MQTTClientBuilder

Description

Builder class to help creating MQTTClient instances.

Functions

All functions except CreateClient returns with the MQTTClientBuilder instance to be able to chain function calls together.

• WithOptions(ConnectionOptions options)

The MQTTClient going to use the options passed to this function.

• WithOptions(ConnectionOptionsBuilder builder)

The MQTTClient going to use the options built by the builder passed to this function.

• WithEventHandler(OnConnectedDelegate onConnected)

The MQTTClient going to be created with this OnConnected event handler. The OnConnected event is called when the client succesfully connects with its transport to the broker and the protocol negotiation completes.

private void OnConnected(MQTTClient client)
{
    // ...
}

• WithEventHandler(OnServerConnectAckMessageDelegate onServerConnectAckMessage)

The MQTTClient going to be created with this OnServerConnectAckMessage event handler. The OnServerConnectAckMessage event is called when the client receives the response for its connect packet (see MQTTClient’s BeginConnect).

private void OnServerConnectAckMessage(MQTTClient client, ServerConnectAckMessage message)
{
    // ...
}

• WithEventHandler(OnApplicationMessageDelegate onApplicationMessage)

The MQTTClient going to be created with this OnApplicationMessage event handler. The OnApplicationMessage event is called for every application message the client receives.

private void OnApplicationMessage(MQTTClient client, ApplicationMessage message)
{
    // ...
}

• WithEventHandler(OnAuthenticationMessageDelegate onAuthenticationMessage)

The MQTTClient going to be created with this OnAuthenticationMessage event handler. The OnAuthenticationMessage event is called when the broker requires more authentication data from the client (see the extended authentication topic).

private void OnAuthenticationCallback(MQTTClient client, AuthenticationMessage message)
{
    // ...
}

• WithEventHandler(OnErrorDelegate onError)

The MQTTClient going to be created with this OnError event handler. The OnError event is called when an unexpected, unrecoverable error happens. After an OnError call the MQTTClient is is in a faulted state and will not be able to send and receive messages.

private void OnError(MQTTClient client, string error)
{
    // ...
}

• WithEventHandler(OnDisconnectDelegate onDisconnect)

The MQTTClient going to be created with this OnDisconnect event handler. The OnDisconnect event is called when the client gracefully disconnects from the broker or after an OnError event. Graceful disconnection can be initiated by both the client or broker.

private void OnDisconnectDelegate(MQTTClient client, DisconnectReasonCodes reasonCode, string reasonMessage)
{
    // ...
}

Possible reason codes from the broker:

• WithEventHandler(OnStateChangedDelegate onStateChanged)

The MQTTClient going to be created with this OnStateChanged event handler. The OnStateChanged event is called when the internal state of the client is changed.

private void OnStateChanged(MQTTClient client, ClientStates oldState, ClientStates newState)
{
    // ...
}

Possible states of an MQTTClient

• CreateClient()

MQTTClient CreateClient()

Creates the final MQTTClient instance with all the options and event handlers.

Examples

var options = new ConnectionOptionsBuilder()
			.WithTCP("localhost", 1883)        
			.WithProtocolVersion(SupportedProtocolVersions.MQTT_3_1_1)
			.Build();
		
var client = new MQTTClientBuilder()
			.WithOptions(options)
			.WithEventHandler(OnConnected)
			.WithEventHandler(OnError)
			.WithEventHandler(OnDisconnect)
			.CreateClient();
	
// Event handler implementations:
	
private void OnConnected(MQTTClient client)
{
    Debug.Log("OnConnected()");
}

private void OnError(MQTTClient client, string error)
{
    Debug.Log($"OnError(\"{error}\")");
}

private void OnDisconnect(MQTTClient client, DisconnectReasonCodes reasonCode, string reasonMessage)
{
    Debug.Log($"OnDisconnect({reasonCode}, \"{reasonMessage}\")");
}

The same setup but passing the ConnectionOptionsBuilder to the MQTTClientBuilder:

var client = new MQTTClientBuilder()
			.WithOptions(new ConnectionOptionsBuilder()
				.WithTCP("localhost", 1883)        
				.WithProtocolVersion(SupportedProtocolVersions.MQTT_3_1_1))
			.WithEventHandler(OnConnected)
			.WithEventHandler(OnError)
			.WithEventHandler(OnDisconnect)
			.CreateClient();