sgcMQ: Delphi & C++ Builder를 위한 MQTT, AMQP, Kafka & STOMP 클라이언트

uses
  sgcTCP_Client_WS, sgcWebSocket_Classes, sgcWebSocket_Types,
  sgcWebSocket_Protocols, sgcWebSocket_Protocol_MQTT_Client,
  sgcWebSocket_Protocol_MQTT_Message;

var
  TCPClient: TsgcTCPClient;
  MQTT: TsgcWSPClient_MQTT;
begin
  TCPClient := TsgcTCPClient.Create(nil);   // plain MQTT over TCP
  TCPClient.Host := 'broker.example.com';
  TCPClient.Port := 1883;
  TCPClient.WatchDog.Enabled := True;

  MQTT := TsgcWSPClient_MQTT.Create(nil);
  MQTT.Client := TCPClient;
  MQTT.MQTTVersion := mqtt5;
  MQTT.Authentication.Enabled  := True;
  MQTT.Authentication.UserName := 'sgc';
  MQTT.Authentication.Password := 'sgc';

  MQTT.LastWillTestament.Enabled := True;
  MQTT.LastWillTestament.Topic   := 'devices/sensor-01/status';
  MQTT.LastWillTestament.Message := 'offline';
  MQTT.LastWillTestament.QoS     := mtqsAtLeastOnce;
  MQTT.LastWillTestament.Retain  := True;

  MQTT.OnMQTTConnect := MQTTConnect;
  MQTT.OnMQTTPublish := MQTTPublish;

  TCPClient.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', mtqsAtLeastOnce);
  MQTT.Publish('devices/sensor-01/status',
    'online', mtqsAtLeastOnce, True);   // retained
end;

procedure TForm1.MQTTPublish(Connection: TsgcWSConnection;
  aTopic, aText: string;
  PublishProperties: TsgcWSMQTTPublishProperties);
begin
  Memo1.Lines.Add(aTopic + ' = ' + aText);
end;

// For an encrypted broker: same code, TLS on the carrier.
TCPClient.Port := 8883;
TCPClient.TLS  := True;