fix: 按 K-00 约定修复 Python SDK 断线重交与退避

sdk/python/src/nixmsg/transport.py

@@ -203,13 +203,21 @@ class PahoTransport:
         self.disconnect()
         url = params.url
         u = urlparse(url if "://" in url else "ws://" + url)
-        use_tcp = params.use_tcp or u.scheme in ("mqtt", "mqtts")
+        use_tcp = params.use_tcp
+        scheme = u.scheme.lower()
+        if scheme == "https":
+            scheme = "wss"
+        elif scheme == "http":
+            scheme = "ws"
+        if scheme in ("mqtt", "mqtts"):
+            use_tcp = True
         # WebSocket 必须显式 transport=websockets；裸 TCP 走默认。
         client = PahoClient(
             callback_api_version=CallbackAPIVersion.VERSION2,
             client_id=params.client_id,
             protocol=MQTTv5,
             transport="tcp" if use_tcp else "websockets",
+            reconnect_on_failure=False,
         )
         client.username_pw_set(params.username, params.password)
         client.on_connect = self._on_connect
@@ -231,16 +239,14 @@ class PahoTransport:
             props = None
         if use_tcp:
             if not u.port:
-                port = 8883 if u.scheme == "mqtts" else 1883
-            if u.scheme == "mqtts":
+                port = 8883 if scheme == "mqtts" else 1883
+            if scheme == "mqtts":
                 client.tls_set()
         else:
             path = u.path or "/mqtt"
-            if not path.endswith("/mqtt"):
-                path = path.rstrip("/") + "/mqtt"
             if not u.port:
-                port = 443 if u.scheme == "wss" else 80
-            if u.scheme == "wss":
+                port = 443 if scheme == "wss" else 80
+            if scheme == "wss":
                 client.tls_set()
             client.ws_set_options(path=path, headers={"Sec-WebSocket-Protocol": "mqtt"})
         client.connect(
@@ -309,11 +315,15 @@ class PahoTransport:
             if self._on_disconnected:
                 self._on_disconnected(None, False)
             return
-        # 0x8E = 142 Session taken over
+        # 0x8E = 142 Session taken over；0x8B = 139 可重试
         if code == 142:
             if self._on_disconnected:
                 self._on_disconnected("taken_over", True)
             return
+        if code == 139:
+            if self._on_disconnected:
+                self._on_disconnected("network", False)
+            return
         stop, reason = _classify_connack(code)
         if self._on_disconnected:
             self._on_disconnected(reason, stop)