Connected Property

Triggers a connection or disconnection.

Syntax

 mqttsn.getConnected([callback])
 mqttsn.setConnected( connected, [callback])

Default Value

FALSE

Callback

The 'callback' parameter specifies a function which will be called when the operation completes (or an error is encountered). If the 'callback' parameter is not specified, then the method will block and will not return until the operation completes (or an error is encountered).

The callback for the getConnected([callback]) method is defined as:

function(err, data){ }

'err' is the error that occurred. If there was no error, then 'err' is 'null'.

'data' is the value returned by the method.

The callback for the setConnected([callback]) method is defined as:

function(err){ }

'err' is the error that occurred. If there was no error, then 'err' is 'null'.

'err' has 2 properties which hold detailed information:

err.code
err.message

Remarks

This property triggers a connection or disconnection. Setting this property to True makes the class send a CONNECT packet to the MQTTSN Gateway identified by the RemoteHost property. If successful, after the connection is achieved the value of the property changes to True and the Connected event is fired.

Setting this property to False sends a DISCONNECT packet, closing the connection.

When connecting to an MQTT gateway, the class sends the following information:

• The values of the ClientId, CleanSession, and KeepAliveInterval properties.
• The values of the WillTopic and WillMessage properties and the WillRetain and WillQOS configuration settings.

Refer to CleanSession for more information about MQTT sessions; refer to WillTopic, WillMessage, WillQOS and WillRetain for more information about MQTT Wills.

Basic Connection Example

mqttsn1.ClientId = "testClient";
mqttsn1.CleanSession = true;
mqttsn1.KeepAliveInterval = 30;
mqttsn1.WillTopic = "wills/" + mqttsn1.ClientId;
mqttsn1.WillMessage = mqttsn1.ClientId + " was disconnected ungracefully!";
mqttsn1.Connect(host, port);

This property is not available at design time.

Data Type

Boolean