Improvements to IPConnection

src/fastcs/connections/ip_connection.py

@@ -1,5 +1,41 @@
 import asyncio
+import codecs
 from dataclasses import dataclass
+from typing import Any, Callable, Coroutine, cast
+
+_AsyncFuncType = Callable[..., Coroutine[Any, Any, Any]]
+
+
+def _with_lock(func: _AsyncFuncType) -> _AsyncFuncType:
+    async def with_lock(*args: Any, **kwargs: Any) -> None:
+        self = args[0]
+        async with self.lock:
+            await func(*args, **kwargs)
+
+    return cast(_AsyncFuncType, with_lock)
+
+
+def _ensure_connected(func: _AsyncFuncType) -> _AsyncFuncType:
+    """
+    Decorator function to check if the wrapper is connected to the device
+    before calling the attached function.
+
+    Args:
+        func: Function to call if connected to device
+
+    Returns:
+        The wrapped function.
+
+    """
+
+    async def check_connected(*args: Any, **kwargs: Any) -> None:
+        self = args[0]
+        if self._reader is None or self._writer is None:
+            raise DisconnectedError("Need to call connect() before using IPConnection.")
+        else:
+            await func(*args, **kwargs)
+
+    return cast(_AsyncFuncType, check_connected)
 
 
 class DisconnectedError(Exception):
@@ -16,39 +52,43 @@
     def __init__(self):
         self._reader, self._writer = (None, None)
         self._lock = asyncio.Lock()
+        self.connected: bool = False
+
+    @property
+    def lock(self) -> asyncio.Lock:
+        return self._lock
 
     async def connect(self, settings: IPConnectionSettings):
         self._reader, self._writer = await asyncio.open_connection(
             settings.ip, settings.port
         )
 
-    def ensure_connected(self):
-        if self._reader is None or self._writer is None:
-            raise DisconnectedError("Need to call connect() before using IPConnection.")
-
-    async def send_command(self, message) -> None:
-        async with self._lock:
-            self.ensure_connected()
-            await self._send_message(message)
+    @_with_lock
+    @_ensure_connected
+    async def send_command(self, message: str) -> None:
+        await self._send_message(message)
 
-    async def send_query(self, message) -> str:
-        async with self._lock:
-            self.ensure_connected()
-            await self._send_message(message)
-            return await self._receive_response()
+    @_with_lock
+    @_ensure_connected
+    async def send_query(self, message: str) -> str:
+        await self._send_message(message)
+        return await self._receive_response()
 
     # TODO: Figure out type hinting for connections. TypeGuard fails to work as expected
+    @_with_lock
+    @_ensure_connected
     async def close(self):
-        async with self._lock:
-            self.ensure_connected()
-            self._writer.close()
-            await self._writer.wait_closed()
-            self._reader, self._writer = (None, None)
-
-    async def _send_message(self, message) -> None:
-        self._writer.write(message.encode("utf-8"))
+        assert isinstance(self._writer, asyncio.StreamWriter)
+        self._writer.close()
+        await self._writer.wait_closed()
+        self._reader, self._writer = (None, None)
+
+    async def _send_message(self, message: str) -> None:
+        assert isinstance(self._writer, asyncio.StreamWriter)
+        self._writer.write(codecs.encode(message, "utf-8"))
         await self._writer.drain()
 
     async def _receive_response(self) -> str:
+        assert isinstance(self._reader, asyncio.StreamReader)
         data = await self._reader.readline()
-        return data.decode("utf-8")
+        return codecs.decode(data, "utf-8")