Add param to raise error on Unexpected terminator (#31)

* add param to raise error on Unexpected terminator
* add new exceptions

rcon/exceptions.py

@@ -27,3 +27,7 @@ class UserAbort(Exception):
 
 class WrongPassword(Exception):
     """Indicates a wrong password."""
+
+
+class UnexpectedTerminator(Exception):
+    """Indicates an unexpected terminator in the response."""

rcon/source/async_rcon.py

@@ -23,12 +23,13 @@ async def communicate(
     *,
     frag_threshold: int = 4096,
     frag_detect_cmd: str = "",
+    raise_unexpected_terminator: bool = False,
 ) -> Packet:
     """Make an asynchronous request."""
 
     writer.write(bytes(packet))
     await writer.drain()
-    response = await Packet.aread(reader)
+    response = await Packet.aread(reader, raise_unexpected_terminator)
 
     if len(response.payload) < frag_threshold:
         return response
@@ -36,7 +37,7 @@ async def communicate(
     writer.write(bytes(Packet.make_command(frag_detect_cmd)))
     await writer.drain()
 
-    while (successor := await Packet.aread(reader)).id == response.id:
+    while (successor := await Packet.aread(reader, raise_unexpected_terminator)).id == response.id:
         response += successor
 
     return response
@@ -53,6 +54,7 @@ async def rcon(
     frag_detect_cmd: str = "",
     timeout: int | None = None,
     enforce_id: bool = True,
+    raise_unexpected_terminator: bool = False,
 ) -> str:
     """Run a command asynchronously."""
 
@@ -68,14 +70,14 @@ async def rcon(
     # Wait for SERVERDATA_AUTH_RESPONSE according to:
     # https://developer.valvesoftware.com/wiki/Source_RCON_Protocol
     while response.type != Type.SERVERDATA_AUTH_RESPONSE:
-        response = await Packet.aread(reader)
+        response = await Packet.aread(reader, raise_unexpected_terminator)
 
     if response.id == -1:
         await close(writer)
         raise WrongPassword()
 
     request = Packet.make_command(command, *arguments, encoding=encoding)
-    response = await communicate(reader, writer, request)
+    response = await communicate(reader, writer, request, raise_unexpected_terminator)
     await close(writer)
 
     if enforce_id and response.id != request.id:

rcon/source/client.py

@@ -6,7 +6,6 @@ from rcon.client import BaseClient
 from rcon.exceptions import SessionTimeout, WrongPassword
 from rcon.source.proto import Packet, Type
 
-
 __all__ = ["Client"]
 
 
@@ -25,20 +24,22 @@ class Client(BaseClient, socket_type=SOCK_STREAM):
         self.frag_threshold = frag_threshold
         self.frag_detect_cmd = frag_detect_cmd
 
-    def communicate(self, packet: Packet) -> Packet:
+    def communicate(
+        self, packet: Packet, raise_unexpected_terminator: bool = False
+    ) -> Packet:
         """Send and receive a packet."""
         self.send(packet)
-        return self.read()
+        return self.read(raise_unexpected_terminator)
 
     def send(self, packet: Packet) -> None:
         """Send a packet to the server."""
         with self._socket.makefile("wb") as file:
             file.write(bytes(packet))
 
-    def read(self) -> Packet:
+    def read(self, raise_unexpected_terminator: bool = False) -> Packet:
         """Read a packet from the server."""
         with self._socket.makefile("rb") as file:
-            response = Packet.read(file)
+            response = Packet.read(file, raise_unexpected_terminator)
 
             if len(response.payload) < self.frag_threshold:
                 return response
@@ -65,11 +66,16 @@ class Client(BaseClient, socket_type=SOCK_STREAM):
         return True
 
     def run(
-        self, command: str, *args: str, encoding: str = "utf-8", enforce_id: bool = True
+        self,
+        command: str,
+        *args: str,
+        encoding: str = "utf-8",
+        enforce_id: bool = True,
+        raise_unexpected_terminator: bool = False,
     ) -> str:
         """Run a command."""
         request = Packet.make_command(command, *args, encoding=encoding)
-        response = self.communicate(request)
+        response = self.communicate(request, raise_unexpected_terminator)
 
         if enforce_id and response.id != request.id:
             raise SessionTimeout("packet ID mismatch")

rcon/source/proto.py

@@ -8,7 +8,7 @@ from logging import getLogger
 from random import randint
 from typing import IO, NamedTuple
 
-from rcon.exceptions import EmptyResponse
+from rcon.exceptions import EmptyResponse, UnexpectedTerminator
 
 
 __all__ = ["LittleEndianSignedInt32", "Type", "Packet", "random_request_id"]
@@ -118,7 +118,9 @@ class Packet(NamedTuple):
         return size + payload
 
     @classmethod
-    async def aread(cls, reader: StreamReader) -> Packet:
+    async def aread(
+        cls, reader: StreamReader, raise_unexpected_terminator: bool = False
+    ) -> Packet:
         """Read a packet from an asynchronous file-like object."""
         LOGGER.debug("Reading packet asynchronously.")
         size = await LittleEndianSignedInt32.aread(reader)
@@ -137,12 +139,14 @@ class Packet(NamedTuple):
         LOGGER.debug("  => terminator: %s", terminator)
 
         if terminator != TERMINATOR:
+            if raise_unexpected_terminator:
+                raise UnexpectedTerminator(terminator)
             LOGGER.warning("Unexpected terminator: %s", terminator)
 
         return cls(id_, type_, payload, terminator)
 
     @classmethod
-    def read(cls, file: IO) -> Packet:
+    def read(cls, file: IO, raise_unexpected_terminator: bool = False) -> Packet:
         """Read a packet from a file-like object."""
         LOGGER.debug("Reading packet.")
         size = LittleEndianSignedInt32.read(file)
@@ -161,6 +165,8 @@ class Packet(NamedTuple):
         LOGGER.debug("  => terminator: %s", terminator)
 
         if terminator != TERMINATOR:
+            if raise_unexpected_terminator:
+                raise UnexpectedTerminator(terminator)
             LOGGER.warning("Unexpected terminator: %s", terminator)
 
         return cls(id_, type_, payload, terminator)