Implement client goodbye in client

flapi/__comms.py

@@ -20,6 +20,7 @@
     FlapiServerError,
     FlapiClientError,
     FlapiServerExit,
+    FlapiClientExit,
 )
 
 
@@ -78,7 +79,7 @@ def handle_received_message(msg: bytes) -> Optional[bytes]:
     if remaining_msg[2] == MessageType.CLIENT_GOODBYE:
         code = int(b64decode(remaining_msg[3:]).decode())
         log.info(f"Received exit command with code {code}")
-        raise SystemExit(code)
+        raise FlapiClientExit(code)
 
     # Handle server disconnect
     if remaining_msg[2] == MessageType.SERVER_GOODBYE:
@@ -154,10 +155,8 @@ def receive_message() -> bytes:
 
 def hello() -> bool:
     """
-    Send a heartbeat message to FL Studio, and check whether we receive another
-    heartbeat in response.
-
-    If no data is received, this function returns `False`.
+    Send a "client hello" message to FL Studio to attempt to establish a
+    connection.
     """
     client_id = get_context().client_id
     log.debug(f"Attempt hello with {client_id=}")
@@ -179,6 +178,32 @@ def hello() -> bool:
         return False
 
 
+def client_goodbye(code: int) -> None:
+    """
+    Send a "client goodbye" message to FL Studio to close the connection.
+    """
+    client_id = get_context().client_id
+    log.debug(f"Attempt hello with {client_id=}")
+    assert client_id is not None
+    send_msg(
+        consts.SYSEX_HEADER
+        + bytes([
+            MessageOrigin.CLIENT,
+            client_id,
+            MessageType.CLIENT_GOODBYE,
+        ])
+        + b64encode(str(code).encode())
+    )
+    try:
+        res = receive_message()
+        # We should never reach this point, as receiving the message should
+        # have raised a SystemExit
+        log.critical(f"Failed to SystemExit -- instead received message {res}")
+        assert False
+    except FlapiClientExit:
+        return
+
+
 def version_query() -> tuple[int, int, int]:
     """
     Query and return the version of Flapi installed to FL Studio.

flapi/__enable.py

@@ -10,7 +10,13 @@
 from mido.ports import BaseOutput, BaseInput  # type: ignore
 from . import _consts as consts
 from .__context import set_context, get_context, pop_context, FlapiContext
-from .__comms import fl_exec, hello, version_query, poll_for_message
+from .__comms import (
+    fl_exec,
+    hello,
+    version_query,
+    poll_for_message,
+    client_goodbye,
+)
 from .__decorate import restore_original_functions, add_wrappers
 from .errors import FlapiPortError, FlapiConnectionError, FlapiVersionError
 
@@ -183,12 +189,20 @@ def version_check():
     # If we reach this point, the versions match
 
 
-def disable():
+def disable(code: int = 0):
     """
-    Disable Flapi, closing its MIDI ports and its connection to FL Studio
+    Disable Flapi, closing its MIDI ports and its connection to FL Studio.
 
     This restores the original functions for the FL Studio API.
+
+    ## Args
+
+    * `code` (`int`, optional): the exit code to relay to the server. Defaults
+      to `0`.
     """
+    # Send a client goodbye
+    client_goodbye(code)
+
     # Close all the ports
     ctx = pop_context()
     ctx.req_port.close()

flapi/cli/repl.py

@@ -137,6 +137,7 @@ def start_server_shell():
             line = input(">>> " if not len(lines) else "... ")
         except KeyboardInterrupt:
             if last_was_interrupted:
+                disable()
                 exit()
             else:
                 print("\nKeyboard interrupt. Press again to quit")

flapi/errors.py

@@ -91,6 +91,15 @@ def __init__(self) -> None:
         )
 
 
+class FlapiClientExit(SystemExit):
+    """
+    The flapi client requested to exit
+    """
+
+    def __init__(self, code: int) -> None:
+        super().__init__(code)
+
+
 class FlapiClientError(Exception):
     """
     An unexpected error occurred on the client side.