I'm currently trying to publish and receive Protobuf messages via a Mosquitto MQQT Server. I am succesfully publishing the proper to the Server. However, when a client receives it, the method parseFrom() hangs and never returns. This is a very similar issue to this one, occuring when a Protobuf message is sent via a Socket that's never closed.
Publisher :
MqttClient adapterClient = new MqttClient(broker, clientID);
SpecsMessage.Specs protoNotifyMessage = SpecsMessage.Specs.newBuilder()
.setNodeType("basic")
.setAddress(serverSocket.getInetAddress().getHostName())
.setPort(serverSocket.getLocalPort())
.build();
MqttMessage notifyMessage = new MqttMessage(protoNotifyMessage.toString().getBytes());
adapterClient.publish("availableNodes", notifyMessage);
Subscriber :
public class TestController implements MqttCallback {
public void messageArrived(String topic, MqttMessage message){
System.out.println("New node connected");
System.out.println("Payload: \n" + new String(message.getPayload()));
SpecsMessage.Specs protoMessage = SpecsMessage.Specs.parseFrom(message.getPayload());
}
}
I could not find a way to specify to the MQQT Server a correct way to send the message.
I also tried using the writeDelimitedFrom() method.
MqttClient adapterClient = new MqttClient(broker, clientID);
SpecsMessage.Specs protoNotifyMessage = SpecsMessage.Specs.newBuilder()
.setNodeType("basic")
.setAddress(serverSocket.getInetAddress().getHostName())
.setPort(serverSocket.getLocalPort())
.build();
ByteArrayOutputStream output = new ByteArrayOutputStream();
protoNotifyMessage.writeDelimitedTo(output);
MqttMessage notifyMessage = new MqttMessage(output.toByteArray());
adapterClient.publish("availableNodes", notifyMessage);
However, the message is not correctly converted in byte[], here's what it should look like :
nodeType: "basic"
address: "0.0.0.0"
port: 43101
And here's what I get :
basic0.0.0.0��
Is there a way to make this work, either by correcting the sending method or by solving the byte[] conversion problem?
You're trying to use parseFrom to parse the text-formatted proto. parseFrom is for parsing the wire format.
Send the proto in the wire format instead - message.toByteArray().
(If you want to parse from the text format, use TextFormat).