IPWorks IoT 2020 Node.js Edition

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Connect Method

Connects to the MQTTSN Gateway.

Syntax

mqttsn.connect(host, port, [callback])

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 this 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 method connects to the MQTTSN Gateway by sending a CONNECT packet. Calling this method is equivalent to setting the RemoteHost property to Host, setting RemotePort to Port, and then setting the Connected property to True.

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

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);

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IPWorks IoT 2020 Node.js Edition - Version 20.0 [Build 8265]