Move blobs to BlobManager

Blob URLs now start with `blob/` and are easier to generate. Blob
objects are `BaseModel` subclasses that can be serialised/deserialised, using contextvars to generate URLs and retrieve BlobData objects.

This obviates file responses from invocation outputs and also the `invocations/<id>/files`  endpoint

Author: rwb27

src/labthings_fastapi/actions/__init__.py

@@ -9,7 +9,7 @@
 import weakref
 from fastapi import FastAPI, HTTPException, Request
 from fastapi.responses import FileResponse
-from pydantic import BaseModel, RootModel
+from pydantic import BaseModel
 
 from labthings_fastapi.utilities import model_to_dict
 from labthings_fastapi.utilities.introspection import EmptyInput
@@ -176,16 +176,6 @@ def run(self):
 
             action = self.action
             thing = self.thing
-            #kwargs = self.input.model_dump() or {}
-            # if isinstance(self.input, RootModel):
-            #     if self.input.root is not None:
-            #         print(f"confused by {self.input}")
-            #         raise ValueError("RootModel inputs are only used for None")
-            #     kwargs = {}
-            # elif isinstance(self.input, BaseModel):
-            #     kwargs = dict(self.input)
-            # else:
-            #     kwargs = {}
             kwargs = model_to_dict(self.input)
             assert action is not None
             assert thing is not None
@@ -338,7 +328,9 @@ def list_all_invocations(request: Request, _blob_manager: BlobIOContextDep):
             response_model=InvocationModel,
             responses={404: {"description": "Invocation ID not found"}},
         )
-        def action_invocation(id: uuid.UUID, request: Request, _blob_manager: BlobIOContextDep):
+        def action_invocation(
+            id: uuid.UUID, request: Request, _blob_manager: BlobIOContextDep
+        ):
             try:
                 with self._invocations_lock:
                     return self._invocations[id].response(request=request)

src/labthings_fastapi/descriptors/action.py

@@ -20,7 +20,7 @@
     input_model_from_signature,
     return_type,
 )
-from ..outputs.blob import blob_to_model, get_model_media_type
+from ..outputs.blob import BlobIOContextDep
 from ..thing_description import type_to_dataschema
 from ..thing_description.model import ActionAffordance, ActionOp, Form, Union
 
@@ -70,7 +70,7 @@ def __init__(
             remove_first_positional_arg=True,
             ignore=[p.name for p in self.dependency_params],
         )
-        self.output_model = blob_to_model(return_type(func))
+        self.output_model = return_type(func)
         self.invocation_model = create_model(
             f"{self.name}_invocation",
             __base__=InvocationModel,
@@ -165,6 +165,7 @@ def add_to_fastapi(self, app: FastAPI, thing: Thing):
         # the function to the decorator.
         def start_action(
             action_manager: ActionManagerContextDep,
+            _blob_manager: BlobIOContextDep,
             request: Request,
             body,
             id: InvocationID,
@@ -221,8 +222,8 @@ def start_action(
         except AttributeError:
             print(f"Failed to generate response model for action {self.name}")
         # Add an additional media type if we may return a file
-        if get_model_media_type(self.output_model):
-            responses[200]["content"][get_model_media_type(self.output_model)] = {}
+        if hasattr(self.output_model, "media_type"):
+            responses[200]["content"][self.output_model.media_type] = {}
         # Now we can add the endpoint to the app.
         app.post(
             thing.path + self.name,