Fix Issue #90: Remaining length issues

adafruit_minimqtt/adafruit_minimqtt.py

@@ -181,7 +181,7 @@ def __init__(
                 randint(0, int(time.monotonic() * 100) % 1000), randint(0, 99)
             )
             # generated client_id's enforce spec.'s length rules
-            if len(self.client_id) > 23 or not self.client_id:
+            if len(self.client_id.encode("utf-8")) > 23 or not self.client_id:
                 raise ValueError("MQTT Client ID must be between 1 and 23 bytes")
 
         # LWT
@@ -450,16 +450,16 @@ def connect(self, clean_session=True, host=None, port=None, keep_alive=None):
         var_header[6] = clean_session << 1
 
         # Set up variable header and remaining_length
-        remaining_length = 12 + len(self.client_id)
+        remaining_length = 12 + len(self.client_id.encode("utf-8"))
         if self._username:
-            remaining_length += 2 + len(self._username) + 2 + len(self._password)
+            remaining_length += 2 + len(self._username.encode("utf-8")) + 2 + len(self._password.encode("utf-8"))
             var_header[6] |= 0xC0
         if self.keep_alive:
             assert self.keep_alive < MQTT_TOPIC_LENGTH_LIMIT
             var_header[7] |= self.keep_alive >> 8
             var_header[8] |= self.keep_alive & 0x00FF
         if self._lw_topic:
-            remaining_length += 2 + len(self._lw_topic) + 2 + len(self._lw_msg)
+            remaining_length += 2 + len(self._lw_topic.encode("utf-8")) + 2 + len(self._lw_msg)
             var_header[6] |= 0x4 | (self._lw_qos & 0x1) << 3 | (self._lw_qos & 0x2) << 3
             var_header[6] |= self._lw_retain << 5
 
@@ -586,10 +586,10 @@ def publish(self, topic, msg, retain=False, qos=0):
         pub_hdr_fixed = bytearray([0x30 | retain | qos << 1])
 
         # variable header = 2-byte Topic length (big endian)
-        pub_hdr_var = bytearray(struct.pack(">H", len(topic)))
+        pub_hdr_var = bytearray(struct.pack(">H", len(topic.encode("utf-8"))))
         pub_hdr_var.extend(topic.encode("utf-8"))  # Topic name
 
-        remaining_length = 2 + len(msg) + len(topic)
+        remaining_length = 2 + len(msg) + len(topic.encode("utf-8"))
         if qos > 0:
             # packet identifier where QoS level is 1 or 2. [3.3.2.2]
             remaining_length += 2
@@ -668,15 +668,15 @@ def subscribe(self, topic, qos=0):
                 topics.append((t, q))
         # Assemble packet
         packet_length = 2 + (2 * len(topics)) + (1 * len(topics))
-        packet_length += sum(len(topic) for topic, qos in topics)
+        packet_length += sum(len(topic.encode("utf-8")) for topic, qos in topics)
         packet_length_byte = packet_length.to_bytes(1, "big")
         self._pid = self._pid + 1 if self._pid < 0xFFFF else 1
         packet_id_bytes = self._pid.to_bytes(2, "big")
         # Packet with variable and fixed headers
         packet = MQTT_SUB + packet_length_byte + packet_id_bytes
         # attaching topic and QOS level to the packet
         for t, q in topics:
-            topic_size = len(t).to_bytes(2, "big")
+            topic_size = len(t.encode("utf-8")).to_bytes(2, "big")
             qos_byte = q.to_bytes(1, "big")
             packet += topic_size + t.encode() + qos_byte
         if self.logger:
@@ -717,13 +717,13 @@ def unsubscribe(self, topic):
                 )
         # Assemble packet
         packet_length = 2 + (2 * len(topics))
-        packet_length += sum(len(topic) for topic in topics)
+        packet_length += sum(len(topic.encode("utf-8")) for topic in topics)
         packet_length_byte = packet_length.to_bytes(1, "big")
         self._pid = self._pid + 1 if self._pid < 0xFFFF else 1
         packet_id_bytes = self._pid.to_bytes(2, "big")
         packet = MQTT_UNSUB + packet_length_byte + packet_id_bytes
         for t in topics:
-            topic_size = len(t).to_bytes(2, "big")
+            topic_size = len(t.encode("utf-8")).to_bytes(2, "big")
             packet += topic_size + t.encode()
         if self.logger:
             for t in topics:
@@ -914,10 +914,11 @@ def _send_str(self, string):
         :param str string: String to write to the socket.
 
         """
-        self._sock.send(struct.pack("!H", len(string)))
         if isinstance(string, str):
+            self._sock.send(struct.pack("!H", len(string.encode("utf-8"))))
             self._sock.send(str.encode(string, "utf-8"))
         else:
+            self._sock.send(struct.pack("!H", len(string)))
             self._sock.send(string)
 
     @staticmethod