UART & Sensors

shared/mqtt.py

@@ -13,13 +13,13 @@ except ImportError:
         from umqtt.simple import MQTTClient as _MQTTClient
         BACKEND_NAME = "umqtt.simple"
         IS_MICROPYTHON = True
-    except ImportError:
-        try:
-            from umqtt.robust import MQTTClient as _MQTTClient
-            BACKEND_NAME = "umqtt.robust"
-            IS_MICROPYTHON = True
-        except ImportError as exc:
-            raise ImportError("No MQTT client found. Expected paho.mqtt or umqtt.") from exc
+    # except ImportError:
+    #     try:
+    #         from umqtt.robust import MQTTClient as _MQTTClient
+    #         BACKEND_NAME = "umqtt.robust"
+    #         IS_MICROPYTHON = True
+    except ImportError as exc:
+        raise ImportError("No MQTT client found. Expected paho.mqtt or umqtt.") from exc
 
 
 DEFAULT_PORT = 8884
@@ -179,6 +179,38 @@ class BrokerClient:
             topic = topic.decode('utf-8')
             
         return client.subscribe(topic, qos=qos)
+    
+    def unsubscribe(self, topic):
+        client = self.open()
+        if IS_MICROPYTHON:
+            import struct
+            # Ensure the topic is bytes for writing to the socket
+            topic_bytes = topic if isinstance(topic, bytes) else topic.encode('utf-8')
+            
+            # 1. Build the MQTT unsubscribe packet header
+            pkt = bytearray(b"\xa2\0\0\0")
+            client.pid += 1
+            
+            # Packet length is: 2 bytes (PID) + 2 bytes (topic length indicator) + topic string length
+            struct.pack_into("!BH", pkt, 1, 2 + 2 + len(topic_bytes), client.pid)
+            
+            # 2. Write the packet to the socket
+            client.sock.write(pkt)
+            client._send_str(topic_bytes)
+            
+            # 3. Wait for the UNSUBACK confirmation frame (0xB0) from the broker
+            while True:
+                op = client.wait_msg()
+                if op == 0xB0:
+                    resp = client.sock.read(3)
+                    assert resp[1] == pkt[2] and resp[2] == pkt[3]
+                    return client
+            return client
+            
+        if isinstance(topic, bytes):
+            topic = topic.decode('utf-8')
+            
+        return client.unsubscribe(topic)
 
     def _on_micropython_message(self, topic, payload):
         self._store_message(topic, payload, None, False)