super().__init__()
client = _client or context.client
self._client = weakref.ref(client)
self.id = client.next_element_id
client.next_element_id += 1
self.tag = tag if tag else self.component.tag if self.component else 'div'
if not TAG_PATTERN.match(self.tag):
raise ValueError(f'Invalid HTML tag: {self.tag}')
self._classes: Classes[Self] = Classes(self._default_classes, element=cast(Self, self))
self._style: Style[Self] = Style(self._default_style, element=cast(Self, self))
self._props: Props[Self] = Props(self._default_props, element=cast(Self, self))
self._markers: List[str] = []
self._event_listeners: Dict[str, EventListener] = {}
self._text: Optional[str] = None
self.slots: Dict[str, Slot] = {}
self.default_slot = self.add_slot('default')
self._update_method: Optional[str] = None
self._deleted: bool = False
client.elements[self.id] = self
self.parent_slot: Optional[Slot] = None
slot_stack = context.slot_stack
if slot_stack:
self.parent_slot = slot_stack[-1]
self.parent_slot.children.append(self)
self.tailwind = Tailwind(self)
client.outbox.enqueue_update(self)
if self.parent_slot:
client.outbox.enqueue_update(self.parent_slot.parent)
def __init_subclass__(cls, *,
component: Union[str, Path, None] = None,
dependencies: List[Union[str, Path]] = [], # noqa: B006
libraries: List[Union[str, Path]] = [], # noqa: B006 # DEPRECATED
exposed_libraries: List[Union[str, Path]] = [], # noqa: B006 # DEPRECATED
extra_libraries: List[Union[str, Path]] = [], # noqa: B006 # DEPRECATED
default_classes: Optional[str] = None,
default_style: Optional[str] = None,
default_props: Optional[str] = None,
) -> None:
super().__init_subclass__()
base = Path(inspect.getfile(cls)).parent
def glob_absolute_paths(file: Union[str, Path]) -> List[Path]:
path = Path(file)
if not path.is_absolute():
path = base / path
return sorted(path.parent.glob(path.name), key=lambda p: p.stem)
if libraries:
helpers.warn_once(f'The `libraries` parameter for subclassing "{cls.__name__}" is deprecated. '
'It will be removed in NiceGUI 3.0. '
'Use `dependencies` instead.')
if exposed_libraries:
helpers.warn_once(f'The `exposed_libraries` parameter for subclassing "{cls.__name__}" is deprecated. '
'It will be removed in NiceGUI 3.0. '
'Use `dependencies` instead.')
if extra_libraries:
helpers.warn_once(f'The `extra_libraries` parameter for subclassing "{cls.__name__}" is deprecated. '
'It will be removed in NiceGUI 3.0. '
'Use `dependencies` instead.')
cls.component = copy(cls.component)
cls.libraries = copy(cls.libraries)
cls.extra_libraries = copy(cls.extra_libraries)
cls.exposed_libraries = copy(cls.exposed_libraries)
if component:
max_time = max((path.stat().st_mtime for path in glob_absolute_paths(component)), default=None)
for path in glob_absolute_paths(component):
cls.component = register_vue_component(path, max_time=max_time)
for library in libraries:
max_time = max((path.stat().st_mtime for path in glob_absolute_paths(library)), default=None)
for path in glob_absolute_paths(library):
cls.libraries.append(register_library(path, max_time=max_time))
for library in extra_libraries:
max_time = max((path.stat().st_mtime for path in glob_absolute_paths(library)), default=None)
for path in glob_absolute_paths(library):
cls.extra_libraries.append(register_library(path, max_time=max_time))
for library in exposed_libraries + dependencies:
max_time = max((path.stat().st_mtime for path in glob_absolute_paths(library)), default=None)
for path in glob_absolute_paths(library):
cls.exposed_libraries.append(register_library(path, expose=True, max_time=max_time))
cls._default_props = copy(cls._default_props)
cls._default_classes = copy(cls._default_classes)
cls._default_style = copy(cls._default_style)
cls.default_classes(default_classes)
cls.default_style(default_style)
cls.default_props(default_props)
@property
def client(self) -> Client:
"""The client this element belongs to."""
client = self._client()
if client is None:
raise RuntimeError('The client this element belongs to has been deleted.')
return client
def add_resource(self, path: Union[str, Path]) -> None:
"""Add a resource to the element.
:param path: path to the resource (e.g. folder with CSS and JavaScript files)
"""
path_ = Path(path)
resource = register_resource(path_, max_time=path_.stat().st_mtime)
self._props['resource_path'] = f'/_nicegui/{__version__}/resources/{resource.key}'
def add_dynamic_resource(self, name: str, function: Callable) -> None:
"""Add a dynamic resource to the element which returns the result of a function.
:param name: name of the resource
:param function: function that returns the resource response
"""
register_dynamic_resource(name, function)
self._props['dynamic_resource_path'] = f'/_nicegui/{__version__}/dynamic_resources'
def add_slot(self, name: str, template: Optional[str] = None) -> Slot:
"""Add a slot to the element.
NiceGUI is using the slot concept from Vue:
Elements can have multiple slots, each possibly with a number of children.
Most elements only have one slot, e.g. a `ui.card` (QCard) only has a default slot.
But more complex elements like `ui.table` (QTable) can have more slots like "header", "body" and so on.
If you nest NiceGUI elements via with `ui.row(): ...` you place new elements inside of the row's default slot.
But if you use with `table.add_slot(...): ...`, you enter a different slot.
The slot stack helps NiceGUI to keep track of which slot is currently used for new elements.
The `parent` field holds a reference to its element.
Whenever an element is entered via a `with` expression, its default slot is automatically entered as well.
:param name: name of the slot
:param template: Vue template of the slot
:return: the slot
"""
self.slots[name] = Slot(self, name, template)
return self.slots[name]
def __enter__(self) -> Self:
self.default_slot.__enter__()
return self
def __exit__(self, *_) -> None:
self.default_slot.__exit__(*_)
def __iter__(self) -> Iterator[Element]:
for slot in self.slots.values():
yield from slot
def _collect_slot_dict(self) -> Dict[str, Any]:
return {
name: {
'ids': [child.id for child in slot],
**({'template': slot.template} if slot.template is not None else {}),
}
for name, slot in self.slots.items()
if slot != self.default_slot
}
def _to_dict(self) -> Dict[str, Any]:
return {
'tag': self.tag,
**({'text': self._text} if self._text is not None else {}),
**{
key: value
for key, value in {
'class': self._classes,
'style': self._style,
'props': self._props,
'slots': self._collect_slot_dict(),
'children': [child.id for child in self.default_slot.children],
'events': [listener.to_dict() for listener in self._event_listeners.values()],
'update_method': self._update_method,
'component': {
'key': self.component.key,
'name': self.component.name,
'tag': self.component.tag
} if self.component else None,
'libraries': [
{
'key': library.key,
'name': library.name,
} for library in self.libraries
],
}.items()
if value
},
}
@property
def classes(self) -> Classes[Self]:
"""The classes of the element."""
return self._classes
@classmethod
def default_classes(cls,
add: Optional[str] = None, *,
remove: Optional[str] = None,
toggle: Optional[str] = None,
replace: Optional[str] = None) -> type[Self]:
"""Apply, remove, toggle, or replace default HTML classes.
This allows modifying the look of the element or its layout using `Tailwind `_ or `Quasar `_ classes.
Removing or replacing classes can be helpful if predefined classes are not desired.
All elements of this class will share these HTML classes.
These must be defined before element instantiation.
:param add: whitespace-delimited string of classes
:param remove: whitespace-delimited string of classes to remove from the element
:param toggle: whitespace-delimited string of classes to toggle (*added in version 2.7.0*)
:param replace: whitespace-delimited string of classes to use instead of existing ones
"""
cls._default_classes = Classes.update_list(cls._default_classes, add, remove, toggle, replace)
return cls
@property
def style(self) -> Style[Self]:
"""The style of the element."""
return self._style
@classmethod
def default_style(cls,
add: Optional[str] = None, *,
remove: Optional[str] = None,
replace: Optional[str] = None) -> type[Self]:
"""Apply, remove, or replace default CSS definitions.
Removing or replacing styles can be helpful if the predefined style is not desired.
All elements of this class will share these CSS definitions.
These must be defined before element instantiation.
:param add: semicolon-separated list of styles to add to the element
:param remove: semicolon-separated list of styles to remove from the element
:param replace: semicolon-separated list of styles to use instead of existing ones
"""
if replace is not None:
cls._default_style.clear()
for key in Style.parse(remove):
cls._default_style.pop(key, None)
cls._default_style.update(Style.parse(add))
cls._default_style.update(Style.parse(replace))
return cls
@property
def props(self) -> Props[Self]:
"""The props of the element."""
return self._props
@classmethod
def default_props(cls,
add: Optional[str] = None, *,
remove: Optional[str] = None) -> type[Self]:
"""Add or remove default props.
This allows modifying the look of the element or its layout using `Quasar `_ props.
Since props are simply applied as HTML attributes, they can be used with any HTML element.
All elements of this class will share these props.
These must be defined before element instantiation.
Boolean properties are assumed ``True`` if no value is specified.
:param add: whitespace-delimited list of either boolean values or key=value pair to add
:param remove: whitespace-delimited list of property keys to remove
"""
for key in Props.parse(remove):
if key in cls._default_props:
del cls._default_props[key]
for key, value in Props.parse(add).items():
cls._default_props[key] = value
return cls
def mark(self, *markers: str) -> Self:
"""Replace markers of the element.
Markers are used to identify elements for querying with `ElementFilter `_
which is heavily used in testing
but can also be used to reduce the number of global variables or passing around dependencies.
:param markers: list of strings or single string with whitespace-delimited markers; replaces existing markers
"""
self._markers = [word for marker in markers for word in marker.split()]
return self
def tooltip(self, text: str) -> Self:
"""Add a tooltip to the element.
:param text: text of the tooltip
"""
from .elements.tooltip import Tooltip # pylint: disable=import-outside-toplevel, cyclic-import
with self:
Tooltip(text)
return self
def on(self,
type: str, # pylint: disable=redefined-builtin
handler: Optional[events.Handler[events.GenericEventArguments]] = None,
args: Union[None, Sequence[str], Sequence[Optional[Sequence[str]]]] = None,
*,
throttle: float = 0.0,
leading_events: bool = True,
trailing_events: bool = True,
js_handler: Optional[str] = '(...args) => emit(...args)', # DEPRECATED: None will be removed in version 3.0
) -> Self:
"""Subscribe to an event.
The event handler can be a Python function, a JavaScript function or a combination of both:
- If you want to handle the event on the server with all (serializable) event arguments,
use a Python ``handler``.
- If you want to handle the event on the client side without emitting anything to the server,
use ``js_handler`` with a JavaScript function handling the event.
- If you want to handle the event on the server with a subset or transformed version of the event arguments,
use ``js_handler`` with a JavaScript function emitting the transformed arguments using ``emit()``, and
use a Python ``handler`` to handle these arguments on the server side.
The ``js_handler`` can also decide to selectively emit arguments to the server,
in which case the Python ``handler`` will not always be called.
Note that the arguments ``throttle``, ``leading_events``, and ``trailing_events`` are only relevant
when emitting events to the server.
*Updated in version 2.18.0: Both handlers can be specified at the same time.*
:param type: name of the event (e.g. "click", "mousedown", or "update:model-value")
:param handler: callback that is called upon occurrence of the event
:param args: arguments included in the event message sent to the event handler (default: ``None`` meaning all)
:param throttle: minimum time (in seconds) between event occurrences (default: 0.0)
:param leading_events: whether to trigger the event handler immediately upon the first event occurrence (default: ``True``)
:param trailing_events: whether to trigger the event handler after the last event occurrence (default: ``True``)
:param js_handler: JavaScript function that is handling the event on the client (default: "(...args) => emit(...args)")
"""
if js_handler is None:
helpers.warn_once('Passing `js_handler=None` to `on()` is deprecated. '
'Use the default "(...args) => emit(...args)" instead or remove the parameter.')
if js_handler == '(...args) => emit(...args)':
js_handler = None
if handler or js_handler:
listener = EventListener(
element_id=self.id,
type=helpers.event_type_to_camel_case(type),
args=[args] if args and isinstance(args[0], str) else args, # type: ignore
handler=handler,
js_handler=js_handler,
throttle=throttle,
leading_events=leading_events,
trailing_events=trailing_events,
request=storage.request_contextvar.get(),
)
self._event_listeners[listener.id] = listener
self.update()
return self
def _handle_event(self, msg: Dict) -> None:
listener = self._event_listeners[msg['listener_id']]
storage.request_contextvar.set(listener.request)
args = events.GenericEventArguments(sender=self, client=self.client, args=msg['args'])
events.handle_event(listener.handler, args)
def update(self) -> None:
"""Update the element on the client side."""
if self.is_deleted:
return
self.client.outbox.enqueue_update(self)
def run_method(self, name: str, *args: Any, timeout: float = 1) -> AwaitableResponse:
"""Run a method on the client side.
If the function is awaited, the result of the method call is returned.
Otherwise, the method is executed without waiting for a response.
:param name: name of the method
:param args: arguments to pass to the method
:param timeout: maximum time to wait for a response (default: 1 second)
"""
if not core.loop:
return NullResponse()
return self.client.run_javascript(f'return runMethod({self.id}, "{name}", {json.dumps(args)})', timeout=timeout)
def get_computed_prop(self, prop_name: str, *, timeout: float = 1) -> AwaitableResponse:
"""Return a computed property.
This function should be awaited so that the computed property is properly returned.
:param prop_name: name of the computed prop
:param timeout: maximum time to wait for a response (default: 1 second)
"""
if not core.loop:
return NullResponse()
return self.client.run_javascript(f'return getComputedProp({self.id}, "{prop_name}")', timeout=timeout)
def ancestors(self, *, include_self: bool = False) -> Iterator[Element]:
"""Iterate over the ancestors of the element.
:param include_self: whether to include the element itself in the iteration
"""
if include_self:
yield self
if self.parent_slot:
yield from self.parent_slot.parent.ancestors(include_self=True)
def descendants(self, *, include_self: bool = False) -> Iterator[Element]:
"""Iterate over the descendants of the element.
:param include_self: whether to include the element itself in the iteration
"""
if include_self:
yield self
for child in self:
yield from child.descendants(include_self=True)
def clear(self) -> None:
"""Remove all child elements."""
self.client.remove_elements(self.descendants())
for slot in self.slots.values():
slot.children.clear()
self.update()
def move(self,
target_container: Optional[Element] = None,
target_index: int = -1, *,
target_slot: Optional[str] = None) -> None:
"""Move the element to another container.
:param target_container: container to move the element to (default: the parent container)
:param target_index: index within the target slot (default: append to the end)
:param target_slot: slot within the target container (default: default slot)
"""
assert self.parent_slot is not None
self.parent_slot.children.remove(self)
self.parent_slot.parent.update()
target_container = target_container or self.parent_slot.parent
if target_slot is None:
self.parent_slot = target_container.default_slot
elif target_slot in target_container.slots:
self.parent_slot = target_container.slots[target_slot]
else:
raise ValueError(f'Slot "{target_slot}" does not exist in the target container. '
f'Add it first using `add_slot("{target_slot}")`.')
target_index = target_index if target_index >= 0 else len(self.parent_slot.children)
self.parent_slot.children.insert(target_index, self)
target_container.update()
def remove(self, element: Union[Element, int]) -> None:
"""Remove a child element.
:param element: either the element instance or its ID
"""
if isinstance(element, int):
children = list(self)
element = children[element]
self.client.remove_elements(element.descendants(include_self=True))
assert element.parent_slot is not None
element.parent_slot.children.remove(element)
self.update()
def delete(self) -> None:
"""Delete the element and all its children."""
assert self.parent_slot is not None
self.parent_slot.parent.remove(self)
def _handle_delete(self) -> None:
"""Called when the element is deleted.
This method can be overridden in subclasses to perform cleanup tasks.
"""
@property
def is_deleted(self) -> bool:
"""Whether the element has been deleted."""
return self._deleted
def __str__(self) -> str:
result = self.tag if type(self) is Element else self.__class__.__name__ # pylint: disable=unidiomatic-typecheck
def shorten(content: Any, length: int = 20) -> str:
text = str(content).replace('\n', ' ').replace('\r', ' ')
return text[:length].strip() + '...' if len(text) > length else text
additions = []
if self._markers:
additions.append(f'markers={", ".join(self._markers)}')
if self._text:
additions.append(f'text={shorten(self._text)}')
if hasattr(self, 'content') and self.content: # pylint: disable=no-member
additions.append(f'content={shorten(self.content)}') # pylint: disable=no-member
IGNORED_PROPS = {'loopback', 'color', 'view', 'innerHTML', 'dynamic_resource_path'}
additions += [
f'{key}={shorten(value)}'
for key, value in self._props.items()
if not key.startswith('_') and key not in IGNORED_PROPS and value
]
if not self.visible:
additions.append(f'visible={self.visible}')
if additions:
result += f' [{", ".join(additions)}]'
for child in self.default_slot.children:
for line in str(child).split('\n'):
result += f'\n {line}'
return result
@property
def html_id(self) -> str:
"""The ID of the element in the HTML DOM.
*Added in version 2.16.0*
"""
return f'c{self.id}'