21. nqMqtt

The nqMqtt object is a built-in object that provides MQTT communication function with NEQTO Console.

Functional overview:

• Provides functions to send measurements and arbitrary data to NEQTO Console.
• Provides a function to receive push notifications from NEQTO Console.

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nqMqtt Global Object

Methods()/Properties	Summary	Version	Note
nqMqtt.on()	Registers an event handler.	00.00.15+
nqMqtt.publish()	Publishes a message to NEQTO Console.	00.00.15+
nqMqtt.end()	Terminates nqMqtt.	00.00.15+
nqMqtt.isConnected()	Gets MQTT connection status.	00.00.15+
nqMqtt.isReconnecting()	Gets the status of MQTT when reconnecting.	00.00.15+
nqMqtt.canPublish()	Gets the status of whether the MQTT message can be published.	00.00.18+
nqMqtt.get()	Gets information related to the given argument.	00.00.15+	The following arguments can be used as of version 00.00.20+: 'LwM2MObjectS', 'LwM2MArgStrS', 'LwM2MString'

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Details

nqMqtt.on(event,callback)

Registers an event handler.

Name	Type	M/O	Summary	Note
event	string	mandatory	Event name Names that can be used are; push, connect, reconnect, close, error
callback()	function	mandatory	Executes callback processing when an event occurs.
return	undefined	-	-

event: ’push’

Registers a push event handler. Executes callback processing when receiving a push notification of a custom message from NEQTO Console. The arguments for the callback are as follows:

Arguments	Type	Summary	Note
message	string	Received message A string of up to 380 bytes. If the maximum number of bytes is exceeded, the message is discarded.

event: ’connect’

Registers a connect event handler. Executes callback when MQTT connection and reconnection are successful. MQTT connection may be completed before the script starts. In that case, the callback will not be executed. The arguments for the callback are as follows:

Arguments	Type	Summary	Note
connack	Object	connack is the content of the recieved connack packet. This argument is not mandatory.

event: ’reconnect’

Registers a reconnect event handler. Executes callback when MQTT reconnection is started.

event: ’close’

Registers a close event handler. Executes callback when MQTT is disconnected.

event: ’error’

Registers an error event handler. Executes callback when an error occurs or the MQTT connection fails. The arguments for the callback are as follows:

Arguments	Type	Summary	Note
err	{MqttError}	Error information

nqMqtt.publish(topic,message[,options][,callback])

Publishes a message to NEQTO Console.

Name	Type	M/O	Summary	Note
topic	null	mandatory	Topic Name This value must always be set to null.
message	string, Object	mandatory	Message to publish Specify the object returned by nqMqtt.get('LwM2MObject') or nqMqtt.get('LwM2MArgStr'). If the message to be published is more than 2500 bytes, an argument error occurs and the callback process of .on('error') is executed.
options	Object	optional	Publish Options Not used. Please omit it.
callback(err)	function	optional	Execute the callback process when the publish process is completed. err : {MqttError} Error information When err.code is 0, it means success.
return	undefined	-	-

Note: If the next .publish() is performed before the current .publish() callback, the latter .publish() may be discarded. Before performing a .publish(), it is recommended to check whether the callback of the previous .publish() has been executed, or check whether publishing is possible with .canPublish().

nqMqtt.end([callback])

Terminates nqMqtt. Use this function only when you need to terminate the script.

Name	Type	M/O	Summary	Note
callback()	function	optional	Executes callback processing when nqMqtt terminates.
return	undefined	-	-

nqMqtt.isConnected()

Gets MQTT connection status.

Name	Type	M/O	Summary	Note
return	boolean	-	MQTT connection status true: MQTT connected false: Not connected

nqMqtt.isReconnecting()

Gets the status of MQTT when reconnecting.

Name	Type	M/O	Summary	Note
return	boolean	-	MQTT reconnecting status true: MQTT reconnecting false: Not reconnecting

nqMqtt.canPublish()

Gets the status of whether the MQTT message can be published.

Name	Type	M/O	Summary	Note
return	boolean	-	Whether the MQTT message can be published true: Can publish false: Cannot publish

nqMqtt.get(name[,args...])

Gets information related to the given argument.

Name	Type	M/O	Summary	Note
name	string	mandatory	The name of the data object to be obtained Names that can be used are; LwM2MObject, LwM2MArgStr, LwM2MString, LwM2MObjectS, LwM2MArgStrS, LwM2MStringS Generally, use 'LwM2MObject'. Use 'LwM2MArgStr' when temporarily saving to a memory block. Use 'LwM2MString' when sending sensor data using nqService.
args	string, number	optional	Arguments used when getting the value
return	Object, string, undefined	-	Object : The requested object string : The requested string data undefined : Failure due to request error

nqMqtt.get(’LwM2MObject’,timestamp,objId,insId,resId,datatype,value[,resId2,datatype2,value2][,resId3,datatype3,value3][,resId4,datatype4,value4][,unit])

Creates a LwM2M object data to be used in the message of nqMqtt.publish().

For Object ID, Instance ID, Resource ID and Data Type, please refer to here. In addition, this setting must match the component settings on the NEQTO Console.

Name	Type	M/O	Summary	Note
’LwM2MObject’	string	mandatory	Name to get LwM2M object data
timestamp	number	mandatory	Timestamp Specify unixtime [ms].
objId	number	mandatory	Object ID The object ID uses the number defined by LwM2M.
insId	number	mandatory	Instance ID If there are multiple of the same Resource ID pairs, this is used to differentiate between them.
resId	number	mandatory	Resource ID The resource ID uses the number defined by LwM2M.
datatype	string	mandatory	Data Type The data type uses the number defined by LwM2M. ('Float', 'Integer', 'String', 'Boolean')
value	string	mandatory	Value Specify a string type value. When referencing data of type number, convert it to a string and specify it.
resId2	number	optional	The second resource ID. Same as resId. resId, resId2, resId3, resId4 must specify different values for each.
datatype2	string	optional	The second data type Same as datatype.
value2	string	optional	The second value Same as value.
resId3	number	optional	The third resource ID. Same as resId. resId, resId2, resId3, resId4 must specify different values for each.
datatype3	string	optional	The third data type Same as datatype.
value3	string	optional	The third value Same as value.
resId4	number	optional	The fourth resource ID. Same as resId. resId, resId2, resId3, resId4 must specify different values for each.
datatype4	string	optional	The fourth data type Same as datatype.
value4	string	optional	The fourth value Same as value.
unit	string	optional	Unit Specify any string indicating the unit. ('G', 'm', 's', 'ms', ...)
return	Object, undefined	-	Object : The created object data undefined : If creation fails

Up to 4 objects created by nqMqtt.get(’LwM2MObject’) can be combined and used in nqMqtt.publish(). This sample publishes by combining temperature and humidity.

var utime = new Date().getTime();
var tempObj = nqMqtt.get(   'LwM2MObject',
                            utime,
                            3303,
                            0,
                            5700,'Float','25.0');
var humiObj = nqMqtt.get(   'LwM2MObject',
                            utime,
                            3304,
                            0,
                            5700,'Float','50.0');
var pubObj = [ tempObj , humiObj ];
nqMqtt.publish(null, pubObj, function(err){
    if(0 == err.code){
        print('publish OK');
    }
    else{
        print('publish NG');
    }
});

Note the allowable size of the publish message.

nqMqtt.get(’LwM2MArgStr’,timestamp,objId,insId,resId,datatype,value[,resId2,datatype2,value2][,resId3,datatype3,value3][,resId4,datatype4,value4][,unit])

Creates a LwM2M string data to be used in the message of nqMqtt.publish().

Name	Type	M/O	Summary	Note
’LwM2MArgStr’	string	mandatory	Name to get LwM2M string data
:	:	:	Subsequent arguments are the same as LwM2MObject.
return	string, undefined	-	string : The created string data undefined : If creation fails

Up to 4 objects created by nqMqtt.get(’LwM2MArgStr’) can be combined and used in nqMqtt.publish(). This sample publishes by combining temperature and humidity.

var utime = new Date().getTime();
var tempObj = nqMqtt.get(   'LwM2MArgStr',
                            utime,
                            3303,
                            0,
                            5700,'Float','25.0');
var humiObj = nqMqtt.get(   'LwM2MArgStr',
                            utime,
                            3304,
                            0,
                            5700,'Float','50.0');
var pubObj = tempObj + ',' + humiObj;
nqMqtt.publish(null, pubObj, function(err){
    if(0 == err.code){
        print('publish OK');
    }
    else{
        print('publish NG');
    }
});

Note the allowable size of the publish message.

nqMqtt.get(’LwM2MString’,timestamp,objId,insId,resId,datatype,value[,resId2,datatype2,value2][,resId3,datatype3,value3][,resId4,datatype4,value4][,unit])

Creates a LwM2M string data to be used in the batch transmission method of nqService.

Name	Type	M/O	Summary	Note
’LwM2MString’	string	mandatory	Name to get LwM2M string data
:	:	:	Subsequent arguments are the same as LwM2MObject.
return	string, undefined	-	string : The created string data undefined : If creation fails

nqMqtt.get(’LwM2MObjectS’,timestamp,objId,insId,resId,datatype,value[,resId2,datatype2,value2][,resId3,datatype3,value3][,resId4,datatype4,value4][,unit])

Creates a LwM2M object data to be used in the message of nqMqtt.publish(). Functionally the same as LwM2MObject, but each of the returned values are encrypted.

nqMqtt.get(’LwM2MArgStrS’,timestamp,objId,insId,resId,datatype,value[,resId2,datatype2,value2][,resId3,datatype3,value3][,resId4,datatype4,value4][,unit])

Creates a LwM2M string data to be used in the message of nqMqtt.publish(). Functionally the same as LwM2MArgStr, but each of the returned values are encrypted.

nqMqtt.get(’LwM2MStringS’,timestamp,objId,insId,resId,datatype,value[,resId2,datatype2,value2][,resId3,datatype3,value3][,resId4,datatype4,value4][,unit])

Creates a LwM2M string data to be used in the batch transmission method of nqService. Functionally the same as LwM2MString, but each of the returned values are encrypted.

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Appendix

Object ID, Instance ID, Resource ID and Data Type

In NEQTO Console, you can select data display format and graph by resource ID. For the object ID, select any from the available IDs. See the LwM2M specification for examples of object ID and resource ID combinations. The instance ID is used to distinguish between multiple combinations of the same resource ID and object ID. The data type is defined in relation to the resource ID.

The object ID, resource ID and data type supported by NEQTO are as follows;

Name Object ID Generic Sensor 3300 Illuminance 3301 Temperature 3303 Humidity 3304 Accelerometer 3313 Magnetometer 3314 Current 3317 Pressure 3323 Acidity(pH) 3326 Conductivity 3327 Distance 3330 Colour 3335 Location 3336 Addressable Text Display 3341 On/Off switch 3342 Multi-state Selector 3348

Name Resource ID Data Display Format Data Type Digital Input State 5500 Boolean Digital Input Counter 5501 Float, Integer Latitude 5514 String Longitude 5515 String Text 5527 String Multi-state Input 5547 Float, Integer Sensor Value 5700 Float, Integer X Value 5702 Float, Integer Y Value 5703 Float, Integer Z Value 5704 Float, Integer Colour 5706 String Application Type 5750 Float, Integer

The following are examples of temperature sensor, humidity sensor, and acceleration sensor.

//value,Xvalue,Yvalue,Zvalue: Any numeric character string

var timestamp = new Date().getTime();

//Temperature sensor (ObjectID:Temperature, ResourceID:Sensor Value, DataType:Float)
nqMqtt.get('LwM2MObject',timestamp,3303,0,5700,"Float",value);

//Humidity sensor (ObjectID:Humidity, ResourceID:Sensor Value, DataType:Float)
nqMqtt.get('LwM2MObject',timestamp,3304,0,5700,"Float",value);

//Acceleration sensor (ObjectID:Accelerometer, ResourceID:X/Y/Z Value, DataType:Float)
nqMqtt.get('LwM2MObject',timestamp,3313,0,5702,"Float",Xvalue,5703,"Float",Yvalue,5704,"Float",Zvalue);

{MqttError}

Methods()/Properties	Type	Summary	Note
.code	number	Error code Refer to mqtt errors table for error code details.
.message	string	Error contents Refer to mqtt errors table for error content details.

mqtt errors table

Error code table.

.code	.message	Note
0	OK	No error
1	Connection failed	Connection (reconnection) failure
10	Illegal argument	Invalid argument error
11	Disconnected	Disconnect error
12	Publish failed	Publish failed
13	Subscribe failed	Subscribe failed
14	Unsubscribe failed	Unsubscribe failed
255	Other error	Other errors
Others	Reserved	Reserved

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Object Usage Examples

Sample 1

This is a sample to perform the following processing.

• Prints custom messages received from the NEQTO Console.
• Create and publish "acceleration", "temperature", and "color" data respectively.

//Register event handler
nqMqtt.on('connect',function(connack){
    print('mqttConnect');
});
nqMqtt.on('close',function(){
    print('nqMqttClose');
});
nqMqtt.on('error',function(err){
    print('mqttError:'+err.code.toString());
});
nqMqtt.on('push',function(message){
    print(message); //Received custom message
});

//Publish "Acceleration"
while(false==nqMqtt.canPublish()){setTimeout(100).wait();}
var valX = 1.0; /* dummy X value */
var valY = 1.1; /* dummy Y value */
var valZ = 1.2; /* dummy Z value */
var strX = valX.toFixed(1);
var strY = valY.toFixed(1);
var strZ = valZ.toFixed(1);
var utime = new Date().getTime();
var acceObj = nqMqtt.get(   'LwM2MObject',
                            utime,
                            3313,
                            0,
                            5702,'Float',strX,
                            5703,'Float',strY,
                            5704,'Float',strZ);
nqMqtt.publish(null,acceObj,function(err){
    if(0==err.code){
        print('publish OK');
    }
    else{
        print('publish NG');
    }
});

//Publish "Temperature"
while(false==nqMqtt.canPublish()){setTimeout(100).wait();}
var valT = 20.2; /* dummy Temperature */
var strT = valT.toFixed(1);
var utime = new Date().getTime();
var tempObj = nqMqtt.get(   'LwM2MObject',
                            utime,
                            3303,
                            0,
                            5700,'Float',strT);
nqMqtt.publish(null,tempObj,function(err){
    if(0==err.code){
        print('publish OK');
    }
    else{
        print('publish NG');
    }
});

//Publish "Color"
while(false==nqMqtt.canPublish()){setTimeout(100).wait();}
var strC = '"#FFFF99"'; /* dummy Color */
var utime = new Date().getTime();
var colorObj = nqMqtt.get(  'LwM2MObject',
                            utime,
                            3335,
                            0,
                            5706,'String',strC);
nqMqtt.publish(null,colorObj,function(err){
    if(0==err.code){
        print('publish OK');
    }
    else{
        print('publish NG');
    }
});

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Updated: 2021-05-06