labthings_fastapi.dependencies.action_manager
=============================================

.. py:module:: labthings_fastapi.dependencies.action_manager

.. autoapi-nested-parse::

   Context Var access to the Action Manager.

   This module provides a context var to access the Action Manager instance.
   While LabThings tries pretty hard to conform to FastAPI's excellent convention
   that everything should be passed as a parameter, there are some cases where
   that's hard. In particular, generating URLs when responses are serialised is
   difficult, because `pydantic` doesn't have a way to access the `fastapi.Request`
   object and use `fastapi.Request.url_for`.

   If an endpoint uses the `.ActionManagerDep` dependency, then the `.ActionManager`
   is supplied as an argument. More usefully, when the output is serialised the
   `.ActionManager` is available using `.ActionManagerContext.get()`.

   This is currently only used by `.Blob` objects, as "serialising" a `.Blob`
   involves adding it to the `.ActionManager` and generating a download URL.



Attributes
----------

.. autoapisummary::

   labthings_fastapi.dependencies.action_manager.ActionManagerDep
   labthings_fastapi.dependencies.action_manager.ActionManagerContext
   labthings_fastapi.dependencies.action_manager.ActionManagerContextDep


Functions
---------

.. autoapisummary::

   labthings_fastapi.dependencies.action_manager.action_manager_from_thing_server
   labthings_fastapi.dependencies.action_manager.make_action_manager_context_available


Module Contents
---------------

.. py:function:: action_manager_from_thing_server(request: fastapi.Request) -> labthings_fastapi.actions.ActionManager

   Retrieve the Action Manager from the Thing Server.

   This is for use as a FastAPI dependency. We use the ``request`` to
   access the `.ThingServer` and thus access the `.ActionManager`.

   :param request: the FastAPI request object. This will be supplied by
       FastAPI when this function is used as a dependency.

   :return: the `.ActionManager` object associated with our `.ThingServer`.


.. py:data:: ActionManagerDep

   A ready-made dependency type for the `ActionManager` object.


.. py:data:: ActionManagerContext

.. py:function:: make_action_manager_context_available(action_manager: ActionManagerDep) -> AsyncGenerator[labthings_fastapi.actions.ActionManager]
   :async:


   Make the Action Manager available in the context variable.

   The action manager may be accessed using `ActionManagerContext.get()` within
   this context manager.

   :param action_manager: The `.ActionManager` object. Note that this is an
       annotated type so it will be supplied automatically when used as a FastAPI
       dependency.

   :yield: the `.ActionManager` object.


.. py:data:: ActionManagerContextDep
   :type:  typing_extensions.TypeAlias