使用python在 QoS0 级下,实现以下 MQTT 报文: a) CONNECT b) CONNACK c) PUBLISH d) PUBACK e) SUBSCRIBE f) SUBACK g) UNSUBSCRIBE h) UNSUBACK i) PINGREQ j) PINGRESP k) DISCONNECT
时间: 2024-03-17 14:42:43 浏览: 138
使用python实现mqtt的发布和订阅
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好的,以下是使用 Python 实现 QoS0 级下 MQTT 报文的示例代码:
a) CONNECT:
```python
import socket
# 构造 CONNECT 报文
def construct_connect_packet(client_id):
packet = bytearray()
packet.append(0x10) # 固定报头,MQTT 控制报文类型 CONNECT
packet.extend(b'\x00\x04') # 剩余长度为 4,即协议名长度和协议版本号长度之和
packet.extend(b'MQTT\x04') # 协议名和协议版本号,MQTT 4.0
packet.append(0xC2) # 连接标志位,Clean Session=1,不保留会话
packet.extend(b'\x00\x0A') # 保持连接时间 10 秒
packet.extend(len(client_id).to_bytes(2, 'big')) # 客户端标识符长度,两个字节
packet.extend(client_id.encode('utf-8')) # 客户端标识符
return packet
# 发送 CONNECT 报文
def send_connect_packet(client_id, host, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((host, port))
packet = construct_connect_packet(client_id)
sock.send(packet)
# 接收 CONNACK 报文,省略
```
b) CONNACK:
```python
import socket
# 构造 CONNACK 报文
def construct_connack_packet():
packet = bytearray()
packet.append(0x20) # 固定报头,MQTT 控制报文类型 CONNACK
packet.extend(b'\x00\x02') # 剩余长度为 2,只有连接响应码一个字节和会话标识符一个字节
packet.append(0x00) # 连接响应码,连接已接受
packet.append(0x01) # 会话标识符,不保留会话,为 1
return packet
# 接收 CONNECT 报文并发送 CONNACK 报文
def handle_connect_packet(sock):
# 接收 CONNECT 报文,省略
packet = construct_connack_packet()
sock.send(packet)
```
c) PUBLISH:
```python
import socket
# 构造 PUBLISH 报文
def construct_publish_packet(topic, payload):
packet = bytearray()
packet.append(0x30) # 固定报头,MQTT 控制报文类型 PUBLISH,QoS 等级为 0
packet.extend(len(topic).to_bytes(2, 'big')) # 主题长度
packet.extend(topic.encode('utf-8')) # 主题
packet.extend(payload.encode('utf-8')) # 负载
return packet
# 发送 PUBLISH 报文
def send_publish_packet(topic, payload, host, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((host, port))
packet = construct_publish_packet(topic, payload)
sock.send(packet)
```
d) PUBACK:
```python
import socket
# 接收 PUBLISH 报文并发送 PUBACK 报文
def handle_publish_packet(sock):
# 接收 PUBLISH 报文,省略
packet = bytearray()
packet.append(0x40) # 固定报头,MQTT 控制报文类型 PUBACK,QoS 等级为 0
packet.append(0x00) # 剩余长度为 0
sock.send(packet)
```
e) SUBSCRIBE:
```python
import socket
# 构造 SUBSCRIBE 报文
def construct_subscribe_packet(topic):
packet = bytearray()
packet.append(0x82) # 固定报头,MQTT 控制报文类型 SUBSCRIBE,QoS 等级为 1
packet.extend(b'\x00\x01') # 剩余长度为 1,一个字节的报文标识符
packet.extend(b'\x00') # 报文标识符为 0
packet.extend(len(topic).to_bytes(2, 'big')) # 主题长度
packet.extend(topic.encode('utf-8')) # 主题
packet.append(0x00) # QoS 等级为 0
return packet
# 发送 SUBSCRIBE 报文
def send_subscribe_packet(topic, host, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((host, port))
packet = construct_subscribe_packet(topic)
sock.send(packet)
# 接收 SUBACK 报文,省略
```
f) SUBACK:
```python
import socket
# 构造 SUBACK 报文
def construct_suback_packet():
packet = bytearray()
packet.append(0x90) # 固定报头,MQTT 控制报文类型 SUBACK
packet.extend(b'\x00\x03') # 剩余长度为 3,一个字节的报文标识符、一个字节的主题过滤器长度、一个字节的 QoS 等级
packet.extend(b'\x00') # 报文标识符为 0
packet.extend(b'\x00') # 主题过滤器长度为 0
packet.append(0x00) # QoS 等级为 0
return packet
# 接收 SUBSCRIBE 报文并发送 SUBACK 报文
def handle_subscribe_packet(sock):
# 接收 SUBSCRIBE 报文,省略
packet = construct_suback_packet()
sock.send(packet)
```
g) UNSUBSCRIBE:
```python
import socket
# 构造 UNSUBSCRIBE 报文
def construct_unsubscribe_packet(topic):
packet = bytearray()
packet.append(0xA2) # 固定报头,MQTT 控制报文类型 UNSUBSCRIBE,QoS 等级为 1
packet.extend(b'\x00\x01') # 剩余长度为 1,一个字节的报文标识符
packet.extend(b'\x00') # 报文标识符为 0
packet.extend(len(topic).to_bytes(2, 'big')) # 主题长度
packet.extend(topic.encode('utf-8')) # 主题
return packet
# 发送 UNSUBSCRIBE 报文
def send_unsubscribe_packet(topic, host, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((host, port))
packet = construct_unsubscribe_packet(topic)
sock.send(packet)
# 接收 UNSUBACK 报文,省略
```
h) UNSUBACK:
```python
import socket
# 构造 UNSUBACK 报文
def construct_unsuback_packet():
packet = bytearray()
packet.append(0xB0) # 固定报头,MQTT 控制报文类型 UNSUBACK
packet.extend(b'\x00\x02') # 剩余长度为 2,一个字节的报文标识符和一个字节的主题过滤器长度
packet.extend(b'\x00') # 报文标识符为 0
packet.extend(b'\x00') # 主题过滤器长度为 0
return packet
# 接收 UNSUBSCRIBE 报文并发送 UNSUBACK 报文
def handle_unsubscribe_packet(sock):
# 接收 UNSUBSCRIBE 报文,省略
packet = construct_unsuback_packet()
sock.send(packet)
```
i) PINGREQ:
```python
import socket
# 构造 PINGREQ 报文
def construct_pingreq_packet():
packet = bytearray()
packet.append(0xC0) # 固定报头,MQTT 控制报文类型 PINGREQ
packet.append(0x00) # 剩余长度为 0
return packet
# 发送 PINGREQ 报文
def send_pingreq_packet(host, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((host, port))
packet = construct_pingreq_packet()
sock.send(packet)
# 接收 PINGRESP 报文,省略
```
j) PINGRESP:
```python
import socket
# 接收 PINGREQ 报文并发送 PINGRESP 报文
def handle_pingreq_packet(sock):
# 接收 PINGREQ 报文,省略
packet = bytearray()
packet.append(0xD0) # 固定报头,MQTT 控制报文类型 PINGRESP
packet.append(0x00) # 剩余长度为 0
sock.send(packet)
```
k) DISCONNECT:
```python
import socket
# 构造 DISCONNECT 报文
def construct_disconnect_packet():
packet = bytearray()
packet.append(0xE0) # 固定报头,MQTT 控制报文类型 DISCONNECT
packet.append(0x00) # 剩余长度为 0
return packet
# 发送 DISCONNECT 报文
def send_disconnect_packet(host, port):
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((host, port))
packet = construct_disconnect_packet()
sock.send(packet)
```
以上是 QoS0 级下 MQTT 报文的 Python 实现示例代码,具体实现时可以根据自己的需要进行修改。
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