First attempt rest api

Author: marcelldls

pyproject.toml

@@ -12,6 +12,7 @@ classifiers = [
 description = "Control system agnostic framework for building Device support in Python that will work for both EPICS and Tango"
 dependencies = [
     "aioserial",
+    "fastapi[standard]",
     "numpy",
     "pydantic",
     "pvi~=0.10.0",
@@ -43,6 +44,7 @@ dev = [
     "types-mock",
     "aioca",
     "p4p",
+    "httpx",
 ]
 
 [project.scripts]
@@ -61,7 +63,7 @@ version_file = "src/fastcs/_version.py"
 
 [tool.pyright]
 typeCheckingMode = "standard"
-reportMissingImports = false # Ignore missing stubs in imported modules
+reportMissingImports = false  # Ignore missing stubs in imported modules
 
 [tool.pytest.ini_options]
 # Run pytest with all our checkers, and don't spam us with massive tracebacks on error

src/fastcs/backends/rest/__init__.py

@@ -0,0 +1,14 @@
+from fastcs.backend import Backend
+from fastcs.controller import Controller
+
+from .rest import RestServer
+
+
+class RestBackend(Backend):
+    def __init__(self, controller: Controller):
+        super().__init__(controller)
+
+        self._server = RestServer(self._mapping)
+
+    def _run(self):
+        self._server.run()

src/fastcs/backends/rest/backend.py

@@ -0,0 +1,147 @@
+from collections.abc import Awaitable, Callable, Coroutine
+from dataclasses import dataclass
+from types import MethodType
+from typing import Any
+
+import uvicorn
+from fastapi import FastAPI
+from pydantic import create_model
+
+from fastcs.attributes import AttrR, AttrRW, AttrW, T
+from fastcs.controller import BaseController
+from fastcs.mapping import Mapping
+
+
+@dataclass
+class RestServerOptions:
+    host: str = "localhost"
+    port: int = 8080
+    log_level: str = "info"
+
+
+class RestServer:
+    def __init__(self, mapping: Mapping):
+        self._mapping = mapping
+        self._app = self._create_app()
+
+    def _create_app(self):
+        app = FastAPI()
+        _add_dev_attributes(app, self._mapping)
+        _add_dev_commands(app, self._mapping)
+
+        return app
+
+    def run(self, options: RestServerOptions | None = None) -> None:
+        if options is None:
+            options = RestServerOptions()
+
+        uvicorn.run(
+            self._app,
+            host=options.host,
+            port=options.port,
+            log_level=options.log_level,
+        )
+
+
+def _put_request_body(attribute: AttrW[T]):
+    return create_model(
+        f"Put{str(attribute.datatype.dtype)}Value",
+        **{"value": (attribute.datatype.dtype, ...)},  # type: ignore
+    )
+
+
+def _wrap_attr_put(
+    attribute: AttrW[T],
+) -> Callable[[T], Coroutine[Any, Any, None]]:
+    async def attr_set(request):
+        await attribute.process_without_display_update(request.value)
+
+    # Fast api uses type annotations for validation, schema, conversions
+    attr_set.__annotations__["request"] = _put_request_body(attribute)
+
+    return attr_set
+
+
+def _get_response_body(attribute: AttrR[T]):
+    return create_model(
+        f"Get{str(attribute.datatype.dtype)}Value",
+        **{"value": (attribute.datatype.dtype, ...)},  # type: ignore
+    )
+
+
+def _wrap_attr_get(
+    attribute: AttrR[T],
+) -> Callable[[], Coroutine[Any, Any, Any]]:
+    async def attr_get() -> Any:  # Must be any as response_model is set
+        value = attribute.get()  # type: ignore
+        return {"value": value}
+
+    return attr_get
+
+
+def _add_dev_attributes(app: FastAPI, mapping: Mapping) -> None:
+    for single_mapping in mapping.get_controller_mappings():
+        path = single_mapping.controller.path
+
+        for attr_name, attribute in single_mapping.attributes.items():
+            attr_name = attr_name.title().replace("_", "")
+            d_attr_name = f"{'/'.join(path)}/{attr_name}" if path else attr_name
+
+            match attribute:
+                # https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods
+                case AttrRW():
+                    app.add_api_route(
+                        f"/{d_attr_name}",
+                        _wrap_attr_get(attribute),
+                        methods=["GET"],  # Idemponent and safe data retrieval,
+                        status_code=200,  # https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/GET
+                        response_model=_get_response_body(attribute),
+                    )
+                    app.add_api_route(
+                        f"/{d_attr_name}",
+                        _wrap_attr_put(attribute),
+                        methods=["PUT"],  # Idempotent state change
+                        status_code=204,  # https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/PUT
+                    )
+                case AttrR():
+                    app.add_api_route(
+                        f"/{d_attr_name}",
+                        _wrap_attr_get(attribute),
+                        methods=["GET"],
+                        status_code=200,
+                        response_model=_get_response_body(attribute),
+                    )
+                case AttrW():
+                    app.add_api_route(
+                        f"/{d_attr_name}",
+                        _wrap_attr_put(attribute),
+                        methods=["PUT"],
+                        status_code=204,
+                    )
+
+
+def _wrap_command(
+    method: Callable, controller: BaseController
+) -> Callable[..., Awaitable[None]]:
+    async def command() -> None:
+        await MethodType(method, controller)()
+
+    return command
+
+
+def _add_dev_commands(app: FastAPI, mapping: Mapping) -> None:
+    for single_mapping in mapping.get_controller_mappings():
+        path = single_mapping.controller.path
+
+        for name, method in single_mapping.command_methods.items():
+            cmd_name = name.title().replace("_", "")
+            d_cmd_name = f"{'/'.join(path)}/{cmd_name}" if path else cmd_name
+            app.add_api_route(
+                f"/{d_cmd_name}",
+                _wrap_command(
+                    method.fn,
+                    single_mapping.controller,
+                ),
+                methods=["PUT"],
+                status_code=204,
+            )

src/fastcs/backends/rest/rest.py

@@ -0,0 +1,48 @@
+from fastcs.attributes import AttrR
+from fastcs.datatypes import Bool, Float, Int
+
+
+class TestRestServer:
+    def test_read_int(self, rest_client):
+        response = rest_client.get("/ReadInt")
+        assert response.status_code == 200
+        assert response.json() == {"value": AttrR(Int())._value}
+
+    def test_read_write_int(self, rest_client):
+        response = rest_client.get("/ReadWriteInt")
+        assert response.status_code == 200
+        assert response.json() == {"value": AttrR(Int())._value}
+        response = rest_client.put("/ReadWriteInt", json={"value": AttrR(Int())._value})
+        assert response.status_code == 204
+
+    def test_read_write_float(self, rest_client):
+        response = rest_client.get("/ReadWriteFloat")
+        assert response.status_code == 200
+        assert response.json() == {"value": AttrR(Float())._value}
+        response = rest_client.put(
+            "/ReadWriteFloat", json={"value": AttrR(Float())._value}
+        )
+        assert response.status_code == 204
+
+    def test_read_bool(self, rest_client):
+        response = rest_client.get("/ReadBool")
+        assert response.status_code == 200
+        assert response.json() == {"value": AttrR(Bool())._value}
+
+    def test_write_bool(self, rest_client):
+        response = rest_client.put("/WriteBool", json={"value": AttrR(Bool())._value})
+        assert response.status_code == 204
+
+    # # We need to discuss enums
+    # def test_string_enum(self, rest_client):
+
+    def test_big_enum(self, rest_client):
+        response = rest_client.get("/BigEnum")
+        assert response.status_code == 200
+        assert response.json() == {
+            "value": AttrR(Int(), allowed_values=list(range(1, 18)))._value
+        }
+
+    def test_go(self, rest_client):
+        response = rest_client.put("/Go")
+        assert response.status_code == 204

tests/backends/rest/test_rest.py

@@ -8,8 +8,10 @@
 
 import pytest
 from aioca import purge_channel_caches
+from fastapi.testclient import TestClient
 
 from fastcs.attributes import AttrR, AttrRW, AttrW, Handler, Sender, Updater
+from fastcs.backends.rest.backend import RestBackend
 from fastcs.controller import Controller
 from fastcs.datatypes import Bool, Float, Int, String
 from fastcs.mapping import Mapping
@@ -120,3 +122,10 @@ def ioc():
     except ValueError:
         # Someone else already called communicate
         pass
+
+
+@pytest.fixture(scope="class")
+def rest_client():
+    app = RestBackend(TestController())._server._app
+    client = TestClient(app)
+    return client