lightweightm2m-iotagent

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Hello,

We didn't find a way to execute a resource without provide an attribute value. Maybe someone knows how to carry out this?

We used a query such as the next one:

(curl http://127.0.0.1:1026/v1/updateContext -s -S --header 'Content-Type: application/json' --header 'Accept: application/json' --header 'fiware-service: HOPBeacon' --header 'fiware-servicepath: /hopbeacon' \
 -d @- | python -mjson.tool) <<EOF
{
    "contextElements": [
        {
            "type": "HOPBeacon",
            "isPattern": "false",
            "id": "HOPe0e5cfb1f4df",
            "attributes": [
            {
                "name": "Temperature Reset Min and Max Measured Values",
                "type": "String",
                "value": ""
            }
            ]
        }
    ],
    "updateAction": "UPDATE"
}
EOF

When value field is empty or value field is not present, the next error is raised in the Lightweight-IOTAgent:

time=2016-11-16T17:53:00.330Z | lvl=DEBUG | corr=n/a | trans=n/a | op=LWM2MLib.DeviceManagement | msg=Writting a new value [function (err, v) {
                results[index] = v;
                callback(err);
            }] on resource /3303/0/5605 in device [1]
time=2016-11-16T17:55:25.859Z | lvl=FATAL | corr=n/a | trans=n/a | op=n/a | msg=An unexpected exception has been raised. Ignoring: TypeError: Invalid non-string/buffer chunk

And the query receives the next response:

{
    "errorCode": {
        "code": "404", 
        "details": "error forwarding update", 
        "reasonPhrase": "No context element found"
    }
}

This is what happen in our devices in case of specify a dummy value:

And the query receives the next response:

{
    "errorCode": {
        "code": "404", 
        "reasonPhrase": "No context element found"
    }
}

Not all the available LwM2M Clients are able to manage this extra value.

If there is no way to send an execute command without value, send a dummy value isn't a correct behaviour to execute some resources in LwM2M, most of the executable resources does not receive value, some example of executable resources without value are:

• Reset device (3/0/4)
• Factory reset (3/0/5)
• Registration Update Trigger (1/0/8)
• Reset Min/Max values for some sensor (some IPSO objects)
• ...

We expect to hear about other way to carry out this, but in the meantime we introduced a condition to allow execute commands without specify a value.

and the query result is ok:

{
    "contextResponses": [
        {
            "contextElement": {
                "attributes": [
                    {
                        "name": "Temperature Reset Min and Max Measured Values", 
                        "type": "String", 
                        "value": ""
                    }
                ], 
                "id": "HOPe0e5cfb1f4df", 
                "isPattern": "false", 
                "type": "HOPBeacon"
            }, 
            "statusCode": {
                "code": "200", 
                "reasonPhrase": "OK"
            }
        }
    ]
}

Tests are passed correctly.

BR, David