MQTT 协议
专为 IoT 和受限设备设计的轻量级发布-订阅消息协议。完整支持 MQTT 3.1.1 和 MQTT 5.0 规范。
专为 IoT 和受限设备设计的轻量级发布-订阅消息协议。完整支持 MQTT 3.1.1 和 MQTT 5.0 规范。
适用于 IoT 和受限设备的轻量级发布-订阅消息传递。完整支持 MQTT 3.1.1 和 MQTT 5.0，支持 WebSocket 或原始 TCP。
TsgcWSPClient_MQTT
Windows, macOS, Linux, iOS, Android
Standard / Professional / Enterprise
将 TsgcWebSocketClient 与 TsgcWSPClient_MQTT 配对，连接 OnMQTTConnect / OnMQTTPublish 事件，然后订阅和发布。
uses
sgcWebSocket, sgcWebSocket_Protocol_MQTT_Client,
sgcWebSocket_Protocol_MQTT_Message;
var
WSClient: TsgcWebSocketClient;
MQTT: TsgcWSPClient_MQTT;
begin
WSClient := TsgcWebSocketClient.Create(nil);
WSClient.Host := 'www.esegece.com';
WSClient.Port := 15675;
MQTT := TsgcWSPClient_MQTT.Create(nil);
MQTT.Client := WSClient;
MQTT.Authentication.Enabled := True;
MQTT.Authentication.UserName := 'sgc';
MQTT.Authentication.Password := 'sgc';
MQTT.OnMQTTConnect := MQTTConnect;
MQTT.OnMQTTPublish := MQTTPublish;
WSClient.Active := True;
end;
procedure TForm1.MQTTConnect(Connection: TsgcWSConnection;
const Session: Boolean; const ReasonCode: Integer;
const ReasonName: string;
const ConnectProperties: TsgcWSMQTTCONNACKProperties);
begin
MQTT.Subscribe('sensors/temperature/#');
end;
procedure TForm1.MQTTPublish(Connection: TsgcWSConnection;
aTopic, aText: string;
PublishProperties: TsgcWSMQTTPublishProperties);
begin
Memo1.Lines.Add(aTopic + ': ' + aText);
end;
// Publish a retained QoS 1 message
MQTT.Publish('sensors/temperature/room1',
'{"value":22.5,"unit":"C"}', mtqsAtLeastOnce, True);// uses: sgcWebSocket, sgcWebSocket_Protocol_MQTT_Client
TsgcWebSocketClient *WSClient = new TsgcWebSocketClient(this);
WSClient->Host = "www.esegece.com";
WSClient->Port = 15675;
TsgcWSPClient_MQTT *MQTT = new TsgcWSPClient_MQTT(this);
MQTT->Client = WSClient;
MQTT->Authentication->Enabled = true;
MQTT->Authentication->UserName = "sgc";
MQTT->Authentication->Password = "sgc";
MQTT->OnMQTTConnect = MQTTConnect;
MQTT->OnMQTTPublish = MQTTPublish;
WSClient->Active = true;
void __fastcall TForm1::MQTTPublish(TsgcWSConnection *Connection,
UnicodeString aTopic, UnicodeString aText,
TsgcWSMQTTPublishProperties PublishProperties)
{
Memo1->Lines->Add(aTopic + ": " + aText);
}
MQTT->Publish("sensors/temperature/room1",
"{\"value\":22.5,\"unit\":\"C\"}", mtqsAtLeastOnce, true);using esegece.sgcWebSockets;
var WSClient = new TsgcWebSocketClient();
WSClient.Options.Parameters = "/ws";
var MQTT = new TsgcWSPClient_MQTT();
MQTT.Client = WSClient;
MQTT.Authentication.Enabled = true;
MQTT.Authentication.UserName = "sgc";
MQTT.Authentication.Password = "sgc";
MQTT.HeartBeat.Enabled = true;
MQTT.HeartBeat.Interval = 5;
MQTT.OnMQTTConnect += (conn, session, code, name, props) => MQTT.Subscribe("sensors/temperature/#");
MQTT.OnMQTTPublish += (conn, topic, text, props) => Console.WriteLine(topic + ": " + text);
WSClient.Host = "www.esegece.com";
WSClient.Port = 15675;
WSClient.Active = true;
MQTT.Publish("sensors/temperature/room1",
"{\"value\":22.5,\"unit\":\"C\"}", TmqttQoS.mtqsAtLeastOnce, true);10 个已发布属性、9 个方法、13 个事件 — 对应 TsgcWSPClient_MQTT 参考文档。
MQTTVersion 选择 CONNECT 包中通告的级别 — MQTT 3.1.1 或 MQTT 5.0。ConnectProperties 携带 MQTT 5 的会话过期、接收最大值、包大小、主题别名和扩展认证字段。
将 Client 属性连接到 TsgcWebSocketClient 以通过 WebSocket 运行 MQTT，或通过 Broker 连接到 TsgcWSMQTTBroker 以在端口 1883/8883 上使用原生 TCP 传输。
以 QoS 0、1 或 2 发布消息，并可选保留。QoS 属性控制默认级别、重试间隔和超时。PublishAndWait 阻塞直到代理确认 — 适用于事务性发布。
LastWillTestament 注册主题、载荷、QoS 和保留标志，当连接异常断开时代理将代表此客户端发布 — 一种优雅的设备断线信号方式。
Subscribe / UnSubscribe 接受带有 + 和 # 通配符的主题过滤器。OnMQTTPublish 传递入站消息；OnMQTTPublishEx 提供原始字节/流。完整 QoS 2 握手通过 OnMQTTPubRec、OnMQTTPubRel、OnMQTTPubComp 暴露。
HeartBeat 定时发送 PINGREQ 并检测静默代理断线。Authentication 在 CONNECT 中发送用户名/密码。MQTT 5 增强认证：调用 Auth 并处理 OnMQTTAuth 实现 SCRAM 式挑战。
该组件实现的协议权威来源。