Mqtt
来自Jack's Lab
（版本间的差异）
(→Turn On/Off) |
(→Prepare) |
||
| 第163行： | 第163行： | ||
==== Prepare ==== | ==== Prepare ==== | ||
| − | 安装 Go lang 编译环境: | + | Windows 下安装 Go 语言环境： |
| + | |||
| + | Go 语言官网（https://golang.google.cn/dl/）下载安装包 go1.14.1.windows-amd64.msi | ||
| + | |||
| + | 详细可参考：http://c.biancheng.net/view/3992.html | ||
| + | |||
| + | |||
| + | Linux 安装 Go lang 编译环境: | ||
<source lang=bash> | <source lang=bash> | ||
2020年3月23日 (一) 18:31的版本
目录 |
1 Overview
MQTT是一个轻量的发布订阅模式消息传输协议，专门针对低带宽和不稳定网络环境的物联网应用设计。
MQTT官网: http://mqtt.org
MQTT V3.1.1协议规范: http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html
特点：
- 开放消息协议，简单易实现
- 发布订阅模式，一对多消息发布
- 基于TCP/IP网络连接
- 1字节固定报头，2字节心跳报文，报文结构紧凑
- 消息QoS支持，可靠传输保证
应用：
MQTT协议广泛应用于物联网、移动互联网、智能硬件、车联网、电力能源等领域。
- 物联网M2M通信，物联网大数据采集
- Android消息推送，WEB消息推送
- 移动即时消息，例如Facebook Messenger
- 智能硬件、智能家具、智能电器
- 车联网通信，电动车站桩采集
- 智慧城市、远程医疗、远程教育
- 电力、石油与能源等行业市场
2 Quickstart
MQTT 协议基于主题 (Topic) 进行消息路由
主题 (Topic) 类似 URL 路径，例如:
dev/gateway dev2srv/DEV1202 srv2dev/DEV1203
- 发布者通过主题 (Topic) 发送消息
- 所有订阅 (Subscribe) 该主题的订阅者，都会收到消息
主题 (Topic) 通过 '/' 分割层级，支持 '+', '#' 通配符：
'+': 表示通配一个层级，例如 a/+，匹配 a/x, a/y '#': 表示通配多个层级，例如 a/#，匹配 a/x, a/b/c
订阅者可以订阅含通配符主题，但发布者不允许向含通配符主题发布消息
3 Python
3.1 Install Python3
- Install python3.8 from https://www.python.org/downloads/
Install pip:
$ curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py $ sudo python get-pip.py
3.2 Install mqtt package
$ python3 --version
Python 3.5.3rc1
$ pip3 install paho-mqtt
Collecting paho-mqtt
Downloading paho-mqtt-1.2.tar.gz (49kB)
100% |████████████████████████████████| 51kB 308kB/s
Building wheels for collected packages: paho-mqtt
Running setup.py bdist_wheel for paho-mqtt ... done
Stored in directory: /home/comcat/.cache/pip/wheels/fa/db/fb/b495e37057e2f40534726b3c00ab26a58fc80fb8d17223df07
Successfully built paho-mqtt
Installing collected packages: paho-mqtt
Successfully installed paho-mqtt-1.2
More infor: https://pypi.python.org/pypi/paho-mqtt
3.3 mqtt client
import json
import paho.mqtt.client as mqtt
import sys
# replace it to your id
###########################################
mqtt_uname = 'test'
mqtt_pass = 'test'
devid = '12020030001'
###########################################
def help_msg():
print("Supported cmd:")
print("\tmqtt.py message")
if len(sys.argv) >= 2:
set_state = sys.argv[1]
else:
help_msg()
sys.exit(-2)
mqtt_tx_topic = 'dev/gw'
mqtt_rx_topic = 'app2dev/' + devid
mqtt_host = '192.168.1.97'
mqtt_port = 1883
mqtt_msg = set_state
def on_connect(client, u_dat, rc):
if rc == 0:
print("Connected successfully")
else:
print("Connection failed. rc = "+str(rc))
def on_publish(client, u_dat, rc):
print("Message "+str(rc)+" published.")
def on_subscribe(client, u_dat, mid, qos):
print("Subscribe with "+str(mid)+" received")
def on_message(client, udat, msg):
print("Message received on topic "+msg.topic+" and payload "+str(msg.payload))
mqttc = mqtt.Client()
mqttc.on_connect = on_connect
mqttc.on_publish = on_publish
mqttc.on_subscribe = on_subscribe
mqttc.on_message = on_message
mqttc.username_pw_set(mqtt_uname, mqtt_pass)
mqttc.connect(mqtt_host, mqtt_port)
mqttc.publish(mqtt_tx_topic, mqtt_msg)
3.4 Go 语言
3.4.1 Prepare
Windows 下安装 Go 语言环境：
Go 语言官网（https://golang.google.cn/dl/）下载安装包 go1.14.1.windows-amd64.msi
详细可参考：http://c.biancheng.net/view/3992.html
Linux 安装 Go lang 编译环境:
$ sudo apt-get install golang-go $ sudo apt-get install golang-eclipse-paho-dev $ export GOPATH=/usr/share/gocode
Refer to:
3.4.2 Turn On/Off
package main
import (
"fmt"
"os"
"strings"
"net/http"
"encoding/json"
MQTT "git.eclipse.org/gitroot/paho/org.eclipse.paho.mqtt.golang.git"
)
//define a function for the default message handler
var f MQTT.MessageHandler = func(client *MQTT.Client, msg MQTT.Message) {
fmt.Printf("TOPIC: %s\n", msg.Topic())
fmt.Printf("MSG: %s\n", msg.Payload())
}
var uid string = "YOUR_mqtt_uname"
func main() {
if len(os.Args[1:]) >= 2 {
devid := os.Args[1]
cmd := os.Args[2]
msg := ""
if cmd == "on" {
msg = "on"
} else if cmd == "off" {
msg = "off"
} else if cmd == "ota" {
msg = "ota"
}
pass := get_token(uid)
send_msg(devid, msg, pass)
} else {
help_msg()
}
}
func help_msg() {
fmt.Println("Supported cmd:")
fmt.Println("\tmqtt dev_id on")
fmt.Println("\tmqtt dev_id off")
}
// 往主题 app2dev/DEV_ID 处发送消息
func send_msg(devid string, msg string, pass string) {
opts := MQTT.NewClientOptions().AddBroker("tcp://mqtt.xxx.net:1883")
opts.SetClientID("cid_" + devid)
opts.SetUsername(devid)
opts.SetPassword(pass)
opts.SetDefaultPublishHandler(f)
c := MQTT.NewClient(opts)
if token := c.Connect(); token.Wait() && token.Error() != nil {
panic(token.Error())
}
mqtt_tx_topic := "app2dev/" + devid
token := c.Publish(mqtt_tx_topic, 0, false, msg)
token.Wait()
}
func get_token(user_id string) (string) {
url := "http://api.xxx.net/user/token"
type Body struct {
UID string `json:"user_id"`
}
var body = Body {
UID: user_id,
}
data, err := json.Marshal(body)
//fmt.Println(string(data))
if err == nil {
resp, err := http.Post(url, "application/json", strings.NewReader(string(data)))
if err != nil {
fmt.Println(err)
}
defer resp.Body.Close()
dec := json.NewDecoder(resp.Body)
var v map[string]interface{}
if err := dec.Decode(&v); err != nil {
fmt.Printf("error: %v\n", err)
} else {
if val, ok := v["user_token"].(string); ok {
return val
}
}
}
return ""
}
$ go build mqtt.go $ ./mqtt 12020030001 on $ ./mqtt 12020030001 off
4 Reference
