Every broker, one carrier

uses
  sgcTCP_Client_WS, sgcWebSocket_Classes, sgcWebSocket_Protocols;
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);
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;

uses
  sgcTCP_Client_WS, sgcWebSocket_Protocols, sgcAMQP_Classes;
var
  TCPClient: TsgcTCPClient;
  AMQP: TsgcWSPClient_AMQP;
begin
  TCPClient := TsgcTCPClient.Create(nil);
  TCPClient.Host := 'broker.example.com';
  TCPClient.Port := 5672;                  // 5671 for the amqps listener

  AMQP := TsgcWSPClient_AMQP.Create(nil);
  AMQP.Client := TCPClient;
  AMQP.AMQPOptions.VirtualHost := '/';
  AMQP.HeartBeat.Enabled  := True;
  AMQP.HeartBeat.Interval := 30;

  AMQP.OnAMQPConnect      := AMQPConnect;
  AMQP.OnAMQPBasicDeliver := AMQPBasicDeliver;

  TCPClient.Active := True;
end;

procedure TForm1.AMQPConnect(Sender: TObject);
begin
  AMQP.OpenChannel('ch1');
  AMQP.DeclareExchange('ch1', 'orders', 'direct');
  AMQP.DeclareQueue('ch1', 'orders_in');
  AMQP.BindQueue('ch1', 'orders_in', 'orders', 'create');
  AMQP.Consume('ch1', 'orders_in');

  // Publish to the exchange with a routing key
  AMQP.PublishMessage('ch1', 'orders', 'create', '{"id":42}');
end;

uses
  sgcTCP_Client_WS, sgcWebSocket_Protocols, sgcKafka_Classes;
var
  TCPClient: TsgcTCPClient;
  Kafka: TsgcWSPClient_Kafka;
begin
  Kafka := TsgcWSPClient_Kafka.Create(nil);
  Kafka.KafkaOptions.ClientId := 'my-delphi-app';
  Kafka.KafkaOptions.Producer.Acks        := kafkaAcksLeader;
  Kafka.KafkaOptions.Producer.Compression := kafkaCompressionGzip;
  Kafka.KafkaOptions.Consumer.GroupId     := 'my-group';
  Kafka.KafkaOptions.Consumer.OffsetReset := kafkaOffsetEarliest;
  Kafka.OnKafkaMessage := KafkaMessage;

  TCPClient := TsgcTCPClient.Create(nil);
  Kafka.Client := TCPClient;
  TCPClient.Host := '127.0.0.1';
  TCPClient.Port := 9092;
  TCPClient.Active := True;

  // produce a record to a topic
  Kafka.Produce('my-topic', 'Hello Kafka', 'key-1');

  // consume: subscribe once, then Poll repeatedly (e.g. from a timer)
  Kafka.Subscribe(['my-topic']);
end;

procedure TForm1.KafkaMessage(Sender: TObject;
  const Message: TsgcKafkaMessage);
begin
  Memo1.Lines.Add(Message.GetKeyString + ' = ' + Message.GetValueString);
end;

// fetch records from a timer, commit when a batch is processed
var
  Messages: TsgcKafkaMessages;
begin
  Messages := Kafka.Poll(1000);
  try
    if Messages.Count > 0 then
      Kafka.CommitSync;
  finally
    Messages.Free;
  end;
end;

uses
  sgcTCP_Client_WS, sgcWebSocket_Classes, sgcWebSocket_Protocols,
  sgcWebSocket_Protocol_STOMP_Broker_Client,
  sgcWebSocket_Protocol_STOMP_RabbitMQ_Client;
var
  TCPClient: TsgcTCPClient;
  STOMP: TsgcWSPClient_STOMP_RabbitMQ;
begin
  TCPClient := TsgcTCPClient.Create(nil);
  TCPClient.Host := 'rabbit.example.com';
  TCPClient.Port := 61613;             // 61614 for the plugin's TLS listener

  STOMP := TsgcWSPClient_STOMP_RabbitMQ.Create(nil);
  STOMP.Client := TCPClient;
  STOMP.Authentication.Enabled  := True;
  STOMP.Authentication.UserName := 'guest';
  STOMP.Authentication.Password := 'guest';

  STOMP.OnRabbitMQConnected := RabbitMQConnected;
  STOMP.OnRabbitMQMessage   := RabbitMQMessage;

  TCPClient.Active := True;
end;

procedure TForm1.RabbitMQConnected(Connection: TsgcWSConnection;
  Headers: TsgcWSRabbitMQSTOMPHeadersConnected);
begin
  // /queue/orders
  STOMP.SubscribeQueue('orders');
  STOMP.PublishQueue('orders', '{"orderId":12345}');
end;

procedure TForm1.RabbitMQMessage(Connection: TsgcWSConnection;
  MessageText: string; Headers: TsgcWSRabbitMQSTOMPHeadersMessage;
  Subscription: TsgcWSBrokerSTOMPSubscriptionItem);
begin
  Memo1.Lines.Add(Headers.Destination + ': ' + MessageText);
end;