First implementation of bindings

src/myfasthtml/core/commands.py

@@ -1,14 +1,9 @@
-import logging
 import uuid
 from typing import Optional
 
-from fasthtml.fastapp import fast_app
+from myutils.observable import NotObservableError, ObservableEvent, add_event_listener, remove_event_listener
 
 from myfasthtml.core.constants import Routes, ROUTE_ROOT
-from myfasthtml.core.utils import mount_if_not_exists
-
-commands_app, commands_rt = fast_app()
-logger = logging.getLogger("Commands")
 
 
 class BaseCommand:
@@ -32,18 +27,62 @@ class BaseCommand:
     self.id = uuid.uuid4()
     self.name = name
     self.description = description
+    self._htmx_extra = {}
+    self._bindings = []
     
     # register the command
     CommandsManager.register(self)
   
   def get_htmx_params(self):
-    return {
+    return self._htmx_extra | {
         "hx-post": f"{ROUTE_ROOT}{Routes.Commands}",
         "hx-vals": f'{{"c_id": "{self.id}"}}',
     }
   
   def execute(self):
     raise NotImplementedError
+  
+  def htmx(self, target="this", swap="innerHTML"):
+    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 != "innerHTML":
+      self._htmx_extra["hx-swap"] = swap
+    return self
+  
+  def bind_ft(self, ft):
+    """
+    Update the FT with the command's HTMX parameters.
+
+    :param ft:
+    :return:
+    """
+    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
 
 
 class Command(BaseCommand):
@@ -72,7 +111,26 @@ class Command(BaseCommand):
     self.kwargs = kwargs
   
   def execute(self):
-    return self.callback(*self.args, **self.kwargs)
+    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)
+    
+    ret = self.callback(*self.args, **self.kwargs)
+    
+    for data in self._bindings:
+      remove_event_listener(ObservableEvent.AFTER_PROPERTY_CHANGE, data, "", binding_result_callback)
+    
+    if not ret_from_bindings:
+      return ret
+    
+    if isinstance(ret, list):
+      return ret + ret_from_bindings
+    else:
+      return [ret] + ret_from_bindings
   
   def __str__(self):
     return f"Command({self.name})"
@@ -92,31 +150,3 @@ class CommandsManager:
   @staticmethod
   def reset():
     return CommandsManager.commands.clear()
-
-
-@commands_rt(Routes.Commands)
-def post(session: str, c_id: str):
-  """
-  Default routes for all commands.
-  :param session:
-  :param c_id:
-  :return:
-  """
-  logger.debug(f"Entering {Routes.Commands} with {session=}, {c_id=}")
-  command = CommandsManager.get_command(c_id)
-  if command:
-    return command.execute()
-  
-  raise ValueError(f"Command with ID '{c_id}' not found.")
-
-
-def mount_commands(app):
-  """
-  Mounts the commands_app to the given application instance if the route does not already exist.
-
-  :param app: The application instance to which the commands_app will be mounted.
-  :type app: Any
-  :return: Returns the result of the mount operation performed by mount_if_not_exists.
-  :rtype: Any
-  """
-  return mount_if_not_exists(app, ROUTE_ROOT, commands_app)