Files
MyFastHtml/src/myfasthtml/core/commands.py

224 lines
6.7 KiB
Python

import inspect
import json
import uuid
from typing import Optional
from myutils.observable import NotObservableError, ObservableEvent, add_event_listener, remove_event_listener
from myfasthtml.core.constants import Routes, ROUTE_ROOT
class BaseCommand:
"""
Represents the base command class for defining executable actions.
This class serves as a foundation for commands that can be registered,
executed, and utilized within a system. Each command has a unique identifier,
a name, and a description. Commands should override the `execute` method
to provide specific functionality.
:ivar id: A unique identifier for the command.
:type id: uuid.UUID
:ivar name: The name of the command.
:type name: str
:ivar description: A brief description of the command's functionality.
:type description: str
"""
def __init__(self, name, description):
self.id = uuid.uuid4()
self.name = name
self.description = description
self._htmx_extra = {}
self._bindings = []
self._ft = None
# register the command
CommandsManager.register(self)
def get_htmx_params(self):
return {
"hx-post": f"{ROUTE_ROOT}{Routes.Commands}",
"hx-swap": "outerHTML",
"hx-vals": {"c_id": f"{self.id}"},
} | self._htmx_extra
def execute(self, client_response: dict = None):
raise NotImplementedError
def htmx(self, target: Optional[str] = "this", swap="outerHTML", trigger=None):
# Note that the default value is the same than in get_htmx_params()
if target is None:
self._htmx_extra["hx-swap"] = "none"
elif target != "this":
self._htmx_extra["hx-target"] = target
if swap is None:
self._htmx_extra["hx-swap"] = "none"
elif swap != "outerHTML":
self._htmx_extra["hx-swap"] = swap
if trigger is not None:
self._htmx_extra["hx-trigger"] = trigger
return self
def bind_ft(self, ft):
"""
Update the FT with the command's HTMX parameters.
:param ft:
:return:
"""
self._ft = ft
htmx = self.get_htmx_params()
ft.attrs |= htmx
return ft
def bind(self, data):
"""
Attach a binding to the command.
When done, if a binding is triggered during the execution of the command,
the results of the binding will be passed to the command's execute() method.
:param data:
:return:
"""
if not hasattr(data, '_listeners'):
raise NotObservableError(
f"Object must be made observable with make_observable() before binding"
)
self._bindings.append(data)
# by default, remove the swap on the attached element when binding is used
self._htmx_extra["hx-swap"] = "none"
return self
@property
def url(self):
return f"{ROUTE_ROOT}{Routes.Commands}?c_id={self.id}"
def ajax_htmx_options(self):
return {
"url": self.url,
"target": self._htmx_extra.get("hx-target", "this"),
"swap": self._htmx_extra.get("hx-swap", "outerHTML"),
"values": {}
}
def get_ft(self):
return self._ft
def __str__(self):
return f"Command({self.name})"
class Command(BaseCommand):
"""
Represents a command that encapsulates a callable action with parameters.
This class is designed to hold a defined action (callback) alongside its arguments
and keyword arguments.
:ivar name: The name of the command.
:type name: str
:ivar description: A brief description of the command.
:type description: str
:ivar callback: The function or callable to be executed.
:type callback: Callable
:ivar args: Positional arguments to be passed to the callback.
:type args: tuple
:ivar kwargs: Keyword arguments to be passed to the callback.
:type kwargs: dict
"""
def __init__(self, name, description, callback, *args, **kwargs):
super().__init__(name, description)
self.callback = callback
self.callback_parameters = dict(inspect.signature(callback).parameters) if callback else {}
self.args = args
self.kwargs = kwargs
def _convert(self, key, value):
if key in self.callback_parameters:
param = self.callback_parameters[key]
if param.annotation == bool:
return value == "true"
elif param.annotation == int:
return int(value)
elif param.annotation == float:
return float(value)
elif param.annotation == list:
return value.split(",")
elif param.annotation == dict:
return json.loads(value)
return value
def ajax_htmx_options(self):
res = super().ajax_htmx_options()
if self.kwargs:
res["values"] |= self.kwargs
res["values"]["c_id"] = f"{self.id}" # cannot be overridden
return res
def execute(self, client_response: dict = None):
ret_from_bindings = []
def binding_result_callback(attr, old, new, results):
ret_from_bindings.extend(results)
for data in self._bindings:
add_event_listener(ObservableEvent.AFTER_PROPERTY_CHANGE, data, "", binding_result_callback)
new_kwargs = self.kwargs.copy()
if client_response:
for k, v in client_response.items():
if k in self.callback_parameters:
new_kwargs[k] = self._convert(k, v)
if 'client_response' in self.callback_parameters:
new_kwargs['client_response'] = client_response
ret = self.callback(*self.args, **new_kwargs)
for data in self._bindings:
remove_event_listener(ObservableEvent.AFTER_PROPERTY_CHANGE, data, "", binding_result_callback)
# Set the hx-swap-oob attribute on all elements returned by the callback
if isinstance(ret, (list, tuple)):
for r in ret[1:]:
if hasattr(r, 'attrs') and r.get("id", None) is not None:
r.attrs["hx-swap-oob"] = r.attrs.get("hx-swap-oob", "true")
if not ret_from_bindings:
return ret
if isinstance(ret, (list, tuple)):
return list(ret) + ret_from_bindings
else:
return [ret] + ret_from_bindings
class LambdaCommand(Command):
def __init__(self, delegate, name="LambdaCommand", description="Lambda Command"):
super().__init__(name, description, delegate)
self.htmx(target=None)
def execute(self, client_response: dict = None):
return self.callback(client_response)
class CommandsManager:
commands = {}
@staticmethod
def register(command: BaseCommand):
CommandsManager.commands[str(command.id)] = command
@staticmethod
def get_command(command_id: str) -> Optional[BaseCommand]:
return CommandsManager.commands.get(command_id)
@staticmethod
def reset():
return CommandsManager.commands.clear()