From cc873fc4ff771f957b10894de0c1ced5bd5e7a72 Mon Sep 17 00:00:00 2001
From: Christoph Stahl <christoph.stahl@tu-dortmund.de>
Date: Fri, 31 Jan 2025 22:17:29 +0100
Subject: [PATCH] check compatible versions on connect (playback client)

---
 syng/__init__.py |  2 ++
 syng/client.py   | 27 +++++++++++++++++++++++--
 syng/server.py   | 51 +++++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 77 insertions(+), 3 deletions(-)

diff --git a/syng/__init__.py b/syng/__init__.py
index e69de29..c78e69b 100644
--- a/syng/__init__.py
+++ b/syng/__init__.py
@@ -0,0 +1,2 @@
+SYNG_VERSION = (2, 1, 1)
+SYNG_PROTOCOL_VERSION = (2, 1, 0)
diff --git a/syng/client.py b/syng/client.py
index 5c9ac1b..3a18e8e 100644
--- a/syng/client.py
+++ b/syng/client.py
@@ -38,7 +38,7 @@ from yaml import load, Loader
 
 from syng.player_libmpv import Player, QRPosition
 
-from . import jsonencoder
+from . import SYNG_VERSION, jsonencoder
 from .entry import Entry
 from .sources import configure_sources, Source
 from .log import logger
@@ -156,6 +156,27 @@ class Client:
         self.sio.on("search", self.handle_search)
         self.sio.on("client-registered", self.handle_client_registered)
         self.sio.on("request-config", self.handle_request_config)
+        self.sio.on("msg", self.handle_msg)
+
+    async def handle_msg(self, data: dict[str, Any]) -> None:
+        """
+        Handle the "msg" message.
+
+        This function is used to print messages from the server to the console.
+
+        :param data: A dictionary with the `msg` entry.
+        :type data: dict[str, Any]
+        :rtype: None
+        """
+
+        msg_type = data.get("type", "info")
+        match msg_type:
+            case "info":
+                logger.info(data["msg"])
+            case "warning":
+                logger.warning(data["msg"])
+            case "error":
+                logger.error(data["msg"])
 
     async def handle_update_config(self, data: dict[str, Any]) -> None:
         """
@@ -242,6 +263,7 @@ class Client:
             "waiting_room": self.state.waiting_room,
             "recent": self.state.recent,
             "config": self.state.config,
+            "version": SYNG_VERSION,
         }
         await self.sio.emit("register-client", data)
 
@@ -389,7 +411,8 @@ class Client:
             if self.state.current_source is None:  # A possible race condition can occur here
                 await self.sio.emit("get-first")
         else:
-            logger.warning("Registration failed")
+            reason = data.get("reason", "Unknown")
+            logger.warning(f"Registration failed: {reason}")
             await self.sio.disconnect()
 
     async def handle_request_config(self, data: dict[str, Any]) -> None:
diff --git a/syng/server.py b/syng/server.py
index bb72b73..a6daf9c 100644
--- a/syng/server.py
+++ b/syng/server.py
@@ -35,6 +35,7 @@ from profanity_check import predict
 from .result import Result
 
 from . import jsonencoder
+from . import SYNG_VERSION, SYNG_PROTOCOL_VERSION
 from .log import logger
 from .entry import Entry
 from .queue import Queue
@@ -746,6 +747,7 @@ class Server:
             - `recent`, a list of initial entries for the recent list. The entries
                         are encoded as a dictionary.
             - `secret`, the secret of the room
+            - `version`, the version of the client as a triple of integers
             - `key`, a registration key given out by the server administrator
 
         This will register a new playback client to a specific room. If there
@@ -779,6 +781,49 @@ class Server:
         :rtype: None
         """
 
+        if "version" not in data:
+            await self.sio.emit(
+                "client-registered",
+                {"success": False, "room": None, "reason": "NO_VERSION"},
+                room=sid,
+            )
+            return
+
+        client_version = tuple(data["version"])
+
+        if client_version < SYNG_PROTOCOL_VERSION:
+            await self.sio.emit(
+                "msg",
+                {"type": "error", "msg": "Client is incompatible and outdated. Please update."},
+                room=sid,
+            )
+            await self.sio.emit(
+                "client-registered",
+                {"success": False, "room": None, "reason": "PROTOCOL_VERSION"},
+                room=sid,
+            )
+            return
+
+        if client_version > SYNG_VERSION:
+            await self.sio.emit(
+                "msg",
+                {"type": "error", "msg": "Server is outdated. Please update."},
+                room=sid,
+            )
+            await self.sio.emit(
+                "client-registered",
+                {"success": False, "room": None, "reason": "PROTOCOL_VERSION"},
+                room=sid,
+            )
+            return
+
+        if client_version < SYNG_VERSION:
+            await self.sio.emit(
+                "msg",
+                {"type": "warning", "msg": "Client is compatible but outdated. Please update."},
+                room=sid,
+            )
+
         def gen_id(length: int = 4) -> str:
             client_id = "".join([random.choice(string.ascii_letters) for _ in range(length)])
             if client_id in self.clients:
@@ -793,7 +838,11 @@ class Server:
         ):
             await self.sio.emit(
                 "client-registered",
-                {"success": False, "room": None},
+                {
+                    "success": False,
+                    "room": None,
+                    "reason": "PRIVATE",
+                },
                 room=sid,
             )
             return