Http接口封装Mqtt协议
前言
- .Net Core 3.1 WebApi
- 列出了mqtt客户端的封装目的是为了了解运作机制
1、封装mqtt客户端
- mqtt底层协议基于MQTTnet 版本2.8.5 github地址
- 实例化【单例注入AOC】
- 发布消息
- 订阅消息
实例化
public MqttNetClient(MqttConfig _mqttConfig, EventHandler<MqttApplicationMessageReceivedEventArgs> receivedMessageHanddler,
ICache iCache)
{
mqttConfig = _mqttConfig;
_iCache=iCache;
var factory = new MqttFactory();
mqttClient = factory.CreateMqttClient() as MqttClient;
clientId = "MQTT:Cloud:Client:" + _mqttConfig.ClientIdPre + ":" + Guid.NewGuid();
//实例化一个MqttClientOptionsBulider
options = new MqttClientOptionsBuilder()
.WithTcpServer(_mqttConfig.Server, _mqttConfig.Port)
.WithCredentials(_mqttConfig.Username, _mqttConfig.Password)
.WithClientId(clientId)
.Build();
if (receivedMessageHanddler != null)
{
//是服务器接收到消息时触发的事件，可用来响应特定消息
mqttClient.ApplicationMessageReceived +=receivedMessageHanddler;
}
//是客户端连接成功时触发的事件
mqttClient.Connected+=Connected;
//是客户端断开连接时触发的事件
mqttClient.Disconnected+=Disconnected;
//连接服务器
mqttClient.ConnectAsync(options);
}
发布消息
public async Task PublishAsync(string topic, string content)
{
var message = new MqttApplicationMessageBuilder();
message.WithTopic(topic);
message.WithPayload(content);
message.WithAtMostOnceQoS();
message.WithRetainFlag(false);
await mqttClient.PublishAsync(message.Build());
}
订阅消息
public async Task SubscribeAsync(string topic)
{
await mqttClient.SubscribeAsync(topic);
}
监听mqtt回复消息
随WebApi应用自启动单例MqttClient去消费消息
- 初始化mqtt连接配置
- 主动订阅Topic
- 消费mqtt消息handler
初始化mqtt连接配置&主动订阅Topic代码
var mqttConfig = new MqttConfig
{
Server = _config.Get("EMQServer"),//服务器IP
Port = int.Parse(_config.Get("EMQPort")),//端口
ClientIdPre = "IoT.MQTT"//IoT MQTT连接
};
mqttConfig.TopicList = new List<string>()
{
IoTSubscribeMqttTopicEnum.主动订阅.GetEnumDescription()
};
_mqttNetClient = new MqttNetClient(mqttConfig, ReceivedMessageHandler, _cache);
消费mqtt消息handler
public static void ReceivedMessageHandler(object sender, MqttApplicationMessageReceivedEventArgs e)
{
var topic = e.ApplicationMessage.Topic;
var payload = EncryptUtil.Base64Decode(Encoding.UTF8.GetString(e.ApplicationMessage.Payload));
//如果Topic是主动订阅，则去订阅http接口入参传过来的回复Topic字段
if (topic.Equals(IoTSubscribeMqttTopicEnum.主动订阅.GetEnumDescription()))
{
_mqttNetClient.SubscribeAsync(payload);
}
else
{
var mqttPayloadModel = JsonConvert.DeserializeObject<MqttPayloadModel<MqttContentModel>>(payload);
//插入缓存是为了在回复的时候用，通过MID保持一致
var cacheKey = $"{RedisKeyEnum.MQTT接收消息.GetEnumDescription()}:{mqttPayloadModel.Con.Mid}";
var _cache = _serviceProvider.GetService<ICache>();
_cache.InsertAsync(cacheKey, payload, 5 * 60);
}
}
2、封装http接口
发布消息代码
public async Task<BaseOutModel<PublishMessageOutModel>> PublishMessage(PublishMessageInModel publishInModel)
{
//如果回复Topic不为空，则需要等待mqtt返回消息，通过MID来保持一致
if (!String.IsNullOrEmpty(publishInModel.ReceiveTopic))
{
//先主动订阅
_mqttNetClient.PublishMessageAsync(IoTSubscribeMqttTopicEnum.主动订阅.GetEnumDescription(), EncryptUtil.Base64Encode(publishInModel.ReceiveTopic));
//发布消息
_mqttNetClient.PublishMessageAsync(publishInModel.Topic, publishInModel.Content);
var messageId= JsonConvert.DeserializeObject<MqttPayloadModel<MqttContentModel>>(EncryptUtil.Base64Decode(publishInModel.Content)).Con.Mid;
var cacheKey = $"{RedisKeyEnum.MQTT接收消息.GetEnumDescription()}:{messageId}";
//8秒为超时
var endTime = DateTime.Now.AddSeconds(8);
var received = false;
var cacheMsg = String.Empty;
while (!received)
{
cacheMsg = await _cache.GetAsync<String>(cacheKey);
if (cacheMsg != null || DateTime.Now > endTime)
{
received = true;
}
}
//缓存不为空，代表收到了mqtt客户端的响应
if (cacheMsg != null)
{
//移除回复消息缓存
_cache.RemoveAsync(cacheKey);
return new BaseOutModel<PublishMessageOutModel>
{
Message = "发布消息成功，接收消息成功",
Data = new PublishMessageOutModel { Content = cacheMsg, ReceiveStatus = MqttReceiveStatusEnum.Yes.IntToEnum() }
};
}
return new BaseOutModel<PublishMessageOutModel>
{
Message = "发布消息成功，接收消息失败",
Data = new PublishMessageOutModel { ReceiveStatus = MqttReceiveStatusEnum.No.IntToEnum() }
};
}
//如果Topic为空，则只需要发布消息就好
await _mqttNetClient.PublishMessageAsync(publishInModel.Topic, publishInModel.Content);
return new BaseOutModel<PublishMessageOutModel> { Message = "发布消息成功",Data=new PublishMessageOutModel { } };
}
接口请求入参
| 参数名 |
必选 |
类型 |
说明 |
| Topic |
是 |
string |
发布的Topic |
| Content |
是 |
string |
发布的消息体，需要Base64字符串 |
| ReceiveTopic |
否 |
string |
接收消息Topic【只有不为空，才会去处理接收设备端mqtt的回复消息】 |
| DeviceSn |
是 |
string |
设备编号 |
接口请求出参
| 参数名 |
类型 |
说明 |
| Data - Content |
string |
回复消息的内容 |
| Data - ReceiveStatus |
integer |
回复状态【1 已回复，0 未回复 即超时】 |
| Code |
integer |
返回状态码【200正常，0有错误】 |
| Message |
string |
错误描述，Code为0使用 |
接口请求示例
1、在Startup中将HttpClient注入IOC
services.AddHttpClient("iotmqtt", x =>
{
x.BaseAddress= new Uri("http://iotmqtt.liyunzhi.com");
});
2、调用
//请求mqtt的消息体
var content = new
{
Met = "Reboot",
Con = new
{
Mid = Mid,
Ts = Ts,
Sign = Sign,
Cid = Cid
}
};
//请求入参模型
var iotPublishMessageModel = new
{
//请求Topic
Topic = "Device/Reboot",
//请求mqtt的消息体
Content = EncryptUtil.Base64Encode(JsonConvert.SerializeObject(content)),
//消息ID
MessageId = Mid,
//可选参数 需要消息回复则传
ReceiveTopic = Mid+"Device/Reboot",
//设备号
DeviceSn = "123123123"
};
//
var client = _httpClientFactory.CreateClient("iotmqtt");
var httpResponseMessage = client.PostAsJsonAsync("Api/PublishMessage", iotPublishMessageModel).Result;
//如果当前方法用async异步修饰，请不要.Result 请await
//var httpResponseMessage =await client.PostAsJsonAsync("Api/PublishMessage", iotPublishMessageModel);
if (httpResponseMessage.IsSuccessStatusCode)
{
//成功，返回内容自己自行解析，解析参考接口请求出参
var data= httpResponseMessage.Content.ReadAsStringAsync().Result;
//如果当前方法用async异步修饰，请不要.Result 请await
//var data= await httpResponseMessage.Content.ReadAsStringAsync();
}
else
{
//这里是失败的代码了，即发送失败了
}
3、Github开源地址
